JP6401109B2 - Fuel control apparatus and fuel control method for gas turbine - Google Patents

Description

  The present disclosure relates to a fuel control apparatus and a fuel control method for a gas turbine.

The gas turbine has a combustor and a turbine, and the turbine generates a rotational force by using combustion gas generated by burning the fuel by the combustor. The gas turbine is provided with a fuel control device, and the fuel control device is configured to control the flow rate of the fuel supplied to the combustor.
For example, in the fuel control device disclosed in Patent Document 1, the opening degree of the fuel flow control valve is determined based on at least one signal from various measurement devices including a pressure detector, a fuel flow control valve, and the measurement device. And a controllable opening degree control unit.
Further, for example, the fuel control device disclosed in Patent Document 2 includes a fuel flow rate adjustment valve, a fuel command calculation circuit for obtaining an opening command signal of the fuel flow rate adjustment valve based on a turbine speed signal and a generator load signal, an adjustment A fuel pressure adjusting means that is provided upstream of the flow rate control valve and adjusts the upstream pressure, and a pressure controller that outputs an opening degree command of the fuel flow rate control valve based on a deviation between the upstream pressure and the pressure set value. .

JP-A-11-210496 JP2013-44251A

As disclosed in Patent Document 2, the fuel gas flow control valve is opened based on the turbine speed signal and the generator load signal while the fuel gas pressure control valve is adjusted so that the upstream pressure of the fuel gas approaches the pressure set value. When adjusting the degree, the adjustment accuracy of the flow rate of the fuel supplied to the combustor depends solely on the adjustment accuracy of the pressure by the fuel gas pressure control valve.
In such a configuration, when the pressure of the fuel gas supplied to the fuel gas pressure control valve (source pressure) fluctuates, if there is a delay in the pressure adjustment by the fuel gas pressure control valve, the fuel gas pressure control valve is supplied to the combustor. The adjustment accuracy of the flow rate of the fuel gas is reduced. Also, if the supply pressure fluctuates greatly and exceeds the pressure adjustment range by the fuel gas pressure control valve, for example, if the fuel gas pressure control valve is fully opened, the flow rate of the fuel gas supplied to the combustor Adjustment accuracy is greatly reduced.

  On the other hand, Patent Document 1 describes that the opening degree of the fuel flow control valve is controlled based on at least one signal from the measuring device, but the fuel flow control valve when the supply pressure fluctuates is described. There is no description on how to control the opening.

  In view of the above circumstances, an object of at least one embodiment of the present invention is to provide a gas turbine capable of accurately controlling the amount of fuel supplied to a combustor even when the pressure of fuel supplied to a pressure control valve changes. A fuel control apparatus and a fuel control method are provided.

(1) A fuel control apparatus for a gas turbine according to at least one embodiment of the present invention includes:
In a fuel control device for a gas turbine capable of controlling the amount of fuel supplied to a combustor of a gas turbine,
A pressure control valve disposed in the fuel supply path;
A flow rate control valve disposed downstream of the pressure control valve and disposed in the supply path;
A pressure gauge capable of measuring the pressure of the fuel between the pressure control valve and the flow control valve;
A pressure control valve controller capable of controlling the opening of the pressure control valve based on the measurement result of the pressure gauge;
A flow control valve controller capable of controlling the opening of the flow control valve;
Including
The pressure control valve control unit is capable of controlling the opening of the pressure control valve so that the measured pressure measured by the pressure gauge approaches a target pressure,
The flow rate control valve control unit can control the opening degree of the flow rate control valve in one mode selected from a plurality of modes,
The plurality of modes are:
A first mode for adjusting the opening of the flow rate control valve based on the target pressure;
A second mode for adjusting the opening of the flow control valve based on the measured pressure;
including.

  In the fuel control device for the gas turbine having the above configuration (1), the flow rate control valve control unit can selectively execute the first mode and the second mode, and in the second mode, the flow rate is based on the measured pressure. The opening degree of the control valve is adjusted. For this reason, even if the pressure of the fuel supplied to the pressure control valve fluctuates and the pressure of the fuel flowing into the flow control valve changes from the target pressure, the flow rate of the fuel passing through the flow control valve based on the measured pressure, That is, the amount of fuel supplied to the combustor can be accurately controlled.

(2) In some embodiments, in the configuration (1),
The flow rate control valve control unit is configured to select and execute the second mode when at least one condition is satisfied,
The at least one condition includes a condition related to an opening degree of the pressure control valve.

  For example, if the pressure of fuel supplied to the pressure control valve (supplier pressure) drops and the pressure control valve is fully opened, the pressure control function of the pressure control valve reaches its limit, and the measured pressure is set to the target pressure. It becomes difficult to approach. In this regard, in the fuel control device for the gas turbine having the above-described configuration (2), the flow rate control valve control unit is configured to execute the second mode when the condition regarding the opening degree of the pressure control valve is satisfied. Even if the pressure control function of the pressure control valve is reduced, the flow rate of the fuel passing through the flow rate control valve, that is, the amount of fuel supplied to the combustor can be accurately controlled based on the measured pressure. it can.

(3) In some embodiments, in the configuration (1) or (2),
The flow control valve control unit is
The second mode is selected and executed when the opening of the pressure control valve reaches an upper limit during execution of the first mode, and
The first mode is selected and executed when the opening of the pressure control valve reaches a lower limit value during execution of the second mode.

  In the fuel control device for a gas turbine having the above configuration (3), the flow rate control valve control unit is configured to execute the second mode when the opening of the pressure control valve reaches the upper limit value. Even if the pressure control function by the pressure control valve is lowered, the flow rate of the fuel passing through the flow rate control valve, that is, the amount of fuel supplied to the combustor can be accurately controlled based on the measured pressure. On the other hand, when the opening degree of the pressure control valve reaches the lower limit value, the flow control valve control unit is configured to execute the first mode, and passes through the flow control valve by executing the first mode. The flow rate of fuel, that is, the amount of fuel supplied to the combustor can be stably controlled.

(4) In some embodiments, in any one of the configurations (1) to (3),
The flow rate control valve control unit is configured to adjust the opening of the flow rate control valve based on a ratio of the measured pressure to the target pressure during execution of the second mode.

  In the fuel control device for the gas turbine having the above configuration (4), the second flow rate control valve is adjusted by adjusting the opening of the flow rate control valve based on the ratio of the measured pressure to the target pressure during the second mode. It is possible to accurately control the flow rate of the fuel, that is, the amount of fuel supplied to the combustor.

(5) In some embodiments, in the configuration (4),
The flow rate control valve control unit is configured to limit the amount of change per unit time of the flow rate control valve opening when the difference between the target pressure and the measured pressure exceeds a threshold value in the second mode. Has been.

  In the fuel control apparatus for a gas turbine having the above configuration (5), when the difference between the target pressure and the measured pressure exceeds the threshold value in the second mode, the amount of change per unit time of the opening of the flow control valve is limited. Is done. For this reason, even when the measured pressure changes greatly, it is possible to suppress a rapid change in the opening degree of the flow rate control valve, and to stably control the amount of fuel supplied to the combustor.

(6) In some embodiments, in the configuration (3),
The upper limit value is larger than the lower limit value, and the mode transition between the first mode and the second mode is performed with hysteresis.

  In the fuel control device for a gas turbine having the above configuration (6), the upper limit value is larger than the lower limit value, and the mode transition between the first mode and the second mode is performed with hysteresis. Therefore, it is suppressed that the mode is frequently changed between the first mode and the second mode. As a result, the amount of fuel supplied to the combustor can be stably controlled.

(7) In some embodiments, in any one of the configurations (1) to (6),
The flow rate control valve control unit is configured to adjust a change amount per unit time of the opening degree of the pressure control valve at the time of transition between the first mode and the second mode.
In the fuel control device for a gas turbine having the above-described configuration (7), when the flow rate control valve control unit shifts between the first mode and the second mode, the amount of change per time of the opening of the pressure control valve Therefore, it is possible to prevent the opening degree of the flow rate control valve from changing suddenly before and after the mode transition between the first mode and the second mode. As a result, the amount of fuel supplied to the combustor can be stably controlled.

(8) In some embodiments, in the configuration (7),
The flow rate control valve control unit is configured to select and execute the second mode when at least one condition is satisfied,
The at least one condition includes a condition relating to a change in pressure of the fuel supplied to the pressure control valve.

  In the fuel control device for a gas turbine having the above-described configuration (8), the flow rate control valve control unit is configured to select and execute the second mode in accordance with a change in the pressure of the fuel supplied to the pressure control valve. If the fluctuation in the pressure of the fuel supplied to the pressure control valve is large while accurately controlling the amount of fuel supplied to the combustor by executing the second mode, the execution of the second mode is limited. can do.

(9) In some embodiments, in any one of the configurations (1) to (8),
The pressure control valve control unit is configured to control the pressure control valve using the measured pressure as the target pressure when the operating condition of the gas turbine varies.

  When the pressure of the fuel supplied to the pressure control valve fluctuates greatly, the pressure adjustment by the pressure control valve cannot catch up, and the difference between the measured pressure and the target pressure may increase. In such a case, when the opening degree of the flow control valve is adjusted based on the target pressure in the first mode, the mode is changed from the first mode to the second mode, and the measured pressure is measured in the second mode. If the opening degree of the flow control valve is adjusted based on the above, the opening degree changes abruptly. In this regard, in the fuel control device for the gas turbine having the above configuration (9), the pressure control valve control unit uses the measured pressure as the target pressure when the pressure of the fuel supplied to the pressure control valve fluctuates greatly. Since the pressure control valve is configured to be controlled, it is possible to suppress a sudden change in the opening of the flow control valve before and after the mode transition between the first mode and the second mode. Can do. As a result, the amount of fuel supplied to the combustor can be stably controlled.

(10) A fuel control method for a gas turbine according to at least one embodiment of the present invention includes:
A pressure regulating valve disposed in the fuel supply path;
A flow rate control valve disposed downstream of the pressure control valve and disposed in the supply path;
A pressure gauge capable of measuring the pressure of the fuel between the pressure control valve and the flow control valve;
A fuel control method for a gas turbine using a fuel control device for a gas turbine capable of controlling a supply amount of fuel to a combustor of the gas turbine, comprising:
Controlling the opening of the flow control valve in one mode selected from a plurality of modes;
The plurality of modes are:
A first mode for adjusting an opening of the flow rate control valve based on a target pressure of the pressure control valve;
A second mode for adjusting the opening of the flow control valve based on the measured pressure;
including.

  In the fuel control method for the gas turbine having the above configuration (10), the first mode and the second mode can be selectively executed. In the second mode, the opening degree of the flow control valve is adjusted based on the measured pressure. Is done. For this reason, even if the pressure of the fuel supplied to the pressure control valve fluctuates and the pressure of the fuel flowing into the flow control valve changes from the target pressure, the flow rate of the fuel passing through the flow control valve based on the measured pressure, That is, the amount of fuel supplied to the combustor can be accurately controlled.

  According to at least one embodiment of the present invention, a fuel control device for a gas turbine capable of accurately controlling the amount of fuel supplied to a combustor even when the pressure of fuel supplied to a pressure control valve changes, and A fuel control method is provided.

1 is a view schematically showing a fuel control device for a gas turbine according to an embodiment of the present invention together with a gas turbine. FIG. It is a figure for demonstrating the structure of the fuel control apparatus which concerns on one Embodiment of this invention. It is a flowchart which shows the schematic procedure of the fuel control method for the gas turbine which concerns on one Embodiment of this invention. It is a graph which shows an example of the conditions regarding the opening degree of the pressure control valve applied to the fuel control method of FIG. It is a flowchart which shows the schematic procedure of the fuel control method for the gas turbine which concerns on other embodiment. 6 is a chart for explaining a restriction on a change rate applied to the fuel control method of FIG. 5. It is a flowchart which shows the schematic procedure of the fuel control method for the gas turbine which concerns on other embodiment. It is a graph which shows an example of the conditions regarding the opening degree of the pressure control valve applied to the fuel control method of FIG. It is a chart which shows an example of the time change of the opening degree of a correction coefficient and a flow control valve when the correction coefficient and change rate of Drawing 8 are used. It is a figure for demonstrating the structure of the fuel control apparatus which concerns on other embodiment. It is a flowchart which shows the schematic procedure of the fuel control method for the gas turbine which concerns on other embodiment. 11 schematically shows temporal changes in the fuel flow rate command, the pressure of the fuel supplied to the pressure control valve, and the measured pressure when the operating conditions of the gas turbine change suddenly during the execution of the fuel control method of FIG. It is a chart. It is a figure for demonstrating the structure of the fuel control apparatus which concerns on other embodiment. It is a flowchart which shows the schematic procedure of the fuel control method for the gas turbine which concerns on other embodiment. 14 schematically shows temporal changes in the fuel flow command, the pressure of the fuel supplied to the pressure control valve, and the measured pressure when the operating conditions of the gas turbine change suddenly during the execution of the fuel control method of FIG. It is a chart.

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 in the embodiments or shown in the drawings are not intended to limit the scope of the present invention, but are merely illustrative examples. Absent.
For example, expressions expressing relative or absolute arrangements such as “in a certain direction”, “along a certain direction”, “parallel”, “orthogonal”, “center”, “concentric” or “coaxial” are strictly In addition to such an arrangement, it is also possible to represent a state of relative displacement with an angle or a distance such that tolerance or the same function can be obtained.
For example, an expression indicating that things such as “identical”, “equal”, and “homogeneous” are in an equal state not only represents an exactly equal state, but also has a tolerance or a difference that can provide the same function. It also represents the existing state.
For example, expressions representing shapes such as quadrangular shapes and cylindrical shapes represent not only geometrically strict shapes such as quadrangular shapes and cylindrical shapes, but also irregularities and chamfers as long as the same effects can be obtained. A shape including a part or the like is also expressed.
On the other hand, the expressions “comprising”, “comprising”, “comprising”, “including”, or “having” one constituent element are not exclusive expressions for excluding the existence of the other constituent elements.

FIG. 1 is a diagram schematically showing a fuel control device 10 according to an embodiment of the present invention together with a gas turbine 1. As shown in FIG. 1, the gas turbine 1 includes a compressor (compression unit) 2, a combustor (combustion unit) 3, and a turbine (turbine unit) 4. For example, an external device such as a generator 6 is provided. To drive.
The compressor 2 sucks and compresses atmospheric air, which is external air, and supplies the compressed air to one or more combustors 3.

The combustor 3 generates high-temperature gas (combustion gas) by burning the fuel supplied from the gas compressor 12 through the fuel control device 10 using the air compressed by the compressor 2.
The turbine 4 receives the supply of the high-temperature gas generated by the combustor 3 to generate a rotational driving force, and outputs the generated rotational driving force to the compressor 2 and an external device.

FIG. 2 is a diagram for explaining the configuration of the fuel control device 10. As shown in FIG. 2, the fuel control device 10 includes a pressure control valve 16 disposed in a fuel (fuel gas) supply passage 14 extending between the gas compressor 12 and the combustor 3, and a downstream of the pressure control valve 16. And a pressure gauge 20 that can measure the fuel pressure in the supply passage 14 between the pressure control valve 16 and the flow control valve 18.
The fuel control device 10 is configured to control the opening degree Opcv of the pressure regulating valve 16 based on the measurement result of the pressure gauge 20 and the flow rate capable of controlling the opening degree Ofcv of the flow rate regulating valve 18. And a control valve control unit 24.

The pressure control valve control unit 22 can control the opening degree Opcv of the pressure control valve 16 so that the measured pressure P2 measured by the pressure gauge 20 approaches the target pressure Pt. The target pressure Pt is, for example, a predetermined value set in advance, and is set based on the operating condition of the turbine 4 and the like.
The flow rate control valve control unit 24 can control the opening degree Ofcv of the flow rate control valve 18 in one mode selected from a plurality of modes. The plurality of modes include a first mode for adjusting the opening degree Ofcv of the flow rate adjusting valve 18 based on the target pressure Pt, and a second mode for adjusting the opening degree Ofcv of the flow rate adjusting valve 18 based on the measured pressure P2. Including.

  In the fuel control device 10 configured as described above, the flow rate control valve control unit 24 can selectively execute the first mode and the second mode. In the second mode, the flow rate control valve 18 is opened based on the measured pressure P2. The degree Ofcv is adjusted. For this reason, even if the pressure of the fuel supplied to the pressure regulating valve 16 fluctuates and the pressure of the fuel flowing into the flow regulating valve 18 changes from the target pressure Pt, it passes through the flow regulating valve 18 based on the measured pressure P2. Thus, the flow rate of the fuel, that is, the amount of fuel supplied to the combustor 3 can be accurately controlled.

In some embodiments, the flow control valve controller 24 is configured to select and execute the second mode when at least one condition is met, where the at least one condition is the pressure control valve 16. Including the opening degree Opcv.
For example, when the pressure of the fuel supplied to the pressure control valve 16 (supply source pressure) decreases and the pressure control valve 16 is fully opened, the pressure control function by the pressure control valve 16 reaches the limit, and the target pressure Pt. It is difficult to bring the measurement pressure P2 close to In this regard, in the fuel control device 10 having the above-described configuration, the flow rate control valve control unit 24 is configured to execute the second mode when the condition regarding the opening degree Opcv of the pressure control valve 16 is satisfied. Even if the pressure control function of the pressure control valve 16 is lowered, the flow rate of the fuel passing through the flow rate control valve 18, that is, the amount of fuel supplied to the combustor 3 can be accurately controlled based on the measured pressure P2. it can.

In some embodiments, the flow rate control valve control unit 24 selects and executes the second mode when the opening Opcv of the pressure control valve 16 reaches the upper limit value Oth1 during execution of the first mode. When the opening degree Opcv of the pressure control valve 16 reaches the lower limit value Oth2 during execution of the second mode, the first mode is selected and executed.
The upper limit value Oth1 and the lower limit value Oth2 may be different from each other, may be the same value (threshold value Oth), or may be different.

  In the fuel control device 10 configured as described above, the flow rate control valve control unit 24 is configured to execute the second mode when the opening degree Opcv of the pressure control valve 16 reaches the upper limit value Oth1, and the pressure control valve Even if the pressure adjustment function by 16 is lowered, the flow rate of the fuel passing through the flow rate adjustment valve 18, that is, the amount of fuel supplied to the combustor 3 can be accurately controlled based on the measured pressure P2. On the other hand, when the opening degree Opcv of the pressure control valve 16 reaches the lower limit value Oth2, the flow control valve control unit 24 is configured to execute the first mode, and the flow control is performed by executing the first mode. The flow rate of the fuel passing through the valve 18, that is, the amount of fuel supplied to the combustor 3 can be stably controlled.

FIG. 3 is a flowchart showing a schematic procedure of a fuel control method for the gas turbine 1 according to an embodiment of the present invention, and FIG. 4 is a pressure control valve 16 applied to the fuel control method of FIG. It is a graph which shows an example of the conditions regarding the opening degree Opcv.
The fuel control method of FIG. 3 is executed when the fuel control device 10 is supplying fuel to the combustor 3, and an opening command correction start determination step for determining the opening Opcv of the pressure control valve 16. S10, an opening command correction step S12 that corrects the opening command Cv of the flow control valve 18, an opening command correction end determination step S14, and an opening command that ends the correction of the opening command Cv of the flow control valve 18 And a correction end step S16.

  In the opening command correction start determination step S10, it is determined whether or not the opening Opcv of the pressure control valve 16 is equal to or greater than a threshold value Oth. When the determination result is negative, the opening degree command correction start determination step S10 is repeated, and the flow rate adjustment valve 18 is controlled in the first mode. On the other hand, when the determination result is affirmative, an opening degree command correction step S12 is executed, and the flow rate adjustment valve 18 is controlled in the second mode.

  Here, the opening degree command (target opening degree) Cv of the flow rate control valve 18 in the first mode can be obtained based on the following equation (1), for example. In equation (1), Cv is a capacity coefficient and corresponds to the opening degree command of the flow rate control valve 18. Therefore, in this specification, the opening degree command of the flow rate control valve 18 is also referred to as Cv. Gf is the flow rate of fuel supplied to the turbine 4 and is determined by the operating conditions of the gas turbine 1. ΔP is a pressure difference between the upstream (inlet) and the downstream (outlet) of the flow control valve 18. The pressure downstream of the flow control valve 18 can be measured by, for example, a pressure gauge (not shown). In the first mode, the target pressure Pt of the pressure control valve 16 is used as the pressure upstream of the flow control valve 18. Equation (1) may further include a term relating to the temperature of the fuel in order to consider the density of the fuel.

  In the opening command correction step S12, as shown in the following equation (2), the opening command Cv is corrected to the corrected opening command Cv '. P2 in the equation (2) is a measured pressure, Pt is a target pressure, and f (x) is a function as a correction coefficient. The function f (x) is a function that changes in the range of 0 to 1 according to the opening Opcv of the pressure control valve 16 (x = Opcv), as shown in FIG. For example, the correction coefficient f (x) is 0 when the opening degree Opcv of the pressure control valve 16 is in the range of 0% to 90%, is proportional to the opening degree Opcv in the range of 90% to 100%, and is 1 at 100%. become.

  According to the equation (2), when the opening degree Opcv of the pressure control valve 16 exceeds 90% which is the threshold value Oth (upper limit value Oth1), the ratio of the measured pressure P2 to the target pressure Pt and the correction coefficient f (x) Based on the above, the opening degree command Cv is corrected, and a corrected opening degree command Cv ′ is obtained. Then, the opening degree Ofcv of the flow rate adjusting valve 18 is adjusted so as to coincide with the corrected opening degree instruction Cv ′. Further, the threshold value Oth is also the lower limit value Oth2, and when the opening degree Opcv of the pressure control valve 16 is 90% or less which is the threshold value Oth, the correction of the opening degree command Cv is finished.

  In the fuel control method of FIG. 3 described above and the fuel control apparatus 10 capable of executing the fuel control method, when the opening degree Opcv of the pressure control valve 16 reaches the threshold value Oth (upper limit value Oth1), the flow rate control valve The control unit 24 is configured to execute the second mode, and even if the pressure adjustment function by the pressure adjustment valve 16 is reduced, the flow rate of the fuel passing through the flow rate adjustment valve 18 based on the measured pressure P2, that is, The amount of fuel supplied to the combustor 3 can be accurately controlled. On the other hand, when the opening degree Opcv of the pressure control valve 16 reaches the threshold value Oth (lower limit value Oth2), the flow rate control valve control unit 24 is configured to execute the first mode, and the execution of the first mode is performed. Thus, the flow rate of the fuel passing through the flow rate adjusting valve 18, that is, the amount of fuel supplied to the combustor 3 can be controlled stably.

  Further, in the fuel control method of FIG. 3 and the fuel control apparatus 10 capable of executing the fuel control method, the opening degree command Cv is corrected when the opening degree Opcv exceeds the threshold value Oth, but as shown in FIG. By adopting a correction coefficient composed of a simple function f (x), the weight of the measurement pressure P2 is continuously changed, so that a rapid change in the opening Ofcv of the flow control valve 18 can be suppressed. . For this reason, the amount of fuel supplied to the combustor 3 can be stably controlled.

  In some embodiments, as illustrated in FIG. 2, the flow rate control valve control unit 24 corrects the opening degree command Cv and the opening degree command calculation unit 26 configured to calculate the opening degree command Cv. It has the opening degree instruction | command correction | amendment part 28 comprised in this way. The opening degree command correction unit 28 includes a correction coefficient setting unit 30 configured to set a correction coefficient, and the correction coefficient setting unit 30 substitutes the opening Opcv of the pressure control valve 16 into the function f (x). By doing so, the correction coefficient can be set. Note that the opening degree Opcv of the pressure control valve 16 used in the correction coefficient setting unit 30 may be either a set value or a measured value. And the flow control valve control part 24 has the flow control valve operation part 32, and the flow control valve operation part 32 adjusts the opening degree Ofcv of the flow control valve 18 based on the opening degree command Cv in the 1st mode. In the second mode, the opening degree Ofcv of the flow control valve 18 is adjusted based on the corrected opening degree instruction Cv ′.

In some embodiments, as shown in FIG. 2, the pressure control valve control unit 22 has a feedback function, and is a subtractor configured to calculate a deviation between the target pressure Pt and the measured pressure P2. Based on the operation amount calculated by the operation amount calculation unit 36 and the operation amount calculation unit 36 configured to calculate the operation amount of the pressure control valve 16 based on the deviation obtained by the subtractor 34. And a pressure control valve operating section 38 for operating the pressure control valve 16.
For example, the pressure control valve operation unit 38 and the flow rate control valve operation unit 32 are configured by actuators, and the pressure control valve control unit 22 and the flow rate control valve control unit 24 except for the pressure control valve operation unit 38 and the flow rate control valve operation unit 32. The part is constituted by a computer.

  FIG. 5 is a flowchart illustrating a schematic procedure of a fuel control method for the gas turbine 1 according to another embodiment, and FIG. 6 illustrates a change rate limitation applied to the fuel control method of FIG. It is a chart for doing. The fuel control method of FIG. 5 is a modification of the control method of FIG. 3, and further includes a change rate setting determination step S18 and a change rate setting step S20 when compared with the control method of FIG.

  In change rate setting determination step S18, it is determined whether or not a change rate needs to be set. Specifically, it is determined whether or not the absolute value of the deviation between the target pressure Pt and the measured pressure P2 is larger than a predetermined change width ΔPth. The change width ΔPth is set based on, for example, the necessary minimum pressure of the turbine 1 or an interlock value that causes the gas turbine 1 to stop urgently.

When the determination result of the change rate setting determination step S18 is affirmative, the change rate setting step S20 is executed. In the change rate setting step, a change rate is set. The change rate is an upper limit value of the change amount of the opening degree Ofcv of the flow rate control valve 18 per unit time. When the change rate is set in the change rate setting step S20, the corrected opening degree command Cv ′ is further corrected so that the amount of change per unit time of the opening degree Ofcv of the flow rate control valve 18 does not exceed the changing rate.
On the other hand, when the determination result of the change rate setting determination step S18 is negative, the change rate setting step S20 is not executed and the change rate is not set. For this reason, the opening degree Ofcv of the flow control valve 18 is controlled based on the corrected opening degree instruction Cv ′.

  In some embodiments, as shown in FIG. 2, the opening degree command correction unit 28 of the fuel control device 10 further includes a change rate setting unit 40, and the change rate setting unit 40 performs the change rate setting determination step S <b> 18. And it is comprised so that change rate setting step S20 may be performed.

In the fuel control method of FIG. 5 and the fuel control apparatus 10 capable of executing the fuel control method described above, in the second mode, when the difference between the target pressure Pt and the measured pressure P2 exceeds the threshold change width ΔPth. The amount of change (change rate) per unit time of the opening degree Ofcv of the flow control valve 18 is limited. For this reason, even when the measured pressure P2 changes greatly, a rapid change in the opening degree Ofcv of the flow rate control valve 18 can be suppressed, and the amount of fuel supplied to the combustor 3 can be stably controlled. .
The change rate (upper limit value of the change rate) set in the change rate setting step S20 can be obtained in advance by simulation or the like.

FIG. 7 is a flowchart showing a schematic procedure of the fuel control method for the gas turbine 1 according to another embodiment, and FIG. 8 shows the opening of the pressure control valve 16 applied to the fuel control method of FIG. It is a graph which shows an example of the conditions regarding degree Opcv.
In the fuel control method of FIG. 7, a function f (x) different from that of FIG. 4 is used in the opening degree command correction step S12. FIG. 8 schematically shows a function f (x) used in the control method of FIG. 7. In the function f (x) of FIG. 8, the opening command correction start determination step S10 and the opening command correction end determination are performed. The upper limit value Oth1 and the lower limit value Oth2 used in step S14 are different from each other. The upper limit value Oth1 is larger than the lower limit value Oth2, and the function f (x) is 0 when the opening degree Opcv of the pressure control valve 16 is 0% to 90%, and 1 when it is 80% to 100%. Hysteresis is drawn in the range of 80% to 90%.

  According to the fuel control method shown in FIG. 7 and the fuel control apparatus 10 capable of executing the fuel control method, the upper limit value Oth1 is larger than the lower limit value Oth2, and between the first mode and the second mode with hysteresis. Therefore, frequent changes in the mode are suppressed. As a result, the amount of fuel supplied to the combustor 3 can be stably controlled.

In some embodiments, as shown in FIG. 7, the fuel control method further includes a change rate setting step S22. In this case, the opening Ofcv of the flow rate control valve 18 is changed at the change rate set in the change rate setting step S22.
In the fuel control method shown in FIG. 7 and the fuel control apparatus 10 capable of executing the fuel control method, the opening degree Ofcv of the flow rate control valve 18 changes during the transition between the first mode and the second mode. The rate is changed slowly corresponding to the predetermined change rate set in the rate setting step S22. As a result, a rapid change in the opening degree Ofcv of the flow rate control valve 18 is suppressed, and the amount of fuel supplied to the combustor 3 can be controlled stably.

The change rate setting step S22 may be executed before the opening degree command correction step S12. Further, the change rate when the opening degree Ofcv increases and the change rate when it decreases may be the same or different from each other. Alternatively, the change rate in the opening command correction step S12 and the change rate in the opening command correction end step S16 may be the same or different from each other. The change rate (upper limit value of the change rate) set in the change rate setting step S22 can be obtained in advance by simulation or the like.
The change rate setting step S22 is performed by the change rate setting unit 40, for example.

  Here, FIG. 9 is a chart showing an example of a temporal change of the correction coefficient f (x) and the opening degree Ofcv of the flow rate control valve 18 when the correction coefficient and the change rate of FIG. 8 are used. In the example of FIG. 9, with the start of the second mode, the opening degree Ofcv of the flow control valve 18 gradually changes according to the change rate from the opening degree Ofcv1 in the first mode to the opening degree Ofcv2 in the second mode. Along with the end of the second mode, the opening degree Ofcv2 in the second mode gradually changes from the opening degree Ofcv1 in the first mode according to the change rate.

  FIG. 10 schematically shows the configuration of a fuel control apparatus 10 according to another embodiment. FIG. 11 shows a schematic procedure of a fuel control method that can be executed by the fuel control apparatus 10 of FIG. FIG. 12 is a chart for explaining the operation of the fuel control device of FIG.

In some embodiments, the flow control valve controller 24 is configured to select and execute the second mode when at least one condition is met, where the at least one condition is the pressure control valve 16. The conditions regarding the fluctuation of the pressure of the fuel supplied to are included.
The information on the fluctuation of the fuel pressure is, for example, information on a trip of the gas compressor 12, a runback (output reduction) of the gas turbine 1, or a frequency fluctuation in the power network to which the generator 6 is connected. Such information is input to the fuel control apparatus 10 as an operating condition sudden change command, for example, as shown in FIG.

  The fuel control method of FIG. 11 differs from the fuel control method of FIG. 7 in that it further includes operating condition sudden change determination steps S30 and S32. In each operation condition sudden change determination step S30 and S32, it is determined whether or not an operation condition sudden change command has been input. The operating condition sudden change determination step S30 is performed during execution of the first mode, and the operating condition sudden change determination step S32 is performed during execution of the second mode.

During execution of the first mode, when the determination result of the operating condition sudden change determination step S30 is affirmative, that is, when the pressure of the fuel supplied to the pressure control valve 16 is changing or is about to change Transition to the second mode is prohibited.
On the other hand, if the determination result of the operating condition sudden change determination step S32 is affirmative during execution of the second mode, the opening command correction end determination step S14 is skipped, and the opening command correction end step S16 is performed. That is, when the determination result of the operating condition sudden change determination step S32 is affirmative, the correction of the opening degree command Cv is ended regardless of the opening degree Ofcv of the flow rate control valve 18.
When the correction of the opening degree command Cv is completed, the opening degree Ofcv is changed according to a predetermined change rate.

  In the fuel control method of FIG. 11 and the fuel control apparatus 10 capable of executing the fuel control method, the flow rate control valve control unit 24 is in the second mode according to the fluctuation of the pressure of the fuel supplied to the pressure control valve 16. The pressure of the fuel supplied to the pressure control valve 16 is greatly varied while accurately controlling the amount of fuel supplied to the combustor 3 by executing the second mode. In some cases, execution of the second mode can be restricted.

Here, FIG. 12 is supplied to the fuel flow rate command and the pressure control valve 16 when the operating condition of the gas turbine 1 suddenly changes during the execution of the fuel control method of FIG. 11, for example, when the gas compressor 12 trips. It is a chart which shows roughly change with time of fuel pressure P1 and measurement pressure P2.
As shown in FIG. 12, when the operating condition of the gas turbine 1 changes suddenly during execution of the first mode and the fuel flow rate command decreases rapidly, the second mode is not executed. Alternatively, when the operating condition of the gas turbine 1 changes suddenly during execution of the second mode, the mode is shifted from the second mode to the first mode.

  As shown in FIG. 12, when the operating condition of the gas turbine 1 changes suddenly, if the execution of the second mode is limited, the opening degree Ofcv of the flow control valve 18 is suppressed from becoming excessively large. For this reason, the fuel pressure drop at the outlet of the flow control valve 18 is suppressed. Thereby, the emergency stop of the gas turbine 1 by the pressure drop of the fuel at the exit of the flow control valve 18 can be prevented.

In some embodiments, as shown in FIG. 10, the fuel control device 10 further includes a pressure gauge 42 that can measure the pressure of the fuel supplied to the pressure control valve 16.
In this case, the fuel control device 10 can perform the operation condition sudden change determination steps S30 and S32 based on the fuel pressure P1 measured by the pressure gauge 42 instead of the operation condition sudden change command.

  FIG. 13 schematically shows the configuration of the fuel control apparatus 10 according to another embodiment. FIG. 14 shows a schematic procedure of a fuel control method that can be executed by the fuel control apparatus 10 of FIG. FIG. 15 is a chart for explaining the operation of the fuel control device 10 of FIG.

  In some embodiments, the pressure control valve control unit 22 of the fuel control device 10 further includes a target pressure correction unit 44 that corrects the target pressure Pt. The target pressure correction unit 44 is configured to use the measured pressure P2 as the target pressure Pt when the operating condition of the gas turbine 1 changes.

  14 has a schematic procedure of a fuel control method that can be executed by the fuel control apparatus 10 of FIG. 13. The fuel control method of FIG. 14 is a target when compared with the fuel control method of FIG. The pressure correction step S34, the target pressure correction execution determination step S36, the operation condition recovery determination step S38, and the target pressure correction end step S40 are further included, and the operation condition sudden change determination step S32 is not included.

In the fuel control method of FIG. 14, during the execution of the first mode, when the determination result of the operating condition sudden change determination step S30 becomes affirmative, the target pressure correction step S34 is executed. In the target pressure correction step S34, the target pressure Pt is corrected. Specifically, the measured pressure P2 is adopted as the target pressure Pt, and the target pressure Pt is corrected so as to follow or match the measured pressure P2. Based on the corrected target pressure Pt ′, the opening degree Opcv of the pressure regulating valve 16 is controlled, while the opening degree Ofcv of the flow rate regulating valve 18 is controlled.
Specifically, the corrected target pressure Pt ′ is used instead of the target pressure Pt when calculating the capacity coefficient Cv using the above-described equation (1).

In the target pressure correction execution determination step S36, it is determined whether or not the target pressure Pt is corrected. When the determination result of the target pressure correction execution determination step S36 is negative, the operating condition sudden change determination step S30 is executed. When the determination result is positive, the operation condition recovery determination step S38 is executed.
In operating condition recovery determination step S38, it is determined whether or not the operating conditions of the gas turbine 1 have recovered. When the determination result of the operation condition recovery determination step S38 is negative, the operation condition sudden change determination step S30 is executed. When the determination result is affirmative, the target pressure correction end step S40 is performed.
In the target pressure correction end step S40, the correction of the target pressure Pt is ended, the pressure control valve 16 is controlled using the uncorrected target pressure Pt, and the capacity coefficient Cv is calculated by the above equation (1).

  When the pressure of the fuel supplied to the pressure control valve 16 greatly fluctuates due to a sudden change in the operating conditions of the gas turbine 1, the pressure adjustment by the pressure control valve 16 cannot catch up, and the difference between the measured pressure P2 and the target pressure Pt is large. May be. In such a case, when the opening degree Ofcv of the flow control valve 18 is adjusted based on the target pressure Pt in the first mode, the mode is changed from the first mode to the second mode, and the mode is changed to the second mode. If the opening degree Ofcv of the flow rate control valve 18 is adjusted based on the measured pressure, the opening degree Ofcv changes abruptly.

  In this regard, according to the fuel control method of FIG. 14 and the fuel control apparatus 10 capable of executing the fuel control method, when a sudden change in the operating conditions of the gas turbine 1 is detected, the measured pressure P2 is set as the target pressure Pt. The pressure control valve 16 is used to control the opening degree command of the flow rate control valve 18, so that the flow rate is changed before and after the mode transition between the first mode and the second mode. A sudden change in the opening degree Ofcv of the control valve 18 can be suppressed. As a result, the amount of fuel supplied to the combustor 3 can be stably controlled.

Here, FIG. 15 is supplied to the fuel flow rate command and the pressure control valve 16 when the operating condition of the gas turbine 1 suddenly changes during the execution of the fuel control method of FIG. 14, for example, when the gas compressor 12 trips. It is a chart which shows roughly change with time of fuel pressure P1 and measurement pressure P2.
As shown in FIG. 15, during the execution of the first mode, when the operating condition of the gas turbine 1 changes suddenly and the fuel flow rate command suddenly decreases, the target pressure Pt is corrected to Pt ′. By correcting the opening degree command Cv calculated using the corrected target pressure Pt ′ in the same manner as in the fuel control method of FIG. 3 or FIG. 5, the opening degree Ofcv of the flow rate control valve 18 changes rapidly. The amount of fuel supplied to the combustor 3 can be stably controlled while suppressing this.

  The present invention is not limited to the above-described embodiments, and includes forms obtained by changing the above-described embodiments and forms obtained by combining these forms.

1 Gas Turbine 2 Compressor 3 Combustor 4 Turbine 6 Generator (External Equipment)
DESCRIPTION OF SYMBOLS 10 Fuel control apparatus 12 Gas compressor 14 Supply path 16 Pressure control valve 18 Flow control valve 20 Pressure gauge 22 Pressure control valve control part 24 Flow control valve control part 26 Opening degree command calculating part 28 Opening degree command correction part 30 Correction coefficient setting part 32 Flow control valve operation unit 34 Subtractor 36 Operation amount calculation unit 38 Pressure control valve operation unit 40 Change rate setting unit 42 Pressure gauge 44 Target pressure correction unit

Claims (10)

In a fuel control device for a gas turbine capable of controlling the amount of fuel supplied to a combustor of a gas turbine,
A pressure control valve disposed in the fuel supply path;
A flow rate control valve disposed downstream of the pressure control valve and disposed in the supply path;
A pressure gauge capable of measuring the pressure of the fuel between the pressure control valve and the flow control valve;
A pressure control valve controller capable of controlling the opening of the pressure control valve based on the measurement result of the pressure gauge;
A flow control valve controller capable of controlling the opening of the flow control valve;
Including
The pressure control valve control unit is capable of controlling the opening of the pressure control valve so that the measured pressure measured by the pressure gauge approaches a target pressure,
The flow rate control valve control unit can control the opening degree of the flow rate control valve in one mode selected from a plurality of modes,
The plurality of modes are:
A first mode for adjusting the opening of the flow rate control valve based on the target pressure;
A second mode for adjusting the opening of the flow control valve based on the measured pressure;
A fuel control device for a gas turbine, comprising: The flow rate control valve control unit is configured to select and execute the second mode when at least one condition is satisfied,
The fuel control apparatus for a gas turbine according to claim 1, wherein the at least one condition includes a condition related to an opening degree of the pressure control valve. The flow control valve control unit is
The second mode is selected and executed when the opening of the pressure control valve reaches an upper limit during execution of the first mode, and
The first mode is selected and executed when the opening degree of the pressure control valve reaches a lower limit during execution of the second mode. A fuel control device for a gas turbine according to claim 1. The flow rate control valve control unit is configured to adjust an opening degree of the flow rate control valve based on a ratio of the measured pressure to the target pressure during the execution of the second mode. A fuel control device for a gas turbine according to any one of claims 1 to 3. The flow rate control valve control unit is configured to limit the amount of change per unit time of the flow rate control valve opening when the difference between the target pressure and the measured pressure exceeds a threshold value in the second mode. The fuel control device for a gas turbine according to claim 4, wherein the fuel control device is a gas turbine. The gas according to claim 3, wherein the upper limit value is larger than the lower limit value, and mode transition between the first mode and the second mode is performed with hysteresis. Fuel control device for turbine.   The flow rate control valve control unit is configured to adjust a change amount per unit time of an opening degree of the pressure control valve at the time of transition between the first mode and the second mode. The fuel control device for a gas turbine according to any one of claims 1 to 6, wherein the fuel control device is for a gas turbine. The flow rate control valve control unit is configured to select and execute the second mode when at least one condition is satisfied,
The fuel control for a gas turbine according to any one of claims 1 to 7, wherein the at least one condition includes a condition related to a change in pressure of the fuel supplied to the pressure control valve. apparatus. The pressure control valve control unit is configured to control the pressure control valve using the measured pressure as the target pressure when an operating condition of the gas turbine fluctuates. Item 9. A fuel control device for a gas turbine according to any one of Items 1 to 8. A pressure regulating valve disposed in the fuel supply path;
A flow rate control valve disposed downstream of the pressure control valve and disposed in the supply path;
A pressure gauge capable of measuring the pressure of the fuel between the pressure control valve and the flow control valve;
A fuel control method for a gas turbine using a fuel control device for a gas turbine capable of controlling a supply amount of fuel to a combustor of the gas turbine, comprising:
Controlling the opening of the flow control valve in one mode selected from a plurality of modes;
The plurality of modes are:
A first mode for adjusting an opening of the flow rate control valve based on a target pressure of the pressure control valve;
A second mode for adjusting the opening of the flow control valve based on the measured pressure measured by the pressure gauge ;
A fuel control device for a gas turbine, comprising:

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