Gas turbine control method and gas turbine

Abstract

Improve surge margin. [Solution] A control method for a gas turbine having a compressor, a combustor, a turbine, an exhaust duct, inlet guide vanes that introduce air into the compressor, an extraction pipe that extracts air compressed by the compressor and branches into a first pipe that connects to the exhaust duct and a second pipe for cooling the turbine blades, a first control valve provided in the first pipe, a second control valve provided in the second pipe, a turbine bypass pipe that extends from the combustor casing to the exhaust duct, a third control valve provided in the turbine bypass pipe, and a control device that controls the amount of fuel, the opening of the inlet guide vane, and the first control valve, second control valve, and third control valve, wherein, upon receiving a load rejection signal, the control device sends control signals to the first to third control valves instructing them to open, and adjusts the amount of fuel and the opening of the inlet guide vane to control the gas turbine to no-load operation.

Description

[Technical Field]

[0001] The present disclosure relates to a gas turbine control method and a gas turbine. [Background technology]

[0002] A request for grid shedding may be made when a gas turbine is operating under load (see, for example, Patent Documents 1 to 3). This operation (load shedding) disconnects a gas turbine operating under load from the grid and instantly transitions it to a no-load, constant-speed state (hereinafter, this operation is referred to as load shedding). During load shedding, the fuel flow and inlet guide vanes (IGVs) are throttled to values ​​corresponding to the no-load state. Since fuel remaining in the piping flows into the gas turbine when there is no load, control is required to prevent excessive overspeeding, excessive fuel throttling that could result in misfire, and IGVs that close too quickly and cause surge. Furthermore, there is a trade-off between overspeeding, misfire, and surging during load shedding.

[0003] In the gas turbine compressor control method described in Patent Document 1, the outlet air pressure, rotation speed, and inlet guide vane angle of the compressor are detected, and the inlet guide vanes and air extraction valves are controlled based on the detected values ​​and a compressor map determined in advance at the design stage, thereby maintaining a maximum surge margin.

[0004] Furthermore, in order to prevent misfires after load rejection, the gas turbine described in Patent Document 2 controls the amount of fuel supplied so that the rotation speed of the gas turbine does not exceed a predetermined threshold when load is rejected, and also controls a bypass valve that adjusts the amount of compressed air extracted from the combustor casing from a closed state to an open state.

[0005] Furthermore, the gas turbine rotation control device described in Patent Document 3 controls the bleed valve, which bleeds compressed air from the compressor, to fully open and controls the inlet guide vane to an intermediate opening to suppress a decrease in rotation speed during load rejection. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 6-42368 [Patent Document 2] Japanese Patent Application Laid-Open No. 2017-106324 [Patent Document 3] Japanese Patent Application Laid-Open No. 2010-216441 Summary of the Invention [Problem to be solved by the invention]

[0007] The present disclosure has been made in consideration of the above circumstances, and has an object to provide a gas turbine control method and a gas turbine that can shorten the time required to reduce the pressure ratio of a compressor during load rejection and improve the surge margin. [Means for solving the problem]

[0008] In order to solve the above-mentioned problems, a control method for a gas turbine according to the present disclosure is a control method for a gas turbine having a compressor, a combustor, a turbine, an exhaust duct, an inlet guide vane that introduces air into the compressor, a bleeding pipe that extracts air compressed by the compressor and branches into a first pipe that connects to the exhaust duct and a second pipe that cools turbine blades, a first control valve provided in the first pipe, a second control valve provided in the second pipe, a turbine bypass pipe that extends from a casing of the combustor to the exhaust duct, a third control valve provided in the turbine bypass pipe, and a control device that controls a fuel amount that is the amount of fuel supplied to the combustor, an aperture of the inlet guide vane, and the first control valve, the second control valve, and the third control valve, wherein, upon receiving a load shedding signal, the control device sends control signals instructing the first control valve, the second control valve, and the third control valve to open the valves, and controls the gas turbine to operate in no-load mode by adjusting the fuel amount and the aperture of the inlet guide vane.

[0009] A gas turbine according to the present disclosure includes a compressor, a combustor, a turbine, an exhaust duct, an inlet guide vane that introduces air into the compressor, a bleed pipe that extracts the air compressed by the compressor and branches into a first pipe that connects to the exhaust duct and a second pipe that cools turbine blades, a first control valve provided in the first pipe, a second control valve provided in the second pipe, a turbine bypass pipe that extends from a casing of the combustor to the exhaust duct, a third control valve provided in the turbine bypass pipe, and a control device that controls a fuel amount that is the amount of fuel supplied to the combustor, an aperture of the inlet guide vane, and the first control valve, the second control valve, and the third control valve, and when the control device receives a load rejection signal, it sends control signals instructing the first control valve, the second control valve, and the third control valve to open the valves, and adjusts the fuel amount and the aperture of the inlet guide vane to control the gas turbine to operate in no-load mode. [Effects of the Invention]

[0010] According to the gas turbine control method and gas turbine of the present disclosure, it is possible to improve the surge margin. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a configuration diagram that schematically illustrates an example configuration of a gas turbine according to an embodiment of the present disclosure. FIG. [Figure 2] 1 is a configuration diagram that schematically illustrates an example configuration of a gas turbine according to an embodiment of the present disclosure. FIG. [Figure 3] 3A and 3B are diagrams illustrating an example of a control state of a control valve by a control device according to an embodiment of the present disclosure. [Figure 4] 10 is a flowchart illustrating an example of the operation of a control device according to an embodiment of the present disclosure. [Figure 5] FIG. 1 is a schematic block diagram illustrating a configuration of a computer according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0012] A gas turbine and a gas turbine control method according to an embodiment of the present disclosure will be described below with reference to FIGS. 1 to 5. In each drawing, the same or corresponding components are designated by the same reference numerals, and their description will be omitted as appropriate. In this embodiment, "piping" refers to a pipeline for transporting a fluid, and includes pipes, valves, pipe fittings, meters, piping support devices, and the like. However, unless otherwise specified, the name of a component "XX pipe" (where "XX" is an arbitrary character) can be read as "XX piping," and "XX piping" can be read as "XX pipe."

[0013] Fig. 1 is a configuration diagram that schematically shows the configuration of a gas turbine 2 according to an embodiment of the present disclosure. As shown in Fig. 1, the gas turbine 2 is a power-generating gas turbine that drives a generator 7 as a load. The gas turbine 2 includes a compressor 3, multiple combustors 4, a turbine 5, and a control device 100 as its main components.

[0014] The compressor 3 is connected to the turbine 5 via a rotary shaft 8A. The compressor 3 is rotationally driven by the rotational energy of the turbine 5 and compresses gas (air) drawn in through an intake duct 10 to generate compressed gas (compressed air). The compressed gas generated by the compressor 3 is introduced (supplied) to the combustor 4 via a casing 4A of the combustor 4. The intake duct 10 and an inlet guide vane 9, which is provided upstream of the compressor 3 and introduces air into the compressor 3, are provided on the inlet side of the compressor 3. The opening of the inlet guide vane 9 can be adjusted by driving an actuator 9A. The operation of the actuator 9A is controlled by a control device 100. The intake air flow rate of the compressor 3 is controlled by the control device 100 by adjusting the opening of the inlet guide vane 9 using the actuator 9A.

[0015] The combustor 4 is connected to a fuel supply line 12, and injects fuel supplied from the fuel supply line 12 into the compressed gas supplied from the compressor 3, and burns the fuel to generate combustion gas, which is the working fluid of the turbine 5. The combustion gas generated in the combustor 4 is sent from the combustor 4 to the turbine 5 in the downstream stage. The flow rate of the fuel supplied to the combustor 4 is adjusted by a fuel flow control valve 14 provided in the fuel supply line 12 under the control of the control device 100, for example, to set the output of the gas turbine 2 to a desired value.

[0016] The turbine 5 rotates using the combustion gas generated in the combustor 4. The turbine 5 is connected to the generator 7 by a rotating shaft 8B, and the generator 7 generates electricity using the rotational energy of the turbine 5. Exhaust gas from the turbine 5 is discharged from the turbine 5 into an exhaust duct 25. Signals such as instructions for the output value of the generator 7 (instructions for rated output, partial load less than rated output, etc.) and load shedding signals instructing load shedding are transmitted (notified) to the control device 100 from, for example, another control device (not shown).

[0017] As shown in FIG. 1 , the gas turbine 2 also includes an extraction pipe 18 and a turbine bypass pipe 23. The extraction pipe 18 extracts air compressed by the compressor 3 and branches into a first pipe 19 connected to an exhaust duct 25 and a second pipe 21 for cooling the blades (stationary vanes) of the turbine 5. The first pipe 19 is provided with an extraction valve (first control valve) 20. The second pipe 21 is provided with a cooling valve (second control valve) 22. The turbine bypass pipe 23 is a pipe extending from the casing 4A of the combustor 4 to the exhaust duct 25. The turbine bypass pipe 23 is provided with a bypass valve (third control valve) 24. The extraction valve 20, the cooling valve 22, and the bypass valve 24 are control valves, and their opening degrees are controlled by a control device 100, for example, continuously from fully open to fully closed or to either fully closed or fully open. 1, the extraction pipe 18, the first pipe 19, and the second pipe 21 are each shown as one system, but they may be provided as multiple systems. Also, the turbine bypass pipe 23 may be provided for each of the multiple casings 4A.

[0018] FIG. 2 shows an example of introducing compressed gas from the compressor 3 to the bleed pipe 18. In the example shown in FIG. 2, the gas turbine 2 is provided with, as an example of the bleed pipe 18 shown in FIG. 1, a bleed pipe 18A that introduces compressed gas from the low-pressure stage 3A of the compressor 3, a bleed pipe 18B that introduces compressed gas from the intermediate-pressure stage 3B of the compressor 3, and a bleed pipe 18C that introduces compressed gas from the high-pressure stage 3C of the compressor 3. The bleed pipe 18A branches into a first pipe 19A having a bleed valve 20A and a second pipe 21A having an orifice O2. The bleed pipe 18B branches into a first pipe 19B having a bleed valve 20B and a second pipe 21B having a cooling valve 22B that bypasses the orifice O1. The bleed pipe 18C branches into a first pipe 19C having a bleed valve 20C and a second pipe 21C having a cooling valve 22C. In Figure 2, bleed valves 20A, 20B and 20C correspond to the bleed valve 20 shown in Figure 1. Also, cooling valves 22B and 22C correspond to the cooling valve 22 shown in Figure 1.

[0019] The low-pressure compressed gas from the bleed pipe 18A is introduced into the exhaust casing 5A of the turbine 5 through the orifice O2, and is also introduced into the exhaust duct 25 through the bleed valve 20A when the bleed valve 20A is open. The medium-pressure compressed gas from the bleed pipe 18B is introduced into the exhaust duct 25 through the bleed valve 20B when the bleed valve 20B is open, and is introduced into the casing 5B of the turbine 5 through the cooling valve 22B when the cooling valve 22B is open, thereby cooling the stator blades in the turbine 5. The high-pressure compressed gas from the bleed pipe 18C is introduced into the exhaust duct 25 through the bleed valve 20C when the bleed valve 20C is open, and is introduced into the casing 5C of the turbine 5 through the cooling valve 22C when the cooling valve 22C is open, thereby cooling the stator blades in the turbine 5.

[0020] FIG. 3 shows an example of the correspondence between the operating states of the gas turbine 2 shown in FIG. 1 and the valve control states of the bleed valve 20, the cooling valve 22, and the bypass valve 24. The operating state is normal operation, rated operation is operation at rated output, and partial load is operation below rated output. The switching instant refers to operation immediately after load rejection (operation until no-load operation stabilizes after load rejection). The post-stabilization state refers to operation when the operation (no-load operation) of the gas turbine 2 reaches a predetermined stable state after load rejection. Here, the no-load operation is operation in which the output of the generator 7 is cut off from the grid, for example, and the turbine 3 rotates at a constant speed while the flame of the combustor 4 is held (maintained) so that the next power supply request can be responded to quickly. The predetermined stable state is, for example, a state in which the rotational speed (rotational speed) of the turbine 2 is maintained within a predetermined range for a predetermined period of time or more.

[0021] When the operating state is rated operation, the bleed valve 20 is closed (fully closed), the cooling valve 22 is partially open, and the bypass valve 24 is closed (fully closed). The partial opening is determined depending on the degree of cooling required, etc. When the operating state is partial load, the bleed valve 20 is closed (fully closed), the cooling valve 22 is partially open, and the bypass valve 24 is partially open. The partial opening is determined depending on the degree of cooling required, the load state, etc.

[0022] At the transfer instant, both for load dump from rated load and for load dump from partial load, the bleed valve 20, cooling valve 22 and bypass valve 24 are all fully open.

[0023] After stabilization, the extraction valve 20 is closed (fully closed), the cooling valve 22 is partially open, and the bypass valve 24 is partially open. Partial opening can be a control state similar to the no-load state at the start of the gas turbine 2, for example.

[0024] Next, with reference to Fig. 4, an example of the operation of the control device 100 at the time of load rejection in the gas turbine 2 shown in Fig. 1 will be described. The processing shown in Fig. 4 is started when the control device 100 receives a load rejection signal, for example, from another control device. When the processing shown in Fig. 4 is started, the control device 100 first outputs control signals to the extraction valve 20, the bypass valve 24, and the cooling valve 22 to instruct them to fully open (step S1). Next, the control device 100 controls the gas turbine 2 to operate at no load by adjusting the amount of fuel and the opening degree of the inlet guide vane 9 (step S2).

[0025] Next, the control device 100 waits for a predetermined time, for example, and then determines whether the no-load operation has reached a predetermined stable state (step S3). If the predetermined stable state has not been reached (step S3: NO), the control device 100 adjusts the fuel amount and the opening degree of the inlet guide vane 9 as necessary, and controls the gas turbine 2 to no-load operation (step S2).

[0026] If a predetermined stable state is reached (step S3: YES), the control device 100 outputs a control signal to the air bleed valve 20 to instruct it to fully close the valve (step S4), and ends the processing shown in Fig. 4. After the processing shown in Fig. 4 ends, the control device 100 waits in a no-load operation state for the next power supply request (signal) to be issued.

[0027] As described above, the present embodiment relates to the gas turbine 2 and a control method for the gas turbine 2, which has the compressor 3, the combustor 4, the turbine 5, the exhaust duct 25, the inlet guide vane 9 that introduces air into the compressor 3, the bleed pipe 18 that takes out the air compressed by the compressor 3 and branches into a first pipe 19 that connects to the exhaust duct 25 and a second pipe 21 that cools blades (stationary vanes) of the turbine 5, the bleed valve (first control valve) 20 provided in the first pipe 19, the cooling valve (second control valve) 22 provided in the second pipe 21, the turbine bypass pipe 23 that extends from the casing 4A of the combustor 4 to the exhaust duct 25, the bypass valve (third control valve) 24 provided in the turbine bypass pipe 23, and the control device 100 that controls the fuel amount that is the amount of fuel supplied to the combustor 4, the aperture of the inlet guide vane 9, the bleed valve 20, the cooling valve 22, and the bypass valve 24. In this embodiment, upon receiving a load rejection signal, the control device 100 sends control signals to the bleed valve 20, the cooling valve 22, and the bypass valve 24 to open the valves. The control device also adjusts the fuel flow rate and the opening of the inlet guide vane 9 to control the gas turbine 2 to no-load operation. This configuration shortens the time required to reduce the pressure ratio of the compressor 3 during load rejection, thereby improving the surge margin. That is, according to this embodiment, upon receiving (or generating) a load rejection signal, the bleed valve 20, the stator vane cooling valve 22, and the bypass valve 24 are opened to quickly reduce the pressure ratio of the compressor 3 and increase the surge margin (surge tolerance). This expands the range of control over overspeed, misfire prevention, and surge, which previously had a trade-off relationship. For example, after opening the bleed valve 20, the cooling valve 22, and the bypass valve 24, careful attention is paid to preventing overspeed and misfire, and the fuel flow rate and IGV throttling speed are adjusted to control the gas turbine 2 to no-load operation, resulting in an easier operation method compared to before the surge margin was increased.

[0028] In this embodiment, when the no-load operation after the load rejection reaches a predetermined stable state, the extraction valve (first control valve) 20 is closed. According to this configuration, it is possible to respond quickly to the next power supply request.

[0029] Furthermore, the control signal that instructs the valve to be open is a signal that instructs the valve to be fully open. By fully opening the valve, the pressure ratio of the compressor 3 can be reduced in a shorter time.

[0030] (Action and effect) According to the gas turbine control method and gas turbine configured as described above, it is possible to shorten the time required to reduce the pressure ratio of the compressor 3 during load rejection, and improve the surge margin.

[0031] (Other embodiments) The above describes in detail the embodiments of the present disclosure with reference to the drawings, but the specific configuration is not limited to this embodiment, and design changes and the like are also included within the scope that does not deviate from the gist of the present disclosure.

[0032] <Computer Configuration> FIG. 5 is a schematic block diagram showing the configuration of a computer according to an embodiment of the present disclosure. The computer 90 includes a processor 91 , a main memory 92 , a storage 93 , and an interface 94 . The above-described control device 100 is implemented in a computer 90. The operations of the above-described processing units are stored in the form of a program in a storage 93. A processor 91 reads the program from the storage 93, loads it into a main memory 92, and executes the above-described processing in accordance with the program. The processor 91 also allocates storage areas in the main memory 92 corresponding to the above-described storage units in accordance with the program.

[0033] The program may be for realizing some of the functions to be performed by the computer 90. For example, the program may be combined with other programs already stored in storage or other programs implemented in other devices to perform the functions. In other embodiments, the computer may include a custom LSI (Large Scale Integrated Circuit) such as a PLD (Programmable Logic Device) in addition to or instead of the above configuration. Examples of PLDs include PAL (Programmable Array Logic), GAL (Generic Array Logic), CPLD (Complex Programmable Logic Device), and FPGA (Field Programmable Gate Array). In this case, some or all of the functions realized by the processor may be realized by the integrated circuit.

[0034] Examples of storage 93 include a hard disk drive (HDD), a solid state drive (SSD), a magnetic disk, a magneto-optical disk, a compact disc read-only memory (CD-ROM), a digital versatile disc read-only memory (DVD-ROM), and a semiconductor memory. Storage 93 may be an internal medium directly connected to the bus of computer 90, or an external medium connected to computer 90 via interface 94 or a communication line. Furthermore, when this program is distributed to computer 90 via a communication line, computer 90 that receives the program may load the program into main memory 92 and execute the above-described processing. In at least one embodiment, storage 93 is a non-transitory tangible storage medium.

[0035] <Additional Notes> The gas turbine control method and the gas turbine according to the embodiment of the present disclosure can be understood, for example, as follows.

[0036] (1) A first aspect of the present invention provides a method for controlling a gas turbine including a compressor, a combustor, a turbine, an exhaust duct, an inlet guide vane that introduces air into the compressor, a bleed pipe that extracts air compressed by the compressor and branches into a first pipe that connects to the exhaust duct and a second pipe that cools blades of the turbine, a first control valve provided in the first pipe, a second control valve provided in the second pipe, a turbine bypass pipe that extends from a casing of the combustor to the exhaust duct, a third control valve provided in the turbine bypass pipe, and a control device that controls a fuel amount that is an amount of fuel supplied to the combustor, an aperture of the inlet guide vane, and the first control valve, the second control valve, and the third control valve, wherein, upon receiving a load rejection signal, the control device sends control signals instructing the first control valve, the second control valve, and the third control valve to open the valves, and adjusts the fuel amount and the aperture of the inlet guide vane to control the gas turbine to operate in a no-load state. According to this embodiment and the following embodiments, it is possible to shorten the time required to reduce the pressure ratio of the compressor 3 during load rejection, and improve the surge margin.

[0037] (2) A second aspect of the gas turbine control method is the gas turbine control method of (1), in which the first control valve is closed when the no-load operation reaches a predetermined stable state.

[0038] (3) A gas turbine control method according to a third aspect is the gas turbine control method according to (1) or (2), wherein the control signal instructing to open the valve is a signal instructing to fully open the valve.

[0039] (4) A gas turbine according to a fourth aspect includes a compressor, a combustor, a turbine, an exhaust duct, an inlet guide vane that introduces air into the compressor, a bleed pipe that takes out the air compressed by the compressor and branches into a first pipe that connects to the exhaust duct and a second pipe that cools blades of the turbine, a first control valve provided in the first pipe, a second control valve provided in the second pipe, a turbine bypass pipe that extends from a casing of the combustor to the exhaust duct, a third control valve provided in the turbine bypass pipe, and a control device that controls a fuel amount that is the amount of fuel supplied to the combustor, an aperture of the inlet guide vane, and the first control valve, the second control valve, and the third control valve, and when the control device receives a load rejection signal, it sends control signals instructing the first control valve, the second control valve, and the third control valve to open the valves, and controls the gas turbine to operate in no-load mode by adjusting the fuel amount and the aperture of the inlet guide vane. [Explanation of symbols]

[0040] 2...Gas turbine 3...Compressor 3A...Low pressure stage of compressor 3B: Medium pressure stage of compressor 3C: High-pressure stage of compressor 4...Combustor 4A...Combustor casing 5...Turbine 5A...Exhaust compartment 5B, 5C…Car compartment 7...Generator 8A, 8B...Rotating shaft 9...Entrance guide wing 9A...Actuator 10...Intake duct 12...Fuel supply line 14...Fuel flow control valve 18, 18A, 18B, 18C...Bleed pipe 19, 19A, 19B, 19C...First piping 23...Turbine bypass piping 20, 20A, 20B, 20C... Bleed valve (first control valve) 21, 21A, 21B, 21C…Second piping 22, 22B, 22C...Cooling valve (second control valve) 24...Bypass valve (third control valve) 25...Exhaust duct 100...Control device

Claims

1. A compressor; A combustor; The turbine and Exhaust duct and an inlet guide vane for introducing air into the compressor; an air extraction pipe that extracts the air compressed by the compressor and branches into a first pipe connected to the exhaust duct and a second pipe for cooling the turbine blades; a first control valve provided in the first pipe; a second control valve provided in the second pipe; a turbine bypass pipe extending from the combustor casing to the exhaust duct; a third control valve provided in the turbine bypass piping; a control device that controls a fuel amount that is the amount of fuel supplied to the combustor, an opening degree of the inlet guide vane, and the first control valve, the second control valve, and the third control valve; A method for controlling a gas turbine having When the control device receives a load rejection signal, it sends control signals to the first control valve, the second control valve, and the third control valve instructing them to open the valves in a direction so as to reduce the pressure ratio of the compressor in a short period of time from the operating state before the load rejection, and The gas turbine is controlled to operate in a no-load state by narrowing down the fuel amount and the opening degree of the inlet guide vane to values ​​corresponding to the no-load state. A method for controlling a gas turbine.

2. When the no-load operation reaches a predetermined stable state, the first control valve is closed. The method for controlling a gas turbine according to claim 1 .

3. The control signal instructing the valve to open is a signal instructing the valve to be fully open. The gas turbine control method according to claim 1 or 2.

4. A compressor; A combustor; The turbine and Exhaust duct and an inlet guide vane for introducing air into the compressor; an air extraction pipe that extracts the air compressed by the compressor and branches into a first pipe connected to the exhaust duct and a second pipe for cooling the turbine blades; a first control valve provided in the first pipe; a second control valve provided in the second pipe; a turbine bypass pipe extending from the combustor casing to the exhaust duct; a third control valve provided in the turbine bypass piping; a control device that controls a fuel amount that is the amount of fuel supplied to the combustor, an opening degree of the inlet guide vane, and the first control valve, the second control valve, and the third control valve; and When the control device receives a load rejection signal, it sends control signals to the first control valve, the second control valve, and the third control valve instructing them to open the valves in a direction so as to reduce the pressure ratio of the compressor in a short period of time from the operating state before the load rejection, and The gas turbine is controlled to operate in a no-load state by narrowing down the fuel amount and the opening degree of the inlet guide vane to values ​​corresponding to the no-load state. Gas turbine.

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