JP5675527B2 - Gas turbine control device and gas turbine control method - Google Patents

Description

  The present invention relates to a gas turbine control device and a gas turbine control method, and more particularly, to a gas turbine control device and a gas turbine using a cooling air introduction system that cools the turbine using a part of compressed air extracted from the middle of a compressor. It relates to a control method.

  As shown in FIG. 6, the gas turbine 101 including the compressor 102, the combustor 103, and the turbine 104 extracts a part of the compressed air from the middle of the compressor 102 and moves the moving blades in the turbine 104. A cooling air introduction system 105 is further provided to cool the components by supplying them to the casing. The cooling air introduction system 105 is, for example, a cooler having a cooling fan 109. For example, when operating in summer when the temperature is high, air flowing so that the temperature inside the turbine 104 does not become too high. It is cooling.

  As described above, for example, by cooling the moving blades and the casing, the clearance (clearance) between the casing of the gas turbine 101 and the moving blades during operation can be set small. Thereby, the amount of gas leak can be reduced and the efficiency of the gas turbine 101 can be improved. The clearance between the rotor blade and the casing is set to be minimum during a high load operation (rated operation) in which the turbine load increases and the gas temperature becomes high.

Further, by lowering the temperature of the cooling air generated by the cooler, the same cooling effect can be obtained with a smaller flow rate, and the amount of extracted air necessary for cooling can be reduced. The efficiency can be further improved.
As such a technique, Patent Document 1 describes a gas turbine cooling air control device in which cooling air is cooled by an air cooler according to the operating state of the gas turbine and then supplied to a stationary blade. ing.

Japanese Patent Laid-Open No. 7-54669

  However, in the gas turbine cooling air control device described in Patent Document 1, since the cooling air is controlled to be cooled according to the load of the gas turbine and the temperature in the disk cavity, there is a delay in cooling. As a result, cooling may not be sufficiently performed during high-load operation. As a result, contact occurs due to a decrease in the clearance between the moving blade and the casing, and in some cases, the blade may be damaged.

  The present invention has been made in view of such circumstances, and its purpose is to reduce the risk of blade breakage due to a decrease in clearance between the moving blade and the casing during high-load operation of the gas turbine, and to achieve high efficiency. An object of the present invention is to provide a gas turbine control device and a gas turbine control method for realizing a gas turbine.

The present invention employs the following means in order to solve the above problems.
A control device for a gas turbine according to the present invention includes a compressor that sucks combustion air into compressed air, and injects and burns fuel into the compressed air sent from the compressor to produce a high-temperature combustion gas. A combustor that generates a gas, a turbine that is located downstream of the combustor and that is driven by combustion gas that has exited the combustor, and a portion of the compressed air extracted from the middle of the compressor in a cooling unit In a control device applicable to a gas turbine having a cooling air introduction system for reducing the temperature and leading to a high temperature part inside the turbine, a reduction in the cooling part is performed based on an intake flow rate of combustion air to the compressor. It is characterized by controlling the temperature function.

  The gas turbine control method according to the present invention includes a compressor that sucks combustion air into compressed air, and injects and burns fuel into the compressed air sent from the compressor, A combustor that generates combustion gas, a turbine that is located downstream of the combustor and that is driven by the combustion gas exiting the combustor, and cools a portion of the compressed air extracted from the middle of the compressor And a cooling air introduction system for reducing the temperature at a section and leading to a high temperature section inside the turbine, and a gas turbine control method applicable to a gas turbine, on the basis of an intake flow rate of combustion air to the compressor The temperature reducing function in the cooling unit is controlled.

  In the control device for a gas turbine having such characteristics, the load on the turbine fluctuates depending on the intake flow rate of the combustion air to the compressor. Therefore, the temperature reduction function of the cooling unit is controlled according to the turbine load. Can do.

In the gas turbine control device according to the present invention, it is preferable that the temperature reduction function is controlled based on the opening degree of the IGV that varies the amount of combustion air to be sucked.
According to the above configuration, since the IGV having the highest relationship with the intake flow rate is used as a means for specifying the intake flow rate of the combustion air to the compressor, the intake flow rate can be easily controlled and accurate control can be performed. Become. Thereby, the precision of control of the temperature reduction function according to the load of a gas turbine can be improved.

In the gas turbine control device according to the present invention, it is preferable to perform feedback control so that the outlet temperature of the cooling section becomes a target temperature.
According to the said structure, the exit temperature of a cooling part can be set to target temperature.

In the gas turbine control device according to the present invention, it is preferable that the feedback control is performed when the output of the turbine is higher than a predetermined output.
According to the above configuration, when the output of the turbine is lower than the predetermined output, the control is based only on the IGV opening, so that it is not necessary to perform so accurate control.

  According to the present invention, by controlling the temperature reducing function of the cooling unit according to the load of the turbine, it is possible to prevent a decrease in the clearance between the moving blades and the casing constituting the turbine and to perform a highly efficient operation of the gas turbine. Can be secured.

It is a distribution diagram showing a gas turbine concerning one embodiment of the present invention. It is the schematic which shows the compressor of the gas turbine which concerns on one Embodiment of this invention. It is a block diagram which shows the control logic in the control part of the gas turbine which concerns on one Embodiment of this invention. It is a graph which shows the 1st relational expression in the control part of the gas turbine which concerns on one Embodiment of this invention. It is a graph which shows the 2nd relational expression in the control part of the gas turbine which concerns on one Embodiment of this invention. It is a systematic diagram which shows the conventional gas turbine.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the embodiment described here, the present invention is applied to a power generation facility.
In FIG. 1, a gas turbine 1 includes a compressor 2 that sucks combustion air into compressed air, and injects and burns fuel into the compressed air sent from the compressor 2 to generate high-temperature combustion gas. A combustor 3 to be generated, a turbine 4 that is positioned downstream of the combustor 3 and driven by combustion gas exiting the combustor 3, and a part of compressed air is extracted from the middle of the compressor 2 to extract the turbine 4 is provided with a cooling air introduction system 5 that leads to the inside of 4 and a control unit 6. The turbine 4 drives a generator 7.

A thermometer 12 that measures the inlet temperature of the compressor 2 is provided at the inlet of the compressor 2. Furthermore, a thermometer 13 for detecting the outlet temperature of the cooling air introduction system 5, that is, the temperature of the cooled air, is provided at the outlet of the cooling air introduction system 5.
Further, an IGV (Inlet Guide Vane) (intake amount adjusting unit) 8 for adjusting the amount of combustion air to be taken in by changing the opening degree is disposed at the inlet of the compressor 2. The opening degree of the IGV 8 is controlled by the IGV opening degree adjusting unit 14. The IGV opening adjustment unit 14 adjusts the opening of the IGV 8 according to the output of the turbine 4, that is, the load of the turbine 4.

  The cooling air introduction system 5 includes a cooling fan 9, a motor 10 connected to the cooling fan 9, and an inverter 11 that supplies electric power in a predetermined state to the motor 10. The cooling fan 9 is provided so as to cool the compressed air for cooling flowing in the pipe 15 connecting the compressor 2 and the turbine 4. The cooled compressed air is configured to cool the moving blades of the turbine 4 through the pipe 15.

  The control unit 6 includes an IGV opening signal S1 output from the IGV opening adjusting unit 14, an intake air temperature signal detected by a thermometer 12 provided at the inlet of the compressor 2, that is, an atmospheric temperature signal S2. The output of the inverter 11 is controlled based on the outlet temperature signal S3 detected by the thermometer 13 for detecting the outlet temperature of the cooling air introduction system 5 and the turbine output signal S4 detected by the sensor provided at the outlet of the turbine 4. Thus, it is provided to control the rotational speed of the cooling fan 9.

That is, the controller 6 receives the IGV opening signal S1, the atmospheric temperature signal S2, the cooling air introduction system outlet temperature signal S3, and the turbine output signal S4. Then, a rotation command to the inverter 11 is output.
The control unit 6 controls the inverter 11, and the cooling fan 9 is rotated by the motor 10 supplied with power by the inverter 11, but in the following description, for the sake of simplification, the control unit 6 is controlled. The description will be made assuming that the unit 6 controls the rotation speed of the cooling fan 9 (hereinafter referred to as cooling fan rotation speed).

FIG. 2 is a schematic view showing a part of the compressor 2.
As shown in FIG. 2, the IGV 8 is a portion of the compressor 2 into which combustion air flows, in other words, a blade disposed further upstream of the moving blade 22 formed in the rotor 21. The IGV 8 extends from the inner peripheral surface of the casing 23 of the compressor 2 toward the radially inner side of the casing 23, and a plurality of IGVs 8 are arranged at equal intervals in the circumferential direction of the casing 23.
The IGV 8 can be rotated around the axis line along the radial direction of the casing 23 by the IGV driving unit 16, whereby the opening of the IGV 8 varies and the combustion air amount is adjusted.

  Next, the cooling method of the gas turbine 1 according to the present embodiment will be described based on the cooling fan rotation speed control logic shown in FIG. Here, “×” indicates that the parameters of each equation are multiplied, “Δ” indicates subtraction, and “+” indicates addition. “TR” is a switch function and switches control logic according to conditions.

  The control logic of this embodiment is switched between a low load zone and a high load zone of the gas turbine 1 based on the turbine output signal S4. Specifically, in the low load zone of the gas turbine 1, the cooling fan rotation speed is determined based on the IGV opening and the atmospheric temperature, and in the high load zone, in addition to the determination based on the IGV opening and the atmospheric temperature, Feedback correction is performed so that the outlet temperature of the cooling air introduction system 5 becomes the target temperature. The switching condition will be described later.

First, the control logic of the cooling fan rotation speed in the low load zone of the gas turbine 1 will be described.
In the low load zone of the gas turbine 1, the cooling fan rotation speed is calculated by the IGV opening signal S1 that affects the amount of air extracted from the compressor 2, and is corrected by the atmospheric temperature signal S2.
Specifically, the cooling fan rotation speed is calculated using the first relational expression (f1) shown in FIG. 4 based on the IGV opening signal S1. Further, a correction coefficient is calculated using the second relational expression (f2) shown in FIG. 5 based on the atmospheric temperature signal S2, and the cooling fan rotation speed calculated using (f1) is multiplied by this correction coefficient, Use the final fan speed.
That is, in the low load zone of the gas turbine 1, the cooling fan rotation speed is controlled to increase as the IGV opening increases, and to increase as the atmospheric temperature rises.

  Next, a relational expression used for calculating the cooling fan rotation speed will be described. As described above, the relational expression includes the first relational expression (f1) indicating the relation between the IGV opening and the cooling fan rotation speed, the atmospheric temperature, and the correction coefficient for correcting the cooling fan rotation speed in accordance with the atmospheric temperature. The second relational expression (f2) indicating the relation

  As shown in FIG. 4, the first relational expression (f1) indicates that when the IGV opening is about 16% or less, the inverter rotational speed is a constant value, and when the IGV opening is about 16% or more, the IGV opening is On the other hand, the inverter rotation speed is related to increase in a substantially proportional relationship.

In the second relational expression (f2), as shown in FIG. 5, the correction coefficient increases linearly from about 0.3 to 1 when the atmospheric temperature is in the range of −10 ° to 15 ° C. That is, when the atmospheric temperature is in the range of −10 ° to 15 ° C., the cooling fan rotation speed is set lower than the rotation speed calculated by the first relational expression (f1) by this correction coefficient.
When the atmospheric temperature is in the range of 15 ° C. or higher, the correction coefficient is a value of 1 or more, and also increases linearly. That is, in the range where the atmospheric temperature is 15 ° C. or higher, the cooling fan rotation speed is set higher than the rotation speed calculated by the first relational expression (f1) by this correction coefficient, and the compressed air is further cooled.

Next, switching conditions between the low load zone and the high load zone will be described.
The low load zone and the high load zone are switched based on the turbine output signal S4. Specifically, at the stage where the turbine output is equal to or lower than the predetermined output, the switch function TR adds the numerical value of S = 0 transmitted from the signal SG to the cooling fan rotation speed calculated by the IGV opening and the atmospheric temperature. Switch as follows. That is, in the low load zone, the cooling fan rotation speed is controlled only by the IGV opening and the atmospheric temperature.

When the turbine output becomes equal to or higher than the predetermined output, it is determined that the state has shifted to the high load zone, the switch function TR is switched, and the cooling fan rotation speed is set so that the outlet temperature of the cooling air introduction system 5 is the target temperature (for example, 100 ° C. ) Feedback correction is performed.
Specifically, the rotational speed of the cooling fan is controlled by PI feedback control using the difference between the cooling air introduction system outlet temperature signal S3 and the target temperature of the cooling air introduction system 5.

  According to the above embodiment, the rotation speed of the cooling fan 9 is determined by the intake flow rate of the combustion air corresponding to the load of the turbine 4, so that the cooling fan rotation speed is controlled according to the load of the turbine 4. Can be implemented. Since the intake flow rate of the combustion air is adjusted by the opening degree of the IGV 8, the fan speed can be adjusted more accurately.

  Further, since the cooling fan rotation speed is corrected based on the atmospheric temperature, for example, it is possible to prevent overcooling of the turbine 4 when the atmospheric temperature is low, and when the atmospheric temperature is high, Cooling can be promoted.

  Further, in the high load zone of the turbine 4, feedback control is performed so that the outlet temperature of the cooling air introduction system 5 becomes the target temperature, so that the outlet temperature of the cooling air introduction system 5 can be set to the target temperature. .

  Furthermore, since the feedback control is switched so as to be performed only when the output of the turbine 4 is high, when the output of the turbine 4 is lower than a predetermined output, the control is based only on the IGV opening, and is more responsive. Control can be implemented.

  Due to the above effects, the cooling temperature can be managed within the target value, so that the risk of blade failure due to a decrease in the clearance between the blade and the casing during high load operation is reduced, and high-efficiency operation can be ensured.

  The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, the first relational expression (f1) and the second relational expression (f2) in the above embodiment are examples, and are not limited to these.

  Moreover, the cooling fan rotation speed in the first relational expression (f1) is not limited to being calculated by the IGV opening. For example, a flow meter may be disposed at the inlet of the compressor 2 and the calculation may be performed using a combustion air intake passage measured by the flow meter.

  Moreover, the cooler used for the cooling air introduction system 5 is not limited to the cooling fan, and may be configured to cool the compressed air using a heat exchanger, for example. For example, when applied to a gas turbine of a combined cycle power plant that further includes an exhaust heat recovery boiler and a steam turbine, the compressed air can be cooled by exchanging heat with the water supplied to the exhaust heat recovery boiler. Moreover, it is good also as a structure which cools compressed air by heat-exchanging with the fuel gas before supply.

DESCRIPTION OF SYMBOLS 1 ... Gas turbine, 2 ... Compressor, 3 ... Combustor, 4 ... Turbine, 5 ... Cooling air introduction system, 6 ... Control part (control apparatus), 7 ... Generator, 8 ... IGV, 9 ... Cooling fan (cooling) Part).

Claims (8)

A compressor that sucks combustion air into compressed air;
A combustor for injecting and burning fuel into the compressed air sent from the compressor to generate high-temperature combustion gas;
A turbine located downstream of the combustor and driven by combustion gas exiting the combustor;
A cooling air introduction system that reduces the temperature of a part of the compressed air extracted from the middle of the compressor in a cooling unit and guides it to a high temperature unit inside the turbine;
In a gas turbine control device applicable to a gas turbine comprising:
A control apparatus for a gas turbine, wherein a temperature reduction function in the cooling unit is controlled based on an intake flow rate of combustion air into the compressor.   2. The gas turbine control device according to claim 1, wherein the temperature reduction function is controlled based on an opening degree of an IGV that varies an amount of combustion air to be sucked.   The control apparatus for a gas turbine according to claim 1 or 2, wherein feedback control is performed so that an outlet temperature of the cooling unit becomes a target temperature.   The control apparatus for a gas turbine according to claim 3, wherein the feedback control is performed when the output of the turbine is higher than a predetermined output. A compressor that sucks combustion air into compressed air;
A combustor for injecting and burning fuel into the compressed air sent from the compressor to generate high-temperature combustion gas;
A turbine located downstream of the combustor and driven by combustion gas exiting the combustor;
A cooling air introduction system that reduces the temperature of a part of the compressed air extracted from the middle of the compressor in a cooling unit and guides it to a high temperature unit inside the turbine;
In a gas turbine control method applicable to a gas turbine comprising:
A method for controlling a gas turbine, comprising: controlling a temperature reducing function in the cooling unit based on an intake flow rate of combustion air into the compressor.   6. The gas turbine control method according to claim 5, wherein the temperature reduction function is controlled based on an opening degree of an IGV that varies an amount of combustion air to be sucked.   Furthermore, the control method of the gas turbine of Claim 5 or Claim 6 which performs feedback control so that the exit temperature of the said cooling unit turns into target temperature.   The gas turbine control method according to claim 7, wherein the feedback control is performed when the output of the turbine is higher than a predetermined output.

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