JP6801968B2 - Gas turbine control device and control method, and gas turbine - Google Patents

Description

The present disclosure relates to a gas turbine control device and a control method, and a gas turbine.

Generally, in a gas turbine, an operation of disconnecting the load (load shedding) may be performed during load operation. When shutting off the load, control is required so that misfire does not occur in the combustor after the load is shut off and the turbine speed does not become excessive.

For example, Patent Document 1 describes a fuel command value (minimum) for achieving a target fuel-air ratio obtained from combustion maintenance limit information indicating a limit balance between a pilot ratio and a fuel-air ratio that can maintain combustion stability. It is disclosed that the fuel valve opening is determined based on the higher value of the fuel flow command and the minimum fuel command by calculating the fuel command).

Further, in Patent Document 2, when the load of the gas turbine is shut off, the bleed valve for extracting compressed air from the compressor is controlled to be fully opened, and the inlet guide blade of the compressor has an intermediate opening degree. It is described that the wing is controlled to the closed side.

Japanese Unexamined Patent Publication No. 2011-85105 JP-A-2010-216441

However, the control of the gas turbine described in Patent Document 1 determines the fuel valve opening degree based on the minimum fuel flow rate required to maintain stable combustibility, and only with such a configuration, when the load is shut off. In some cases, it may be difficult to reduce the risk of over-rotation and prevent misfire.

Further, in the gas turbine described in Patent Document 2, when the load is cut off, the bleed valve for extracting compressed air from the compressor is controlled to be fully opened regardless of the magnitude of the risk of over-rotation of the gas turbine. There is. For this reason, bleed air is extracted more than necessary to prevent over-rotation. For example, when compressed air is used to cool the high temperature part of the gas turbine, the high temperature part of the gas turbine cannot be cooled. It is possible that it will be sufficient.

In view of the above circumstances, at least some embodiments of the present invention are appropriate depending on the magnitude of the risk of over-rotation of the gas turbine while achieving both reduction of the risk of over-rotation and prevention of misfire when the load is shut off. It is an object of the present invention to provide a gas turbine control device and a control method capable of performing various controls, and a gas turbine.

(1) The gas turbine control device according to at least some embodiments of the present invention is
A compressor for generating compressed air, a combustor for burning fuel using the compressed air to generate combustion gas, a turbine configured to be driven by the combustion gas, and the compression. A gas turbine control device equipped with a regulating valve for adjusting the flow rate of extracted air extracted from the machine.
It is configured to open the regulating valve when the load of the gas turbine is shut off and to control the opening degree of the regulating valve based on an index correlated with the output of the gas turbine immediately before the load shutoff of the gas turbine. ..

According to the configuration of (1) above, by opening the regulating valve when the load of the gas turbine is shut off, the flow rate of the bleed air from the compressor increases, so that the flow rate of the compressed air supplied to the combustor decreases. As a result, the fuel-air ratio in the combustor becomes high, and misfire in the combustor can be prevented while suppressing over-rotation. The fuel-air ratio is the ratio of fuel to the compressed air supplied to the combustor.
By the way, the larger the gas turbine output immediately before the load is cut off, the greater the risk that the gas turbine will over-rotate when the load is cut off. In this regard, in the configuration of (1) above, since the opening degree of the regulating valve is controlled based on an index correlated with the gas turbine output immediately before the load is cut off of the gas turbine, the risk of over-rotation of the gas turbine is increased. The opening degree of the adjusting valve can be appropriately controlled according to the size.

(2) In some embodiments, in the configuration of (1) above,
When the load of the gas turbine is shut off, the opening degree of the adjusting valve is increased as the index increases.

For example, when the gas turbine is operated at a high output before the load is cut off, the rotation speed increases when the load is cut off, and the risk of over-rotation increases. In this case, according to the configuration of (2) above, the adjusting valve is opened with a relatively large opening degree so as to be able to cope with a large increase in the rotation speed, and the amount of air extracted from the compressor is increased. Therefore, it is possible to significantly reduce the fuel flow rate as compared with the load operation while maintaining the fuel-air ratio so as not to misfire. As a result, the energy of the combustion gas generated by the combustor and flowing into the turbine can be significantly reduced, and over-rotation after the load is cut off can be reliably prevented.
On the other hand, when the gas turbine is operated at a low output before the load is cut off, the increase in the number of revolutions when the load is cut off is small, and the risk of over-rotation is small. In this case, since the increase in the number of revolutions is small, the adjusting valve is opened with a relatively small opening, and the amount of air extracted from the compressor is small. As a result, it is possible to prevent over-rotation after the load is cut off while avoiding a sudden change in the operating state of the gas turbine.

(3) In some embodiments, in the configuration of (1) or (2) above,
The index is the output of the gas turbine immediately before the load cutoff of the gas turbine, or the opening degree of the inlet guide blade of the compressor immediately before the load cutoff of the gas turbine.

According to the configuration of (3) above, the value of the output of the gas turbine itself or the opening degree of the inlet guide blade that correlates with the output of the gas turbine is used as an index, so that the risk of over-rotation is increased. The opening degree of the regulating valve can be controlled with high accuracy.

(4) In some embodiments, in any of the configurations (1) to (3) above,
A valve opening degree calculation unit that calculates the opening degree of the adjusting valve according to the index when the load of the gas turbine is cut off.
The valve opening degree correction unit is provided so as to correct the opening degree calculated by the valve opening degree calculation unit based on the atmospheric temperature.

Normally, the mass flow rate of the air flowing into the compressor changes depending on the atmospheric temperature. Therefore, the atmospheric temperature is corrected by correcting the opening calculated by the valve opening calculation unit as in the configuration of (4) above. Regardless, the extracted air of a desired mass flow rate according to the risk of over-rotation can be discharged from the compressor.

(5) In some embodiments, in any of the configurations (1) to (4) above,
The minimum opening degree is selected from the required opening degree of the adjusting valve corresponding to the temperature measurement value of the high temperature portion of the gas turbine and the opening degree of the adjusting valve determined based on the index. The minimum opening degree selection unit is further provided.

According to the configuration (5) above, after ensuring the air flow rate required for cooling the high temperature part (for example, cooling the turbine blades), which is one of the most important matters when operating the gas turbine, over-rotation and over-rotation and Misfire can be suppressed.

(6) In some embodiments, in any of the configurations (1) to (5) above,
The adjusting valve is a circulation valve provided in a circulation line for returning the extracted air to the intake side of the compressor, or at least for adjusting the supply amount of the extracted air from the compressor to the turbine. At least one of the bleed valves.

(7) In some embodiments, in any of the configurations (1) to (6) above,
It is configured to control the opening / closing timing and opening degree of each of the plurality of adjusting valves independently of the other adjusting valves.

According to the configuration of (7) above, when a plurality of adjusting valves are provided, the opening / closing timing and opening degree of each adjusting valve are controlled independently of the other adjusting valves, so that when the load of the gas turbine is shut off. The impact of the response on gas turbine operation can be minimized.

(8) The gas turbine according to at least some embodiments of the present invention is
With a compressor to generate compressed air,
A combustor for burning fuel using the compressed air to generate combustion gas,
A turbine configured to be driven by the combustion gas,
A regulating valve that adjusts the flow rate of the extracted air extracted from the compressor,
The control device according to any one of (1) to (7) above, which is configured to control the opening degree of the adjusting valve.
To be equipped.

According to the configuration of (8) above, misfire in the combustor can be prevented while suppressing over-rotation, and the opening degree of the adjusting valve is appropriately controlled according to the magnitude of the risk of over-rotation of the gas turbine. Since it is provided with a control device capable of providing a highly reliable gas turbine, it can be provided.

(9) The method for controlling a gas turbine according to at least some embodiments of the present invention is as follows.
A compressor for generating compressed air, a combustor for burning fuel using the compressed air to generate combustion gas, a turbine configured to be driven by the combustion gas, and the compression. It is a control method of a gas turbine equipped with a regulating valve for adjusting the flow rate of extracted air extracted from the machine.
When the load of the gas turbine is shut off, the regulating valve is opened, and the opening degree of the regulating valve is controlled based on an index correlated with the output of the gas turbine immediately before the load is shut off of the gas turbine.

According to the method (9) above, by opening the regulating valve when the load of the gas turbine is shut off, the flow rate of the bleed air from the compressor increases, so that the flow rate of the compressed air supplied to the combustor decreases. As a result, the fuel-air ratio in the combustor becomes high, and misfire in the combustor can be prevented while suppressing over-rotation.
In addition, since the opening of the regulating valve is controlled based on an index that correlates with the gas turbine output immediately before the load of the gas turbine is shut off, the regulating valve is opened according to the magnitude of the risk of over-rotation of the gas turbine. Degree control can be performed appropriately.

(10) In some embodiments, in the method (9) above,
When the load of the gas turbine is shut off, the opening degree of the adjusting valve is increased as the index increases.

According to the method (10) above, when the index correlating with the output of the gas turbine is large, the energy of the combustion gas generated by the combustor and flowing into the turbine is released by opening the regulating valve with a relatively large opening. It can be significantly reduced, and over-rotation after the load is cut off can be reliably prevented. On the other hand, when the index that correlates with the output of the gas turbine is small, the regulating valve is opened with a relatively small opening, so that overrotation after load shutoff is avoided while avoiding sudden changes in the operating state of the gas turbine. Can be prevented.

(11) In some embodiments, in the method (9) or (10) above,
The index is the output of the gas turbine immediately before the load cutoff of the gas turbine, or the opening degree of the inlet guide blade of the compressor immediately before the load cutoff of the gas turbine.

According to the method (11) above, the value of the output of the gas turbine itself or the opening degree of the inlet guide blade that correlates with the output of the gas turbine is used as an index, so that the risk of over-rotation is increased. The opening degree of the regulating valve can be controlled with high accuracy.

(12) In some embodiments, in any of the methods (9) to (11) above,
When the load of the gas turbine is shut off, a step of calculating the opening degree of the adjusting valve according to the index, and
A step of correcting the opening degree of the adjusting valve calculated in the step of calculating the opening degree by the atmospheric temperature, and a step of correcting the opening degree.
To be equipped.

According to the method (12) above, by correcting the opening degree calculated based on the index correlated with the gas turbine output by the atmospheric temperature, the desired mass according to the risk of over-rotation regardless of the atmospheric temperature. The bleed air of the flow rate can be discharged from the compressor.

(13) In some embodiments, in any of the methods (9) to (12) above,
The step includes a step of selecting the minimum opening degree of the required opening degree of the adjusting valve corresponding to the temperature measurement value of the high temperature portion of the gas turbine and the opening degree of the adjusting valve determined based on the index.

According to the method (13) above, after ensuring the air flow rate required for cooling the high temperature part (for example, cooling the turbine blades), which is one of the highest priorities when operating the gas turbine, over-rotation and over-rotation and Misfire can be suppressed.

(14) In some embodiments, in any of the methods (9) to (13) above,
The adjusting valve is a circulation valve provided in a circulation line for returning the extracted air to the intake side of the compressor, or at least for adjusting the supply amount of the extracted air from the compressor to the turbine. At least one of the bleed valves.

(15) In some embodiments, in any of the methods (9) to (14) above,
The opening / closing timing and opening degree of each of the plurality of adjusting valves are controlled independently of the other adjusting valves.

According to the method (15) above, when a plurality of adjusting valves are provided, the opening / closing timing and opening degree of each adjusting valve are controlled independently of the other adjusting valves, so that when the load of the gas turbine is shut off. The impact of the response on gas turbine operation can be minimized.

According to at least some embodiments of the present invention, opening the regulating valve when the load of the gas turbine is shut off increases the flow rate of the bleed air from the compressor, so that the flow rate of the compressed air supplied to the combustor is increased. Decrease. As a result, the fuel-air ratio in the combustor becomes high, and misfire in the combustor can be prevented while suppressing over-rotation.
In addition, since the opening of the regulating valve is controlled based on an index that correlates with the gas turbine output immediately before the load of the gas turbine is shut off, the regulating valve is opened according to the magnitude of the risk of over-rotation of the gas turbine. Degree control can be performed appropriately.

It is a figure which shows the schematic structure of the gas turbine which concerns on one Embodiment. It is a block diagram of the control device of the gas turbine which concerns on one Embodiment. It is a block diagram which shows the basic control of the control valve in one Embodiment. It is a figure which shows the correlation of a gas turbine output and a control valve opening degree. It is a block diagram which shows the basic control of the control valve in the modification of one Embodiment. It is a figure which shows the correlation of the IGV opening degree and the adjustment valve opening degree. It is a block diagram which shows the control of the control valve in another embodiment. It is a block diagram which shows the control of the control valve in still another embodiment. It is a figure for demonstrating the opening / closing timing and opening degree of each adjustment valve.

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

First, the overall configuration of the gas turbine 1 according to some embodiments will be described with reference to FIG. Here, FIG. 1 is a diagram showing a schematic configuration of a gas turbine 1 according to an embodiment.

The gas turbine 1 according to some embodiments is driven by a compressor 3 for generating compressed air, a combustor 4 for burning fuel using compressed air to generate combustion gas, and combustion gas. A turbine 5 configured to be used is provided.
Further, the gas turbine 1 further includes a regulating valve 10 for adjusting the flow rate of bleed air extracted from the compressor 3.

In the gas turbine 1, the air taken into the compressor 3 is compressed by passing through an inlet guide blade 2, a plurality of stationary blades, and a moving blade provided in the passenger compartment of the compressor, whereby high temperature and high pressure air (compression) is obtained. Air) is generated.
Fuel and high-temperature and high-pressure air from the compressor 3 are supplied to the combustor 4. In the combustor 4, combustion gas is generated by mixing and burning fuel and air in the combustor vehicle interior. During partial load operation or full load operation of the gas turbine 1, the flow rate of fuel supplied to the combustor 4 is determined by the operating state and load of the gas turbine 1. For example, the fuel flow rate is determined based on at least one of the load of the gas turbine 1, the rotation speed (rotational speed), and the combustion gas temperature.
Combustion gas from the combustor 4 is introduced into the turbine 5. By passing this combustion gas through a plurality of stationary blades and moving blades arranged in the turbine cabin, a rotor provided so as to penetrate the turbine cabin and the compressor chassis is rotated. When the gas turbine 1 is used for power generation, power is generated by a generator (not shown) connected to the rotor by the rotation of the rotor.
An exhaust duct 6 communicating with the turbine casing is connected to the downstream side of the turbine 5. The exhaust gas after driving the turbine 5 is discharged to the outside through the exhaust duct 6.

The gas turbine 1 further includes at least one bleed line 20 (20a to 20c) bleeding from the compressor 3 and a regulating valve 10 for adjusting the flow rate of the bleed air extracted from the compressor 3. There is.

The bleeding line 20 is connected to the cooling line 21 (21a to 21c). The cooling line 21 is arranged so as to guide at least a part of the bleed air from the compressor 3 to the turbine 5 as cooling air via the bleed line 20. The cooling line 21 is provided with an orifice 22 (22a to 22c).

Further, the bleed air line 20 is connected to at least one of the circulation line 23 and the exhaust line 24 (24a to 24c).
The circulation line 23 is arranged so as to return at least a part of the extracted air from the compressor 3 to the inlet side of the compressor 3.
The exhaust line 24 is arranged so as to guide at least a part of the air extracted from the compressor 3 to the downstream side of the turbine 5, that is, to the exhaust duct 6 in FIG.

The regulating valve 10 includes at least one of a circulation valve 11 provided in the circulation line 23 and an air extraction valve 12 (12a to 12c) provided in the exhaust line 24.
The circulation valve 11 is configured to adjust the circulation amount of the extracted air returned to the inlet side of the compressor 3 through the circulation line 23.
The bleed valve 12 adjusts the front-rear differential pressure of the orifice 22 by adjusting the pressure of the bleed line 10, and adjusts the flow rate of the cooling air supplied to the turbine 5.
These circulation valves 11 or bleed air valves 12 can also be used as adjusting valves 10 for adjusting the bleed air flow rate from the compressor 3 when the load of the gas turbine 1 is cut off. During load operation of the gas turbine 1, the circulation valve 11 and the bleed valve 12 (12a to 12c) are normally closed, and a predetermined flow rate of cooling air is sent to the turbine 5 via the orifice 22. There is. When changing the flow rate of the cooling air, the front-rear differential pressure of the orifice 22 on the cooling line 21 is changed and supplied to the turbine 5 by controlling the opening degree of at least one of the circulation valve 11 and the bleeding valve 12. The flow rate of cooling air is adjusted.

In the embodiment shown in FIG. 1, the bleeding line 20 includes a high-pressure bleeding line 20a for drawing air from the high-pressure stage (outlet side) of the compressor 3 and a medium-pressure bleeding line 20b for drawing air from the medium-pressure stage (intermediate) of the compressor 3. And a low-pressure bleed line 20c for bleeding air from the low-pressure stage (inlet side) of the compressor 3.
Further, the cooling line 21 is connected to the high-pressure bleeding line 20a and is connected to the high-pressure cooling line 21a for introducing air into the high-pressure stage (inlet side) of the turbine 5 and the medium-pressure bleeding line 20b, and is connected to the medium-pressure stage of the turbine 5. It includes a medium-pressure cooling line 21b that introduces air into the (middle), and a low-pressure cooling line 21c that is connected to the low-pressure bleeding line 20c and introduces air into the low-pressure stage (outlet side) of the turbine 5. Each of these cooling lines 21a to 21c is provided with a high-pressure orifice 22a, a medium-pressure orifice 22b, and a low-pressure orifice 22c, respectively.
The circulation line 23 is connected to all of the high pressure extraction line 20a, the medium pressure extraction line 20b, and the low pressure extraction line 20c.
The exhaust line 24 includes a high-pressure exhaust line 24a connected to the high-pressure bleeding line 20a and the high-pressure cooling line 21a, a medium-pressure exhaust line 24b connected to the medium-pressure bleeding line 20b and the medium-pressure cooling line 21b, and a low-pressure bleeding line 20c. And a low pressure exhaust line 24c connected to a low pressure cooling line 21c. In this case, the high-pressure exhaust line 24a, the medium-pressure exhaust line 24b, and the low-pressure exhaust line 24c are each provided with a high-pressure bleed valve 12a, a medium-pressure bleed valve 12b, and a low-pressure bleed valve 12c.

In the gas turbine 1 as described above, an operation of disconnecting the load (load shedding) may be performed during the load operation. In this case, if the combustor 4 does not misfire after the load is shut off and the rotation speed of the gas turbine 1 is equal to or less than the overspeed trip specified value (for example, 110%), it can be considered that the load shutoff has been appropriately performed.

However, there is a trade-off between prevention of misfire and reduction of the risk of over-rotation after the load is cut off, and it may be difficult to achieve both. In a general gas turbine 1, when the load is cut off, for example, the fuel to the combustor 4 is throttled to suppress an increase in the rotation speed. That is, in the combustor 4, the fuel flow rate is set so that the rotation speed of the gas turbine 1 is maintained within the set range even in the no-load operation. However, depending on the gas turbine 1, if the fuel flow rate is set to a level that can suppress over-rotation, the fuel-air ratio may become too large and the gas turbine 1 may stop due to a misfire of the combustor 4. .. The fuel-air ratio is the ratio of fuel to the compressed air supplied to the combustor 4. Normally, the air flow rate supplied to the combustor 4 is determined by the rotation speed and the opening degree (IGV opening degree) of the inlet guide blade 2, but the compressor 3 is coaxial with the turbine 5, and the air flow rate is determined by the rotation speed. Is difficult to operate. On the other hand, the IGV opening degree is normally controlled to be fully closed when the load is shut off, but the air that has already passed through the inlet guide blade 2 and is compressed is introduced into the combustor 4. Therefore, it is difficult to increase the fuel-air ratio without increasing the fuel flow rate of the combustor 4.

Therefore, in the following embodiment, control that can both reduce the risk of over-rotation and prevent misfire when the load is cut off, and can perform appropriate control according to the magnitude of the risk of over-rotation of the gas turbine 1. The device 30 will be described.
FIG. 2 is a block diagram of the control device 30 of the gas turbine 1 according to the embodiment.
In the following description, each part of the gas turbine 1 is designated by a reference numeral shown in FIG.

As illustrated in FIG. 2, the control device 30 according to some embodiments mainly controls the opening degree of the regulating valve 10 of the gas turbine 1, and the regulating valve 10 is used when the load of the gas turbine 1 is cut off. Is opened, and the opening degree of the regulating valve 10 is controlled based on an index (hereinafter, referred to as an output index) that correlates with the output of the gas turbine 1 immediately before the load of the gas turbine 1 is cut off.
The control device 30 may be configured to increase the opening degree of the regulating valve 10 as the output index increases when the load of the gas turbine 1 is cut off.
As the output index, the gas turbine output immediately before the load cutoff of the gas turbine 1 or the opening degree of the inlet guide blade 2 of the compressor 3 immediately before the load cutoff of the gas turbine 1 may be used.

According to the above configuration, by opening the regulating valve 10 when the load of the gas turbine 1 is cut off, the flow rate of the bleed air from the compressor 3 increases, so that the flow rate of the compressed air supplied to the combustor 4 decreases. As a result, the fuel-air ratio in the combustor 4 can be increased without increasing the amount of fuel input to the combustor 4, and misfire in the combustor 4 can be prevented while suppressing over-rotation.
By the way, the larger the gas turbine output immediately before the load is cut off, the greater the risk that the gas turbine 1 will over-rotate when the load is cut off. In this regard, in the above configuration, since the opening degree of the adjusting valve 10 is controlled based on the output index immediately before the load is cut off of the gas turbine 1, the adjusting valve 10 is adjusted according to the magnitude of the risk of over-rotation of the gas turbine 1. The opening degree control of 10 can be appropriately performed.

For example, when the gas turbine 1 is operated at a high output before the load is cut off, the rotation speed increase at the time of the load cutoff is large, and the risk of over-rotation is large. In this case, according to the above configuration, the adjusting valve 10 is opened with a relatively large opening degree so as to be able to cope with a large increase in the rotation speed, and the amount of air extracted from the compressor 3 increases. Therefore, it is possible to significantly reduce the fuel flow rate as compared with the load operation while maintaining the fuel-air ratio so as not to misfire. As a result, the energy of the combustion gas generated by the combustor 4 and flowing into the turbine can be significantly reduced, and over-rotation after the load is cut off can be reliably prevented.
On the other hand, when the gas turbine 1 is operated at a low output before the load is cut off, the increase in the number of revolutions at the time of the load cutoff is small and the risk of over-rotation is small. In this case, since the increase width of the rotation speed is small, the adjusting valve 10 is opened with a relatively small opening degree, and the amount of air extracted from the compressor 3 is small. As a result, over-rotation after the load is cut off can be prevented while avoiding a sudden change in the operating state of the gas turbine 1.

In the above-described embodiment, the control device 30 sets the opening degree of the adjusting valve 10 to the opening degree before the load shutoff (for example, fully closed) after the set time (for example, several seconds to ten and several seconds) has elapsed from the time when the load is shut off. It may be configured to control the return (see FIG. 7). In this case, the set time may correspond to the time zone immediately after the load is cut off, which has a high risk of over-rotation and misfire. For example, the set time can be set from the results of a simulation or a combustor unit test.
In this way, the control valve 10 is controlled to open immediately after the load is shut off, which has a high risk of over-rotation and misfire. After the load is shut off, the no-load operation state becomes stable, and over-rotation and misfire occur. When the risk becomes small, the opening degree of the adjusting valve 10 is returned. This enables stable operation of the gas turbine 1 after the load is cut off. For example, even if the cooling air is reduced by opening the regulating valve 10 immediately after the load is shut off, returning the opening degree of the regulating valve 10 after the lapse of the set time has an effect on the cooling of the turbine 5. It can be suppressed.

Here, a specific configuration of the control device 30 will be described with reference to FIGS. 2 to 6.
As illustrated in FIG. 2, the control device 30 according to some embodiments includes a valve opening degree calculation unit 31 for calculating the opening degree of the adjusting valve 10 and a valve opening for generating a valve opening degree command. It is provided with a degree command output unit 34.
The control device 30 may further include at least one of the valve opening degree correction unit 32 and the minimum opening degree selection unit 33.

The valve opening degree calculation unit 31 is configured to calculate the opening degree of the adjusting valve 10 according to the output index at the time of load shutoff of the gas turbine 1 and immediately before the load shutoff.
The valve opening command output unit 34 is configured to generate a valve opening command based on the opening of the adjusting valve 10 calculated by the valve opening calculating unit 31 and output this valve opening command to the adjusting valve 10. Will be done.

FIG. 3A is a block diagram showing the basic control of the regulating valve 10 in one embodiment. FIG. 3B is a diagram showing a correlation between the gas turbine output and the adjustment valve opening degree. These figures are diagrams related to control when the gas turbine output immediately before the load is cut off of the gas turbine 1 is used as the output index.
In the embodiment shown in FIG. 3A, the valve opening degree calculation unit 31 (see FIG. 2) includes a switch 311 and a function calculator 312, and a switch 313.
The current value of the gas turbine output is input to the switch 311 and the previous value of the gas turbine output is input to the switch 311. If the switch 311 does not detect the load cutoff signal, the current value of the gas turbine output is re-input to the switch 311 as the previous value. On the other hand, when the switch 311 detects the load cutoff signal, the previous value of the gas turbine output is input to the function calculator 312.
The function calculator 312 calculates the opening degree of the regulating valve 10 from the previous value of the gas turbine output based on the correlation between the gas turbine output and the regulating valve opening degree as shown in FIG. 3B.
The opening degree of the adjusting valve 10 calculated by the function calculator 312 is input to the switch 313. If the switch 313 does not detect the load cutoff signal, the switch 313 outputs a valve opening command to set the opening degree to zero. When the switch 313 detects the load cutoff signal, the opening degree of the adjusting valve 10 calculated by the function calculator 312 is output, and the valve opening command output unit 34 (see FIG. 2) is based on this opening degree. A valve opening command is generated.

According to the above configuration, since the opening degree of the adjusting valve 10 is determined based on the previous value of the gas turbine output, the opening degree of the adjusting valve 10 is controlled according to the magnitude of the risk of over-rotation of the gas turbine. Can be done properly.
Further, by using the value of the output itself of the gas turbine 1 as an index, it is possible to accurately control the opening degree of the adjusting valve 10 according to the magnitude of the risk of over-rotation.
When the turbine 5 of the gas turbine 1 is configured to drive the generator, the generator output may be used as the gas turbine output.

FIG. 4A is a block diagram showing the basic control of the regulating valve 10 in the modified example of one embodiment. FIG. 4B is a diagram showing a correlation between the IGV opening degree and the adjusting valve opening degree. These figures are diagrams related to control when the opening degree (IGV opening degree) of the inlet guide blade 2 of the compressor 3 immediately before the load shutoff of the gas turbine 1 is used as the output index.
The current value of the IGV opening is input to the switch 311 and the previous value of the IGV opening is input to the switch 311. If the switch 311 does not detect the load cutoff signal, the current value of the IGV opening is input again to the switch 311 as the previous value. On the other hand, when the switch 311 detects the load cutoff signal, the previous value of the IGV opening degree is input to the function calculator 312.
The function calculator 312 calculates the opening degree of the adjusting valve 10 from the previous value of the IGV opening degree based on the correlation between the IGV opening degree and the adjusting valve opening degree as shown in FIG. 4B.
The opening degree of the adjusting valve 10 calculated by the function calculator 312 is input to the switch 313. If the switch 313 does not detect the load cutoff signal, the switch 313 outputs a valve opening command to set the opening degree to zero. When the switch 313 detects the load cutoff signal, the opening degree of the adjusting valve 10 calculated by the function calculator 312 is output, and the valve opening command output unit 34 (see FIG. 2) is based on this opening degree. A valve opening command is generated.

According to the above configuration, since the opening degree of the adjusting valve 10 is determined based on the previous value of the IGV opening degree, the opening degree control of the adjusting valve 10 is performed according to the magnitude of the risk of over-rotation of the gas turbine. Can be done properly.
Further, by using the IGV opening degree having a correlation with the turbine output as an output index, it is possible to accurately control the opening degree of the adjusting valve 10 according to the magnitude of the over-rotation risk.

FIG. 5 is a block diagram showing the control of the regulating valve 10 in another embodiment, and in addition to the basic control of FIGS. 3A and 4A, an operation by the valve opening correction unit 32 (see FIG. 2) is added. Shows control. Since the control of the valve opening degree calculation unit 31 (see FIG. 2) in FIG. 5 is the same as that in FIGS. 3A and 4A, the description thereof will be omitted.

As shown in FIG. 2, the valve opening degree correction unit 32 is configured to correct the opening degree of the adjusting valve 10 calculated by the valve opening degree calculation unit 31 according to the atmospheric temperature.
In the embodiment shown in FIG. 5, the valve opening correction unit 32 has a function calculator 321 and a multiplier 322.
Atmospheric temperature is input to the function calculator 321. Then, the function calculator 321 calculates the correction coefficient from the atmospheric temperature based on the correlation between the atmospheric temperature and the correction coefficient of the opening degree of the regulating valve 10. Normally, the mass flow rate of the air flowing into the compressor 3 changes depending on the atmospheric temperature. Therefore, the function calculator 321 calculates the correction coefficient of the opening degree of the regulating valve 10 so as to absorb the fluctuation of the mass flow rate due to the atmospheric temperature, for example, by using the equation of state.
When the load control command was detected, the multiplier 322 multiplied the opening degree of the regulating valve 10 input from the switch 312 described above by the correction coefficient input from the function calculator 321 and corrected by the atmospheric temperature. The opening degree of the adjusting valve 10 is output. Then, a valve opening command is generated in the valve opening command output unit 34 (see FIG. 2) based on the corrected opening degree of the adjusting valve 10.

According to the above configuration, by correcting the opening degree calculated by the valve opening degree calculation unit 31 with the atmospheric temperature, the bleed air having a desired mass flow rate according to the risk of over-rotation is produced by the compressor 3 regardless of the atmospheric temperature. Can be discharged from. As a result, even in a gas turbine plant having a large atmospheric temperature difference throughout the year, it is not necessary to change the specifications for setting the opening degree of the adjusting valve 10, and the opening degree of the adjusting valve 10 can be appropriately controlled.

FIG. 6 is a block diagram showing the control of the regulating valve 10 in still another embodiment, and in addition to the basic control of FIGS. 3A and 4A, an operation by the minimum opening degree selection unit 33 (see FIG. 2) is added. Shows the controlled control. Since the control of the valve opening degree calculation unit 31 (see FIG. 2) in FIG. 6 is the same as that in FIGS. 3A and 4A, the description thereof will be omitted.

As shown in FIG. 2, the minimum opening degree selecting unit 33 opens the adjusting valve 10 determined based on the required opening degree of the adjusting valve 10 corresponding to the temperature measurement value of the high temperature portion of the gas turbine 1 and the output index. It is configured to select the minimum opening of the degree.
In the embodiment shown in FIG. 6, the minimum opening degree selection unit 33 includes a function calculator 331 and a comparator 332.
The temperature measurement value of the high temperature portion of the gas turbine 1 is input to the function calculator 331. The high temperature portion referred to here is a cooling target portion of the gas turbine 1 that is cooled by the bleed air from the compressor 3, and is particularly a cooling target portion that should be prioritized over securing the fuel-air ratio when the load is cut off. There may be. For example, the high temperature part is a turbine blade. In this case, the temperature measurement value of the high temperature portion may be a temperature that correlates with the blade temperature of the turbine 5. Examples of the temperature correlated with the blade temperature include a disc cavity temperature, a blade path temperature, an exhaust gas temperature, and the like. Then, the function calculator 331 calculates the required opening degree of the regulating valve 10 corresponding to the temperature measurement value of the high temperature portion, that is, the required opening degree of the regulating valve 10 capable of supplying the cooling air required for cooling the high temperature portion. To do.
When the load control command is detected, the comparator 332 compares the opening degree of the adjusting valve 10 input from the switch 312 described above with the required opening degree of the adjusting valve 10 input from the function calculator 331, and these Of these, the smallest opening is output. In the comparator 332, the corrected opening degree output from the multiplier 322 shown in FIG. 5 may be input instead of the opening degree input from the switch 312.

According to the above configuration, the risk of over-rotation and misfire is ensured while ensuring the air flow rate required for cooling the high temperature part (for example, cooling the turbine blades), which is one of the highest priorities when operating the gas turbine 1. Can be reduced.

In the above-described embodiment, the adjusting valve 10 whose opening degree is controlled may be at least one of the circulation valve 11 already described in FIG. 1 or at least one bleed valve 12a to 12c.
In a typical gas turbine plant, for example, a circulation valve 10 for adjusting the amount of extracted air returned to the suction side of the compressor 3 for the purpose of preventing a surge of the compressor 3, or a high temperature portion of the turbine 5, for example, Some are provided with bleed valves 12a to 12c for adjusting the amount of bleed air for cooling.
Therefore, by using the circulation valve 11 and the bleeding valves 12a to 12c typically provided in the gas turbine plant as the adjusting valve 10 used to prevent over-rotation and misfire when the load is shut off. The configuration of the above-described embodiment can be easily applied to an existing gas turbine plant.

FIG. 7 is a diagram for explaining the opening / closing timing and opening degree of each adjusting valve 10.
With reference to FIGS. 1 and 7, the control device 30 according to the embodiment is configured to control the opening / closing timing and opening degree of each of the plurality of regulating valves 10 independently of the other regulating valves 10. You may.
As shown in FIG. 1, when the circulation valve 11 and the plurality of bleed valves 12a to 12c are used as the adjusting valve 10, the valve opening degree determination criteria are individually set, and the opening / closing timing and opening degree of each valve can be controlled. To do. For example, as shown in FIG. 7, since the cooling requirement is stricter in the high pressure system, the opening time of the high pressure bleed valve 12a may be shortened and the flow rate of the cooling air may be increased. Further, the medium pressure bleeding valve 12b may be opened at the timing of closing the high pressure bleeding valve 12a, and then the low pressure bleeding valve 12c may be opened. Further, the circulation valve 11, the high pressure bleeding valve 12a and the medium pressure bleeding valve 12b may be closed after a lapse of a predetermined time, and the low pressure bleeding valve 12c may be kept open.

According to the above configuration, when a plurality of adjusting valves 10 are provided, the opening / closing timing and opening degree of each adjusting valve 10 are controlled independently of the other adjusting valves 10, so that when the load of the gas turbine 1 is cut off. The influence of the response on the operation of the gas turbine 1 can be minimized.

As illustrated in FIG. 1, the gas turbine 1 according to some embodiments includes a compressor 3, a combustor 4, a turbine 5, and a regulating valve 10 (for example, a circulation valve 11 or an bleed valve 12a to 12c). , The control device 30 according to any of the above-described embodiments.
With this configuration, misfire in the combustor 4 can be prevented while suppressing over-rotation, and the opening degree of the adjusting valve 10 can be appropriately controlled according to the magnitude of the risk of over-rotation of the gas turbine 1. Since the control device 30 is provided, a highly reliable gas turbine 1 can be provided.

Next, the control method of the gas turbine 1 according to some embodiments will be described with reference to FIG. Since the configuration of the gas turbine 1 is the same as the configuration described above, it will be omitted.
In the control method of the gas turbine 1 according to some embodiments, the regulating valve 10 is opened when the load of the gas turbine 1 is shut off, and the opening degree of the regulating valve 10 is adjusted based on the output index immediately before the load shutoff of the gas turbine 1. Control.
In this method, when the load of the gas turbine 1 is cut off, the opening degree of the regulating valve 10 may be increased as the output index increases.

According to the above method, by opening the regulating valve 10 when the load of the gas turbine 1 is cut off, the fuel-air ratio in the combustor 4 can be increased without increasing the amount of fuel input to the combustor 4, and the combustor 4 can be over-rotated. It is possible to prevent misfire in the combustor 4 while suppressing the above.
Further, by controlling the opening degree of the adjusting valve 10 based on the output index immediately before the load is cut off of the gas turbine 1, the opening degree control of the adjusting valve 10 is appropriately controlled according to the magnitude of the risk of over-rotation of the gas turbine 1. It can be carried out.

The control method of the gas turbine 1 according to one embodiment is a control valve calculated in a step of calculating the opening degree of the adjusting valve 10 according to an output index and a step of calculating the opening degree when the load of the gas turbine 1 is cut off. A step of correcting the opening degree of 10 by the atmospheric temperature is provided.
According to this method, by correcting the opening degree calculated according to the output index by the atmospheric temperature, bleed air having a desired mass flow rate according to the risk of over-rotation is discharged from the compressor 3 regardless of the atmospheric temperature. can do.

The control method of the gas turbine 1 according to another embodiment is the required opening degree of the adjusting valve 10 corresponding to the temperature measurement value of the high temperature portion of the gas turbine 1 and the opening degree of the adjusting valve 10 determined based on the output index. A step of selecting the minimum opening degree is provided.
According to this method, there is a risk of over-rotation and misfire while ensuring the air flow rate required for cooling the high temperature part (for example, cooling the turbine blades), which is one of the highest priorities when operating the gas turbine 1. Can be reduced.

In any of the above-described embodiments, the opening / closing timing and opening degree of each of the plurality of adjusting valves 10 may be controlled independently of the other adjusting valves 10.
According to this method, when a plurality of adjusting valves 10 are provided, the opening / closing timing and opening degree of each adjusting valve 10 are controlled independently of the other adjusting valves 10, so that when the load of the gas turbine 1 is cut off. The influence of the response on the operation of the gas turbine 1 can be minimized.

As described above, according to at least some embodiments of the present invention, opening the regulating valve 10 when the load of the gas turbine 1 is cut off increases the flow rate of the bleed air from the compressor 3, so that the combustor 4 The flow rate of compressed air supplied to the turbine decreases. As a result, the fuel-air ratio in the combustor 4 becomes high, and misfire in the combustor 4 can be prevented while suppressing over-rotation.
Further, since the opening degree of the regulating valve 10 is controlled based on an index correlated with the output of the gas turbine immediately before the load is cut off of the gas turbine 1, it is adjusted according to the magnitude of the risk of over-rotation of the gas turbine 1. The opening degree of the valve 10 can be appropriately controlled.

The present invention is not limited to the above-described embodiment, and includes a modification of the above-described embodiment and a combination of these embodiments as appropriate.
For example, in the above-described embodiment, the gas turbine 1 used for power generation in a gas turbine plant for power generation or the like has been specifically described, but the application of the gas turbine 1 is not limited to this, and it is applied to other plants. It may be applied or it may be operated by the gas turbine alone.

For example, expressions that represent relative or absolute arrangements such as "in a certain direction", "along a certain direction", "parallel", "orthogonal", "center", "concentric" or "coaxial" are exact. Not only does it represent such an arrangement, but it also represents a state of relative displacement with tolerances or angles and distances to the extent that the same function can be obtained.
For example, expressions such as "same", "equal", and "homogeneous" that indicate that things are in the same state not only represent exactly the same state, but also have tolerances or differences to the extent that the same function can be obtained. It shall also represent the state of existence.
For example, an expression representing a shape such as a quadrangular shape or a cylindrical shape not only represents a shape such as a quadrangular shape or a cylindrical shape in a geometrically strict sense, but also an uneven portion or chamfering within a range in which the same effect can be obtained. The shape including the part and the like shall also be represented.
On the other hand, the expression "includes", "includes", or "has" one component is not an exclusive expression that excludes the existence of another component.

1 Gas turbine 2 Inlet guide blade 3 Compressor 4 Combustor 5 Turbine 6 Exhaust gas duct 10 Adjusting valve 11 Circulation valve 12 Extraction valve 12a High pressure extraction valve 12b Medium pressure extraction valve 12c Low pressure extraction valve 20 Extraction line 20a High pressure extraction line 20b Medium pressure Extraction line 20c Low-pressure air extraction line 21 Cooling line 21a High-pressure cooling line 21b Medium-pressure cooling line 21c Low-pressure cooling line 22 (22a to 22c) orifice 23 Circulation line 24 Exhaust line 24a High-pressure exhaust line 24b Medium-pressure exhaust line 24c Low-pressure exhaust line 30 Control Device 31 Valve opening calculation unit 32 Valve opening correction unit 33 Minimum opening selection unit 34 Valve opening command output unit

Claims (15)

A compressor for generating compressed air, a combustor for burning fuel using the compressed air to generate combustion gas, a turbine configured to be driven by the combustion gas, and the compression. A gas turbine control device equipped with a regulating valve for adjusting the flow rate of extracted air extracted from the machine.
It is configured to open the regulating valve when the load of the gas turbine is shut off and to control the opening degree of the regulating valve based on an index correlated with the output of the gas turbine immediately before the load shutoff of the gas turbine.
When the output of the gas turbine immediately before the load is cut off is a second output larger than the first output, the second opening degree of the regulating valve is the output of the gas turbine immediately before the load cutoff is the first output. said to be larger than the first opening of the control valve when, Ri adjustable der between the fully closed and fully open state of the opening during load rejection of the gas turbine,
When the load cutoff signal of the gas turbine is not detected, the current value of the index is held as the previous value of the index, and when the load cutoff signal is detected, the previous value is acquired as the index immediately before the load cutoff. A gas turbine control device characterized by having an index acquisition unit configured in . The gas turbine control device according to claim 1, wherein the load shedding is an operation of disconnecting the gas turbine from the load during load operation. Claim 1 or 2 characterized in that the index is the output of the gas turbine immediately before the load cutoff of the gas turbine, or the opening degree of the inlet guide blade of the compressor immediately before the load cutoff of the gas turbine. The gas turbine control device according to. A compressor for generating compressed air, a combustor for burning fuel using the compressed air to generate combustion gas, a turbine configured to be driven by the combustion gas, and the compression. A gas turbine control device equipped with a regulating valve for adjusting the flow rate of extracted air extracted from the machine.
It is configured to open the regulating valve when the load of the gas turbine is shut off and to control the opening degree of the regulating valve based on an index correlated with the output of the gas turbine immediately before the load shutoff of the gas turbine.
When the output of the gas turbine immediately before the load is cut off is a second output larger than the first output, the second opening degree of the regulating valve is the output of the gas turbine immediately before the load cutoff is the first output. The opening degree at the time of load interruption of the gas turbine can be adjusted between the fully open state and the fully closed state so as to be larger than the first opening degree of the adjusting valve in the case.
A valve opening degree calculation unit that calculates the opening degree of the adjusting valve according to the index when the load of the gas turbine is cut off.
Controller features and to Ruga turbines in that it comprises a valve opening correction unit configured to correct the ambient temperature to the angle calculated by said valve opening calculation section. The minimum opening degree is selected from the required opening degree of the adjusting valve corresponding to the temperature measurement value of the high temperature portion of the gas turbine and the opening degree of the adjusting valve determined based on the index. The gas turbine control device according to any one of claims 1 to 4, further comprising a minimum opening degree selection unit. The adjusting valve is a circulation valve provided in a circulation line for returning the extracted air to the intake side of the compressor, or at least for adjusting the supply amount of the extracted air from the compressor to the turbine. The control device for a gas turbine according to any one of claims 1 to 5, wherein the bleed valve is at least one of them. The gas turbine according to any one of claims 1 to 6, wherein the opening / closing timing and opening degree of each of the plurality of adjusting valves are controlled independently of the other adjusting valves. Control device. With a compressor to generate compressed air,
A combustor for burning fuel using the compressed air to generate combustion gas,
A turbine configured to be driven by the combustion gas,
A regulating valve that adjusts the flow rate of the extracted air extracted from the compressor,
Wherein configured to control the opening degree of the adjustment valve, and a control device according to any one of claims 1 to 7,
A gas turbine characterized by being equipped with. A compressor for generating compressed air, a combustor for burning fuel using the compressed air to generate combustion gas, a turbine configured to be driven by the combustion gas, and the compression. It is a control method of a gas turbine equipped with a regulating valve for adjusting the flow rate of extracted air extracted from the machine.
When the load of the gas turbine is shut off, the regulating valve is opened, and the opening degree of the regulating valve is controlled based on an index correlated with the output of the gas turbine immediately before the load is shut off of the gas turbine.
When the output of the gas turbine immediately before the load is cut off is a second output larger than the first output, the second opening degree of the regulating valve is the output of the gas turbine immediately before the load cutoff is the first output. The opening degree at the time of load interruption of the gas turbine is adjusted between the fully open state and the fully closed state so as to be larger than the first opening degree of the adjusting valve in the case .
When the load cutoff signal of the gas turbine is not detected, the current value of the index is held as the previous value of the index, and when the load cutoff signal is detected, the previous value is acquired as the index immediately before the load cutoff. A method of controlling a gas turbine, characterized in that. The gas turbine control method according to claim 9, wherein the load shedding is an operation of disconnecting the gas turbine from the load during load operation. 9 or 10 according to claim 9, wherein the index is the output of the gas turbine immediately before the load cutoff of the gas turbine, or the opening degree of the inlet guide blade of the compressor immediately before the load cutoff of the gas turbine. The method for controlling a gas turbine according to. A compressor for generating compressed air, a combustor for burning fuel using the compressed air to generate combustion gas, a turbine configured to be driven by the combustion gas, and the compression. It is a control method of a gas turbine equipped with a regulating valve for adjusting the flow rate of extracted air extracted from the machine.
When the load of the gas turbine is shut off, the regulating valve is opened, and the opening degree of the regulating valve is controlled based on an index correlated with the output of the gas turbine immediately before the load is shut off of the gas turbine.
When the output of the gas turbine immediately before the load is cut off is a second output larger than the first output, the second opening degree of the regulating valve is the output of the gas turbine immediately before the load cutoff is the first output. The opening degree at the time of load interruption of the gas turbine is adjusted between the fully open state and the fully closed state so as to be larger than the first opening degree of the adjusting valve in the case.
When the load of the gas turbine is shut off, a step of calculating the opening degree of the adjusting valve according to the index, and
A step of correcting the opening degree of the adjusting valve calculated in the step of calculating the opening degree by the atmospheric temperature, and a step of correcting the opening degree.
Features and to Ruga turbines control method further comprising the. The step includes a step of selecting the minimum opening degree of the required opening degree of the adjusting valve corresponding to the temperature measurement value of the high temperature portion of the gas turbine and the opening degree of the adjusting valve determined based on the index. The method for controlling a gas turbine according to any one of claims 9 to 12, wherein the gas turbine is controlled. The adjusting valve is a circulation valve provided in a circulation line for returning the extracted air to the intake side of the compressor, or at least for adjusting the supply amount of the extracted air from the compressor to the turbine. The method for controlling a gas turbine according to any one of claims 9 to 13, wherein the bleed valve is at least one of them. The method for controlling a gas turbine according to any one of claims 9 to 14, wherein the opening / closing timing and opening degree of each of the plurality of adjusting valves are controlled independently of the other adjusting valves.

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