A dual-shaft turbine system and a starting method of an ultra-high parameter dual-shaft turbine system

Abstract

The application discloses a kind of double-shaft steam turbine and the starting method of superhigh parameter double-shaft steam turbine system, belong to thermal power field;The system includes the boiler for providing steam, the boiler is communicated with steam turbine module A and module B by pipeline, the module A is connected with generator A, module B is connected with generator B;The module A includes high-pressure cylinder A and medium-pressure cylinder A, the steam inlet of the boiler is communicated high-pressure cylinder A, the exhaust steam of high-pressure cylinder A is communicated to the steam inlet of medium-pressure cylinder A by reheater, the exhaust steam of medium-pressure cylinder A is communicated to the steam inlet of module B, the exhaust steam of module B is communicated to condenser;The application is suitable for superhigh parameter double-shaft steam turbine in the design of structure, effectively the structure design of traditional is adopted double-shaft design, only in the design of pipeline has certain difference, relatively can effectively improve steam turbine starting efficiency, and can effectively shorten starting time, realize the smooth transition of unit from starting state to running state.

Description

Technical Field

[0001] This invention relates to a starting method for a twin-shaft steam turbine and an ultra-high parameter twin-shaft steam turbine system, belonging to the field of steam turbine thermal power. Background Technology

[0002] One of the most effective ways to improve the power generation efficiency of thermal power units is to increase the steam inlet parameters of the units. Therefore, with the development of thermal power technology, the steam inlet parameters of thermal power units are becoming higher and higher. Currently, the highest operating parameter performance of thermal power generating units is 620°C, and major domestic groups have also set 650°C as the next research and development target for the steam inlet parameters of thermal power units.

[0003] With the steam inlet parameters reaching 650℃, the material development, manufacturing process, and manufacturing cost of high-temperature components have become the challenges in the development of the unit. In order to reduce the amount of nickel-based high-temperature materials used at 650℃, improve the manufacturing process of high-temperature components, and reduce manufacturing costs, the industry has proposed a scheme for a 650℃ ultra-high parameter dual-shaft steam turbine generator set. This scheme designs a separate shaft system for the high-temperature sections of the high-pressure module and the intermediate-pressure module of the steam turbine, and designs a separate shaft system for the low-temperature section of the intermediate-pressure module and the low-pressure module. The entire unit is a dual-shaft steam turbine generator set. Summary of the Invention

[0004] The purpose of this invention is to address the aforementioned problems by providing a startup method for a dual-shaft steam turbine and an ultra-high parameter dual-shaft steam turbine system. This system and method can effectively improve the startup efficiency of the steam turbine, shorten the startup time, and achieve a smooth transition of the unit from the startup state to the operating state.

[0005] The technical solution adopted in this invention is as follows:

[0006] A twin-shaft steam turbine includes a boiler for supplying steam, the boiler being connected via pipes to a turbine module A and a module B, the module A being connected to a generator A and the module B being connected to a generator B;

[0007] Module A includes a high-pressure cylinder A and an intermediate-pressure cylinder A. The boiler is connected to the steam inlet of the high-pressure cylinder A. The exhaust steam of the high-pressure cylinder A is connected to the steam inlet of the intermediate-pressure cylinder A through a reheater. The exhaust steam of the intermediate-pressure cylinder A is connected to the steam inlet of module B. The exhaust steam of module B is connected to the condenser. The condenser is connected to a feedwater and regeneration system and is connected to the boiler through the feedwater and regeneration system.

[0008] A first bypass branch is also provided on the branch connecting the boiler and the high-pressure cylinder A. This first bypass branch is connected to the reheat cold section of the reheater and the steam inlet branch of module B through a high-pressure bypass valve.

[0009] A second bypass branch is also provided on the branch connecting the reheater and the low-pressure cylinder A, and is connected to the condenser through the second bypass branch. A medium-pressure bypass valve is provided on the second bypass branch to regulate the steam inlet pressure of the medium-pressure cylinder A.

[0010] A third bypass branch is also provided on the branch connecting the intermediate pressure cylinder A and module B, and is connected to the condenser through the third bypass branch. A low-pressure bypass valve is provided on the third bypass branch.

[0011] Furthermore, a high-pressure main steam valve and a high-pressure regulating valve are provided on the branch connecting the boiler and the high-pressure cylinder A. The high-pressure main steam valve is located at the rear section of the first bypass branch connection point and at the front end of the high-pressure regulating valve.

[0012] Furthermore, a high-pressure discharge check valve is provided on the branch connecting the high-pressure cylinder A to the reheater, and the high-pressure discharge check valve is located at the front end of the first bypass branch connection point.

[0013] Furthermore, a medium-pressure main steam valve and a medium-pressure regulating valve are provided on the branch connecting the reheater and the medium-pressure cylinder A. The medium-pressure main steam valve is located at the rear section of the second bypass branch connection point and at the front end of the medium-pressure regulating valve.

[0014] Furthermore, a low-pressure regulating valve and a medium-pressure cylinder inlet check valve are provided on the branch connecting the intermediate-pressure cylinder A and module B. The low-pressure regulating valve is located at the front end of the first bypass branch connection point and at the rear end of the intermediate-pressure cylinder inlet check valve.

[0015] A start-up regulating valve is also installed on the first bypass branch, located near the connection point between the first bypass branch and the branch connecting the intermediate pressure cylinder A and module B.

[0016] Furthermore, module B includes an intermediate-pressure cylinder B, a low-pressure cylinder A, and a low-pressure cylinder B. The steam inlet of the intermediate-pressure cylinder B is connected to the steam outlet of the intermediate-pressure cylinder A and a first bypass branch. The steam outlet of the intermediate-pressure cylinder B is connected to the steam inlet of the low-pressure cylinder A and the low-pressure cylinder B. The steam outlet of the low-pressure cylinder A and the low-pressure cylinder B is connected to the condenser.

[0017] Furthermore, a first pressure monitoring point is provided at the exhaust end of the intermediate pressure cylinder A, and a second pressure monitoring point is provided at the inlet end of the intermediate pressure cylinder B.

[0018] A starting method for an ultra-high parameter twin-shaft steam turbine generator set, employing the aforementioned twin-shaft steam turbine, includes the following steps:

[0019] S1. When the steam turbine is working normally, the high-temperature steam from the boiler enters the reheater through the high-pressure cylinder A, and then enters the intermediate-pressure cylinder A, intermediate-pressure cylinder B, low-pressure cylinder A, and low-pressure cylinder B in sequence to do work. Finally, it enters the condenser, forms condensate, and then enters the next cycle.

[0020] S2. Turbine startup: The intermediate pressure cylinder A and intermediate pressure cylinder B are started together. Steam from the boiler enters the reheat cold section after passing through the high pressure bypass valve, and then enters the reheat hot section after absorbing heat in the reheater.

[0021] S3. When the unit starts running, steam from the reheat hot section enters the A intermediate pressure cylinder through the intermediate pressure main steam valve and the intermediate pressure regulating valve until the turbine speed stabilizes at the required speed. Its exhaust steam enters the condenser through the low pressure bypass valve. At the same time, steam from the reheat cold section enters the intermediate pressure cylinder B, the low pressure cylinder A, and the low pressure cylinder B through the start regulating valve until the turbine speed stabilizes at the required speed. The start regulating valve position is locked, and its exhaust steam enters the condenser. At this time, the low pressure regulating valve is in the closed state.

[0022] S4. When the unit starts grid connection, gradually increase the opening of the intermediate pressure regulating valve to increase the steam intake of intermediate pressure cylinder A, driving motor A to connect to the grid. When the power of motor A reaches the required power, the intermediate pressure regulating valve engages the power closed loop, and then gradually closes the low-pressure bypass valve. When the exhaust pressure of intermediate pressure cylinder A is greater than the steam intake pressure of intermediate pressure cylinder B, the intermediate pressure cylinder inlet check valve opens, and at the same time, the low-pressure regulating valve opens gradually, and motor B starts grid connection until the low-pressure bypass valve is completely closed and the low-pressure regulating valve is completely open. Then, release the valve position lock of the starting regulating valve and gradually close it until it is fully closed. During this period, the power of motor B gradually increases.

[0023] S5. When the turbine load increases, the power closed loop of the intermediate pressure regulating valve is released, the high pressure regulating valve is opened, steam enters the high pressure cylinder A, and the high pressure regulating valve and the intermediate pressure regulating valve open synchronously. The grid-connected load of module A and module B increases steadily until the high pressure regulating valve and the intermediate pressure regulating valve are fully open, and the entire unit reaches the rated load.

[0024] Furthermore, in step S3, when the intermediate pressure cylinder A is started, the acceleration rate is 200-500 r / min / min until the turbine speed stabilizes at 3000 r / min; when module B is started, the acceleration rate is 200-500 r / min / min until the turbine speed stabilizes at 3000 r / min.

[0025] Furthermore, in step S2, the steam parameters for the reheat cold section are: pressure 1.5-2.0 MPa, temperature 250-300℃; the steam parameters for the reheat hot section are: 1.5-2.0 MPa, temperature 350-400℃; the pressure of the reheat hot section is regulated by the medium-pressure bypass valve.

[0026] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0027] The present invention discloses a dual-shaft steam turbine system and a starting method for an ultra-high parameter dual-shaft steam turbine system. The structural design is suitable for ultra-high parameter dual-shaft steam turbines, effectively adopting a dual-shaft design instead of the traditional structural design. The only difference is in the pipeline design. Relatively speaking, it can effectively improve the turbine starting efficiency and shorten the starting time, achieving a smooth transition of the unit from the starting state to the running state. Attached Figure Description

[0028] The present invention will be described by way of example and with reference to the accompanying drawings, wherein:

[0029] Figure 1 This is a schematic diagram of the structure of the present invention.

[0030] The diagram is labeled as follows: 1-Boiler, 2-Reheater, 3-High-pressure cylinder A, 4-Intermediate-pressure cylinder A, 5-Intermediate-pressure cylinder B, 6-Low-pressure cylinder A, 7-Low-pressure cylinder B, 8-Motor A, 9-Motor B, 10-Condenser, 11-Feedwater and regeneration system, 12-High-pressure main steam valve, 13-High-pressure regulating valve, 14-Intermediate-pressure main steam valve, 15-Intermediate-pressure regulating valve, 16-Low-pressure regulating valve, 17-High-pressure bypass valve, 18-Intermediate-pressure bypass valve, 19-Low-pressure bypass valve, 20-High-pressure exhaust check valve, 21-Start-up regulating valve, 22-Intermediate-pressure cylinder inlet steam check valve, 23-First air pressure monitoring point, 24-Second air pressure monitoring point. Detailed Implementation

[0031] All features disclosed in this specification, or all steps in all disclosed methods or processes, may be combined in any way, except for mutually exclusive features and / or steps.

[0032] Any feature disclosed in this specification, unless otherwise stated, may be replaced by other equivalent or similar features. That is, unless otherwise stated, each feature is merely one example of a series of equivalent or similar features.

[0033] Example 1

[0034] A twin-shaft steam turbine system, such as Figure 1 As shown, it includes a boiler 1 for providing steam, the boiler 1 being connected to a steam turbine module A and a module B via pipes, the module A being connected to a generator A8, and the module B being connected to a generator B9;

[0035] Module A includes a high-pressure cylinder A3 and an intermediate-pressure cylinder A4. The boiler 1 is connected to the steam inlet of the high-pressure cylinder A3. The exhaust steam of the high-pressure cylinder A3 is connected to the steam inlet of the intermediate-pressure cylinder A4 through the reheater 2. The exhaust steam of the intermediate-pressure cylinder A4 is connected to the steam inlet of module B. The exhaust steam of module B is connected to the condenser 10. The condenser 10 is connected to the feedwater and regeneration system 11 and is connected to the boiler 1 through the feedwater and regeneration system.

[0036] A first bypass branch is also provided on the branch connecting boiler 1 and high-pressure cylinder A3. This first bypass branch is connected to the reheat cold section of reheater 2 and the steam inlet branch of module B through high-pressure bypass valve 17.

[0037] A second bypass branch is also provided on the branch connecting reheater 2 and low-pressure cylinder A6, and is connected to condenser 10 through the second bypass branch. A medium-pressure bypass valve 18 is provided on the second bypass branch to regulate the steam inlet pressure of medium-pressure cylinder A4.

[0038] A third bypass branch is also provided on the branch connecting the intermediate pressure cylinder A4 and module B, and is connected to the condenser 10 through the third bypass branch. A low-pressure bypass valve 19 is provided on the third bypass branch.

[0039] Based on the above specific design, and according to the relevant pipeline settings, specifically, a high-pressure main steam valve 12 and a high-pressure regulating valve 13 are provided on the branch connecting the boiler 1 and the high-pressure cylinder A3. The high-pressure main steam valve 12 is located at the rear section of the first bypass branch connection point and at the front end of the high-pressure regulating valve 13.

[0040] In a further design, a high-pressure discharge check valve 20 is provided on the branch connecting the high-pressure cylinder A3 to the reheater 2, and the high-pressure discharge check valve 20 is located at the front end of the first bypass branch connection point.

[0041] Based on the above specific design, as a more specific design, a medium-pressure main steam valve 14 and a medium-pressure regulating valve 15 are provided on the branch connecting the reheater 2 and the medium-pressure cylinder A4. The medium-pressure main steam valve 14 is located at the rear section of the second bypass branch connection point and at the front end of the medium-pressure regulating valve 15.

[0042] Synchronously, a low-pressure regulating valve 16 and a medium-pressure cylinder steam inlet check valve are provided on the branch connecting the intermediate-pressure cylinder A4 and module B. The low-pressure regulating valve 16 is located at the front end of the first bypass branch connection point and at the rear end of the intermediate-pressure cylinder steam inlet check valve.

[0043] A start-up regulating valve 21 is also provided on the first bypass branch, and is located near the connection point of the first bypass branch and the branch that connects the intermediate pressure cylinder A4 and module B.

[0044] In a further design, module B includes an intermediate-pressure cylinder B5, a low-pressure cylinder A6, and a low-pressure cylinder B7. The steam inlet of the intermediate-pressure cylinder B5 is connected to the steam outlet of the intermediate-pressure cylinder A4 and the first bypass branch. The steam outlet of the intermediate-pressure cylinder B5 is connected to the steam inlet of the low-pressure cylinders A6 and B7. The steam outlet of the low-pressure cylinders A6 and B7 is connected to the condenser 10.

[0045] In a further optimization, a first pressure monitoring point 23 is provided at the exhaust end of the intermediate pressure cylinder A4, and a second pressure monitoring point 24 is provided at the inlet end of the intermediate pressure cylinder B5. More specifically, the first pressure monitoring point 23 and the second pressure monitoring point 24 are equipped with pressure gauges to detect the pressure.

[0046] Example 2

[0047] To facilitate the explanation of the working principle of the steam turbine system designed in Example 1, and to demonstrate a startup method for an ultra-high parameter twin-shaft steam turbine system, more specifically, as follows... Figure 1 As shown, it includes the following steps:

[0048] S1. When the steam turbine is working normally, the high-temperature steam from boiler 1 (preferably 650°C) enters the reheater 2 through the high-pressure cylinder A3, and then enters the intermediate-pressure cylinder A4, intermediate-pressure cylinder B5, low-pressure cylinder A6, and low-pressure cylinder B7 in sequence to do work. Finally, it enters the condenser 10, forms condensate, and then enters the next cycle.

[0049] S2. The turbine is started using a combination of intermediate pressure cylinder A4 and intermediate pressure cylinder B5. Steam from boiler 1 enters the reheat cold section after passing through high pressure bypass valve 17, and then enters the reheat hot section after absorbing heat from reheater 2.

[0050] S3. When the unit starts running, steam from the reheat hot section enters the A intermediate pressure cylinder through the intermediate pressure main steam valve 14 and the intermediate pressure regulating valve 15 until the turbine speed stabilizes at the required speed. Its exhaust steam enters the condenser 10 through the low pressure bypass valve 19. At the same time, steam from the reheat cold section enters the intermediate pressure cylinder B5, low pressure cylinder A6 and low pressure cylinder B7 through the start regulating valve 21 until the turbine speed stabilizes at the required speed. The valve position of the start regulating valve 21 is locked, and its exhaust steam enters the condenser 10. At this time, the low pressure regulating valve 16 is in the closed state.

[0051] S4. When the unit starts grid connection, gradually increase the opening of the intermediate pressure regulating valve 15 to increase the steam intake of the intermediate pressure cylinder A4, driving the motor A8 to connect to the grid. When the power of the motor A8 reaches 10% of the THA power, the intermediate pressure regulating valve 15 engages in power closed-loop control. Then, gradually close the low-pressure bypass valve 19. When the exhaust pressure of the intermediate pressure cylinder A4 is greater than the steam intake pressure of the intermediate pressure cylinder B5, the intermediate pressure cylinder inlet check valve 22 opens. At the same time, the low-pressure regulating valve 16 is gradually opened, and the motor B9 starts grid connection until the low-pressure bypass valve 19 is completely closed and the low-pressure regulating valve 16 is completely open. Then, release the valve position lock of the starting regulating valve 21 and gradually close it until it is fully closed. During this period, the power of the motor B9 gradually increases.

[0052] S5. When the turbine load increases, the power closed loop of the intermediate pressure regulating valve 15 is released, the high pressure regulating valve 13 is opened, steam enters the high pressure cylinder A3, and the high pressure regulating valve 13 and the intermediate pressure regulating valve 15 open synchronously. The grid-connected load of module A and module B increases steadily until the high pressure regulating valve 13 and the intermediate pressure regulating valve 15 are fully open, and the entire unit reaches the rated load.

[0053] In the specific design described above, in step S3, when the intermediate pressure cylinder A4 is turned on, the acceleration rate is 200-500 r / min until the turbine speed stabilizes at 3000 r / min; when module B is turned on, the acceleration rate is 200-500 r / min until the turbine speed stabilizes at 3000 r / min.

[0054] Furthermore, in step S2, the steam parameters for the reheat cold section are: pressure 1.5-2.0 MPa, temperature 250-300℃; the steam parameters for the reheat hot section are: 1.5-2.0 MPa, temperature 350-400℃; the pressure of the reheat hot section is regulated by the medium-pressure bypass valve 18.

[0055] To be more specific, the high-parameter twin-shaft steam turbine drives motors A8 and B9 to perform work, and their working media belong to the same thermodynamic cycle system.

[0056] In the specific design described above, the high-parameter dual-shaft steam turbine generator set is started with two working steam sources: a reheat hot section and a reheat cold section. Both steam sources come from boiler 1, eliminating the need for an additional starting steam source for module B, thus achieving full utilization of energy. Simultaneously, the dual steam source design enables synchronous startup of modules A and B, eliminating the need for sequential steam intake and effectively saving startup time.

[0057] As a more specific design, when module A is started up to a low load (below 10%) stage, the exhaust steam enters condenser 10. During the start-up process of module B, the steam source comes from the reheat cold section. Furthermore, the grid connection and initial load process of module B are achieved by cutting the exhaust steam from module A into the intermediate pressure cylinder B5 and cutting off the start-up steam source of the reheat cold section.

[0058] In summary, the starting method of the dual-shaft steam turbine system and the ultra-high parameter dual-shaft steam turbine system of the present invention is suitable for ultra-high parameter dual-shaft steam turbines in terms of structural design. It effectively adopts the dual-shaft design of the traditional structural design, with only certain differences in the pipeline design. Relatively speaking, it can effectively improve the steam turbine starting efficiency and effectively shorten the starting time, so as to achieve a smooth transition of the unit from the starting state to the running state.

[0059] This invention is not limited to the specific embodiments described above. The invention extends to any new feature or combination disclosed in this specification, as well as any new method or process step or combination disclosed herein.

Claims

1. A twin-shaft steam turbine system, characterized in that: It includes a boiler for providing steam, the boiler being connected via pipes to a steam turbine module A and a module B, module A being connected to a generator A and module B being connected to a generator B; Module A includes a high-pressure cylinder A and an intermediate-pressure cylinder A. The boiler is connected to the steam inlet of the high-pressure cylinder A. The exhaust steam of the high-pressure cylinder A is connected to the steam inlet of the intermediate-pressure cylinder A through a reheater. The exhaust steam of the intermediate-pressure cylinder A is connected to the steam inlet of module B. The exhaust steam of module B is connected to the condenser. The condenser is connected to a feedwater and regeneration system and is connected to the boiler through the feedwater and regeneration system. A first bypass branch is also provided on the branch connecting the boiler and the high-pressure cylinder A. This first bypass branch is connected to the reheat cold section of the reheater and the steam inlet branch of module B through a high-pressure bypass valve. A second bypass branch is also provided on the branch connecting the reheater and the intermediate-pressure cylinder A, and is connected to the condenser through the second bypass branch. An intermediate-pressure bypass valve is provided on the second bypass branch to regulate the inlet steam pressure of the intermediate-pressure cylinder A. An intermediate-pressure main steam valve and an intermediate-pressure regulating valve are provided on the branch connecting the reheater and the intermediate-pressure cylinder A. The intermediate-pressure main steam valve is located at the end of the connection point of the second bypass branch on the branch connecting the reheater and the intermediate-pressure cylinder A, and is located at the front end of the intermediate-pressure regulating valve. A low-pressure regulating valve and a medium-pressure cylinder inlet check valve are provided on the branch connecting the intermediate-pressure cylinder A and module B. The low-pressure regulating valve is located at the front end of the connection point of the first bypass branch on the branch connecting the reheater and the intermediate-pressure cylinder A, and at the rear end of the intermediate-pressure cylinder inlet check valve. A start-up regulating valve is also provided on the first bypass branch, and is located near the connection point of the first bypass branch on the branch connecting the intermediate pressure cylinder A and module B; A third bypass branch is also provided on the branch connecting the intermediate pressure cylinder A and module B, and is connected to the condenser through the third bypass branch. A low-pressure bypass valve is provided on the third bypass branch. A high-pressure main steam valve and a high-pressure regulating valve are provided on the branch connecting the boiler and the high-pressure cylinder A. The high-pressure main steam valve is located at the rear section of the connection point of the first bypass branch on the branch connecting the boiler and the high-pressure cylinder A, and is located at the front end of the high-pressure regulating valve. A high-pressure discharge check valve is provided on the branch line connecting the high-pressure cylinder A to the reheater, and the high-pressure discharge check valve is located at the front end of the connection point of the first bypass branch on the branch line connecting the high-pressure cylinder A to the reheater. The module B includes an intermediate-pressure cylinder B, a low-pressure cylinder A, and a low-pressure cylinder B. The steam inlet of the intermediate-pressure cylinder B is connected to the steam outlet of the intermediate-pressure cylinder A and a first bypass branch. The steam outlet of the intermediate-pressure cylinder B is connected to the steam inlet of the low-pressure cylinder A and the low-pressure cylinder B. The steam outlet of the low-pressure cylinder A and the low-pressure cylinder B is connected to the condenser.

2. The twin-shaft steam turbine system as described in claim 1, characterized in that: The exhaust end of the intermediate pressure cylinder A is equipped with a first air pressure monitoring point, and the inlet end of the intermediate pressure cylinder B is equipped with a second air pressure monitoring point.

3. A starting method for an ultra-high parameter twin-shaft steam turbine system, employing a twin-shaft steam turbine system as described in claim 1 or 2, characterized in that: Includes the following steps: S1. When the steam turbine is working normally, the high-temperature steam from the boiler enters the reheater through the high-pressure cylinder A, and then enters the intermediate-pressure cylinder A, intermediate-pressure cylinder B, low-pressure cylinder A, and low-pressure cylinder B in sequence to do work. Finally, it enters the condenser, forms condensate, and then enters the next cycle. S2. Turbine startup: The intermediate pressure cylinder A and intermediate pressure cylinder B are started together. Steam from the boiler enters the reheat cold section after passing through the high pressure bypass valve, and then enters the reheat hot section after absorbing heat in the reheater. S3. When the unit starts running, steam from the reheat hot section enters the intermediate pressure cylinder A through the intermediate pressure main steam valve and the intermediate pressure regulating valve until the turbine speed stabilizes at the required speed. Its exhaust steam enters the condenser through the low pressure bypass valve. At the same time, steam from the reheat cold section enters the intermediate pressure cylinder B, low pressure cylinder A, and low pressure cylinder B through the start regulating valve until the turbine speed stabilizes at the required speed. The start regulating valve position is locked, and its exhaust steam enters the condenser. At this time, the low pressure regulating valve is in the closed state. S4. When the unit starts grid connection, gradually increase the opening of the intermediate pressure regulating valve to increase the steam intake of intermediate pressure cylinder A, driving motor A to connect to the grid. When the power of motor A reaches the required power, the intermediate pressure regulating valve engages the power closed loop, and then gradually closes the low-pressure bypass valve. When the exhaust pressure of intermediate pressure cylinder A is greater than the steam intake pressure of intermediate pressure cylinder B, the intermediate pressure cylinder inlet check valve opens, and at the same time, the low-pressure regulating valve opens gradually, and motor B starts grid connection until the low-pressure bypass valve is completely closed and the low-pressure regulating valve is completely open. Then, release the valve position lock of the starting regulating valve and gradually close it until it is fully closed. During this period, the power of motor B gradually increases. S5. When the turbine load increases, the power closed loop of the intermediate pressure regulating valve is released, the high pressure regulating valve is opened, steam enters the high pressure cylinder A, and the high pressure regulating valve and the intermediate pressure regulating valve open synchronously. The grid-connected load of module A and module B increases steadily until the high pressure regulating valve and the intermediate pressure regulating valve are fully open, and the entire unit reaches the rated load.

4. The starting method for an ultra-high parameter twin-shaft steam turbine system as described in claim 3, characterized in that: In step S3, when the intermediate pressure cylinder A is started, the acceleration rate is 200-500 r / min / min until the turbine speed stabilizes at 3000 r / min; when module B is started, the acceleration rate is 200-500 r / min / min until the turbine speed stabilizes at 3000 r / min.

5. The starting method for an ultra-high parameter twin-shaft steam turbine system as described in claim 3, characterized in that: In step S2, the steam parameters for the reheat cold section are: pressure 1.5-2.0 MPa, temperature 250-300℃; the steam parameters for the reheat hot section are: 1.5-2.0 MPa, temperature 350-400℃; the pressure of the reheat hot section is regulated by the medium-pressure bypass valve.

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