JP2018127987A - Biaxial-type gas turbine power generation system and control method of biaxial-type gas turbine power generation system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a highly reliable biaxial-type gas turbine power generation system capable of safely shifting to a no-load rating state while restricting the over-speed of a low pressure turbine during load breaking and a control method thereof.SOLUTION: A biaxial-type gas turbine power generation system comprises: a compressor for compressing air; a combustion chamber for burning the air compressed by the compressor and fuel; a high pressure turbine driven by the combustion gas produced in the combustion chamber coaxially with the compressor; a low pressure turbine driven by the combustion gas which has driven the high pressure turbine with a separate shaft from the compressor; and means for extracting the compressed air to the compressor, in which by setting the temperature of the mixed gas of extracted gas from the combustion gas which has driven the high pressure turbine and the compressed air extracted from the compressor to the rated exhaust gas temperature or lower, the output of the low pressure turbine is reduced and the over-speed is safely prevented while protecting an exhaust system from the high temperature of the combustion gas.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a two-shaft gas turbine power generation system and a control method thereof, and more particularly to a technique effective for preventing over-rotation of a low-pressure turbine at the time of load interruption.

  In the event of an abnormality in the power transmission system, the generator is shut off from the system for the purpose of protecting the power transmission system, and the load interruption operation that rapidly reduces the fuel flow rate of the gas turbine that drives the generator to the flow rate of the no-load rating To implement.

  In load shedding operation, the gas turbine is affected by the time difference from generator shutoff to fuel flow rate drop, fuel flow response delay due to valve opening and closing speed, and combustion of fuel remaining in the piping from the fuel flow control valve to the combustor. There is also a temporary increase in the generator speed (turbine speed).

  An excessive increase in the turbine rotational speed damages the drive shaft and the turbine blades and causes a reduction in the service life. Therefore, it is necessary to perform an operation for preventing the turbine from over-rotating when the load is interrupted.

  As a background art in this technical field, for example, there is a technique such as Patent Document 1. Patent Document 1 states that “a combustion gas is extracted from between a high-pressure turbine outlet and a low-pressure turbine inlet in a two-shaft gas turbine to an exhaust system, thereby reducing the flow rate of the combustion gas flowing into the low-pressure turbine to prevent over-rotation of the low-pressure turbine. Is disclosed.

  Further, in Patent Document 2, a bypass passage having a bypass flow rate adjusting valve branched from the middle of a conduit from the turbine to the booster compressor drive turbine and connected to the outlet side of the booster compressor drive turbine is provided. Disclosed is a gas turbine power generator that prevents wasteful consumption of the power of a booster compressor when a relatively large amount of gas fuel is not required at the time of start-up or partial load, etc., by controlling the opening / closing of a flow regulating valve. ing. (See FIG. 6 and paragraph [0053] of Patent Document 2)

JP 2005-233157 A JP 2003-166428 A

  As described above, in a gas turbine power generation system, it is necessary to prevent over-rotation of the turbine at the time of load interruption. In particular, a compressor and a driving turbine (high-pressure turbine) are connected by a compressor shaft (high-pressure driving shaft), In a two-shaft gas turbine power generation system in which a generator and an output turbine (low pressure turbine) are connected by an output shaft, the output turbine (low pressure turbine) is not connected to a compressor with a large load. Turbine) is likely to over-rotate, and countermeasures are an important issue.

  The method of using a bleed valve at the high-pressure turbine outlet disclosed in Patent Document 1 can suppress the increase in the rotational speed of the low-pressure turbine because the combustion gas inflow amount is reduced and the output of the low-pressure turbine is reduced.

  However, if the combustion gas is directly connected to the exhaust system, there is a problem that the exhaust system is damaged due to a high temperature or the gas turbine system is stopped due to detection of an abnormal exhaust temperature.

  Similarly, as in Patent Document 2, a bypass path that connects the turbine outlet and the booster compressor drive turbine outlet is provided, and the combustion gas flows without going through the booster compressor drive turbine. Damage to the exhaust system due to high-temperature combustion gas and detection of abnormal exhaust temperature are problematic.

  Therefore, an object of the present invention is to provide a highly reliable two-shaft gas turbine power generation system and a control method thereof that can safely shift to a no-load rated state while suppressing over-rotation of a low-pressure turbine at the time of load interruption. It is to provide.

  In order to achieve the above object, the present invention is connected to the compressor by a compressor that compresses air, a combustor that combusts compressed air and fuel compressed by the compressor, and a high-pressure drive shaft, A high-pressure turbine that is driven by combustion gas generated by a combustor, a low-pressure turbine that is driven by combustion gas that drives the high-pressure turbine, and a power generation that is connected to the low-pressure turbine by a low-pressure drive shaft and generates power by driving the low-pressure turbine Machine, a power transmission system obtained by the generator and a breaker that cuts off the connection between the generator, an exhaust system that guides exhaust discharged from the low-pressure turbine to the outside, the compressor and the exhaust system A compressed air extraction system through which compressed air passes, a compressor extraction valve for extracting compressed air from the compressor to the exhaust system, an outlet of the high-pressure turbine, and the exhaust A compressor connected to the exhaust system, connected to the exhaust system, a combustion gas extraction system through which the combustion gas passes through, a combustion gas extraction valve for extracting combustion gas from an outlet of the high-pressure turbine to the exhaust system, A two-shaft gas turbine power generation system comprising a mixed gas exhaust system through which a mixed gas obtained by mixing compressed air from the high-pressure turbine and a combustion gas from an outlet of the high-pressure turbine passes. During load shutoff operation of the power generation system, compressed air is extracted from the compressor to the exhaust system via the compressed air extraction system, and the combustion gas is discharged from the outlet of the high pressure turbine to the exhaust system via the combustion gas extraction system The flow rate of the combustion gas flowing into the low-pressure turbine is reduced by extracting the gas.

  The present invention also relates to a control method for a two-shaft gas turbine power generation system, wherein compressed air is supplied from a compressor to an exhaust system via a compressed air bleed system during a load shut-off operation of the two-shaft gas turbine power generation system. Extracting and extracting the combustion gas from the outlet of the high-pressure turbine to the exhaust system through the combustion gas extraction system reduces the flow rate of the combustion gas flowing into the low-pressure turbine.

  According to the present invention, the exhaust system is protected from a high temperature above the rated exhaust temperature by preventing the over-rotation of the low-pressure turbine by extracting the combustion gas discharged from the high-pressure turbine outlet at the time of load interruption, and the exhaust temperature abnormality, etc. Therefore, the gas turbine power generation system can be prevented from being stopped, and can be safely shifted to a no-load rated state.

  As a result, the reliability of the two-shaft gas turbine power generation system can be improved.

  Problems, configurations, and effects other than those described above will be clarified by the following description of embodiments.

1 is a schematic view of a two-shaft gas turbine power generation system according to an embodiment of the present invention. 1 is a schematic diagram of a low-pressure turbine overspeed prevention control device according to an embodiment of the present invention. 1 is a schematic view of a two-shaft gas turbine power generation system according to an embodiment of the present invention. 1 is a schematic view of a two-shaft gas turbine power generation system according to an embodiment of the present invention. 1 is a schematic view of a two-shaft gas turbine power generation system according to an embodiment of the present invention.

  Embodiments of the present invention will be described below with reference to the drawings. In the drawings, the same components are denoted by the same reference numerals, and detailed description of the overlapping portions is omitted.

  With reference to FIG. 1 and FIG. 2, a two-shaft gas turbine power generation system and a control device at the time of load interruption according to a first embodiment of the present invention will be described. FIG. 1 is a schematic diagram of a two-shaft gas turbine power generation system and a control device thereof according to this embodiment. FIG. 2 is a schematic diagram of the control device (low pressure turbine over-rotation prevention control device) 100 in FIG.

  As shown in FIG. 1, the two-shaft gas turbine power generation system of this embodiment combusts a compressor 2 that compresses air 20, combustion air (compressed air) 22 compressed by the compressor 2, and fuel 21. The combustor 7 to be driven, the high-pressure turbine 1 driven coaxially with the compressor 2 by the combustion gas 23 generated by the combustor 7, the high-pressure drive shaft 10 that transmits the driving force of the high-pressure turbine 1 to the compressor 2, and air Compressor 2 that inhales and pressurizes 20 to form combustion air (compressed air) 22, low-pressure turbine 3 that is driven by using combustion gas 24 from high-pressure turbine 1, and driving force of low-pressure turbine 3 that generates power from generator 4 And a generator 4 that generates electric power using the driving force of the low-pressure turbine 3.

  The electric power obtained by the generator 4 is transmitted from the power transmission system 26 to the power system via the circuit breaker 5 and the transformer 6. When some trouble occurs in the power system, the generator 4 is disconnected from the power transmission system 26 using the circuit breaker 5.

In addition, the two-shaft gas turbine power generation system of the present embodiment includes a combustion gas extraction valve 30 that extracts a part of the combustion gas 24 at the outlet of the high-pressure turbine and a combustion gas 27 that has been extracted in order to suppress excessive rotation of the low-pressure turbine. A combustion gas extraction system 40 is provided. In addition, the compressed air bleed through which the compressed air extracted through the compressor bleed valve 31 for extracting the compressed air 28 from the compressor 2 for reducing (cooling) the extracted combustion gas 27 to the rated exhaust temperature T _{ex, 0} or lower is passed. A system 41 is provided.

Further, a rotational speed meter 32 for measuring a change in the low-pressure turbine rotational speed N _LP , and a mixed gas exhaust through which the mixed gas passes to measure the temperature T _mix of the mixed gas 29 of the extracted combustion gas 27 and compressed air 28 The system 42 includes a thermometer 33. The mixed gas exhaust system 42 is connected to an exhaust system 43 through which exhaust gas discharged from the low-pressure turbine 3 passes. Further comprising a low pressure turbine overspeed prevention control device 100 for calculating the bleed valve opening C _B of the bleed valve opening C _A of the combustion gas compressed air. The mixed gas exhaust system 42 is connected to an exhaust treatment facility 44 such as an exhaust diffuser or an exhaust heat recovery boiler, and the exhaust gas (mixed gas 29) is processed by the exhaust treatment facility 44 and then released to the atmosphere.

Next, with reference to FIG. 2, a control method for preventing low-pressure turbine over-rotation at the time of load interruption of the two-shaft gas turbine power generation system of the present embodiment will be described. The low pressure turbine over-rotation prevention control device 100 includes a combustion gas extraction valve control device 101 that calculates the combustion gas extraction valve opening degree C _A from the low-pressure turbine rated rotation speed N _{LP, 0} and the current low-pressure turbine rotation speed N _LP , and rated exhaust. From the compressor bleed valve control device 102 that calculates the bleed valve opening degree C _B of compressed air from the temperature T _{ex, 0} and the temperature T _mix of the mixed gas 29, and the load cutoff signal detector 103 that detects the load cutoff signal S _CB Composed.

Here, a description will be given of a control method for combustion gas bleed valve opening C _A compressed air bleed valve opening C _B. When the combustion gas bleed valve control device 101 detects the load cutoff signal _SCB by the load cutoff signal detector 103, the low pressure turbine rated rotational speed setter 110 set with the low pressure turbine rated rotational speed N _{LP, 0} and the current low pressure turbine. the rotational speed _{N LP} and compared with the low-pressure turbine speed comparator 111 _{N LP, 0} and _{N LP} coincides combustion gas bleed valve opening command _{C a} calculated in bleed valve position calculator 112, the opening The opening degree of the combustion gas bleed valve 30 is controlled based on the command value.

Similarly, when the compressor bleed valve control device 102 detects the load cutoff signal _SCB with the load cutoff signal detector 103, the rated exhaust temperature setter 120 with the rated exhaust temperature _{Tex, 0} and the mixed exhaust gas temperature T are set. _Ex is compared with the mixed gas temperature comparator 121, and the compressed air bleed valve opening degree C _B at which T _ex becomes T _{ex, 0} or less is calculated by the compressor bleed valve opening degree calculator 122. Based on this, the opening degree of the compressor bleed valve 31 is controlled.

If such a control device is used, when the load cutoff signal _SCB is detected by the load cutoff signal detector, the combustion gas extraction valve 30 is controlled, and the combustion gas 24 flowing into the low pressure turbine is extracted to thereby extract the low pressure turbine speed. N _LP can be controlled so as not to change.

Further, the compressed gas 28 extracted by the compressor extraction valve 31 is mixed with the combustion gas 27 extracted by the combustion gas extraction valve 30 and the mixed gas exhaust system 42 reduces the temperature of the mixed gas 29 to the rated exhaust temperature T _{ex, 0} or less. By (cooling), the exhaust system 43 can be protected from a high temperature equal to or higher than the rated exhaust temperature.

  As described above, according to the two-shaft gas turbine power generation system and the control method thereof according to the present embodiment, a high temperature that is higher than the rated exhaust temperature while preventing over-rotation of the low-pressure turbine due to combustion gas extraction when the load is interrupted. Thus, the exhaust system 43 can be protected, and the stop of the gas turbine power generation system due to the abnormal exhaust temperature can be avoided, and the state can be safely shifted to the no-load rated state.

  With reference to FIG. 3, a two-shaft gas turbine power generation system and a control device at the time of load interruption according to a second embodiment of the present invention will be described. FIG. 3 is a schematic diagram of the two-shaft gas turbine power generation system and its control device according to this embodiment.

  In the first embodiment, as shown in FIG. 1, the combustion gas extraction system 40 is branched from the flow path of the combustion gas 24 connecting the outlet of the high pressure turbine 1 and the inlet of the low pressure turbine 3, and a part of the combustion gas 24 is exhausted. While extracting into the system and reducing the combustion gas 24 flowing from the high-pressure turbine 1 to the low-pressure turbine 3, a part of the compressed air (compressed air 28) is extracted from the compressor 2 into the exhaust system, and each of the extracted combustion gases 24 is extracted. Although a part of the compressed air and a part of the compressed air (compressed air 28) are mixed to form a mixed gas 29, in this embodiment, the combustion gas 24 connecting the outlet of the high-pressure turbine 1 and the inlet of the low-pressure turbine 3 is used. The present embodiment is different from the first embodiment in that a low-pressure turbine gas shut-off valve 34 is provided in the flow path and the opening / closing control is performed by the low-pressure turbine over-rotation prevention controller 100. Other configurations are the same as the configuration in FIG. 1 of the first embodiment.

  By providing the low-pressure turbine gas shut-off valve 34 in the flow path of the combustion gas 24 that connects the outlet of the high-pressure turbine 1 and the inlet of the low-pressure turbine 3, the inflow of the combustion gas 24 to the low-pressure turbine 3 can be shut off. The over-rotation of the low-pressure turbine 3 at the time of interruption can be prevented more reliably.

  The closing operation of the low-pressure turbine gas cutoff valve 34 may be performed simultaneously with or immediately after the input of the load cutoff signal to the load cutoff signal detector 103 of the low-pressure turbine over-rotation prevention control device 100. In consideration of the influence of the pressure rise of 1 and the like, control is performed so that the low-pressure turbine gas shut-off valve 34 is closed after the combustion gas and the compressed air extraction system 41 are extracted from the combustion gas extraction system 40 and the compressed air extraction system 41 to the exhaust system, respectively. May be.

  With reference to FIG. 4, a two-shaft gas turbine power generation system according to a third embodiment of the present invention and a control device during load interruption will be described. FIG. 4 is a schematic diagram of a two-shaft gas turbine power generation system and a control device thereof according to this embodiment.

  In the present embodiment, an extraction system for extracting a part of the compressed air 28 from the compressed air extraction system 41 to the high-pressure turbine 1 is provided, and further, a compressor extraction valve 35 is provided in the extraction system, so that the low-pressure turbine overspeed prevention control device is provided. 100 is different from the first embodiment in that the opening / closing control is performed by 100. Other configurations are the same as the configuration in FIG. 1 of the first embodiment.

  In this embodiment, one end of the compressed air extraction system 41 is connected to the intermediate stage (intermediate pressure stage) of the compressor 2 to extract the compressed air 28 from the intermediate stage (intermediate pressure stage) of the compressor 2 and compress it. A branch system branched from the air extraction system 41 is connected to an intermediate stage of the high-pressure turbine 1 so that the compressed air 28 flows into the intermediate stage of the high-pressure turbine 1. The compressed air 28 is extracted from the intermediate stage (intermediate pressure stage) of the compressor 2 in the intermediate stage (intermediate pressure stage) of the compressor 2 although the degree of air compression is medium (intermediate pressure). This is because the temperature of 28 is lower, and the temperature of the combustion gas can be more effectively reduced (cooled) when mixed with the combustion gas in the exhaust system.

  As in the present embodiment, in addition to the configuration of the first embodiment, by providing a bleed system that allows the compressed air 28 to flow from the intermediate stage (intermediate pressure stage) of the compressor 2 to the intermediate stage of the high-pressure turbine 1, Sometimes the temperature in the high-pressure turbine 1 can be reduced (cooled), and the temperature of the combustion gas extracted from the combustion gas extraction system 40 to the exhaust system can be lowered. Further, the temperature of the combustion gas 24 flowing into the low-pressure turbine 3 can be reduced (cooled), and the over-rotation of the low-pressure turbine 3 can be suppressed.

  With reference to FIG. 5, a description will be given of a two-shaft gas turbine power generation system and a control device at the time of load interruption according to a fourth embodiment of the present invention. FIG. 5 is a schematic diagram of the two-shaft gas turbine power generation system and its control device according to this embodiment.

  In the present embodiment, an extraction system for extracting a part of the compressed air 28 from the rear side of the compressor 2, that is, from the passenger compartment 38 to the exhaust system and the high-pressure turbine 1 is provided, and the compressor extraction valve 36 is provided in each of these extraction systems. , 37 is provided, and the low-pressure turbine over-rotation prevention control device 100 performs opening / closing control thereof, which is different from the first embodiment. Other configurations are the same as the configuration in FIG. 1 of the first embodiment.

  In this embodiment, an extraction system for extracting a part of the compressed air 28 is provided on the rear stage side (chamber compartment 38) of the compressor 2, and the extraction system is branched to the upstream stage of the exhaust system and the high-pressure turbine 1. The compressed air 28 is introduced. Since the compressed air 28 is extracted from the rear stage side (vehicle compartment 38) of the compressor 2, the temperature of the compressed air 28 is increased. However, since the pressure of the compressed air 28 is high, the compressed air extracted from the compressor 2 is exhausted. It is possible to supply the system and the high-pressure turbine 1 more efficiently.

  As in the present embodiment, in addition to the configuration of the first embodiment, a part of the compressed air 28 is extracted from the casing 38 of the compressor 2 to the exhaust system and the high-pressure turbine 1, so The temperature of the combustion gas can be reduced (cooled), and the temperature of the combustion gas extracted from the combustion gas extraction system 40 to the exhaust system can be lowered. Further, the temperature of the combustion gas 24 flowing into the low-pressure turbine 3 can be reduced (cooled), and the over-rotation of the low-pressure turbine 3 can be suppressed.

  In addition, this invention is not limited to an above-described Example, Various modifications are included. For example, the above-described embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described. Further, a part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. Further, it is possible to add, delete, and replace other configurations for a part of the configuration of each embodiment.

DESCRIPTION OF SYMBOLS 1 ... High pressure turbine 2 ... Compressor 3 ... Low pressure turbine 4 ... Generator 5 ... Circuit breaker 6 ... Transformer 7 ... Combustor 10 ... High pressure drive shaft 11 ... Low pressure drive shaft 20 ... Air 21 ... Fuel 22 ... Combustion air ( Compressed air)
23, 24 ... Combustion gas 25 ... Exhaust gas 26 ... Power transmission system 27 ... Extracted combustion gas 28 ... Compressed air 29 ... Mixed gas 30 ... Combustion gas bleed valve 31, 35, 36, 37 ... Compressor bleed valve 32 ... Number of revolutions Total 33 ... Thermometer 34 ... Low pressure turbine gas shut-off valve 38 ... Cabin 40 ... Combustion gas extraction system 41 ... Compressed air extraction system 42 ... Mixed gas exhaust system 43 ... Exhaust system 44 ... Exhaust treatment equipment 100 ... Control device (low pressure turbine) Over-rotation prevention control device)
DESCRIPTION OF SYMBOLS 101 ... Combustion gas bleed valve control apparatus 102 ... Compressor bleed valve control apparatus 103 ... Load interruption | blocking signal detector 110 ... Low pressure turbine rated speed setting device 111 ... Low pressure turbine speed comparator 112 ... Extraction valve opening calculator 120 ... Rated exhaust gas temperature setting device 121 ... Mixed gas temperature comparator 122 ... Compressor bleed valve opening calculator.

Claims (14)

A compressor for compressing air;
A combustor that burns compressed air and fuel compressed by the compressor;
A high-pressure turbine connected to the compressor by a high-pressure drive shaft and driven by combustion gas generated in the combustor;
A low pressure turbine driven by the combustion gas driving the high pressure turbine;
A generator connected to the low-pressure turbine by a low-pressure drive shaft and generating electric power by driving the low-pressure turbine;
A circuit breaker for cutting off the connection between the power transmission system of the electric power obtained by the generator and the generator;
An exhaust system for guiding the exhaust discharged from the low-pressure turbine to the outside;
Connecting the compressor and the exhaust system, and a compressed air extraction system through which compressed air passes;
A compressor bleed valve for extracting compressed air from the compressor to the exhaust system;
A combustion gas extraction system that connects the outlet of the high-pressure turbine and the exhaust system, and the combustion gas passes through the interior;
A combustion gas extraction valve for extracting combustion gas from an outlet of the high pressure turbine to the exhaust system;
A twin-shaft gas turbine power generation system that includes a mixed gas exhaust system that is connected to the exhaust system and through which a mixed gas obtained by mixing compressed air from the compressor and combustion gas from an outlet of the high-pressure turbine passes. Because
During the load shutoff operation of the two-shaft gas turbine power generation system, compressed air is extracted from the compressor to the exhaust system via the compressed air extraction system, and from the outlet of the high-pressure turbine via the combustion gas extraction system A two-shaft gas turbine power generation system characterized in that the flow rate of the combustion gas flowing into the low-pressure turbine is reduced by extracting the combustion gas into the exhaust system. A two-shaft gas turbine power generation system according to claim 1,
A low pressure turbine overspeed prevention control system having a compressor bleed valve control device and a combustion gas bleed valve control device;
The opening degree of the compressor bleed valve and the combustion gas bleed valve is controlled so that the temperature of the mixed gas is equal to or lower than a rated exhaust temperature during the load shutoff operation of the two-shaft gas turbine power generation system. Two-shaft gas turbine power generation system. A two-shaft gas turbine power generation system according to claim 2,
The compressor bleed valve control device includes a rated exhaust temperature setter, a mixed gas temperature comparator, and a compressor bleed valve opening calculator, a two-shaft gas turbine power generation system. A two-shaft gas turbine power generation system according to claim 2 or 3,
The combustion gas extraction valve control device includes a low-pressure turbine rated rotation speed setter, a low-pressure turbine rotation speed comparator, and an extraction valve opening calculator. A two-shaft gas turbine power generation system according to any one of claims 1 to 4,
A two-shaft gas turbine power generation system comprising a low-pressure turbine gas shut-off valve in a combustion gas flow path connecting an outlet of the high-pressure turbine and an inlet of the low-pressure turbine. A two-shaft gas turbine power generation system according to any one of claims 1 to 5,
The two-shaft gas turbine power generation system, wherein the compressed air bleed system is connected to an intermediate pressure stage of the compressor. The two-shaft gas turbine power generation system according to claim 6,
The compressed air extraction system has a branch system for extracting compressed air to an intermediate stage of the high-pressure turbine,
A two-shaft gas turbine power generation system, wherein the branch system is provided with a compressor bleed valve different from the compressor bleed valve. The two-shaft gas turbine power generation system according to claim 6,
Connected to the compressor cabin, and having a compressed air extraction system different from the compressed air extraction system,
The different compressed air bleed systems comprise a first branch system connected to the mixed gas exhaust system and a second branch system connected to the front stage of the high-pressure turbine,
A two-shaft gas turbine power generation system, wherein a first compressor bleed valve and a second compressor bleed valve are provided in the first branch system and the second branch system, respectively. A control method for a two-shaft gas turbine power generation system, comprising:
During the load shutoff operation of the two-shaft gas turbine power generation system, compressed air is extracted from the compressor to the exhaust system via the compressed air extraction system,
A control method for a two-shaft gas turbine power generation system, wherein the flow rate of the combustion gas flowing into the low-pressure turbine is reduced by extracting the combustion gas from the outlet of the high-pressure turbine to the exhaust system via the combustion gas extraction system. . A control method for a two-shaft gas turbine power generation system according to claim 9,
During the load shut-off operation of the two-shaft gas turbine power generation system, the amount of compressed air and the amount of combustion gas are adjusted so that the temperature of the mixed gas of compressed air and combustion gas in the exhaust system is equal to or lower than the rated exhaust temperature. A control method for a two-shaft gas turbine power generation system, characterized by controlling an extraction amount. A control method for a two-shaft gas turbine power generation system according to claim 9 or 10,
The flow rate of the combustion gas flowing into the low-pressure turbine is reduced by closing a low-pressure turbine gas shut-off valve provided in a combustion gas flow path connecting the outlet of the high-pressure turbine and the inlet of the low-pressure turbine. A control method for a two-shaft gas turbine power generation system. A control method for a two-shaft gas turbine power generation system according to any one of claims 9 to 11,
A control method for a two-shaft gas turbine power generation system, wherein compressed air is extracted from an intermediate pressure stage of the compressor to the exhaust system. A control method for a two-shaft gas turbine power generation system according to claim 12,
A control method for a two-shaft gas turbine power generation system, wherein compressed air is extracted from an intermediate pressure stage of the compressor to an intermediate stage of the high-pressure turbine. A control method for a two-shaft gas turbine power generation system according to claim 12,
A control method for a two-shaft gas turbine power generation system, wherein compressed air is extracted from a casing of the compressor to a front stage of the exhaust system and the high-pressure turbine.

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