JPH07166891A - Gas turbine control device - Google Patents

Abstract

PURPOSE:To sufficiently display a NOx reducing effect by preventing instability of switching action for opening/closing a valve when fuel is switched, and suppressing an error to a minimum limit of a distribution characteristic of fuel. CONSTITUTION:A fuel control valve 20 is provided in a fuel supply path 5, the downstream of this valve branches to first/second supply paths 21, 22, the first/second fuel distributing valves 23, 24 are interposed respectively in these first/second supply paths 21, 22, the first supply path 21 in the downstream of this first fuel distributing valve 23 is connected to a diffusion fuel system and pilot premixing fuel system at high load time of a combustor 4, a three-way switching valve 25 is interposed in the second supply path 22 in the downstream of the second fuel distributing valve 24, and two downstream branch paths of this three-way switching valve 25 are respectively connected to a diffusion fuel system and main fuel system at the time of low load of the combustor.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas turbine control device equipped with a low NOx combustor applied to a power plant or the like, and more specifically, to prevent instability of switching operation of valve opening / closing at fuel switching. The present invention relates to a gas turbine control device capable of sufficiently exerting a NOx reduction effect by suppressing an error in fuel distribution characteristics to a minimum.

[0002]

2. Description of the Related Art Conventionally, light oil, as gas turbine fuel,
Although liquid fuels such as kerosene have been frequently used, in recent years, from the viewpoint of diversified utilization of energy resources, etc., these liquid fuels have been replaced with gasses such as vaporized liquefied natural gas (LNG) and liquefied propane gas (LPG). More and more fuel is being used.

Further, with respect to gas turbines, social demands for pollution control and environmental measures are increasing, and in particular, there is an urgent need to suppress nitrogen oxides (NOx) generated from a combustor of a gas turbine. It is known that the generation of NOx is caused by an increase in combustion temperature including local combustion in the combustor of the gas turbine. Hitherto, a means for injecting water or steam into the combustor has been adopted, thereby reducing the local fuel temperature and reducing NOx. However, by means of water injection, steam injection, etc., the combustion temperature as an average temperature in the combustor decreases, and as a result,
There is a drawback that the combustion efficiency deteriorates and the thermal efficiency of the gas turbine decreases.

Under these circumstances, in recent years, as a combustor of a gas turbine, instead of means such as water injection or steam injection,
A low NOx combustor that can reduce NOx while maintaining the thermal efficiency of the gas turbine has been attracting attention because it has a configuration that sucks gas fuel not only from the combustor inlet side but also from the wake side. There is.

As described above, in the low NOx type combustor, the gas fuel is sucked not only from the inlet side of the combustor but also from the wake side, so that the fuel distribution in the combustor is made uniform,
Local high temperature can be prevented. As a result, not only can low NOx be realized, but also as in the case of using water injection or steam injection, the combustion temperature must be kept as low as possible without lowering the combustion temperature. You can

First, referring to FIG. 4, such a low NO
A control device for a gas turbine in a gas turbine power generation system including an x-type combustor will be described.

As shown in FIG. 4, the compressor 1, the gas turbine 2, and the generator 3 are coaxially arranged. Fuel is injected into the combustor 4, the fuel mixed with the air compressed by the compressor 1 and burned, and the combustion gas drives the gas turbine 2 to rotate.

In order to supply fuel to the combustor 4, a single fuel supply pipe 5 led from a gas fuel supply source (not shown).
Through the fuel stop valve 6, the four branch pipes 7a, 7b,
7c, 7d are branched into 4 systems, and then each branch pipe 7
4 of the combustor 4 via fuel control valves 8a, 8b, 8c, 8d for controlling the fuel flow rates of a, 7b, 7c, 7d.
It is connected to one fuel system A, B, C, D.

Fuel systems A, B, C, D of these combustors 4
Is configured as shown in FIG. 5, and inflow of gas fuel is performed as follows.

That is, the fuel system A is for low load diffusion fuel, and as shown in FIG.
It is supplied from the center of the combustor 4 through the fuel system A, and only this fuel is used from the start of the gas turbine to the rated rotation speed, and thereafter, it is unnecessary in the low load region as the load increases due to the combination. It

The fuel system B is for a high load diffusion fuel, and this fuel is a low load diffusion fuel (fuel system A).
The fuel is supplied from the outer periphery of the gas turbine, and is mainly supplied to maintain the ignition source in the combustor after the gas turbine is installed.

The fuel system C is for the pilot premixed fuel, and this fuel is the fuel supplied from the further outer periphery of the high load diffusion fuel, and in order to realize the low NOx combustion, the compressor is previously prepared. The mixed gas premixed with the discharge air from No. 1 is supplied into the combustor.

The fuel system D is for the main fuel, which is fuel supplied from the outer periphery of the main body of the combustor 4, and has a low NO like the pilot premixed fuel.
x is a fuel for realizing combustion. Also in this, as shown in FIG. 5, the mixed gas premixed with the discharge air from the compressor 1 is supplied into the combustor 4. Since it is possible to obtain the most uniform flow of the mixed gas in the combustor 4, the main fuel ratio is the highest during the gas turbine rated load operation.

Next, the operation of the gas turbine and the injection of gas fuel into the gas turbine will be described.

When the turbine is operated, first, the gas turbine 2 is started to rotate by a starter (not shown) such as a motor arranged coaxially with the gas turbine 2. At the time when the air purge in the gas turbine 2 by the compressor 1 is completed, the fuel stop valve 6 is opened, the fuel control valve 8a is opened according to a fuel injection schedule described later, and the gas fuel is combusted by the combustor 4
It is supplied to the most upstream part of and is ignited. After ignition, the gas turbine 2 is accelerated after warming up for a certain period of time, and after reaching the rated speed, the gas turbine 2 is operated in parallel with the power system, and the load is increased to reach the rated load. During this time, the gas turbine 2
The flow rate of the gas fuel flowing into the combustor 4 of the
It is controlled by a, 8b, 8c and 8d. That is, the fuel control valves 8a, 8b, 8c, 8d are used to control the gas turbine 2
The fuel flow rate required for the speed control and the load control is controlled.

The flow rate control range required for each operation of the gas turbine 2 is a very wide range of fuel flow rate control from an extremely small flow rate during ignition and warm-up to a large flow rate during rated load operation. Is required. Therefore, the opening of the fuel control valves 8a, 8b, 8c, 8d is extremely small in the low rotation speed and low flow rate region such as during ignition and warm-up operation, and as a result, control becomes unstable. Sometimes. In order to avoid this control instability, the fuel stop valve 6 is provided with a control function such that the pressure of the fuel on the downstream side of the fuel stop valve 6 is proportional to the number of revolutions of the gas turbine. By keeping the fuel pressure upstream of the control valves 8a, 8b, 8c, 8d low, the operation is performed such that the opening of the fuel control valves 8a, 8b, 8c, 8d is set to be sufficiently large, and the control is performed. The instability of can be avoided.

Next, the fuel injection to the load of the gas turbine 2 will be described with reference to FIG.

The gas turbine 2 is operated only by the fuel supply from the low load diffusion fuel system A until the ignition and the rated speed are reached. During this period, the fuel control valves 8b, 8c of the other fuel systems B, C and D are operated. 8d is fully closed.

As the speed of the gas turbine 2 increases and approaches the rated speed no-load operation, the NOx concentration also sharply increases as shown in FIG. 7 (III). Therefore, the fuel system A for low-load diffusion fuel is narrowed down immediately after the gas turbine is installed, and instead the fuel system B for high-load diffusion fuel, the fuel system C for pilot premixed fuel, and the fuel system D for main fuel are gradually introduced. To be done. The fuel injection schedule is
As shown in FIG. 7 (III), it is determined corresponding to the NOx amount generated according to the load confirmed in advance by a test or the like. The fuel injection schedule after the merger will be described below with reference to FIGS. 7 (I) and (II).

(A) Immediately after the merger (area (a)), as shown in FIG. 7 (III), the NOx generation amount increases sharply immediately after this merger, so that the fuel system of the low load diffusion fuel is increased. A is narrowed down, and the fuel system C of the pilot premixed fuel is mainly used, and the fuel system B of the high load diffusion fuel and the fuel system C of the pilot premixed fuel are injected.

(B) Since the amount of NOx generated further increases during the period immediately after the merger to the low load region (region (b)),
The fuel system A for low load diffusion fuel is increased, the fuel system B for high load diffusion fuel and the fuel system C for pilot premixed fuel
Is narrowed down.

(C) Between the low load region and the intermediate load region (region (c)), when the load is further increased in region (b), as shown in FIG. 7 (III), Since the NOx amount rapidly increases, the fuel system D for the main fuel and the fuel system A for the low load diffusion fuel are switched so as to operate in reverse. That is, during this period, the fuel system A of the low-load diffusion fuel is narrowed down to the fully closed state, and conversely, the operation is switched to the operation mainly of the fuel system D of the main fuel.

(D) After the intermediate load area ((d) area),
Mainly the main fuel (D) is mainly used, and as shown in FIG. 7 (II), the flow ratio of the fuel system D of the main fuel is gradually increased, while the fuel system B of the high load diffusion fuel and the pilot system The fuel system C of the mixed fuel is gradually reduced, or the flow ratios of the fuel system D of the main fuel, the fuel system B of the high-load diffusion fuel, and the fuel system C of the pilot premixed fuel are both applied at substantially the same ratio. There is.

The above is the typical fuel injection schedule corresponding to the load of the gas turbine and the distribution method according to the fuel injection schedule. However, these may be appropriately changed depending on the operating condition of the gas turbine. Due to
Optimal low NOx combustion is realized.

Next, a conventional control circuit for controlling the fuel control valve will be described with reference to FIG.

In this control circuit, the fuel control valves 8a-8d are used.
Thus, the speed and load of the gas turbine are controlled, and at the same time, the distribution control of each of the low load diffusion A, the high load diffusion B, and the pilot premixing C main D is performed. Therefore, the function generator 11 is provided, and the function generator 1
1, the total valve opening of the fuel control valves 8a to 8d is 1
3 is set according to the load signal X of the turbine.
Furthermore, a function generator 12 is provided, and this function generator 1
2, the gas turbine load signal X shown in FIG.
The distribution ratios 103A to 103D corresponding to are output.
The signal from the function generator 11 and the signal from the function generator 12 are multiplied by the multipliers 15a, 15b, 15c and 15d to set the valve opening degree of each of the fuel control valves 8a, 8b, 8c and 8d. ing. That is, regardless of the value of the gas turbine load signal X, the fuel control valves 8a to 8d
The total valve opening of is the valve opening 13 set by the function generator 11 according to the gas turbine load signal X,
Moreover, the total valve opening 13 is set by the function generator 12 so that the fuel flow rate ratio 14 shown in FIG.
a, 14b, 14c, 14d are distributed.

[0027]

As described above, in the conventional control circuit, the fuel control valves 8a to 8d allow
The speed and load of the gas turbine are controlled, and the distribution control of each fuel system, which is very complicated, is performed.

Therefore, first, when the fuel is switched as the load of the gas turbine rises or falls, the opening and closing of the fuel control valves 8a to 8d are switched. However, due to this switching operation of opening and closing, the front and rear pressures of the fuel control valves 8a to 8d fluctuate, and the load is likely to fluctuate accordingly. As a result, the load fluctuation adversely affects the switching operation and the switching operation is controlled. Instability may result.

Secondly, when the differential pressure across the fuel control valves 8a to 8d is large, a choked fuel flow is obtained in each of the fuel control valves 8a to 8d. However, for example, when the load on the gas turbine increases, the discharge pressure from the compressor 1 increases, and the differential pressure across the fuel control valves 8a to 8d decreases, a choked flow cannot be obtained. As a result, in order to obtain a predetermined gas fuel flow rate, there is a risk that the opening of each valve will be insufficient and load control will become impossible. For example, in FIG. 7 (II), this is the case of the gas turbine high load region where the main side fuel ratio is high.

Third, each fuel control valve 8a-8d.
In consideration of the above hardware, the actual flow rate characteristic with respect to the actual opening degree of each valve is not necessarily linear, but has a convex upward characteristic and a downward concave characteristic. Moreover, the valves have different valve shapes, valve seat shapes, and the like. As a result, even if the valves have the same specifications, the characteristics, the shape of the flow rate curve, the flow rate coefficient, etc. are different for each valve device.
On the other hand, in the conventional control circuit, the flow rate is corrected with respect to the valve opening degree of each valve. However, even if the flow rate correction is performed, it is difficult to linearly correct the flow rate characteristic with respect to the valve position setting signal as described above. Moreover, in the conventional case, the four fuel control valves 8a ...
Since 8d is used, all fuel control valves 8a-8
When the error of d is accumulated, the error of the control characteristic of the gas turbine and the fuel distribution characteristic becomes large, and the predetermined NO
The x reduction effect may not be obtained.

The object of the present invention was made in view of the above-mentioned circumstances, and it is possible to prevent instability of the switching operation of the opening and closing of the valve at the time of fuel switching and to suppress the error of the fuel distribution characteristic to the minimum. The purpose of the present invention is to provide a gas turbine control device that can sufficiently exert the NOx reduction effect.

[0032]

[Means for Solving the Problems] To achieve this purpose,
A gas turbine control device according to claim 1 of the present invention is a gas turbine provided with four fuel systems: a diffusion fuel system at low load, a diffusion fuel system at high load, a pilot premix fuel system, and a main fuel system. A gas turbine control device for controlling the supply of fuel to a combustor of a vehicle, wherein a fuel control valve having a gas turbine speed / load control function is provided in the fuel supply passage, and the fuel supply passage downstream of the fuel control valve is provided. To a first supply path and a second supply path, and a first fuel distribution valve and a second fuel distribution valve are provided in the first supply path and the second supply path, respectively. The first supply path downstream of
The combustor is connected to the diffusion fuel system and the pilot premixed fuel system under high load, and the three-way switching valve is provided in the second supply passage downstream of the second fuel distribution valve. The downstream branch paths are connected to the diffusion fuel system and the main fuel system, respectively, when the combustor has a low load.

Further, in the gas turbine control apparatus according to the second aspect, the ratio of the fuel flow rate supplied to the first supply path to all the fuel flow rate supplied is (m), and the fuel is supplied to the second supply path. The ratio of the fuel flow rate to be set is (1-m),
When (m) + (1-m) = 1, the flow rate ratio (m) is determined based on a predetermined function by receiving the gas turbine speed / load control signal, and the valve opening corresponding to this flow rate ratio (m) is performed. A first function generator for sending a fuel flow signal to the first fuel distribution valve, receiving a valve opening signal to calculate a flow rate ratio (1-m), and opening a valve corresponding to this flow rate ratio (1-m). An arithmetic unit for sending the fuel flow rate signal to the second fuel distribution valve, receiving the gas turbine speed / load control signal, and determining the ratio of the fuel flow rate of the two downstream branch passages of the three-way switching valve based on a predetermined function, It is characterized in that a second function generator for sending a valve position signal corresponding to this flow rate ratio to the three-way switching valve is provided.

[0034]

As described above, according to the first aspect of the present invention, the fuel control valve for performing the gas turbine / load control, the fuel distribution valve for distributing the fuel to the four fuel systems of the combustor, and the three-way switching valve are provided. Are provided independently. Therefore, even if a load change or the like occurs during the fuel switching operation, the load change or the like is controlled by the fuel control valve, while the fuel switching operation is performed by the fuel distribution valve and the three-way switching valve. Therefore, the switching operation of opening / closing the valve at the time of fuel switching does not become unstable.

Regarding fuel distribution, it is not necessary to perform complicated control by four fuel control valves for each of the four fuel systems as in the conventional case, and all fuel is divided into two and distributed. The fuel distribution control is performed by the simple control of the first and second fuel distribution valves and the three-way switching valve that only performs the switching operation. Therefore, the error of the fuel distribution characteristic can be suppressed to the minimum and the NOx reduction effect can be sufficiently exerted.

Further, as described in claim 2, the first function generator and the arithmetic unit control the fuel flow rate ratios of the first and second fuel distribution valves, and the second function generator controls the fuel flow rate. The valve position of the flow rate of the three-way switching valve is controlled. Therefore, the fuel distribution control is realized by a simple control circuit configuration.

[0037]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A gas turbine controller according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing a fuel supply circuit and a control circuit of a gas turbine controller according to an embodiment of the present invention. The same members as those in the related art are designated by the same reference numerals.

As shown in FIG. 1, the compressor 1, the gas turbine 2, and the generator 3 are coaxially arranged. The fuel system of the combustor 4, as shown in FIG. 5, is a fuel system A for diffusion fuel at low load, a fuel system B for diffusion fuel at high load, and a fuel system C for pilot premixed fuel. , And a fuel system D for the main fuel.

Next, in the fuel supply path 5 to the combustor 4, a fuel stop valve 6 is provided on the upstream side, and a fuel control having a gas turbine speed / load control function is provided on the downstream side. The valve 20 is interposed. A fuel supply passage downstream of the fuel control valve 20 is branched into a first supply passage 21 and a second supply passage 22. A first fuel distribution valve 23 and a second fuel distribution valve 24 are provided in the first supply path 21 and the second supply path 22, respectively. Further, this first fuel distribution valve 2
The first supply path 21 downstream of 3 is branched and connected to the diffusion fuel system B and the pilot premix fuel system C when the combustor 4 is under high load. Further, a three-way switching valve 25 is provided in the second supply passage 22 downstream of the second fuel distribution valve 24. The two downstream branch passages of the three-way switching valve 25 are connected to the diffusion fuel system and the main fuel system when the combustor 4 has a low load.

Further, the control circuit is constructed as shown in FIG. First for all fuel flows delivered
The ratio of the fuel flow rate supplied to the supply path 21 is (m), and the ratio of the fuel flow rate supplied to the second supply path 22 is (1
-M) is set. That is, the distribution ratio of the first supply path 21 is set to (m), and the distribution ratio of the second supply path 22 is set to (1-m).

Upon receiving the gas turbine speed / load control signal X, the distribution ratio (m) is determined based on a predetermined function, and the valve opening signal corresponding to this distribution ratio (m) is sent to the first fuel distribution valve 2
There is provided a first function generator 26 which sends to The distribution ratio (m) is set as the sum of the flow rate of the fuel system B and the flow rate of the fuel system C defined in FIG. 7 (II). Further, there is provided a calculator 27 which receives the valve opening signal, calculates a distribution ratio (1-m), and sends a valve opening signal corresponding to the distribution ratio (1-m) to the second fuel distribution valve 24. Has been.
The total valve opening of the first fuel distribution valve 23 and the second fuel distribution valve 24 is always set to (m) + (1-m) = 1.

Further, in response to the gas turbine speed / load control signal X, the ratio of the fuel flow rate of the two downstream branch passages of the three-way switching valve 25 is determined based on a predetermined function, and the valve position corresponding to this flow rate ratio is determined. A second function generator 28 is provided which sends a signal to the 3-way switching valve 25. In this case, the ratio of the flow rate of the fuel system D is set to (n) and the ratio of the flow rate of the fuel system A is set to (1-n). Further, the predetermined function in this case is a function that outputs a flow rate ratio (n) that switches to the fuel system D when the load increases, as shown in FIG.

Next, the operation of the gas turbine control system according to this embodiment will be described.

Until the rated speed is reached after the gas turbine is started, it is operated only by the diffusion fuel system A under low load. Therefore, from the first function generator 26, (m) =
0 is output, the first fuel distribution valve 23 is fully closed, and the second fuel distribution valve 23 is closed.
The fuel distribution valve 24 is fully opened, and the second function generator 2
From (8), (n) = 0 is output. As a result, the main fuel system D is completely shut off, and the fuel flows only to the diffusion fuel system A when the load is low.

Similarly at the start of load increase, as shown in FIG. 1, (m) starts to increase according to the schedule of the function of the first function generator 26, and the opening degree of the first fuel distribution valve 23 gradually increases. It becomes larger, (1-m) begins to decrease, and the opening degree of the second fuel distribution valve 24 is gradually made smaller.

Thereafter, as in the above, the first function generator 2
The first fuel distribution valve 23, the second fuel distribution valve 24, and the three-way switching valve 25 are controlled by 6, the calculator 27, and the second function generator 28.

As described above, in this embodiment, the fuel control valve 20 for controlling the gas turbine / load and the first and second fuel distribution valves 23, 24 for distributing the fuel to the four fuel systems of the combustor. And the three-way switching valve 25 are provided independently. Therefore, even if there is a load change or the like during the fuel switching operation, the load change or the like is controlled by the fuel control valve 20, while the fuel switching operation is performed by the first and second fuel distribution valves 2
3, 24 and a three-way switching valve 25. Therefore, the switching operation of opening / closing the valve at the time of fuel switching does not become unstable.

Further, regarding fuel distribution, it is not necessary to perform complicated control by four fuel control valves for each of the four fuel systems A, B, C, D as in the conventional case, and all the fuel can be controlled to 2 The fuel distribution control is performed by a simple control of the first and second fuel distribution valves 23 and 24 that branch into two and distribute, and the three-way switching valve 25 that performs only the switching operation. Therefore, the error of the fuel distribution characteristic can be suppressed to the minimum and the NOx reduction effect can be sufficiently exerted.

Further, the speed / load control of the gas turbine is performed by the fuel control valve 20, and the fuel control valve 20
Are normally operated in choke flow. for that reason,
The switching operation of each distribution valve and the like on the downstream side of the fuel control valve 20 does not affect the speed / burden control of the gas turbine.

Further, the first function generator 26 and the arithmetic unit 2
7 controls the fuel flow rate of the first and second fuel distribution valves 23 and 24, and the second function generator 28 controls the valve position of the flow rate of the three-way switching valve 25. There is. Therefore, the fuel distribution control is realized by a simple control circuit configuration.

Next, FIG. 2 shows a first modification of the present invention. FIG. 2 is a diagram showing a fuel supply circuit and a control circuit of a gas turbine control device according to a first modification of the present invention.

In this modification, one of the three-way switching valve 25 connected to the diffusion fuel system A at the time of low load of the combustor 4 is connected to one of the downstream branch passages using the air discharged from the compressor 1 as a supply source. A barge pipe 29 is connected and an air barge valve 30 is interposed in the air barge pipe 29. Further, a detection means (not shown) for detecting the fully closed state of the second fuel distribution valve 24 is provided, and the closing means for opening the air / barge valve 30 when the fully closed state is detected ( (Not shown) is provided.

As a result, not only the functions and effects of the above-described embodiment are exhibited, but also the reliability of the device is improved.

Furthermore, FIG. 3 shows a second modification of the present invention. FIG. 3 is a diagram showing a fuel supply circuit and a control circuit of a gas turbine control device according to a second modification of the present invention.

In this modification, the fuel supply ratio of the first supply passage 21 is adjusted to one of the two branch passages that are branched into the pilot premix fuel system C and the diffusion fuel system B under high load. There is provided an orifice 31 for operating the valve, or a valve 31 having an opening adjuster capable of adjusting the opening during gas turbine operation.

As a result, not only the functions and effects of the above-described embodiment are exhibited, but also the distribution control of the two fuel systems B and C is controlled more finely.

The present invention is not limited to the above-mentioned embodiment, and it goes without saying that it can be variously modified.

[0059]

As described above, according to the first aspect of the present invention, even if there is a load change or the like during the fuel switching operation, the load change or the like is controlled by the fuel control valve, while the fuel switching operation is performed. , A fuel distribution valve and a three-way switching valve. Therefore, the switching operation of opening / closing the valve at the time of fuel switching does not become unstable. Regarding the distribution of fuel, the first and second distributions of all fuels are divided into two.
The fuel distribution control is performed by simple control of the fuel distribution valve and the three-way switching valve that only performs the switching operation. Therefore, the error of the fuel distribution characteristic can be suppressed to the minimum and the NOx reduction effect can be sufficiently exerted.

Further, as described in claim 2, the first function generator and the arithmetic unit control the fuel flow rate ratios of the first and second fuel distribution valves, and the second function generator controls. The valve position of the flow rate of the three-way switching valve is controlled. Therefore, the fuel distribution control is realized by a simple control circuit configuration.

[Brief description of drawings]

FIG. 1 is a diagram showing a fuel supply circuit and a control circuit of a gas turbine control device according to an embodiment of the present invention.

FIG. 2 is a diagram showing a fuel supply circuit and a control circuit of a gas turbine control device according to a first modification of the present invention.

FIG. 3 is a diagram showing a fuel supply circuit and a control circuit of a gas turbine control device according to a second modification of the present invention.

FIG. 4 is a diagram showing a fuel supply circuit of a conventional gas turbine control device.

FIG. 5 is a schematic sectional view of a combustor of a gas turbine.

FIG. 6 is a graph for explaining the fuel injection with respect to the load of the gas turbine.

FIG. 7 is a diagram showing a control circuit of a conventional gas turbine control device.

[Explanation of symbols]

 2 gas turbine 4 combustor 5 fuel supply path 20 fuel control valve 21 first supply path 22 second supply path 23 first fuel distribution valve 24 second fuel distribution valve 25 three-way switching valve 26 first function generator 27 calculator 28 2nd function generator A Diffusion fuel system at low load B Diffusion fuel system at high load C Pilot premix fuel system D Main fuel system

Claims (4)

[Claims] 1. A fuel supply to a combustor of a gas turbine having four fuel systems, a diffusion fuel system at low load, a diffusion fuel system at high load, a pilot premix fuel system, and a main fuel system. A gas turbine control device for controlling, wherein a fuel control valve having a gas turbine speed / load control function is provided in a fuel supply passage, and a fuel supply passage downstream of the fuel control valve is provided as a first supply passage and a second supply passage. And a first fuel distribution valve and a second fuel distribution valve are respectively interposed in the first supply path and the second supply path, and the first supply path downstream of the first fuel distribution valve is It is connected to the diffusion fuel system at high load of the combustor and the pilot premix fuel system, and a three-way switching valve is installed in the second supply passage downstream of the second fuel distribution valve. Each of the downstream branches is connected to the diffusion fuel system and A gas turbine control device characterized in that it is connected to a fuel system. 2. The ratio of the fuel flow rate supplied to the first supply path to all the supplied fuel flow rate is (m), and the ratio of the fuel flow rate supplied to the second supply path is (1-m ), Where (m) + (1-m) = 1, the flow rate ratio (m) is determined based on a predetermined function in response to the gas turbine speed / load control signal. Is provided with a first function generator that sends a valve opening signal corresponding to the first fuel distribution valve, and receives the valve opening signal to calculate a flow rate ratio (1-m),
An arithmetic unit for sending a valve opening signal corresponding to the flow rate ratio (1-m) to the second fuel distribution valve is provided, and receives a gas turbine speed / load control signal and receives the two downstream branches of the three-way switching valve. The gas turbine according to claim 1, further comprising a second function generator that determines a fuel flow rate based on a predetermined function and sends a valve position signal corresponding to the flow rate to the three-way switching valve. Control device. 3. An air-barge pipe, which uses the discharge air of the compressor as a supply source, is connected to one downstream branch passage of a three-way switching valve connected to the diffusion fuel system when the combustor has a low load. An air barge valve is interposed in the air barge pipe, and means for detecting the fully closed state of the second fuel distribution valve is provided. When the fully closed state is detected, a means for opening the air barge valve is provided. The gas turbine control device according to claim 1, wherein the gas turbine control device is provided. 4. An orifice for adjusting the fuel distribution ratio of the first supply path to one of the two branch paths branched into the pilot premix fuel system and the diffusion fuel system under high load, or The gas turbine control device according to any one of claims 1 to 3, further comprising a valve having an opening degree adjuster capable of adjusting an opening degree during operation of the gas turbine.