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

Abstract

In order to control a gas turbine in a rated operating state in accordance with a maximum output command, the gas turbine control device is provided with: an inlet guide vane for adjusting the intake flow rate of the gas turbine in accordance with at least one of the intake temperature and the air pressure of the gas turbine; and calculating a basic target opening degree corresponding to the maximum output instruction. The opening degree of the inlet guide vane of the gas turbine is controlled on the basis of a target opening degree obtained by correcting the basic target opening degree using the offset correction value. When the combustion temperature of the gas turbine is lower than the temperature upper limit value corresponding to the maximum output command, the offset correction value is calculated so that the target opening degree is smaller than the basic target opening degree. On the other hand, when the output of the gas turbine is lower than the rated output value corresponding to the maximum output command, the offset correction value is calculated so that the target opening degree is greater than the basic target opening degree.

Description

TECHNICAL FIELD

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

[0002] This application claims priority based on Japanese Patent Application No. 2023-047991 filed on March 24, 2023, in the Japan Patent Office, and the content thereof is incorporated herein. BACKGROUND

[0003] In a gas turbine, a turbine is driven by combustion gas generated by mixing and combusting fuel and intake air, and thus an output is obtained. The combustion state in the gas turbine depends on the state (e.g., temperature or pressure) of intake air (air) that is sucked into the gas turbine. For example, in Patent Literature 1, a technology regarding gas turbine control is disclosed in which, according to the state of intake air that is guided to a compressor of the gas turbine in correspondence with the state of air, by feedback-controlling the opening degree of an inlet guide vane, destabilization of the combustion state of the gas turbine with respect to a change in the state of intake air can be prevented.

[0004] PRIOR ART DOCUMENTS

[0005] PATENT LITERATURE

[0006] Patent Literature 1: Japanese Patent Application Publication No. 2014-47728 SUMMARY

[0007] TECHNICAL PROBLEM TO BE SOLVED BY THE INVENTION

[0008] However, the output control of the gas turbine is performed, for example, in accordance with an output instruction given from the outside, and in particular, in a case where the output instruction is received in such a manner that the output of the gas turbine becomes the maximum (maximum output instruction), a rated output operation is performed. Generally, it is known that the output of the gas turbine depends on the intake air flow rate or the combustion temperature, and for example, the more the intake air flow rate or the higher the combustion temperature, the greater the output of the gas turbine.

[0009] Here, in the gas turbine in the maximum output operation state, the intake air flow rate of the gas turbine sometimes fluctuates due to a change in the surrounding external environment (air temperature or air pressure). For example, in a case where the intake air flow rate fluctuates in an increasing manner, the combustion temperature of the gas turbine decreases, and thus a decrease in efficiency can be caused. On the other hand, in a case where the intake air flow rate fluctuates in a decreasing manner, by controlling in such a manner that the combustion temperature of the gas turbine increases without exceeding a prescribed upper limit temperature by decreasing the fuel flow rate, a decrease in the output of the gas turbine at the time of the rated output operation can sometimes be caused.

[0010] Thus, in a gas turbine in a rated output operation, in order to balance the maximum output and the combustion temperature, it is necessary to control so as to make the intake air flow rate constant even when the environmental conditions change. As a method for solving this problem, for example, by implementing the opening degree control of the inlet guide vanes (IGV) of the gas turbine as feedforward control (feedforward control) using a target opening degree calculated based on the external environment such as the air temperature or the air pressure, it is possible to achieve gas turbine control that takes into account the variation in the intake air flow rate based on the external environment.

[0011] However, in such feedforward control, due to the error of the feedforward control set value (simulation analysis value) from the actual machine, the difference in the detailed conditions, and the like, it is difficult to always balance the maximum output and the combustion temperature at the time of rated operation. As a result, the opening degree of the inlet guide vanes becomes too large and the intake air flow rate becomes too much, which can cause the combustion temperature to decrease, or the opening degree of the inlet guide vanes becomes too small and the intake air flow rate becomes too small, which can cause the output to decrease. Also, due to the degradation of the gas turbine over the years, even if the intake air flow rate decreases with respect to the feedforward control set value, the output of the gas turbine at the time of rated operation is sometimes likely to decrease.

[0012] At least one embodiment of the present application is achieved in view of the above circumstances, and an object thereof is to provide a gas turbine control device, a gas turbine control method, and a gas turbine control program that enable efficient rated operation by balancing the combustion temperature and the output of a gas turbine at the time of rated operation.

[0013] Means for solving the technical problem

[0014] To solve the above problem, the gas turbine control device according to at least one embodiment of the present application is a gas turbine control device for controlling a gas turbine in a rated operation state according to a maximum output command, and includes:

[0015] a basic target opening degree calculation section that calculates a basic target opening degree corresponding to the maximum output command with respect to an inlet guide vane for adjusting the intake air flow rate of the gas turbine according to at least one of the intake air temperature or the air pressure of the gas turbine;

[0016] a bias correction value calculation section that calculates a bias correction value for correcting the basic target opening degree; and

[0017] an inlet guide vane control section that controls the opening degree of the inlet guide vane according to a target opening degree in which the basic target opening degree is corrected using the bias correction value,

[0018] The bias correction value calculation section calculates the bias correction value so that the target opening degree is smaller than the basic target opening degree when a combustion temperature of the gas turbine is lower than an upper limit value of temperature corresponding to the maximum output command,

[0019] or calculates the bias correction value so that the target opening degree is larger than the basic target opening degree when an output of the gas turbine is lower than a rated output value corresponding to the maximum output command.

[0020] To solve the above problem, a gas turbine control method according to at least one embodiment of the present application is a gas turbine control method for controlling a gas turbine in a rated operation state according to a maximum output command, and includes the following steps:

[0021] calculating a basic target opening degree corresponding to the maximum output command with respect to an inlet guide vane for adjusting an intake flow rate of the gas turbine according to at least one of an intake temperature or air pressure of the gas turbine;

[0022] calculating a bias correction value for correcting the basic target opening degree; and

[0023] controlling an opening degree of the inlet guide vane according to a target opening degree in which the basic target opening degree is corrected using the bias correction value,

[0024] in the step of calculating the bias correction value,

[0025] calculating the bias correction value so that the target opening degree is smaller than the basic target opening degree when a combustion temperature of the gas turbine is lower than an upper limit value of temperature corresponding to the maximum output command,

[0026] or calculating the bias correction value so that the target opening degree is larger than the basic target opening degree when an output of the gas turbine is lower than a rated output value corresponding to the maximum output command.

[0027] To solve the above problem, a gas turbine control program according to at least one embodiment of the present application is a gas turbine control program for controlling a gas turbine in a rated operation state according to a maximum output command, and can execute the following steps using a computer device:

[0028] calculating a basic target opening degree corresponding to the maximum output command with respect to an inlet guide vane for adjusting an intake flow rate of the gas turbine according to at least one of an intake temperature or air pressure of the gas turbine;

[0029] calculating a bias correction value for correcting the basic target opening degree; and

[0030] control the opening degree of the inlet guide vanes in accordance with a target opening degree that is corrected from the basic target opening degree using the bias correction value,

[0031] In the process of calculating the bias correction value,

[0032] When the combustion temperature of the gas turbine is lower than the upper limit value of the temperature corresponding to the maximum output command, the bias correction value is calculated so that the target opening degree is smaller than the basic target opening degree.

[0033] Alternatively, when the output of the gas turbine is lower than the rated output value corresponding to the maximum output command, the bias correction value is calculated so that the target opening degree is larger than the basic target opening degree.

[0034] Inventive Effects

[0035] According to at least one embodiment of the present application, a gas turbine control device, a gas turbine control method, and a gas turbine control program that enable efficient rated operation by taking into account the combustion temperature of the gas turbine during rated output operation and the balance with the output can be provided. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 is a schematic configuration diagram of a gas turbine related to one embodiment.

[0037] Figure 2 is a block diagram showing the functional configuration of a gas turbine control device of Figure 1

[0038] Figure 3 is a flowchart showing a gas turbine control method related to one embodiment.

[0039] Figure 4 is a schematic diagram showing a case where the operating point of the gas turbine is shifted by a bias correction value having a negative sign.

[0040] Figure 5 is a schematic diagram showing a case where the operating point of the gas turbine is shifted by a bias correction value having a positive sign.

[0041] Figure 6 is a timing chart showing the operation when the output of the gas turbine is lower than the rated output in the gas turbine in the rated output operation state.

[0042] Figure 7 is a timing chart showing the operation when the combustion temperature of the gas turbine is lower than the upper limit value of the temperature in the gas turbine in the rated output operation state.

[0043] Figure 8 is a timing chart showing the operation when the output of the gas turbine is lower than the rated output in the gas turbine in the rated output operation state. Figure 1 ​A block diagram of control logic for controlling the flow rate of fuel gas supplied from a fuel gas supply device in a gas turbine control device. DETAILED DESCRIPTION

[0044] Hereinafter, several embodiments of the present application will be described with reference to the accompanying drawings. The structures described or illustrated as embodiments are not intended to limit the scope of the present application to them, but are merely illustrative.

[0045] First, a gas turbine 1, which is a control target of a gas turbine control device 100 according to at least one embodiment of the present application, will be described. Figure 1 Fig. 1 is a schematic configuration diagram of the gas turbine 1 according to an embodiment. The gas turbine 1 includes a compressor 2, a combustor 3, a turbine 4, a fuel gas supply device 5, a generator 6, and the gas turbine control device 100.

[0046] The compressor 2 is a structure for taking in air (atmosphere) from the outside to generate compressed air. An inlet guide vane 7 (IGV) for adjusting the intake flow rate with respect to the compressor 2 is provided on the inlet side of the compressor 2. The opening degree of the inlet guide vane 7 is variable, and is one of the control targets of the gas turbine control device 100.

[0047] The compressed air generated by the compressor 2 is supplied to the combustor 3. The combustor 3 performs combustion by mixing the compressed air supplied from the compressor 2 with fuel supplied from the fuel gas supply device 5, thereby generating high-temperature combustion gas. The turbine 4 is driven by the combustion gas generated by the combustor 3, thereby outputting rotational drive force from a rotary shaft 7a. The rotary shaft 7a transmits the rotational drive force output from the turbine 4 to the generator 6, and thus power generation is performed by the generator 6.

[0048] The gas turbine control device 100 is a control unit for controlling each part of the aforementioned gas turbine 1, and is configured by, for example, a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), a storage medium readable by a computer, and the like. Also, a series of processes for realizing various functions are realized by, for example, storing a program in the storage medium or the like, reading out the program to the RAM or the like by the CPU, and performing information processing / operation processing to realize various functions. Alternatively, the program can be provided in a state of being stored in a storage medium readable by a computer, or can be distributed via a wired or wireless communication means. The storage medium readable by a computer refers to a magnetic disk, a magneto-optical disk, a CD-ROM, a DVD-ROM, a semiconductor memory, and the like.

[0049] Next, the structure of the gas turbine control device 100 for controlling the gas turbine 1 having the aforementioned structure will be described. Figure 2 is a block diagram showing the functional structure of the gas turbine control device 100. Figure 1

[0050] Also, in the following description, mainly the structure for controlling the opening degree D of the inlet guide vane 7 in the gas turbine control device 100 will be described, but as for other structures, as long as there is no special description, the known examples will be followed.

[0051] The gas turbine control device 100 is provided with a target opening degree calculation section 102, an opening degree acquisition section 104, and an inlet guide vane control section 106.

[0052] The target opening degree calculation section 102 is a structure for calculating a target value, that is, a target opening degree Dt in the opening degree control of the inlet guide vane 7, and is provided with a basic target opening degree calculation section 102a, a bias correction value calculation section 102b, and a change rate limiting section 102c.

[0053] ​The basic target opening degree calculation section 102a is a structure for calculating the basic target opening degree Dtb in accordance with an operating parameter related to the operating state of the gas turbine 1. The basic target opening degree Dtb is calculated in accordance with at least one operating parameter related to the operating state of the gas turbine 1, but in the present embodiment, as an example, a case where the inlet air temperature T and the atmospheric pressure Pa of the gas turbine 1 are used as the operating parameters is shown. The correlation of the basic target opening degree Dtb with the inlet air temperature T and the atmospheric pressure Pa is prepared as a graph that is stored in advance in a memory or the like. The basic target opening degree calculation section 102a detects the inlet air temperature T and the atmospheric pressure Pa, for example, by a sensor or the like that is not shown, and calculates the corresponding basic target opening degree Dtb using the graph.

[0054] The bias correction value calculation section 102b is a structure for calculating a bias correction value Damd for correcting the basic target opening degree Dtb. The bias correction value Damd is used to calculate the target opening degree Dt by being added to the basic target opening degree Dtb. The bias correction value Damd is calculated in accordance with an operating parameter related to the operating state of the gas turbine, but in the present embodiment, as the operating parameter, at least one of the combustion temperature Tb or the output P of the gas turbine 1 is used for the calculation. The specific calculation method of the bias correction value Damd will be described later in detail, but when the combustion temperature Tb of the gas turbine 1 is lower than the upper limit value Tbmax of the temperature corresponding to the maximum output command, the bias correction value Damd having a negative sign is calculated so as to make the target opening degree Dt smaller than the basic target opening degree Dtb. Also, when the output P of the gas turbine 1 is lower than the rated output value corresponding to the maximum output command, the bias correction value Damd having a positive sign is calculated so as to make the target opening degree Dt larger than the basic target opening degree Dtb.

[0055] The change rate limiting section 102c is a structure for limiting the value of the bias correction value Damd added to the basic target opening degree Dtb so as to reach the bias correction value Damd calculated by the bias correction value calculation section 102b at a prescribed change rate. For example, in the case where the bias correction value Damd has a positive sign, the value of the bias correction value Damd added to the basic target opening degree Dtb is increased at a constant change rate, so as to be limited to reach the calculation result of the bias correction value calculation section 102b (for example, refer to the time t2-1 to t3-1, t4-1 to t5-1 of FIG. 6) from an initial value (zero). Figure 6 On the other hand, in the case where the bias correction value Damd has a negative sign, the value of the bias correction value Damd added to the basic target opening degree Dtb is decreased at a constant change rate, so as to be limited to reach the calculation result of the bias correction value calculation section 102b (for example, refer to the time t2-2 to t3-2, t4-2 to t5-2 of FIG. 6) from an initial value (zero). Figure 7

[0056] ​The opening acquisition section 104 is a structure for acquiring the opening D of the inlet guide vanes 7. The opening D of the inlet guide vanes 7 can be acquired, for example, from a control signal transmitted to an actuator of the inlet guide vanes 7 from the inlet guide vane control section 106, or from a sensor (not shown) provided to the inlet guide vanes 7.

[0057] The inlet guide vane control section 106 is a structure for controlling the opening D of the inlet guide vanes 7. The control by the inlet guide vane control section 106 is performed in such a way that the opening D of the inlet guide vanes 7 becomes the target opening Dt. More specifically, the inlet guide vane control section 106 calculates the difference ΔD (= Dt - D) between the target opening Dt calculated by the target opening calculation section 102 and the opening D acquired by the opening acquisition section 104, and generates a control signal for controlling the opening D of the inlet guide vanes 7 so that the difference ΔD becomes zero. The control signal generated by the inlet guide vane control section 106 is transmitted to the actuator of the inlet guide vanes 7, and thus the opening D of the inlet guide vanes 7 is controlled to become the target opening Dt by driving the actuator.

[0058] Next, a gas turbine control method implemented by the gas turbine control device 100 having the above-described structure will be described. Figure 3 is a flowchart showing a gas turbine control method according to an embodiment.

[0059] First, the gas turbine 1 is in a rated output operation state by receiving a maximum output command (step S1). The rated output operation state is a state in which the output P of the gas turbine 1 reaches a predetermined rated output value Pmax (an upper limit value of the output), or a state in which the combustion temperature Tb of the gas turbine 1 reaches a predetermined upper limit value Tbmax of the temperature even if the output P does not reach the rated output value Pmax.

[0060] In addition, the combustion temperature Tb of the gas turbine 1 can be substituted by the turbine inlet temperature TIT.

[0061] Next, the gas turbine control device 100 acquires the operation state of the gas turbine 1 (step S2). At least one of the combustion temperature Tb and the output P of the gas turbine 1, or a parameter related thereto, is included in the operation state acquired in this step S2.

[0062] Next, the bias correction value calculation section 102b determines whether the combustion temperature Tb of the gas turbine 1 is lower than the temperature upper limit value Tbmax that is set in advance to correspond to the rated output operation state (step S3). The determination of step S3 is made in accordance with the operation state acquired in step S2. In step S2, if the combustion temperature Tb itself is acquired as the operation state, the determination is made by comparing the acquired combustion temperature Tb with the temperature upper limit value Tbmax. Also, in step S2, if a parameter related to the combustion temperature Tb is acquired as the operation state, the determination can be made by comparing the parameter with a threshold value that is converted to correspond to the temperature upper limit value Tbmax.

[0063] When the combustion temperature Tb is lower than the temperature upper limit value Tbmax (step S3: YES), the bias correction value calculation section 102b calculates the bias correction value Damd having a negative sign (step S4). The target opening Dt is found by adding the bias correction value Damd calculated in step S3 to the basic target opening Dtb (step S5). The opening D of the inlet guide vanes 7 is controlled in accordance with the target opening Dt thus found (step S6).

[0064] Here, Figure 4 is a schematic view showing a case where the operation point of the gas turbine 1 shifts by the bias correction value Damd. In Figure 4 a case where the operation point of the gas turbine 1 defined by the exhaust temperature Tex, the output P, and the combustion temperature Tb and the intake air flow rate shifts by the bias correction value Damd is shown.

[0065] At the initial state, i.e., the operation point Al, since the opening D of the inlet guide vanes 7 becomes too large, the intake air flow rate is large, and the combustion temperature Tb is lower than the temperature upper limit value Tbmax. In this case, the correction of the basic target opening Dtb is made using the bias correction value Damd having a negative sign in step S4, and the target opening Dt becomes small, and the opening D of the inlet guide vanes 7 is controlled in a manner to close. As a result, as shown at the operation point A2, the combustion temperature Tb of the gas turbine 1 is raised by reducing the intake air flow rate of the gas turbine 1. As a result, at the operation point A2, the rated output operation state with a good efficiency is achieved by taking into account both the output and the combustion temperature Tb.

[0066] Thus, when the combustion temperature Tb of the gas turbine 1 is lower than the temperature upper limit value Tbmax corresponding to the maximum output command, the basic target opening Dtb is corrected using the bias correction value Damd so as to make the target opening Dt small. As a result, the intake air flow rate that becomes too large is suppressed by reducing the opening D of the inlet guide vanes 7, and the combustion temperature Tb of the gas turbine 1 at the rated output operation state can be suppressed from decreasing. As a result, the efficiency of the gas turbine 1 at the rated output operation state can be improved.

[0067] On the other hand, in the case where the combustion temperature Tb is equal to or higher than the upper limit value Tbmax (Step S3: No), the offset correction value calculation portion 102b further determines whether the output P of the gas turbine 1 is smaller than the rated output value Pmax (Step S7). The determination of Step S7 is made on the basis of the operating state acquired in Step S2. In Step S2, if the output P itself is acquired as the operating state, the determination is made by comparing the acquired output P with the rated output value Pmax. Also, in Step S2, if a parameter related to the output P is acquired as the operating state, the determination can be made by comparing the parameter with a threshold value converted in correspondence with the rated output value Pmax.

[0068] When the output P is smaller than the rated output value Pmax (Step S7: Yes), the offset correction value calculation portion 102b calculates the offset correction value Damd having a positive sign (Step S8). The target opening Dt is found by adding the offset correction value Damd calculated in Step S8 to the basic target opening Dtb (Step S5). The opening D of the inlet guide vanes 7 is controlled in accordance with the target opening Dt thus found (Step S6).

[0069] Here, Figure 5 is a schematic view showing a case where the operating point of the gas turbine 1 shifts by the offset correction value Damd having a positive sign. In Figure 5 a case where the operating point of the gas turbine 1 defined by the exhaust gas temperature Tex, the output P, and the combustion temperature Tb and the intake air flow rate shifts by the offset correction value Damd is shown.

[0070] At the initial state, i.e., the operating point A3, the opening D of the inlet guide vanes 7 becomes too small, and thus the intake air flow rate is small, and the output P is smaller than the rated output value Pmax. In this case, by correcting the basic target opening Dtb using the offset correction value Damd having a positive sign in Step S8, the target opening Dt becomes large, and the opening D of the inlet guide vanes 7 is controlled in a manner to open. Thereby, as shown at the operating point A2, the output P of the gas turbine 1 is raised by increasing the intake air flow rate of the gas turbine 1. Thereby, at the operating point A2, the rated output operating state with a good efficiency is achieved by taking into account both the output and the combustion temperature.

[0071] Thus, when the output of the gas turbine 1 is smaller than the rated output value Pmax corresponding to the maximum output command, the basic target opening Dtb is corrected using the offset correction value Damd so as to make the target opening Dt large. Thereby, the intake air flow rate which becomes too small is increased by increasing the opening D of the inlet guide vanes 7, and it is possible to suppress the decrease in the output of the gas turbine 1 in the rated output operating state.

[0072] Next, the operation of the gas turbine 1 based on the above control will be described in more detail. Figure 6 is a timing chart showing the operation when the output P of the gas turbine 1 is lower than the rated output value Pmax in the gas turbine 1 in the rated output operation state. That is, in Figure 6 is shown in Figure 3 the operation when the output P is determined to be smaller than the rated output value Pmax in step S7 of

[0073] In Figure 6 , the target output Pt reaches the rated output value Pmax at time tl-1 by giving the maximum output command to the gas turbine 1. On the other hand, the actual output P of the gas turbine 1 is Pl which is smaller than the rated output value Pmax. In this case, as to Figure 3 step S8 of

[0074] The bias correction value Damd is kept constant after being changed in an increasing manner from time t2-1 to t3-1 by the change rate limiting section 102c.

[0075] In the present embodiment, at time t4-1, the output P of the gas turbine 1 is still smaller than the rated output value Pmax, so the calculation of the bias correction value Damd is performed again in the same manner, and the bias correction value Damd is increased at a prescribed change rate from time t4-1 to t5-1 and then kept constant. As a result, at time t5-1, the output P of the gas turbine reaches the rated output value Pmax, thereby realizing the rated operation state with good efficiency.

[0076] Figure 7 is a timing chart showing the operation when the combustion temperature Tb of the gas turbine 1 is lower than the temperature upper limit value Tmax in the gas turbine 1 in the rated output operation state. That is, in Figure 7 is shown in Figure 3 the operation when the combustion temperature Tb is determined to be smaller than the temperature upper limit value Tmax in step S3 of

[0077] In the present embodiment, when the bias correction value calculating section 102b compares the combustion temperature Tb with the temperature upper limit value Tmax, as a parameter related to the combustion temperature Tb, the fuel flow rate command value CSO for the fuel gas supply device 5 provided in the gas turbine 1 is used. Here,Figure 8 is a block diagram of control logic (fuel flow rate command value calculation section 110) for performing flow rate control of fuel gas supplied from the fuel gas supply device 5 in the gas turbine control device 100 of Figure 1

[0078] The gas turbine control device 100 is provided with a fuel flow rate command value calculation section 110 for calculating a fuel flow rate command value CSO, which is a control signal for controlling the supply flow rate of fuel gas to the fuel gas supply device 5. The fuel flow rate command value calculation section 110 is provided with a plurality of fuel flow rate command value candidate calculation sections 112 (a first fuel flow rate command value candidate calculation section 112A, a second fuel flow rate command value candidate calculation section 112B, and a third fuel flow rate command value candidate calculation section 112C) that respectively calculate a plurality of fuel flow rate command value candidates, and a low value selection section 114 for selecting a fuel flow rate command value CSO from among the plurality of fuel flow rate command value candidates.

[0079] The plurality of fuel flow rate command value candidate calculation sections 112 respectively calculate a plurality of fuel flow rate command value candidates from different viewpoints from each other. In the present embodiment, there are provided the first fuel flow rate command value candidate calculation section 112A for calculating a first fuel flow rate command value candidate CSO1 based on a first operation parameter PI, the second fuel flow rate command value candidate calculation section 112B for calculating a second fuel flow rate command value candidate CSO2 based on a second operation parameter P2, and the third fuel flow rate command value candidate calculation section 112C for calculating a third fuel flow rate command value candidate CSO3 based on a third operation parameter P3. The first operation parameter PI, the second operation parameter P2, and the third operation parameter P3 are each at least one parameter related to the operation state of the gas turbine 1, and the first operation parameter PI is the exhaust gas temperature Tex of the gas turbine 1. The low value selection section 114 selects the smallest one among these plurality of fuel flow rate command value candidates as the fuel flow rate command value CSO and outputs it.

[0080] ​In the bias correction value calculation section 102b, the determination of whether the combustion temperature Tb of the gas turbine 1 is lower than the temperature upper limit value Tbmax is made using the flow rate control logic of the fuel gas having such a structure. For example, as a parameter related to the combustion temperature Tb of the gas turbine, the difference value ΔCSO (= CSOl - CSO) of the 1st fuel flow rate command value candidate CSOl from the fuel flow rate command value CSO can be used. In the case where the combustion temperature Tb is relatively high to reach the temperature upper limit value Tbmax, the exhaust gas temperature Tex of the gas turbine 1 also becomes high, and therefore, in order not to exceed the temperature upper limit value, the 1st fuel flow rate command value candidate CSOl is calculated to be smaller than the other fuel flow rate command value candidates. In this case, in the low value selection section 114, the 1st fuel flow rate command value candidate CSOl is selected as the fuel flow rate command value CSO, and therefore, ΔCSO is substantially zero (i.e., CSOl « CSO). On the other hand, in the case where the combustion temperature Tb is relatively low, the exhaust gas temperature Tex of the gas turbine 1 also becomes low, and therefore, the 1st fuel flow rate command value candidate CSOl is calculated to be larger than the other fuel flow rate command value candidates. In this case, in the low value selection section 114, the other fuel flow rate command value candidate is selected as the fuel flow rate command value CSO, and therefore, ΔCSO becomes a large value.

[0081] The bias correction value calculation section 102b determines whether the combustion temperature Tb of the gas turbine 1 is lower than the temperature upper limit value Tbmax by comparing this difference value ΔCSO with the threshold value (= zero) corresponding to the temperature upper limit value.

[0082] In Figure 7 , by giving the maximum output command to the gas turbine 1, the target output Pt reaches the rated output value Pmax at time t1-2. On the other hand, the parameter related to the actual combustion temperature of the gas turbine 1, i.e., the difference value ΔCSO, is larger than the reference value (zero) corresponding to the temperature upper limit value. In this case, with respect to Figure 3 , as described above, the bias correction value calculation section 102b calculates the bias correction value Damd having a negative sign. This bias correction value Damd is changed in a decreasing manner from time t2-2 to t3-2 by the change rate limiting section 102c, and then, is kept constant.

[0083] The bias correction value Damd is kept for a prescribed period Tp from time t3-2 to t4-2. Thereby, in the case where the control state of the gas turbine 1 is changed as the target opening Dt is changed according to the bias correction value Damd, by keeping the bias correction value Damd for the prescribed period Tp before the change is stabilized, it is possible to effectively prevent the operating state of the gas turbine 1 from becoming unstable.

[0084] In the present embodiment, at time t4-2, since the difference ΔCSO is larger than the reference value (zero) (i.e., since the combustion temperature Tb is lower than the temperature upper limit value Tbmax), the calculation of the bias correction value Damd is again performed in the same manner, the bias correction value Damd is decreased at a prescribed rate of change from time t4-2 to t5-2, and thereafter is held constant for a prescribed period Tp. As a result, at time t5-2, the difference ΔCSO reaches the reference value (zero), and an efficient rated operation state is achieved.

[0085] Also, in another embodiment, as the parameter related to the combustion temperature Tb, the turbine inlet temperature TIT of the gas turbine 1 can be used. In this case, even in a case where the combustion temperature Tb of the gas turbine 1 cannot be directly detected, the comparison determination of the combustion temperature Tb and the temperature upper limit value Tbmax can be appropriately performed based on the turbine inlet temperature TIT that has a correlation with the combustion temperature Tb of the gas turbine 1.

[0086] The turbine inlet temperature TIT can be estimated based on the exhaust temperature of the gas turbine 1 and the turbine compression ratio. The turbine inlet temperature TIT is generally high and difficult to measure, but the turbine inlet temperature used in the evaluation of the combustion temperature Tb can be appropriately estimated based on the exhaust temperature of the gas turbine and the turbine compression ratio.

[0087] As explained above, according to each of the above-described embodiments, in the gas turbine 1 in the rated output operation state, the opening degree control of the inlet guide vanes 7 is performed based on the target opening degree Dt calculated by correcting the basic target opening degree Dtb using the bias correction value Damd. When the combustion temperature Tb of the gas turbine 1 is lower than the temperature upper limit value Tbmax corresponding to the maximum output command, the basic target opening degree Dtb is corrected using the bias correction value Damd so as to make the target opening degree Dt smaller. Thereby, the intake air flow rate that has become excessively large is suppressed by decreasing the opening degree D of the inlet guide vanes 7, and the combustion temperature Tb of the gas turbine 1 in the rated output operation state can be suppressed from decreasing. As a result, the efficiency of the gas turbine 1 in the rated output operation state can be improved. On the other hand, when the output of the gas turbine 1 is lower than the rated output value corresponding to the maximum output command, the basic target opening degree Dtb is corrected using the bias correction value Damd so as to make the target opening degree Dt larger. Thereby, the intake air flow rate that has become excessively small is increased by increasing the opening degree D of the inlet guide vanes 7, and the output of the gas turbine 1 in the rated output operation state can be suppressed from decreasing.

[0088] Further, the constituent elements in the above-described embodiments can be appropriately replaced with publicly known constituent elements within a range not deviating from the gist of the present application, and the above-described embodiments can be appropriately combined.

[0089] The content described in each of the embodiments described above can be grasped as follows, for example.

[0090] (1) A gas turbine control device for controlling a gas turbine in a rated operation state according to a maximum output command, the gas turbine control device including:

[0091] a basic target opening degree calculation section for calculating a basic target opening degree corresponding to the maximum output command, with respect to an inlet guide vane for adjusting an intake flow rate of the gas turbine according to at least one of an intake temperature or a gas pressure of the gas turbine;

[0092] a bias correction value calculation section for calculating a bias correction value for correcting the basic target opening degree; and

[0093] an inlet guide vane control section for controlling an opening degree of the inlet guide vane according to a target opening degree in which the basic target opening degree is corrected using the bias correction value,

[0094] the bias correction value calculation section calculates the bias correction value so that the target opening degree is smaller than the basic target opening degree when a combustion temperature of the gas turbine is lower than an upper limit value of the temperature corresponding to the maximum output command,

[0095] or, the bias correction value calculation section calculates the bias correction value so that the target opening degree is larger than the basic target opening degree when an output of the gas turbine is lower than a rated output value corresponding to the maximum output command.

[0096] According to the aspect (1) described above, in a gas turbine in a rated output operation state, an opening degree of an inlet guide vane is controlled according to a target opening degree calculated by correcting a basic target opening degree using a bias opening degree. When a combustion temperature of the gas turbine is lower than an upper limit value of the temperature corresponding to a maximum output command, the basic target opening degree is corrected using a bias correction value so that the target opening degree becomes smaller. Thereby, an intake flow rate that becomes too large is suppressed by reducing the opening degree of the inlet guide vane, and a decrease in the combustion temperature of the gas turbine in the rated output operation state can be suppressed. As a result, the efficiency of the gas turbine in the rated output operation state can be improved. On the other hand, when an output of the gas turbine is lower than a rated output value corresponding to the maximum output command, the basic target opening degree is corrected using a bias correction value so that the target opening degree becomes larger. Thereby, an intake flow rate that becomes too small is increased by increasing the opening degree of the inlet guide vane, and a decrease in the output of the gas turbine in the rated output operation state can be suppressed.

[0097] (2) In another aspect, in the aspect (1) described above,

[0098] the bias correction value calculation section holds the bias correction value for a prescribed period.

[0099] According to the above (2), the bias correction value used in correction of the target opening degree of the inlet guide vane of the gas turbine is calculated in a manner to be maintained for a prescribed period. Thus, in a case where the control state of the gas turbine changes as the target opening degree changes according to the bias correction value, by maintaining the bias correction value for the prescribed period before the change stabilizes, it is possible to effectively prevent the operating state of the gas turbine from becoming unstable.

[0100] (3) In another aspect, in the aspect of (1) or (2) above,

[0101] Further provided is a fuel flow rate control section for performing fuel flow rate control to the gas turbine in accordance with a fuel flow rate command value selected as a lower value from among a plurality of fuel flow rate command value candidates including a first fuel flow rate command value candidate calculated based on the exhaust temperature of the turbine,

[0102] The bias correction value calculation section determines whether the combustion temperature is lower than the temperature upper limit value based on a difference between the first fuel flow rate command value and the fuel flow rate command value.

[0103] According to the aspect of (3) above, in a case where fuel flow rate control to the gas turbine is performed using a fuel flow rate command value selected as a lower value from among a plurality of fuel flow rate command value candidates, a comparison determination of the combustion temperature and the temperature upper limit value is performed based on a difference between the first fuel flow rate command value candidate and the fuel flow rate command value. Thus, even in a case where the combustion temperature of the gas turbine cannot be directly detected, a comparison determination of the combustion temperature and the temperature upper limit value can be appropriately performed based on the difference that has a correlation with the combustion temperature of the gas turbine.

[0104] (4) In another aspect, in the aspect of (1) or (2) above,

[0105] The combustion temperature is evaluated based on a turbine inlet temperature.

[0106] According to the aspect of (4) above, even in a case where the combustion temperature of the gas turbine cannot be directly detected, a comparison determination of the combustion temperature and the temperature upper limit value can be appropriately performed based on the turbine inlet temperature that has a correlation with the combustion temperature of the gas turbine.

[0107] (5) In another aspect, in the aspect of (4) above,

[0108] The turbine inlet temperature is estimated based on an exhaust temperature of the gas turbine and a turbine compression ratio.

[0109] According to the aspect (5) described above, the turbine inlet temperature used in the evaluation of the combustion temperature can be appropriately estimated based on the exhaust gas temperature of the gas turbine and the turbine compression ratio.

[0110] (6) A gas turbine control method according to the aspect (5) described above, for controlling a gas turbine in a rated operation state according to a maximum output command, the gas turbine control method including the steps of:

[0111] calculating a basic target opening degree corresponding to the maximum output command, for an inlet guide vane for adjusting an intake flow rate of the gas turbine according to at least one of an intake temperature or a gas pressure of the gas turbine;

[0112] calculating a bias correction value for correcting the basic target opening degree; and

[0113] controlling an opening degree of the inlet guide vane according to a target opening degree in which the basic target opening degree is corrected using the bias correction value,

[0114] in the step of calculating the bias correction value,

[0115] when the combustion temperature of the gas turbine is lower than an upper limit value of the temperature corresponding to the maximum output command, the bias correction value is calculated so that the target opening degree is smaller than the basic target opening degree,

[0116] or, when the output of the gas turbine is lower than a rated output value corresponding to the maximum output command, the bias correction value is calculated so that the target opening degree is larger than the basic target opening degree.

[0117] According to the aspect (6) described above, in a gas turbine in a rated output operation state, an opening degree of an inlet guide vane is controlled according to a target opening degree calculated by correcting a basic target opening degree using a bias opening degree. When the combustion temperature of the gas turbine is lower than an upper limit value of the temperature corresponding to the maximum output command, the basic target opening degree is corrected using the bias correction value so that the target opening degree becomes smaller. Thereby, the intake flow rate that becomes too large is suppressed by reducing the opening degree of the inlet guide vane, and the reduction of the combustion temperature of the gas turbine in the rated output operation state can be suppressed. As a result, the efficiency of the gas turbine in the rated output operation state can be improved. On the other hand, when the output of the gas turbine is lower than a rated output value corresponding to the maximum output command, the basic target opening degree is corrected using the bias correction value so that the target opening degree becomes larger. Thereby, the intake flow rate that becomes too small is increased by increasing the opening degree of the inlet guide vane, and the reduction of the output of the gas turbine in the rated output operation state can be suppressed.

[0118] (7) A gas turbine control program for controlling a gas turbine in a rated operation state according to a maximum output command, the gas turbine control program being executable by a computer device to perform the following procedures:

[0119] calculating a basic target opening degree corresponding to the maximum output command for an inlet guide vane for adjusting an intake flow rate of the gas turbine according to at least one of an intake temperature or a gas pressure of the gas turbine;

[0120] calculating a bias correction value for correcting the basic target opening degree; and

[0121] controlling an opening degree of the inlet guide vane according to a target opening degree in which the basic target opening degree is corrected using the bias correction value,

[0122] in the procedure of calculating the bias correction value,

[0123] when a combustion temperature of the gas turbine is lower than an upper limit value of the temperature corresponding to the maximum output command, the bias correction value is calculated so that the target opening degree is smaller than the basic target opening degree,

[0124] or, when an output of the gas turbine is lower than a rated output value corresponding to the maximum output command, the bias correction value is calculated so that the target opening degree is larger than the basic target opening degree.

[0125] According to the aspect (7) described above, in a gas turbine in a rated output operation state, an opening degree of an inlet guide vane is controlled according to a target opening degree calculated by correcting a basic target opening degree using a bias opening degree. When a combustion temperature of the gas turbine is lower than an upper limit value of the temperature corresponding to the maximum output command, the basic target opening degree is corrected using the bias correction value so that the target opening degree becomes smaller. Thereby, an intake flow rate that becomes too large is suppressed by reducing the opening degree of the inlet guide vane, and a decrease in the combustion temperature of the gas turbine in the rated output operation state can be suppressed. As a result, the efficiency of the gas turbine in the rated output operation state can be improved. On the other hand, when an output of the gas turbine is lower than a rated output value corresponding to the maximum output command, the basic target opening degree is corrected using the bias correction value so that the target opening degree becomes larger. Thereby, an intake flow rate that becomes too small is increased by increasing the opening degree of the inlet guide vane, and a decrease in the output of the gas turbine in the rated output operation state can be suppressed.

[0126] Explanation of Symbols

[0127] 1 - gas turbine, 2 - compressor, 3 - combustor, 4 - turbine, 5 - fuel gas supply device, 6 - generator, 100 - gas turbine control device, 102 - target opening degree calculation section, 102a - basic target opening degree calculation section, 102b - bias correction value calculation section, 102c - change rate limiting section, 104 - opening degree acquisition section, 106 - inlet guide vane control section, 110 - fuel flow rate command value calculation section, 112A - 1st fuel flow rate command value candidate calculation section, 112B - 2nd fuel flow rate command value candidate calculation section, 112C - 3rd fuel flow rate command value candidate calculation section, 114 - low value selection section.

Claims

1. A gas turbine control device for controlling a gas turbine in a rated operation state according to a maximum output command, the gas turbine control device comprising: a basic target opening degree calculation section for calculating a basic target opening degree corresponding to the maximum output command, for an inlet guide vane for adjusting an intake flow rate of the gas turbine according to at least one of an intake temperature or a gas pressure of the gas turbine; a bias correction value calculation section for calculating a bias correction value for correcting the basic target opening degree; and an inlet guide vane control section for controlling an opening degree of the inlet guide vane according to a target opening degree in which the basic target opening degree is corrected using the bias correction value, wherein the bias correction value calculation section calculates the bias correction value so that the target opening degree is smaller than the basic target opening degree when a combustion temperature of the gas turbine is lower than an upper limit value of the temperature corresponding to the maximum output command, or calculates the bias correction value so that the target opening degree is larger than the basic target opening degree when an output of the gas turbine is lower than a rated output value corresponding to the maximum output command.

2. The gas turbine control device according to claim 1, wherein the bias correction value calculation section maintains the bias correction value for a prescribed period.

3. The gas turbine control device according to claim 1 or 2, further comprising a fuel flow rate control section for controlling a fuel flow rate supplied to the gas turbine according to a fuel flow rate command value selected as a low value from among a plurality of fuel flow rate command value candidates including a first fuel flow rate command value candidate calculated based on an exhaust temperature of the turbine, wherein the bias correction value calculation section determines whether the combustion temperature is lower than the upper limit value of the temperature based on a difference between the first fuel flow rate command value and the fuel flow rate command value.

4. The gas turbine control device according to claim 1 or 2, wherein the combustion temperature is evaluated based on a turbine inlet temperature.

5. The gas turbine control device according to claim 4, wherein the turbine inlet temperature is estimated based on an exhaust temperature of the gas turbine and a turbine compression ratio.

6. A gas turbine control method for controlling a gas turbine in a rated operation state according to a maximum output command, the gas turbine control method comprising the steps of: calculating a basic target opening degree corresponding to the maximum output command, for an inlet guide vane for adjusting an intake flow rate of the gas turbine according to at least one of an intake temperature or a gas pressure of the gas turbine; calculating a bias correction value for correcting the basic target opening degree; and controlling an opening degree of the inlet guide vane according to a target opening degree in which the basic target opening degree is corrected using the bias correction value, wherein in the step of calculating the bias correction value, the bias correction value is calculated so that the target opening degree is smaller than the basic target opening degree when a combustion temperature of the gas turbine is lower than an upper limit value of the temperature corresponding to the maximum output command, or the bias correction value is calculated so that the target opening degree is larger than the basic target opening degree when an output of the gas turbine is lower than a rated output value corresponding to the maximum output command. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Alternatively, the bias correction value is calculated so that the target opening degree is larger than the basic target opening degree when the output of the gas turbine is lower than a rated output value corresponding to the maximum output command.

7. A gas turbine control program for controlling a gas turbine in a rated operation state in accordance with a maximum output command, the gas turbine control program being capable of executing the following procedures using a computer device: calculating a basic target opening degree corresponding to the maximum output command for inlet guide vanes for adjusting an intake flow rate of the gas turbine in accordance with at least one of an intake temperature or a gas pressure of the gas turbine; calculating a bias correction value for correcting the basic target opening degree; and controlling an opening degree of the inlet guide vanes in accordance with a target opening degree in which the basic target opening degree is corrected using the bias correction value, in the procedure of calculating the bias correction value, the bias correction value is calculated so that the target opening degree is smaller than the basic target opening degree when a combustion temperature of the gas turbine is lower than an upper limit value of the temperature corresponding to the maximum output command, or the bias correction value is calculated so that the target opening degree is larger than the basic target opening degree when the output of the gas turbine is lower than a rated output value corresponding to the maximum output command.

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