Gas turbine control device, gas turbine facility, gas turbine control method, and gas turbine control program

Abstract

To provide a control device for a gas turbine, a gas turbine facility, a control method for the gas turbine and a control program for the gas turbine, capable of suppressing misfire or increase in fuel cost during operation in a reverse electric power operation mode of the gas turbine.SOLUTION: In a control device for a gas engine coupled to a power generator connectable to an electric power system, the gas turbine is configured to switch an operation mode between a normal operation mode in which the gas turbine rotates and drives the power generator and a reverse electric power operation mode in which the gas turbine is rotated and driven by the power generator that receives supply of electric power from the electric power system and operates as a motor, and a fuel command value calculation section for calculating a fuel command value to be provided for the gas turbine is provided. During an operation in the reverse electric power operation mode of the gas turbine, the fuel command value calculation section is configured to calculate the fuel command value on the basis of a difference between a fixation value of rotational frequency of the gas turbine and target rotational frequency or calculate the fuel command value so as to reduce the fuel command value to a specified fuel set value at a constant rate.SELECTED DRAWING: Figure 3

Description

Technical Field

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

Background Art

[0002] The fuel supply amount of a gas turbine may be controlled based on the deviation between the actual rotational speed of the gas turbine and the target rotational speed (rotational speed reference value).

[0003] Patent Document 1 describes that, for a gas turbine connected to a generator connected to a power grid, the fuel supply amount is controlled based on the deviation between the actual rotational speed of the gas turbine and a predetermined rotational speed (grid frequency). Further, Patent Document 1 describes that when the grid frequency changes in a short period (such as a 1-second period), the deviation between the actual rotational speed and the predetermined rotational speed is reduced by a filter to suppress fluctuations in the fuel supply amount due to fluctuations in the power grid.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the way, a gas turbine device to which a generator is connected usually operates in an operation mode (normal operation mode) in which the generator is rotationally driven by the gas turbine. However, when there is no power generation demand, etc., it may be operated in an operation mode (reverse power operation mode) in which the gas turbine is rotationally driven by a generator that receives power supply from the outside and functions as a motor.

[0006] In the reverse power operation of a gas turbine, since the generator assists in driving the turbine, the fuel supply amount to the gas turbine can be reduced to an amount that does not cause the gas turbine to misfire. On the other hand, in the reverse power operation of a gas turbine, since the generator functioning as a motor receives power supply from the power grid, the control of the fuel supply amount based on the rotational speed (grid frequency) is easily affected by fluctuations in the grid frequency. For this reason, the fuel supply amount may become excessively small and cause misfiring, or the fuel supply amount may become more than necessary and consume extra fuel.

[0007] In view of the above circumstances, at least one embodiment of the present invention aims to provide a control device for a gas turbine, a gas turbine facility, a control method for a gas turbine, and a control program for a gas turbine that can suppress misfiring or an increase in fuel cost during operation in the reverse power operation mode of the gas turbine.

Means for Solving the Problems

[0008] The control device for a gas turbine according to at least one embodiment of the present invention is a control device for a gas turbine connected to a generator connectable to a power grid, wherein the gas turbine is configured to be able to switch the operation mode between a normal operation mode in which the gas turbine rotationally drives the generator and a reverse power operation mode in which the gas turbine is rotationally driven by the generator that receives power supply from the power grid and operates as a motor, and includes a fuel command value calculation unit for calculating a fuel command value to be given to the gas turbine, wherein the fuel command value calculation unit calculates the fuel command value based on the deviation between the fixed value of the rotational speed of the gas turbine and the target rotational speed during operation in the reverse power operation mode of the gas turbine, or is configured to calculate the fuel command value so that the fuel command value decreases to a predetermined fuel setting value at a constant rate.

[0009] Also, a gas turbine facility according to at least one embodiment of the present invention is A gas turbine including a compressor for compressing air, a combustor for generating combustion gas by a combustion reaction of the compressed air from the compressor and fuel, and a turbine driven by the combustion gas from the combustor, and being connected to a generator connectable to a power grid. The above-described control device configured to control the gas turbine. Comprises.

[0010] Also, a control method for a gas turbine according to at least one embodiment of the present invention is A control method for a gas turbine connected to a generator connectable to a power grid, The gas turbine is configured to be able to switch between a normal operation mode in which the gas turbine rotationally drives the generator and a reverse power operation mode in which the gas turbine is rotationally driven by the generator that operates as a motor while receiving power supply from the power grid. Comprises a step of calculating a fuel command value to be given to the gas turbine. In this step, during operation of the gas turbine in the reverse power operation mode, the fuel command value is calculated based on a deviation between a fixed value of the rotational speed of the gas turbine and a target rotational speed, or the fuel command value is calculated so as to decrease to a predetermined fuel setting value at a certain rate.

[0011] Also, a control program for a gas turbine according to at least one embodiment of the present invention is A control program for a gas turbine connected to a generator connectable to a power grid, The gas turbine is configured to be able to switch between a normal operation mode in which the gas turbine rotationally drives the generator and a reverse power operation mode in which the gas turbine is rotationally driven by the generator that operates as a motor while receiving power supply from the power grid. A program for causing a computer to Execute a procedure for calculating a fuel command value to be given to the gas turbine. In the above procedure, during the operation of the gas turbine in the reverse power operation mode, the fuel command value is calculated based on the deviation between the fixed value of the rotational speed of the gas turbine and the target rotational speed, or the fuel command value is calculated so as to decrease to a predetermined fuel setting value at a constant rate.

Advantages of the Invention

[0012] According to at least one embodiment of the present invention, there are provided a control device for a gas turbine, a gas turbine facility, a control method for a gas turbine, and a control program for a gas turbine, which can suppress misfiring or an increase in fuel cost during operation in the reverse power operation mode of the gas turbine.

Brief Description of the Drawings

[0013]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Modes for Carrying Out the Invention

[0014] Hereinafter, some embodiments of the present invention will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of the components described as embodiments or shown in the drawings are not intended to limit the scope of the present invention thereto, but are merely illustrative examples.

[0015] (Configuration of Gas Turbine Facility) Figures 1 and 2 are schematic diagrams of a gas turbine facility according to an embodiment. As shown in FIG. 1, a gas turbine facility 100 according to an embodiment includes a gas turbine 1 connected to a generator 30 and a control device 50 for controlling the gas turbine 1.

[0016] As shown in FIG. 1, the gas turbine 1 includes a compressor 2 for compressing air, a combustor 4 for burning fuel together with the compressed air from the compressor 2, and a turbine 6 configured to be rotationally driven by the combustion gas generated in the combustor 4.

[0017] The generator 30 is connected to the rotor 8 of the gas turbine 1, and the generator 30 is rotationally driven by the gas turbine 1. The generator 30 is configured to be connectable to the power grid 32. A switch 31 is provided between the generator 30 and the power grid 32, and the connection state between the generator 30 and the power grid 32 can be switched.

[0018] The generator 30 can be rotationally driven by the gas turbine 1 to generate electric power, and can also receive power supply from the power grid 32 and function as a motor to rotationally drive the gas turbine 1.

[0019] As shown in FIG. 1, the fuel stored in the fuel storage section 34 is supplied to the combustor 4 via the fuel supply line 33. Note that it is not necessary to provide the fuel storage section 34 in the gas turbine facility, and it is possible to receive fuel supply from a remote location through the fuel supply line 33. The fuel supply line 33 is provided with a fuel control valve 36 for adjusting the flow rate (fuel supply amount) of the fuel supplied to the combustor 4. Although not shown, it is possible to control, for example, the respective fuel supply amounts to the pilot nozzle and the main nozzle of the combustor 4 and the pilot ratio using two or more fuel control valves 36.

[0020] As shown in FIG. 1, an inlet guide vane (IGV) 40 for adjusting the intake air volume of the compressor 2 is provided at the inlet of the compressor 2. The opening degree of the IGV 40 is configured to be adjustable by an inlet guide vane control unit including an actuator 42.

[0021] The gas turbine 1 is provided with a rotational speed measurement unit 44 for measuring the rotational speed of the gas turbine 1. The rotational speed measurement unit 44 may be a rotational speed sensor (such as a rotary encoder or the like) configured to be able to detect the rotational speed of the rotor 8 of the gas turbine 1 or the rotational shaft of the generator 30. Signals indicating the rotational speed of the gas turbine 1 detected by the rotational speed measurement unit 44 are each sent to the control device 50.

[0022] The gas turbine 1 is configured to be able to switch the operating mode between a normal operating mode and a reverse power operating mode.

[0023] The normal operating mode is an operating mode in which the gas turbine 1 rotationally drives the generator 30. In the normal operating mode, the electric power generated by the generator 30 is usually supplied to the power grid 32.

[0024] On the other hand, the reverse power operating mode is an operating mode in which the generator 30 receives power supply from the power grid 32 and operates as a motor to assist in the rotational drive of the gas turbine 1. The gas turbine 1 may be operated in the reverse power operating mode for purposes such as supplying exhaust gas to a supply destination while reducing fuel consumption. During operation in the reverse power mode, since the drive of the turbine 6 of the gas turbine 1 is assisted by the generator 30, the fuel supply amount to the gas turbine 1 can be reduced compared to operation in the normal operating mode.

[0025] The control device 50 is configured to control the gas turbine 1 based on, for example, the rotational speed of the gas turbine 1 detected by the rotational speed measurement unit 44. As shown in FIG. 2, the control device 50 includes a target rotational speed calculation unit 52, a fuel command value calculation unit 54, a switching signal reception unit 56, and / or an operation control unit 58.

[0026] The target rotation speed calculation unit 52 is configured to calculate a target rotation speed, which is a control target value for the rotation speed of the gas turbine 1, based on, for example, an output request value from a higher-level control device or the like.

[0027] The fuel command value calculation unit 54 is configured to calculate a fuel command value (a value indicating the fuel supply amount) to be given to the gas turbine 1. During operation in the reverse power operation mode of the gas turbine 1, the fuel command value calculation unit 54 calculates the fuel command value based on the deviation between the fixed value of the rotation speed of the gas turbine 1 and the target rotation speed, or is configured to calculate the fuel command value so that the fuel command value decreases to a predetermined fuel setting value at a constant rate.

[0028] The fixed value of the rotation speed of the gas turbine 1 may be a value based on the actual rotation speed of the gas turbine 1 when switching from the normal operation mode of the gas turbine 1 to the reverse power operation mode. For example, the fixed value may be a value based on the actual rotation speed of the gas turbine 1 immediately before or after switching from the normal operation mode of the gas turbine 1 to the reverse power operation mode, or during the switching of the operation mode.

[0029] A more specific configuration of the fuel command value calculation unit 54 will be described later.

[0030] The switching signal reception unit 56 is configured to receive a signal for switching the operation mode of the gas turbine 1 from the normal operation mode to the reverse power operation mode or from the reverse power operation mode to the normal operation mode. The switching signal reception unit 56 may be configured to receive a signal for switching the operation mode from the switching signal input unit 60. The switching signal input unit 60 may include a terminal device operable by an operator, and may include, for example, an operation mode switching button, a keyboard, or a mouse.

[0031] The operation control unit 58 is configured to control the gas turbine 1 based on a signal indicating the fuel command value from the fuel command value calculation unit 54 or a signal for switching the operation mode from the switching signal reception unit 56. The operation control unit 58 is configured to control, for example, the opening degree of the fuel control valve 36 or the pilot ratio control unit 38 for adjusting the fuel supply to the combustor 4, or the operation amount of the actuator 42 for adjusting the opening degree of the inlet guide vane 40 based on the above-mentioned signal.

[0032] The control device 50 includes a computer having a processor (such as a CPU), a main storage device (a memory device; such as a RAM), an auxiliary storage device, and an interface. The control device 50 is configured to receive a signal from the rotation speed measurement unit 44 or the switching signal input unit 60 via the interface. The processor is configured to process the signal received in this way. Further, the processor is configured to process a program developed in the main storage device. Thereby, the functions of the above-mentioned respective functional units (the target rotation speed calculation unit 52 or the fuel command value calculation unit 54, etc.) are realized.

[0033] The processing content in the control device 50 is implemented as a program executed by the processor. The program may be stored in the auxiliary storage device, for example. When the program is executed, these programs are developed in the main storage device. The processor is configured to read the program from the main storage device and execute the instructions included in the program.

[0034] With reference to FIGS. 3 and 4, the fuel command value calculation unit 54 of the control device 50 will be described more specifically. FIGS. 3 and 4 are schematic block diagrams of a control device according to an embodiment, respectively.

[0035] In the exemplary embodiment shown in FIG. 3, the fuel command value calculation unit 54 includes a first calculation unit 62, a second calculation unit 64, and a third calculation unit 66 each configured to calculate first to third provisional values of the fuel command value, a first selection unit 68 configured to select one from the first to third provisional values, and a second selection unit configured to select one of the provisional value selected by the first selection unit 68 and a predetermined set value as the fuel command value.

[0036] The first calculation unit 62 is configured to calculate a first provisional value of the fuel command value based on the rotational speed of the gas turbine 1.

[0037] In the example shown in FIG. 3, the first calculation unit 62 calculates the first provisional value of the fuel command value based on the deviation between the value based on the actual rotational speed of the gas turbine 1 acquired from the switch 72 and the target rotational speed acquired from the target rotational speed calculation unit 52.

[0038] A signal for switching the operation mode of the gas turbine 1 from the normal operation mode to the reverse power operation mode is input to the switch 72 from the switch signal input unit 60 or the like, and a signal indicating the actual rotational speed (current rotational speed) of the gas turbine 1 is input from the rotational speed measurement unit 44. Note that when the generator is connected to the power grid 32, the actual rotational speed of the gas turbine 1 is interlocked with the grid frequency of the power grid 32. Therefore, when the grid frequency fluctuates (moves up and down), the actual rotational speed of the gas turbine 1 also fluctuates similarly.

[0039] When a signal for switching from the normal operation mode to the reverse power operation mode is not input to the switch 72 (that is, during operation in the normal operation mode), the input on the "0" side in FIG. 3 is connected in the switch 72, and a signal indicating the actual rotational speed is output from the switch 72. At this time, the signal indicating the actual rotational speed is sent to the first calculation unit 62 and sent to the memory 74 and stored in the memory 74.

[0040] When a signal for switching the switch 72 from the normal operation mode to the reverse power operation mode is input, the input on the "1" side in FIG. 3 of the switch 72 is connected, and a signal indicating the actual rotational speed (fixed value; more precisely, the actual rotational speed immediately before receiving the signal) when receiving the signal is input from the memory 74 to the switch 72 and sent from the switch 72 to the first calculation unit 62.

[0041] Therefore, during the operation of the gas turbine 1 in the normal operation mode, the first calculation unit 62 calculates a first provisional value of the fuel command value based on the deviation between the value based on the actual rotational speed (current value) of the gas turbine 1 obtained from the switch 72 and the target rotational speed obtained from the target rotational speed calculation unit 52. Also, after receiving a signal for switching the operation mode of the gas turbine 1 from the normal operation mode to the reverse power operation mode (including during the operation in the reverse power operation mode), the first calculation unit 62 calculates a first provisional value of the fuel command value based on the deviation between the value based on the fixed value of the actual rotational speed of the gas turbine 1 obtained from the switch 72 (the actual rotational speed immediately before the operation mode switch in FIG. 3) and the target rotational speed obtained from the target rotational speed calculation unit 52.

[0042] The target rotational speed calculation unit 52 may be configured to decrease the target rotational speed at a constant rate to a predetermined rotational speed set value when the operation mode of the gas turbine 1 is switched from the normal operation mode to the forward reverse power operation mode (that is, after the control device 50 receives a signal for switching the operation mode to the reverse power operation mode).

[0043] The second calculation unit 64 is configured to calculate a second provisional value of the fuel command value based on the power generation amount (generator output) by the gas turbine 1.

[0044] The third calculation unit 66 is configured to calculate a third provisional value of the fuel command value based on the exhaust gas temperature of the gas turbine 1.

[0045] The first selection unit 68 selects the minimum value from among the first to third provisional values received from the first calculation unit 62, the second calculation unit 64, and the third calculation unit 66, and outputs it to the second selection unit 70. In this way, by selecting the minimum value among the first to third provisional values, the minimum fuel supply amount required for the operation of the gas turbine 1 is selected.

[0046] The second selection unit 70 is configured to select and output the maximum value between the provisional value of the fuel command value (any one of the first to third provisional values) selected by the first selection unit 68 and a predetermined set value as the fuel command value. As the predetermined set value, the minimum fuel supply amount required for the appropriate operation of the gas turbine 1 (for example, F shown in FIG. 5) A ) may be set.

[0047] The control device 50 including the fuel command value calculation unit 54 configured in this way calculates a fuel command value that can operate the gas turbine 1 appropriately with as little fuel as possible.

[0048] In the exemplary embodiment shown in FIG. 4, the fuel command value calculation unit 54 receives a signal for switching the operation mode from the switching signal input unit 60 or the like, the target rotational speed from the target rotational speed calculation unit 52, the actual rotational speed (current rotational speed) of the gas turbine 1 from the rotational speed measurement unit 44, a preset change rate of the fuel command value, and / or the current fuel command value (calculation result by the fuel command value calculation unit 54), and is configured to calculate the fuel command value based on these.

[0049] In the exemplary embodiment shown in FIG. 4, during the operation of the gas turbine 1 in the normal operation mode, similar to the embodiment shown in FIG. 3, the fuel command value calculation unit 54 may be configured to calculate the fuel command value based on the deviation between the value based on the actual rotational speed (current value) of the gas turbine 1 and the target rotational speed obtained from the target rotational speed calculation unit 52. For example, the fuel command value calculation unit 54 may be configured to calculate the fuel command value based on the first to third provisional values calculated by the first calculation unit 62 to the third calculation unit 66 (not shown in FIG. 4) and the set value of the predetermined fuel command value during the operation in the normal operation mode.

[0050] In the exemplary embodiment shown in FIG. 4, when the operation mode of the gas turbine 1 is switched from the normal operation mode to the reverse power operation mode, the fuel command value calculation unit 54 is configured to calculate the fuel command value based on the current fuel command value and the change rate of the predetermined fuel command value so that the fuel command value decreases at a constant rate to the predetermined fuel setting value.

[0051] According to the control device 50 having the configuration described above (see FIGS. 2 to 4), during operation in the reverse power operation mode where the fuel supply amount is relatively small (after the operation mode is switched from the normal mode to the reverse power operation mode), based on the deviation between the fixed value of the rotational speed of the gas turbine 1 and the target rotational speed, or so that the fuel command value (fuel supply amount) decreases at a constant rate to the predetermined fuel setting value, the fuel command value is calculated. That is, during operation in the reverse power operation mode, the fuel command value is calculated regardless of the actual rotational speed linked to the system frequency, so that the influence of fluctuations in the system frequency on the fuel supply amount can be eliminated. Therefore, it is possible to suppress misfiring of the gas turbine 1 due to insufficient fuel supply and an increase in fuel cost due to excessive fuel supply during operation in the reverse power operation mode.

[0052] (Control Flow of Gas Turbine) Hereinafter, with reference to FIG. 5, a control method for the gas turbine 1 according to some embodiments will be described. In the following, the case of controlling the above-described gas turbine 1 using the above-described control device 50 will be described. However, in some embodiments, the control method of the gas turbine may be executed using other devices, or a part of the procedures described below may be performed manually. In the following example, for the sake of simplicity of explanation, in the example shown in FIG. 3, the procedures for calculating the second to third provisional values of the fuel command value by the second calculation unit 64 to the third calculation unit 66 are omitted, and it is assumed that the first provisional value calculated based on the rotational speed of the gas turbine 1 by the first calculation unit 62 is selected by the first selection unit 68.

[0053] FIG. 5 is a diagram for explaining a control method of the gas turbine 1 according to an embodiment, and is a graph showing an example of the time change of the load during gas turbine operation, the set value of the rotational speed of the gas turbine (target rotational speed), the set value of the fuel supply amount (fuel command value), and the pilot ratio of the fuel.

[0054] In FIG. 5, until time t0, the gas turbine 1 is operating in the normal operation mode at the load L0. The target rotational speed (control target value of the rotational speed) of the gas turbine 1 at time t0 is S0, the fuel command value (fuel supply amount) is F0, and the pilot ratio of the fuel is R0.

[0055] In the example shown in FIG. 5, at time t0, based on an instruction from the operator of the gas turbine facility 100 or the like, preparation for switching the operation mode of the gas turbine 1 to the reverse power operation mode is started. From time t0, by decreasing the target rotational speed of the gas turbine 1, the fuel command value is decreased. As a result, the load of the gas turbine 1 also decreases from L0. During the period including time t0, the fuel command value may be determined based on the deviation between the actual rotational speed of the gas turbine 1 and the rotational speed set value. If the generator 30 is connected to the power grid 32, since the actual rotational speed of the gas turbine 1 is maintained within a range substantially the same as the frequency of the power grid 32, by decreasing the target rotational speed, the fuel command value based on the above deviation will decrease.

[0056] From time t0, in order to prevent misfire due to the decrease in the fuel supply amount, the pilot ratio of the fuel or the IGV opening degree may be appropriately adjusted. For example, as shown in FIG. 5, the pilot ratio of the fuel may be increased from R0.

[0057] At time t1, the load of the gas turbine 1 becomes the minimum load Lmin in the normal operation mode (that is, the target rotational speed and the fuel command value (fuel supply amount) to the combustor 4 become the minimum values Smin and Fmin in the normal operation mode). At time t1, the pilot ratio is R1 (>R0). This operating condition is maintained from time t1 to time t2 after a specified period.

[0058] At time t2, for example, when the operator operates the switching signal input unit 60, a signal for switching the operation mode of the gas turbine 1 from the normal operation mode to the reverse power operation mode is sent to the control device 50. Thereby, the switching from the normal operation mode to the reverse power operation mode is started. When the control device 50 receives a signal for switching the operation mode, it controls the pilot ratio control unit 38 via the operation control unit 58 to increase the pilot ratio.

[0059] At time t3, the control device 50 controls the pilot ratio control unit 38 so that the increase in the pilot ratio stops. After time t3, the pilot ratio is maintained at R2 (>R1). The pilot ratio R2 is a pilot ratio at which the transition to the reverse power operation mode is possible. Also, the control device 50 may control the actuator 42 at time t3 so that the opening degree of the IGV 40 becomes an opening degree suitable for the reverse power operation mode. In this way, at time t3, the conditions for transitioning to the reverse power operation mode, such as the pilot ratio, are satisfied.

[0060] From the time t2 when the control device 50 receives a signal for switching the operation mode from the normal operation mode to the reverse power operation mode, or from the time t3 when the conditions for transitioning to the reverse power operation mode are satisfied, the fuel command value calculation unit 54 calculates the fuel command value based on the deviation between the fixed value of the rotational speed of the gas turbine 1 and the target rotational speed (see FIG. 3), or so that the fuel command value decreases at a constant rate to a predetermined fuel setting value (see FIG. 4).

[0061] From time t3, the target rotational speed calculation unit 52 decreases the target rotational speed from Smin to, for example, a predetermined set value S at a constant rate B until. When the fuel command value is calculated based on the deviation between the fixed value of the rotational speed of the gas turbine 1 and the target rotational speed (see FIG. 3), as the target rotational speed decreases, the difference from the fixed value of the rotational speed further increases, so the fuel command value further decreases. The fuel command value is set to a predetermined fuel setting value at a constant rate (for example, F in FIG. 5) AWhen decreasing to (see Fig. 4), the fuel command value decreases at a constant rate regardless of the change in the target rotational speed. The control device 50 controls the fuel control valve 36 based on the fuel command value. As a result, the load of the gas turbine 1 further decreases from the minimum load Lmin in the normal operation mode.

[0062] At the time t4 when the load of the gas turbine 1 becomes zero, by continuously decreasing the target rotational speed, the fuel command value to the combustor 4 continues to decrease. After the time t4, power from the power grid 32 is supplied to the generator 30, and the generator 30 operates as a motor to assist in driving the rotation of the gas turbine 1. That is, the reverse power operation mode of the gas turbine 1 is started, and the load of the gas turbine is below zero.

[0063] After the time t4, the fuel command value is calculated in the same procedure as the period from time t3 to t4, and the fuel command value further decreases. That is, the fuel command value calculation unit 54 calculates the fuel command value based on the deviation between the fixed value of the rotational speed of the gas turbine 1 and the target rotational speed (see Fig. 3). Alternatively, the fuel command value calculation unit 54 calculates the fuel command value so that the fuel command value decreases at a constant rate to a predetermined fuel setting value (for example, F A ) (see Fig. 4). In either case, the fuel command value is calculated so as to be equal to or greater than the minimum supply amount F A of the gas turbine 1 (in the example shown in Fig. 3, the larger of the provisional value (first provisional value) of the fuel command value based on the rotational speed selected by the first selection unit 68 and the predetermined setting value (F A ) is selected by the second selection unit 70). Also, as the fuel command value decreases, the load of the gas turbine continues to decrease.

[0064] At the time t5, when the fuel command value reaches the above-mentioned minimum supply amount F A , the fuel command value is maintained at this value. Thereby, the load of the gas turbine is maintained at L A (negative value). On the other hand, at the time t5, if the target rotational speed S A is greater than the predetermined setting value S B , the target rotational speed is the setting value S Bcontinues to decrease until it reaches. In FIG. 5, the target rotational speed reaches the predetermined set value S at time t6, and after time t6, the target rotational speed is maintained at the set value S. B and after time t6, the target rotational speed is maintained at the set value S. B

[0065] According to the control device and control method described above, during operation in the reverse power operation mode where the fuel supply amount is relatively small, based on the deviation between the fixed value of the rotational speed of the gas turbine 1 and the target rotational speed, or the fuel command value is calculated so as to decrease to the predetermined fuel set value at a constant rate. That is, during operation in the reverse power operation mode, the fuel command value is calculated regardless of the actual rotational speed linked to the system frequency, so that the influence of the variation of the system frequency on the fuel supply amount can be eliminated. Therefore, it is possible to suppress misfiring due to insufficient fuel supply and an increase in fuel cost due to excessive fuel supply during operation in the reverse power operation mode.

[0066] In the above-described embodiment, during operation in the normal operation mode, the fuel command value is calculated based on the deviation between the actual rotational speed and the target rotational speed of the gas turbine 1, and during operation in the reverse power operation mode, the fuel command value is calculated regardless of the actual rotational speed. Therefore, during operation in the normal operation mode, the fuel command value for realizing the target rotational speed can be appropriately calculated, and during operation in the reverse power operation mode, the influence of the variation of the system frequency on the fuel supply amount is eliminated, and misfiring due to insufficient fuel supply and an increase in fuel cost due to excessive fuel supply can be suppressed.

[0067] Also, in some embodiments (see, for example, FIG. 3), the fuel command value is calculated using the fixed value of the actual rotational speed of the gas turbine 1 when switching from the normal operation mode to the reverse power operation mode of the gas turbine 1. Thereby, based on the deviation between the fixed value and the target rotational speed, the fuel command value in the reverse power operation mode can be appropriately calculated.

[0068] ​Also, in some embodiments, when calculating the fuel command value based on the deviation between the fixed value of the rotational speed of the gas turbine 1 and the target rotational speed during operation in the reverse power operation mode, when the operation mode of the gas turbine 1 is switched to the reverse power operation mode, the target rotational speed is decreased to a predetermined rotational speed setting value at a constant rate. Thereby, when switching to the reverse power operation mode, the fuel command value can be stably decreased at a constant rate in accordance with the decrease in the target rotational speed.

[0069] The content described in each of the above embodiments is understood as follows, for example.

[0070] (1) The control device (50) of a gas turbine according to at least one embodiment of the present invention is a control device of a gas turbine (1) connected to a generator (30) connectable to a power system (32), wherein the gas turbine is configured to be able to switch the operation mode between a normal operation mode in which the gas turbine rotationally drives the generator and a reverse power operation mode in which the gas turbine is rotationally driven by the generator that operates as a motor while receiving power supply from the power system, and includes a fuel command value calculation unit (54) for calculating a fuel command value to be applied to the gas turbine, wherein the fuel command value calculation unit calculates the fuel command value based on the deviation between the fixed value of the rotational speed of the gas turbine and the target rotational speed during operation of the gas turbine in the reverse power operation mode, or is configured to calculate the fuel command value such that the fuel command value decreases to a predetermined fuel setting value at a constant rate.

[0071] According to the configuration of (1) above, during operation in the reverse power operation mode with a relatively small fuel supply amount, the fuel command value (fuel supply amount) is calculated based on the deviation between the fixed value of the gas turbine's rotational speed and the target rotational speed, or such that the fuel command value decreases to a predetermined fuel set value at a constant rate. That is, during operation in the reverse power operation mode, the fuel command value is calculated regardless of the actual rotational speed linked to the system frequency, so the influence of system frequency fluctuations on the fuel supply amount can be eliminated. Therefore, it is possible to suppress misfires due to insufficient fuel supply and an increase in fuel costs due to excessive fuel supply during operation in the reverse power operation mode.

[0072] (2) In some embodiments, in the configuration of (1) above, the fuel command value calculation unit is configured to calculate the fuel command value based on the deviation between the actual rotational speed and the target rotational speed of the gas turbine during operation in the normal operation mode of the gas turbine.

[0073] According to the configuration of (2) above, during operation in the normal operation mode, the fuel command value is calculated based on the deviation between the actual rotational speed and the target rotational speed of the gas turbine, and during operation in the reverse power operation mode, the fuel command value is calculated regardless of the actual rotational speed. Therefore, during operation in the normal operation mode, the fuel command value for achieving the target rotational speed can be appropriately calculated, and during operation in the reverse power operation mode, the influence of system frequency fluctuations on the fuel supply amount can be eliminated, suppressing misfires due to insufficient fuel supply and an increase in fuel costs due to excessive fuel supply.

[0074] (3) In some embodiments, in the configuration of (1) or (2) above, the fuel command value calculation unit is configured to calculate the fuel command value based on the deviation between the fixed value of the rotational speed of the gas turbine and the target rotational speed during operation in the reverse power operation mode of the gas turbine, and the fixed value is a value based on the actual rotational speed of the gas turbine at the time of switching from the normal operation mode to the reverse power operation mode of the gas turbine.

[0075] According to the configuration of (3) above, when switching from the normal operation mode of the gas turbine to the reverse power operation mode, the actual rotational speed of the gas turbine is used as the above-mentioned fixed value. Therefore, based on the deviation between the fixed value and the target rotational speed, the fuel command value in the reverse power operation mode can be appropriately calculated.

[0076] (4) In some embodiments, in the configuration of (1) or (2) above, it is provided with a target rotational speed calculation unit (52) for calculating the target rotational speed of the gas turbine, the target rotational speed calculation unit is configured to decrease the target rotational speed at a constant rate to a predetermined rotational speed set value when the operation mode of the gas turbine is switched from the normal operation mode to the reverse power operation mode, the fuel command value calculation unit is configured to calculate the fuel command value based on the deviation between the fixed value of the rotational speed of the gas turbine and the target rotational speed during the operation of the gas turbine in the reverse power operation mode.

[0077] In the configuration of (4) above, when calculating the fuel command value based on the deviation between the fixed value of the rotational speed of the gas turbine and the target rotational speed during the operation in the reverse power operation mode, when the operation mode of the gas turbine is switched to the reverse power operation mode, the target rotational speed is decreased at a constant rate to a predetermined rotational speed set value. Therefore, when switching to the reverse power operation mode, the fuel command value can be stably decreased at a constant rate as the target rotational speed decreases.

[0078] (5) The gas turbine facility (100) according to at least one embodiment of the present invention includes a compressor (2) for compressing air, a combustor (4) for generating combustion gas by a combustion reaction of the compressed air from the compressor and fuel, and a turbine (6) driven by the combustion gas from the combustor, and a gas turbine (1) connected to a generator (30) that can be connected to the power grid (32), a control device (50) configured to control the gas turbine according to any one of (1) to (4) above. comprises.

[0079] According to the configuration of (5) above, during operation in the reverse power operation mode with a relatively small fuel supply amount, based on the deviation between the fixed value of the rotational speed of the gas turbine and the target rotational speed, or the fuel command value (fuel supply amount) is calculated such that the fuel command value decreases to a predetermined fuel setting value at a constant rate. That is, during operation in the reverse power operation mode, the fuel command value is calculated regardless of the actual rotational speed linked to the system frequency, so the influence of fluctuations in the system frequency on the fuel supply amount can be eliminated. Therefore, it is possible to suppress misfires due to insufficient fuel supply and an increase in fuel costs due to excessive fuel supply during operation in the reverse power operation mode.

[0080] (6) The control method of the gas turbine (1) according to at least one embodiment of the present invention is a control method of a gas turbine connected to a generator (30) connectable to a power system (32), the gas turbine is configured to be able to switch the operation mode between a normal operation mode in which the gas turbine rotationally drives the generator and a reverse power operation mode in which the gas turbine is rotationally driven by the generator that operates as a motor while receiving power supply from the power system, comprises a step of calculating a fuel command value to be given to the gas turbine, in the step, during operation of the gas turbine in the reverse power operation mode, the fuel command value is calculated based on the deviation between the fixed value of the rotational speed of the gas turbine and the target rotational speed, or the fuel command value is calculated such that the fuel command value decreases to a predetermined fuel setting value at a constant rate.

[0081] According to the method of (6) above, during operation in the reverse power operation mode with a relatively small fuel supply amount, based on the deviation between the fixed value of the rotational speed of the gas turbine and the target rotational speed, or the fuel command value (fuel supply amount) is calculated such that the fuel command value decreases to a predetermined fuel setting value at a constant rate. That is, during operation in the reverse power operation mode, the fuel command value is calculated regardless of the actual rotational speed linked to the system frequency, so the influence of system frequency fluctuations on the fuel supply amount can be eliminated. Therefore, it is possible to suppress misfires due to insufficient fuel supply and an increase in fuel costs due to excessive fuel supply during operation in the reverse power operation mode.

[0082] (7) The control program for a gas turbine according to at least one embodiment of the present invention is a control program for a gas turbine (1) connected to a generator (30) connectable to a power system (32), wherein the gas turbine is configured to be able to switch the operation mode between a normal operation mode in which the gas turbine rotationally drives the generator and a reverse power operation mode in which the gas turbine is rotationally driven by the generator that operates as a motor while receiving power supply from the power system, causes a computer to execute a program for calculating a fuel command value to be applied to the gas turbine, wherein in the procedure, during operation of the gas turbine in the reverse power operation mode, the fuel command value is calculated based on the deviation between the fixed value of the rotational speed of the gas turbine and the target rotational speed, or the fuel command value is calculated such that the fuel command value decreases to a predetermined fuel setting value at a constant rate.

[0083] According to the program in (7) above, during operation in the reverse power operation mode with a relatively small fuel supply amount, based on the deviation between the fixed value of the gas turbine speed and the target speed, or the fuel command value (fuel supply amount) is calculated such that the fuel command value decreases to a predetermined fuel setting value at a constant rate. That is, during operation in the reverse power operation mode, the fuel command value is calculated regardless of the actual speed linked to the system frequency, so that the influence of the system frequency variation on the fuel supply amount can be eliminated. Therefore, it is possible to suppress misfires due to insufficient fuel supply and an increase in fuel costs due to excessive fuel supply during operation in the reverse power operation mode.

[0084] As described above, the embodiments of the present invention have been explained. However, the present invention is not limited to the above-described embodiments, and includes forms obtained by modifying the above-described embodiments and forms obtained by appropriately combining these forms.

[0085] In this specification, expressions representing relative or absolute arrangements such as "in a certain direction", "along a certain direction", "parallel", "orthogonal", "center", "concentric", or "coaxial" not only strictly represent such arrangements, but also represent states displaced relatively with tolerances or at angles and distances such that the same function can be obtained. For example, expressions representing that things such as "identical", "equal", and "homogeneous" are in an equal state not only strictly represent an equal state, but also represent states in which there are tolerances or differences to the extent that the same function can be obtained. Also, in this specification, expressions representing shapes such as a rectangular shape or a cylindrical shape not only represent shapes such as a rectangular shape or a cylindrical shape in a geometrically strict sense, but also represent shapes including concave and convex portions, chamfered portions, etc. within a range where the same effect can be obtained. Also, in this specification, the expression that one component "comprises", "includes", or "has" is not an exclusive expression excluding the existence of other components.

Explanation of Reference Numerals

[0086] 1 Gas turbine 2 Compressor 4 Combustor 6 Turbine 8 Rotor 30 Generator 31 Switch 32 Power system 33 Fuel supply line 34 Fuel storage section 36 Fuel control valve 38 Pilot ratio control unit 40 Inlet guide vane 42 Actuator 44 Rotational speed measurement unit 50 Control device 52 Target rotational speed calculation unit 54 Fuel command value calculation unit 56 Switching signal reception unit 58 Operation control unit 60 Switching signal input unit 62 First calculation unit 64 Second calculation unit 66 Third calculation unit 68 First selection unit 70 Second selection unit 72 Switch 74 Memory 100 Gas turbine facility

Claims

1. A control device for a gas turbine connected to a generator capable of being connected to a power system, wherein the gas turbine is configured to be able to switch between a normal operation mode in which the gas turbine rotationally drives the generator and a reverse power operation mode in which the gas turbine is rotationally driven by the generator that operates as a motor while receiving power supply from the power system, a fuel command value calculation unit for calculating a fuel command value for the gas turbine, an operation control unit configured to adjust the fuel supply amount to the gas turbine based on the fuel command value, comprising, the fuel command value calculation unit is configured to calculate the fuel command value based on a deviation between a fixed value of the rotational speed of the gas turbine and a target rotational speed during operation of the gas turbine in the reverse power operation mode, a control device for a gas turbine.

2. The fuel command value calculation unit is configured to calculate the fuel command value based on a deviation between the actual rotational speed and the target rotational speed of the gas turbine during operation of the gas turbine in the normal operation mode, The control device for a gas turbine according to claim 1.

3. The fixed value is a value based on the actual rotational speed of the gas turbine when switching from the normal operation mode to the reverse power operation mode of the gas turbine The control device for a gas turbine according to claim 1 or 2.

4. comprising a target rotational speed calculation unit for calculating a target rotational speed of the gas turbine, the target rotational speed calculation unit is configured to decrease the target rotational speed at a constant rate to a predetermined rotational speed setting value when the operation mode of the gas turbine is switched from the normal operation mode to the reverse power operation mode, the fuel command value calculation unit is configured to calculate the fuel command value based on a deviation between the fixed value of the rotational speed and the target rotational speed of the gas turbine during operation of the gas turbine in the reverse power operation mode, The control device for a gas turbine according to any one of claims 1 or 2.

5. including a compressor for compressing air, a combustor for generating combustion gas by a combustion reaction of the compressed air from the compressor and fuel, and a turbine driven by the combustion gas from the combustor, a gas turbine connected to a generator capable of being connected to a power system, and a control device according to any one of claims 1 to 4 configured to control the gas turbine, a gas turbine facility comprising.

6. A control method for a gas turbine connected to a generator connectable to a power system, comprising: The gas turbine is configured to be able to switch between a normal operation mode in which the gas turbine rotationally drives the generator and a reverse power operation mode in which the gas turbine is rotationally driven by the generator that operates as a motor while receiving power supply from the power system; Calculating a fuel command value to be applied to the gas turbine; Adjusting a fuel supply amount to the gas turbine based on the fuel command value; Comprising: In the step of calculating the fuel command value, during operation of the gas turbine in the reverse power operation mode, the fuel command value is calculated based on a deviation between a fixed value of the rotational speed of the gas turbine and a target rotational speed. A control method for a gas turbine.

7. A control program for a gas turbine connected to a generator connectable to a power system, comprising: The gas turbine is configured to be able to switch between a normal operation mode in which the gas turbine rotationally drives the generator and a reverse power operation mode in which the gas turbine is rotationally driven by the generator that operates as a motor while receiving power supply from the power system; For a computer, A procedure for calculating a fuel command value to be applied to the gas turbine; A procedure for adjusting a fuel supply amount to the gas turbine based on the fuel command value; A program for causing the above to be executed, In the procedure for calculating the fuel command value, during operation of the gas turbine in the reverse power operation mode, the fuel command value is calculated based on a deviation between a fixed value of the rotational speed of the gas turbine and a target rotational speed. A control program for a gas turbine.

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