JP2003148173A - Device for controlling rotation of gas turbine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To apply inlet guide blades as a means for actively controlling the increase of the rotational speed when the load of a gas turbine is cut off. SOLUTION: The device has a control means 14 for opening/closing the inlet guide blades 9 of a compressor 2 when the load of the gas turbine 1 is cut off. The load of the compressor 2 is increased by introducing air into the compressor 2 when the load is cut off so that the increase of the rotational speed is controlled. The inlet guide blades 9 are applied as a means for actively controlling the increase of the rotational speed when the load of the gas turbine 1 is cut off.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotation control device for a gas turbine including a compressor, a combustor, and a turbine when the load is cut off (including a single operation in a plant).

[0002]

2. Description of the Related Art In a gas turbine including a compressor, a combustor, and a turbine, the air compressed by the compressor is burned with fuel in the combustor, and becomes high-temperature combustion gas to expand in the turbine. The turbine drives a compressor, and the remaining output drives a load such as a generator. An inlet guide vane (IGV) is installed at the inlet of the compressor, and the amount of air flowing into the compressor can be increased or decreased by opening and closing the IGV.

In such a gas turbine, at the time of load shedding (including in-house single operation in which load operation is performed independently in the office), the increase in the rotational speed is suppressed by throttling the fuel to the combustor. At the same time, the IGV of the compressor is fully closed to reduce the amount of air flowing into the compressor.

[0004]

In the conventional rotation control when the load of the gas turbine is cut off, the increase in the rotation speed is suppressed by throttling the fuel to the combustor. If the closing speed of the fuel control valve is increased, the minimum throttle opening of the fuel control valve is reduced, or if the fuel is gas, the downstream volume of the flow control valve is reduced to increase the rotation speed when the load is cut off. It can be suppressed to some extent. However, after the completion of the equipment, it is difficult to change the equipment for increasing the closing speed of the fuel control valve or reducing the downstream volume of the flow control valve. After the completion, adjustment to reduce the minimum throttle opening of the fuel control valve is possible, but at present, there is almost no adjustment margin for suppressing the rotation speed. In addition, since the IGV of the compressor shifts to full closure at the same time as the load is cut off, the amount of air flowing into the compressor is reduced, which reduces the load on the compressor and makes it easier for the rotation speed to increase. .

Therefore, in the conventional gas turbine, once the equipment is completed, it is the current situation that the increase in the rotation speed at the time of load shedding is suppressed only by squeezing the fuel.

The present invention has been made in view of the above circumstances, and it is possible to positively suppress an increase in rotation speed when the load of the gas turbine is cut off even after the equipment is completed. An object is to provide a control device.

[0007]

SUMMARY OF THE INVENTION A gas turbine rotation control device of the present invention for achieving the above-mentioned object provides a compressor, a combustor, and a combustor to a combustor when the load of the gas turbine including the turbine is cut off. A rotation control device in which fuel is throttled to control a rotation state of a gas turbine is characterized by comprising control means for controlling opening and closing of inlet guide vanes of a compressor when a load of the gas turbine is cut off.

Further, the control means is provided with a function of not immediately closing the inlet guide vanes when the load of the gas turbine is cut off.

[0009] Further, it is characterized in that it is provided with a rotation status deriving means of the gas turbine, and the control means is provided with a function of controlling opening and closing of the inlet guide vanes according to the rotation status derived by the rotation status deriving means. To do.

Further, the control means is provided with a function of controlling the opening and closing of the inlet guide vanes according to a preset pattern according to the time after the load is cut off.

In addition, the preset pattern is to close the inlet guide vanes in the fully closing direction after the load is cut off,
After the lapse of a predetermined time, the inlet guide vanes are maintained at the same opening degree for a predetermined time or on the open side of the opening degree, and then the inlet guide vanes are fully closed. Characterize.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic configuration showing an entire gas turbine equipped with a rotation control device according to an embodiment of the present invention, and FIGS. 2 to 6 show changes in rotational speed with time and inlet guide. The opening and closing status of the wings is shown.

As shown in FIG. 1, the gas turbine 1 is provided with a compressor 2, a combustor 3 and a turbine 4, and the air compressed by the compressor 2 is combusted in the combustor 3 together with the fuel f, so that It becomes combustion gas and expands in the turbine 4. The turbine 4 drives the compressor 2 and the remaining output powers the generator 20.
It is designed to drive loads such as. The exhaust gas that has finished its work in the turbine 4 is sent to, for example, an exhaust heat recovery boiler (not shown) to recover heat.

The rotor 5 of the compressor 2 is composed of a large number of moving blades 6 annularly stacked in the axial direction, and the stator 7 has a stationary blade 8 between each moving blade 6 and on the rear side of the final stage moving blade 6. Are arranged. An inlet guide vane (IGV) 9 is provided upstream of the first stage moving blade 6. The air is given a circumferential (tangential) velocity by the IGV 9 and is introduced into the compressor 2, and the introduced air is the multistage rotor blades 6.
And the stationary vane 8 are alternately passed through to repeatedly accelerate and decelerate to increase the pressure.

The IGV 9 is provided with a large number of variable blades 10 rotatable in the circumferential direction, and a link 11 is attached to the base end of each variable blade 10. Each link 11 is supported by one drive ring 12, and the rotation of the drive ring 12 causes the links 11 to rotate (open and close) at the same angle all at once. The drive ring 12 is an actuator 13
The actuator 13 is driven by the control means 14
The drive command is output from. The control means 14 receives rotation speed information for deriving the rotation speed of the gas turbine and load cutoff information, as well as status information such as exhaust gas temperature, exhaust pressure and blade path temperature.

The turning angle (opening / closing angle) of the variable blade 10 of the IGV 9 is appropriately controlled according to the operating condition of the gas turbine 4 to adjust the circumferential speed of the air introduced into the compressor 2. The amount of inflow air is increased or decreased by. That is, the actuator 13 is driven based on a command from the control means 14, and the variable blades 10 are simultaneously driven to open and close to a predetermined opening via the drive ring 12 and the link 11 in accordance with the operating condition of the gas turbine 1. Further, the drive command of the fuel supply means (fuel control valve etc.) for the fuel f to the combustor 3 is output from the control means 14.

In the gas turbine 4 described above, at the time of load shedding (including in-house independent operation in which load operation is performed independently in the office), the rotation speed is increased by throttling the fuel f to the combustor 3 according to a command from the control means 14. Is suppressed. At the same time, the control means 1
According to the command of No. 4, the IGV 9 of the compressor 2 is controlled to be opened and closed to suppress a rapid decrease in the compressor load, thereby suppressing an increase in the rotation speed. That is, the control means 14 has a function of not immediately closing the variable blade 10 of the IGV 9 when the load of the gas turbine 4 is cut off.

When the load on the gas turbine 4 is cut off, the variable blade 1
By not immediately closing 0 completely and reducing the amount of air introduced immediately, the load on the compressor 2 does not decrease sharply and the increase in rotation speed is positively suppressed. Therefore, a means for suppressing the increase in the rotation speed when the load is cut off can be secured in addition to the fuel flow rate adjusting means. Moreover, since the opening / closing control of the IGV 9 can be performed by adding a function to the control means 14, it can be applied as a means for suppressing an increase in the rotation speed when the load is cut off even after the equipment is completed. Is.

If the air is excessively increased when the increase in the rotational speed is suppressed by the opening / closing control of the IGV 9, the combustor 3 may be misfired. Therefore, the upper limit of the increased air is set or an appropriate amount of fuel is set. Countermeasures against misfire such as adding f (to the extent that the rotation speed does not increase) can be arbitrarily performed by separate control.

A specific example of opening / closing control of the IGV 9 will be described with reference to FIGS. 2 and 3 are control examples of the IGV 9 that derives the increase rate of the rotation speed according to the rotation speed information input to the control means 14 and that corresponds to the derived increase rate of the rotation speed. FIG. 6 is an example of control of the IGV 9 according to a pattern preset according to the time from load shedding.

Note that, in addition to the examples shown in FIGS. 2 to 6, the characteristics of the gas turbine 4, the entire plant, and the combustor 3
It is possible to control the opening / closing of the IGV 9 by various patterns according to the structural characteristics of the above and suppress the rotation speed.

As shown in FIG. 2, when the load is cut off, the IGV 9 is not closed and the open state is maintained until the rate of increase of the rotation speed becomes substantially zero according to the increase of the rotation speed, and the IGV 9 is kept open to the compressor. The operation is continued without reducing the amount of inflowing air and the IGV 9 is gradually moved to the closing side to be fully closed when the rotation speed starts to decrease. As a result, the increase in rotation speed is reliably suppressed, and there is no risk of an overspeed trip.

As shown in FIG. 3, when the load is cut off, the IGV 9 is closed or opened according to the rate of change of the rotation speed to increase or decrease the amount of air introduced. The air flowing into the compressor 2 gradually decreases, and the increase in the rotation speed gradually decreases without suddenly reducing the load on the compressor 2 until the rate of increase turns to a negative value.
Move IGV 9 gradually to the closing side to fully close it. As a result, the increase is suppressed in accordance with the degree of increase in the rotation speed, and it is possible to suppress a large increase in the rotation speed and make the rotation speed converge to the predetermined rotation speed.

As shown in FIG. 4, when the load is cut off, the rotation speed is increased, and at the same time, the IGV 9 is once closed to a predetermined opening degree to prevent misfiring due to a decrease in the amount of introduced air. To limit the increase in rotation speed. After that, when the rate of increase in rotation speed becomes 0, a little IG
The V 9 is opened to maintain its opening for a predetermined time and then fully closed, and the rotation speed is reduced by increasing the load on the compressor 2 by introducing air. Thereby, the increase of the rotation speed is suppressed while considering the misfire of the combustor 3 by the simple control according to the preset pattern, and the increase of the rotation speed is suppressed without the fear of the misfire and the predetermined rotation speed is suppressed. It becomes possible to condense in.

As shown in FIG. 5, when the load is cut off, the rotation speed is increased, and at the same time, the IGV 9 is closed to a predetermined opening for suppressing misfire due to a decrease in the amount of air introduced and maintained at that opening. Then, the load reduction amount of the compressor 2 is limited to suppress the increase of the rotation speed. After that, it is gradually closed to be fully closed. This makes it possible to suppress an increase in the rotation speed and suppress the increase in the rotation speed by a simple control according to a preset pattern so that the rotation speed falls within a predetermined rotation speed.

As shown in FIG. 6, at the time of load shedding, the IGV 9 is gradually closed to a predetermined opening at the same time as the rotation speed is increased, and the opening is maintained to maintain the opening to prevent misfire due to the introduction of air. The rotation speed is reduced by the load of the compressor 2.
After that, the closing operation is performed in a short time so as to be fully closed, and the opening is made to be a predetermined opening or later. This makes it possible to suppress a large increase in the rotation speed by a simple control according to a preset pattern, and to suppress the large increase in the rotation speed so that the rotation speed falls within a predetermined rotation speed.

[0027]

According to the rotation control device of the gas turbine of the present invention, when the load of the gas turbine including the compressor, the combustor and the turbine is cut off, the fuel to the combustor is throttled so that the rotation state of the gas turbine is reduced. In the controlled rotation control device, since the control means for controlling the opening / closing of the inlet guide vanes of the compressor when the load of the gas turbine is cut off is provided, the air flowing into the compressor suddenly flows when the load is cut off. It is possible to suppress the increase of the rotation speed without reducing the load of the compressor in a state where the rotation speed does not decrease. As a result, even after the equipment is completed, it can be applied as a means for positively suppressing the increase in rotation speed when the load of the gas turbine is cut off.

Further, since the control means is provided with a function of not immediately closing the inlet guide vanes when the load of the gas turbine is cut off, the control means to the compressor when the load is cut off. By not sharply reducing the air amount, it is possible to suppress the increase in rotation speed without sharply reducing the load on the compressor.

Further, the rotation status deriving means of the gas turbine is provided, and the control means is provided with the function of controlling the opening and closing of the inlet guide vanes according to the rotation status derived by the rotation status deriving means. Accordingly, the air can be introduced to delay the decrease of the load on the compressor and suppress the increase of the rotation speed.

Further, since the control means has a function of controlling the opening and closing of the inlet guide vanes according to a preset pattern according to the time after the load is cut off, air can be introduced by simple control. Thus, it is possible to limit the reduction of the load of the compressor and suppress the increase of the rotation speed.

In addition, the preset pattern is to close the inlet guide vanes in the fully closing direction after the load is cut off,
After the lapse of a predetermined time, the inlet guide vanes are maintained at the same opening degree for a predetermined time or on the open side of the same opening degree, and then the inlet guide vanes are operated to be fully closed. With simple control, it is possible to suppress the increase in rotation speed by introducing air while increasing the load on the compressor in consideration of the misfire of the combustor.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an entire gas turbine including a rotation control device according to an embodiment of the present invention.

FIG. 2 is a graph showing changes in rotational speed with time and opening / closing states of inlet guide vanes.

FIG. 3 is a graph showing changes over time in rotational speed and opening / closing states of inlet guide vanes.

FIG. 4 is a graph showing changes over time in rotational speed and opening / closing states of inlet guide vanes.

FIG. 5 is a graph showing changes over time in rotational speed and opening / closing states of inlet guide vanes.

FIG. 6 is a graph showing changes in rotational speed with time and opening / closing states of inlet guide vanes.

[Explanation of symbols]

1 gas turbine 2 compressor 3 combustor 4 turbine 5 rotor 6 moving blades 7 Stator 8 static wings 9 Entrance guide vane (IGV) 10 variable wings 11 links 12 drive ring 13 Actuator 14 Control means

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Chika Tanaka             2-1-1 Niihama, Arai-cho, Takasago City, Hyogo Prefecture             Takasago Works, Mitsubishi Heavy Industries, Ltd. F-term (reference) 3H021 AA02 AA08 BA06 CA01 CA04                       CA06 CA09 DA11 EA03 EA07                       EA16

Claims (5)

[Claims] 1. A rotation control device for controlling a rotational state of a gas turbine by restricting fuel to a combustor when a load of a gas turbine including a compressor, a combustor, and a turbine is cut off. A rotation control device for a gas turbine, comprising control means for controlling opening and closing of inlet guide vanes of a compressor when a load is cut off. 2. The gas turbine according to claim 1, wherein the control means has a function of not immediately closing the inlet guide vanes when the load of the gas turbine is cut off. Rotation control device. 3. The rotation state deriving unit of the gas turbine according to claim 2, wherein the control unit has a function of controlling opening / closing of the inlet guide vanes according to the rotation state derived by the rotation state deriving unit. A rotation control device for a gas turbine, which is characterized in that 4. The control means according to claim 2, wherein the control means is provided with a function of controlling the opening and closing of the inlet guide vanes according to a pattern set in advance according to the time after the load is cut off. Gas turbine rotation control device. 5. The preset pattern according to claim 4, wherein the inlet guide vanes are closed in a fully closed direction after the load is cut off, and after a predetermined period of time, the inlet guide vanes are opened for a predetermined period of time. A rotation control device for a gas turbine, characterized in that the inlet guide vane is operated to be fully closed after the opening is maintained at a certain degree or at an opening side of the present opening.