Generator set turbine steam throttling adjusting system and adjusting method

Abstract

The invention discloses a generator set turbine steam throttling adjusting system which comprises a heat exchange unit, the heat exchange unit is communicated with a first pipeline, a main steam valve is arranged on the first pipeline, the first pipeline is connected with a second pipeline, the second pipeline is divided into two branches, the two branches are a third pipeline and a fourth pipeline respectively, and an adjusting valve a is arranged on the third pipeline. An adjusting valve b is arranged on the fourth pipeline, the third pipeline and the fourth pipeline are converged to a steam pipeline, and the steam pipeline is connected with a steam turbine. The invention further discloses a steam throttling adjusting method for the turbine of the generator set. The problems that in an existing throttling adjusting technology, the heat efficiency is reduced, and the adjusting precision is poor are solved.

Description

Technical Field

[0001] The invention belongs to the technical field of steam regulation of power plant steam turbines, and in particular relates to a steam throttling regulation system of a generator set steam turbine. The invention also relates to a regulation method. Background Art

[0002] As the core power equipment of a power plant, the operating mode of the steam turbine directly affects the efficiency and cost of the entire power production process. Therefore, optimizing the steam turbine's operating mode is crucial to improving overall energy utilization. In the field of steam regulation of generator set steam turbines, traditional throttling control systems generally use a group of regulating valves of the same specifications connected in parallel for regulation. These regulating valves of the same specifications have the same flow area and flow characteristics, and perform synchronous opening and closing actions when the load command changes.

[0003] As power systems continue to demand higher efficiency, stability, and flexibility from generator units, traditional throttling control methods, despite their simple structure and unified control logic, have exposed significant flaws in actual wide-load peak-shaving operations. Flow regulation is increasingly limited across different load stages, making it difficult to meet the operational demands of modern power plants. When unit loads drop to the deep peak-shaving range (25%-50% THA), parallel control valves of the same type are forced to operate at a critically low opening. This creates a strong throttling effect as steam flows through narrow passages, leading to significant fluctuations in steam pressure and flow. This reduces thermal efficiency and poorly regulates the system, making it unable to meet the requirements for safe and stable grid operation under the new circumstances, significantly undermining the economic viability of power plant peak-shaving. Summary of the Invention

[0004] The purpose of the present invention is to provide a steam throttling regulation system for a steam turbine of a generator set, which solves the problems of reduced thermal efficiency and poor regulation accuracy existing in the existing throttling regulation technology.

[0005] A second object of the present invention is to provide a method for regulating steam throttling of a steam turbine of a generator set.

[0006] The first technical solution adopted by the present invention is a steam throttling regulation system for a steam turbine of a generator set, including a heat exchange unit, the heat exchange unit being connected to a first pipeline, a main steam valve being provided on the first pipeline, the first pipeline being connected to a second pipeline, the second pipeline being divided into two branches, the two branches being a third pipeline and a fourth pipeline, a regulating valve a being provided on the third pipeline, a regulating valve b being provided on the fourth pipeline, the third pipeline and the fourth pipeline being merged into a steam pipeline, and the steam pipeline being connected to a steam turbine.

[0007] The first technical solution of the present invention is also characterized in that: Both regulating valve a and regulating valve b are high-pressure regulating valves.

[0008] The nominal diameter of control valve a is larger than that of control valve b.

[0009] The second technical solution adopted by the present invention is a method for regulating steam throttling of a steam turbine of a generator set, which uses a steam throttling regulating system of a steam turbine of a generator set and is specifically implemented according to the following steps: Step 1: Obtain the unit load signal and determine the unit load operation stage; Step 2: When the unit is in the load-increasing stage, the openings of the regulating valves a and b are adjusted respectively to distribute the flow; Step 3: When the unit is in the load reduction stage, the openings of the regulating valve a and the regulating valve b are adjusted respectively to distribute the flow.

[0010] The second technical solution of the present invention is also characterized in that: Step 2 is specifically as follows: Step 2.1: Set 40% load as the second threshold and 85% load as the first threshold to determine the load increase range of the unit. In step 2.2, during the load increase phase between 0% and 40%, the steam inlet required by the steam turbine is small, and the opening is adjusted independently by regulating valve b. The heat exchange unit generates high-temperature, high-pressure steam, which passes through the main steam valve and then enters the steam turbine through regulating valve b. As the load increases, the opening of regulating valve b is adjusted from 0% to 100%, and the maximum flow rate of regulating valve b meets the steam inlet required by the steam turbine. Regulating valve a is in the closed state. In step 2.3, during the load increase phase between 40% and 85%, the steam inlet required by the steam turbine increases, and the maximum flow rate of control valve b cannot meet the required steam inlet of the steam turbine. Control valve b is fully opened, and control valve a takes over the regulation. The heat exchange unit generates high-temperature and high-pressure steam. After passing through the main steam valve, part of the high-temperature and high-pressure steam passes through control valve b, and the other part passes through control valve a. After converging, they enter the steam turbine. As the load increases, the opening of control valve a is adjusted from 0% to 100%, and control valve b remains fully open. In step 2.4, during the load increase phase between 85% and 100%, the steam inlet required by the steam turbine is close to the steam inlet flow rate under rated operating conditions. Both regulating valves b and a are fully open, and the heat exchange unit generates high-temperature and high-pressure steam. After passing through the main steam valve, part of the high-temperature and high-pressure steam passes through regulating valve b, and the other part passes through regulating valve a. After converging, they enter the steam turbine. As the load increases, both regulating valves a and b remain fully open.

[0011] Step 3 is as follows: Step 3.1: Set 40% load as the second threshold and 85% load as the first threshold to determine the load reduction range of the unit. In step 3.2, when the load is reduced from 100% to 85%, the heat exchange unit generates high-temperature, high-pressure steam. After passing through the main steam valve, part of the high-temperature, high-pressure steam passes through regulating valve b, and the other part passes through regulating valve a. After converging, they enter the steam turbine. As the load decreases, regulating valve a and regulating valve b remain fully open. In step 3.3, when the load decreases from 85% to 40%, the heat exchange unit generates high-temperature, high-pressure steam. After passing through the main steam valve, part of the high-temperature, high-pressure steam passes through regulating valve b, and the other part passes through regulating valve a. After converging, the steam enters the steam turbine. As the load decreases, the opening of regulating valve a is adjusted from 100% to 0%, and regulating valve b remains fully open. In step 3.4, when the load drops from 40% to 0%, the heat exchange unit generates high-temperature and high-pressure steam. After passing through the main steam valve, the high-temperature and high-pressure steam enters the steam turbine through the regulating valve b. As the load decreases, the opening of the regulating valve b is adjusted from 100% to 0%, and the regulating valve a is in the closed state.

[0012] In step 3.3, when the control valve a is adjusted in the load range of 40%-85%, the valve opening of the control valve a is always greater than 25% of the critical anti-cavitation opening.

[0013] In step 3.4, when the control valve b is adjusted below 40% load, the valve opening of the control valve b is always greater than 25% of the critical anti-cavitation opening.

[0014] The beneficial effects of the present invention are as follows: the steam throttling regulation system of the steam turbine of the generator set of the present invention reasonably distributes the flow in different load stages of the unit through the sequence of opening the small-diameter high-pressure regulating valve first and the large-diameter high-pressure regulating valve later, reduces throttling loss, improves regulation accuracy, and reduces fluctuations in steam pressure and flow; flexibly adapts to the operating requirements of the unit within a wide load range, especially under conditions of rapid load changes, improves the overall thermal efficiency and operating economy of the unit. The steam throttling regulation method of the steam turbine of the generator set of the present invention is a throttling regulation method that is more efficient, more precise, and more adaptable to wide load changes. It can accurately perform valve control, reduce throttling losses, and improve the thermal efficiency of the unit; it ensures the stability of the unit when it bears industrial steam supply loads, and has important practical promotion significance. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a schematic structural diagram of the steam throttling regulation system of the steam turbine of the generator set of the present invention; Figure 2 The present invention is a control logic diagram of the steam throttling regulation method for the steam turbine of the generator set.

[0016] In the figure, 1. heat exchange unit, 2. first pipeline, 3. main steam valve, 4. second pipeline, 5. third pipeline, 6. fourth pipeline, 7. regulating valve, 8. regulating valve, 9. steam turbine. DETAILED DESCRIPTION

[0017] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0018] Example 1 The steam throttling regulating system structure of the steam turbine of the generator set of the present invention is as follows: Figure 1 As shown, it includes a heat exchange unit 1, which is connected to a first pipeline 2. A main steam valve 3 is provided on the first pipeline 2. The first pipeline 2 is connected to a second pipeline 4. The second pipeline 4 is divided into two branches, which are a third pipeline 5 and a fourth pipeline 6. A regulating valve a7 is provided on the third pipeline 5, and a regulating valve b8 is provided on the fourth pipeline 6. The third pipeline 5 and the fourth pipeline 6 merge into a steam pipeline, and the steam pipeline is connected to a steam turbine 9.

[0019] Example 2 Both regulating valve a7 and regulating valve b8 are high-pressure regulating valves, and the nominal diameter of regulating valve a7 is larger than that of regulating valve b8.

[0020] The operating principle of the steam throttling control system for the steam turbine of a generator set of the present invention is as follows: a heat exchange unit 1 is connected to a main steam valve 3 via a first pipe 2, and the main steam valve 3 is connected to a third pipe 5 and a fourth pipe 6 respectively via a second pipe 4. A regulating valve a7 is provided on the third pipe 5, and a regulating valve b8 is provided on the fourth pipe 6. The third pipe 5 and the fourth pipe 6 converge into a steam pipe and are connected to a steam turbine 9. The combined regulation of the large and small valves of the present invention can more delicately adapt to a wide range of changes in the load of the unit. Whether the load changes slowly or rapidly, the control system can automatically adjust the large and small regulating valves to achieve reasonable coordination and meet the flow requirements of the unit. This optimizes the regulating capacity of the unit and adapts to new operating conditions, thereby improving the overall performance of the unit. This effectively improves the regulating performance of the unit, enabling it to better cope with frequent fluctuations in the power grid and load changes.

[0021] Example 3 The steam regulation method for a steam turbine of a generator set of the present invention adopts the steam throttling regulation system of the steam turbine of the generator set, and is specifically implemented according to the following steps: Step 1: Obtain the unit load signal and determine the unit load operation stage; Step 2: When the unit is in the load-increasing stage, the openings of the regulating valves a7 and b8 are adjusted respectively to distribute the flow; Step 3: When the unit is in the load reduction stage, the openings of the regulating valve a7 and the regulating valve b8 are adjusted respectively to distribute the flow.

[0022] The present invention reasonably distributes the flow at different load stages of the unit by opening the small regulating valve first and the large regulating valve later, thereby reducing throttling losses and improving the overall thermal efficiency and operating economy of the unit. The present invention opens and closes the large and small regulating valves in stages, which can make the changes in parameters such as the steam pressure and temperature of the unit more stable, reduce the large fluctuations in parameters caused by the simultaneous operation of the valves, and thus improve the stability and reliability of the unit operation. The combined adjustment of the large and small valves of the present invention can more delicately adapt to the wide range of changes in the load of the unit. Regardless of whether the load changes slowly or quickly, the automatic adjustment of the control system can achieve reasonable coordination of the large and small regulating valves to meet the flow requirements of the unit.

[0023] Example 4 The steam regulation method for a steam turbine of a generator set of the present invention is specifically implemented according to the following steps: Step 1: Obtain the unit load signal and determine the unit load operation stage; Step 2: When the unit is in the load-increasing stage, the openings of the regulating valves a7 and b8 are adjusted respectively to distribute the flow; Step 2.1: Set 40% load as the second threshold and 85% load as the first threshold to determine the load increase range of the unit. Step 2.2: During the load increase phase between 0% and 40%, the steam inlet required by the steam turbine 9 is small, and the opening is adjusted independently by the regulating valve b8. The heat exchange unit 1 generates high-temperature, high-pressure steam, which passes through the main steam valve 3 and then enters the steam turbine 9 through the regulating valve b8. As the load increases, the opening of the regulating valve b8 is adjusted from 0% to 100%, and the maximum flow rate of the regulating valve b8 meets the steam inlet required by the steam turbine 9. The regulating valve a7 is closed. In step 2.3, during the load increase phase between 40% and 85%, the steam intake required by steam turbine 9 increases, and the maximum flow rate of regulating valve b8 cannot meet the required steam intake of steam turbine 9. Regulating valve b8 is fully opened, and regulating valve a7 takes over the regulation. Heat exchange unit 1 generates high-temperature, high-pressure steam. After passing through main steam valve 3, part of the high-temperature, high-pressure steam passes through regulating valve b8, and the rest passes through regulating valve a7. After converging, the steam enters steam turbine 9. As the load increases, the opening of regulating valve a7 is adjusted from 0% to 100%, and regulating valve b8 remains fully open. In step 2.4, during the load increase phase between 85% and 100%, the steam intake required by the steam turbine 9 is close to the rated steam intake flow rate. The regulating valves b8 and a7 are both fully open. The heat exchange unit 1 generates high-temperature, high-pressure steam. After passing through the main steam valve 3, part of the high-temperature, high-pressure steam passes through the regulating valve b8, and the other part passes through the regulating valve a7. After converging, the steam enters the steam turbine 9. As the load increases, the regulating valves a7 and b8 remain fully open.

[0024] Step 3: When the unit is in the load reduction stage, the openings of the regulating valve a7 and the regulating valve b8 are adjusted respectively to distribute the flow.

[0025] Step 3.1: Set 40% load as the second threshold and 85% load as the first threshold to determine the load reduction range of the unit. In step 3.2, during the load reduction phase from 100% to 85%, the heat exchange unit 1 generates high-temperature, high-pressure steam. After passing through the main steam valve 3, part of the high-temperature, high-pressure steam passes through the regulating valve b8, and the other part passes through the regulating valve a7. After converging, the steam enters the steam turbine 9. As the load decreases, the regulating valves a7 and b8 remain fully open. In step 3.3, during the load reduction phase from 85% to 40%, heat exchange unit 1 generates high-temperature, high-pressure steam. After passing through main steam valve 3, part of the high-temperature, high-pressure steam passes through regulating valve b8, and the other part passes through regulating valve a7. After converging, the steam enters steam turbine 9. As the load decreases, the opening of regulating valve a7 is adjusted from 100% to 0%, and regulating valve b8 remains fully open. In step 3.3, when regulating valve a7 is adjusted in the load range of 40%-85%, the valve opening of regulating valve a7 is always greater than 25% of the critical anti-cavitation opening, avoiding the oscillating adjustment of the opening <10% in traditional control.

[0026] In step 3.4, when the load is reduced from 40% to 0%, the heat exchange unit 1 generates high-temperature and high-pressure steam. After passing through the main steam valve 3, the high-temperature and high-pressure steam enters the turbine 9 through the regulating valve b8. As the load decreases, the opening of the regulating valve b8 is adjusted from 100% to 0%, and the regulating valve a7 is in the closed state.

[0027] In step 3.4, when the regulating valve b8 is adjusted below 40% load, the valve opening of the regulating valve b8 is always greater than 25% of the critical anti-cavitation opening.

[0028] The steam regulation method for a steam turbine of a generator set of the present invention comprises the following steps: during a load increase process, before the load reaches a second threshold value (40%), the opening of the regulating valve b8 is adjusted, and the regulating valve a7 is always closed; when the load reaches a first threshold value (85%), the regulating valve b8 is fully opened, and the opening of the regulating valve a7 is adjusted; after the load reaches the first threshold value (85%), the regulating valves a7 and b8 are fully opened; during a load reduction process, when the load drops to the first threshold value (85%), the regulating valve a7 begins to close; after the regulating valve a7 is fully closed and the load drops to the second threshold value (40%), the regulating valve b8 begins to close.

[0029] After using the control of the present invention, on the one hand, the order of opening the small regulating valve first and the large throttle valve later is reasonable in different load stages of the unit, reducing throttling losses and improving the overall thermal efficiency and operating economy of the unit. On the other hand, opening and closing the large and small regulating valves can make the changes in parameters such as the steam pressure and temperature of the unit more stable, reduce the large fluctuations in parameters caused by the simultaneous operation of the valves, and thus improve the stability and reliability of the unit operation. The combined adjustment of the large and small valves can more delicately adapt to the wide range of changes in the unit load. Whether the load changes slowly or quickly, the automatic adjustment of the control system can achieve reasonable coordination of the large and small regulating valves to meet the flow requirements of the unit.

[0030] Example 5 The steam throttling regulation system structure of the steam turbine of the generator set of the present invention includes a heat exchange unit 1, the heat exchange unit 1 is connected to the first pipeline 2, the main steam valve 3 is provided on the first pipeline 2, the first pipeline 2 is connected to the second pipeline 4, the second pipeline 4 is divided into two branches, the two branches are respectively a third pipeline 5 and a fourth pipeline 6, a regulating valve a7 is provided on the third pipeline 5, and a regulating valve b8 is provided on the fourth pipeline 6. The third pipeline 5 and the fourth pipeline 6 merge into a steam pipeline, and the steam pipeline is connected to the steam turbine 9; the regulating valve a7 and the regulating valve b8 are large-diameter high-pressure regulating valves of the same specifications and models. The steam regulation method for a steam turbine of a generator set of the present invention is based on a 660MW ultra-supercritical, single-intermediate reheat, three-cylinder, two-exhaust, single-shaft, surface-condensing, indirect air-cooled steam turbine with a designed main steam pressure of 28 MPa, a designed main steam temperature of 600°C, a designed high-pressure cylinder exhaust pressure of 6.11 MPa, and a designed high-pressure cylinder exhaust temperature of 358.5°C. The steam throttling regulation system of the steam turbine of the generator set is used and is specifically implemented in the following steps: Step 1: Obtain the unit load signal and determine the unit load operation stage; Step 2: When the unit is in the load-increasing stage, the openings of the regulating valves a7 and b8 are adjusted respectively to distribute the flow; Step 3: When the unit is in the load reduction stage, the openings of the regulating valve a7 and the regulating valve b8 are adjusted respectively to distribute the flow.

[0031] In the steam regulation process of the generator turbine in this embodiment, two valve groups of the same specifications are connected in parallel. The regulating valves have the same flow area and flow characteristics, and perform synchronous opening / closing actions when the load instruction changes. When the unit is at medium or low load, the steam demand is lower than the full-open capacity of the valve, and the two valves need to be throttled or partially closed at the same time.

[0032] After calculation, the unit heat consumption under 75% operating conditions is: 7928kJ / kWh; the unit heat consumption under 50% operating conditions is: 8368kJ / kWh; the unit heat consumption under 40% operating conditions is: 8650kJ / kWh; the unit heat consumption under 30% operating conditions is: 8901kJ / kWh.

[0033] Example 6 The steam throttling regulation system structure of the steam turbine of the generator set of the present invention includes a heat exchange unit 1, which is connected to a first pipeline 2. A main steam valve 3 is provided on the first pipeline 2. The first pipeline 2 is connected to a second pipeline 4. The second pipeline 4 is divided into two branches, which are a third pipeline 5 and a fourth pipeline 6. A regulating valve a7 is provided on the third pipeline 5, and a regulating valve b8 is provided on the fourth pipeline 6. The third pipeline 5 and the fourth pipeline 6 merge into a steam pipeline, and the steam pipeline is connected to a steam turbine 9. The regulating valve a7 adopts a large-diameter high-pressure regulating valve, and the regulating valve b8 adopts a small-diameter high-pressure regulating valve.

[0034] The steam regulation method for a steam turbine of a generator set of the present invention is based on a 660MW ultra-supercritical, single-intermediate reheat, three-cylinder, two-exhaust, single-shaft, surface-condensing, indirect air-cooled steam turbine with a designed main steam pressure of 28 MPa, a designed main steam temperature of 600°C, a designed high-pressure cylinder exhaust pressure of 6.11 MPa, and a designed high-pressure cylinder exhaust temperature of 358.5°C. The steam throttling regulation system of the steam turbine of the generator set is used and is specifically implemented in the following steps: Step 1: Obtain the unit load signal and determine the unit load operation stage; Step 2: When the unit is in the load-increasing stage, the openings of the regulating valves a7 and b8 are adjusted respectively to distribute the flow; Step 3: When the unit is in the load reduction stage, the openings of the regulating valve a7 and the regulating valve b8 are adjusted respectively to distribute the flow.

[0035] In this embodiment, one large and one small high-pressure regulating valve are used. As the load increases, in the low-load range, the flow demand can be met by precisely controlling the opening of the regulating valve b8 of the small-diameter high-pressure regulating valve. When the load demand exceeds the supply capacity of the regulating valve b8 of the small-diameter high-pressure regulating valve, the regulating valve a7 of the large-diameter high-pressure regulating valve begins to open on demand and shares the flow supply with the regulating valve b8 of the small-diameter high-pressure regulating valve until the high-load demand is met. As the load decreases, when the load demand decreases, the opening of the regulating valve a7 of the large-diameter high-pressure regulating valve is preferentially reduced or closed. In the medium and low load ranges, the flow is regulated only by the regulating valve b8 of the small-diameter high-pressure regulating valve.

[0036] After calculation, the unit heat consumption under 75% operating conditions is: 7848kJ / kWh; the unit heat consumption under 50% operating conditions is: 8238kJ / kWh; the unit heat consumption under 40% operating conditions is: 8450kJ / kWh; the unit heat consumption under 30% operating conditions is: 8651kJ / kWh.

[0037] Comparing the calculation results in Examples 5 and 6 shows that using two regulating valves of different specifications, one large and one small, in parallel, results in low-load conditions where only the small valve operates at a wide opening (close to its designed optimal operating range), resulting in low steam throttling and minimal losses. In medium- and high-load conditions, the small valve is typically close to full open (with minimal throttling losses), relying primarily on the large valve for regulation. While the large valve may partially throttle in this situation, overall throttling losses are still significantly reduced compared to the conventional solution where both valves throttle simultaneously. The present invention, by opening and closing the large and small regulating valves in stages, stabilizes the changes in parameters such as the unit's steam pressure and temperature, reducing significant parameter fluctuations caused by simultaneous valve operation, thereby improving the unit's operational stability and reliability.

[0038] The present invention optimizes the load regulation process by opening and closing the large and small caliber regulating valves in stages, and differentially configuring the high-pressure regulating valve. When in use, the small regulating valve is opened first and the large throttle valve is opened later to reasonably distribute the flow, reduce throttling losses, reduce throttling losses, and improve the operating efficiency and stability of the unit. The present invention meets the flow ratio required by the full load section of the unit and improves the regulating ability and flexibility of the unit. By opening and closing the large and small regulating valves in stages, the load regulation process is optimized, throttling losses are reduced, the operating efficiency and stability of the unit are improved, the overall heat consumption of the system is further reduced, and the operating economy of the system is improved.

Claims

1. The steam throttling control system of the steam turbine of the generator set is characterized by: The heat exchange unit (1) is connected to a first pipe (2), a main steam valve 3 is provided on the first pipe (2), the first pipe (2) is connected to a second pipe (4), the second pipe (4) is divided into two branches, the two branches are a third pipe (5) and a fourth pipe (6), a regulating valve a (7) is provided on the third pipe (5), a regulating valve b (8) is provided on the fourth pipe (6), the third pipe (5) and the fourth pipe (6) are merged into a steam pipe, and the steam pipe is connected to a steam turbine (9).

2. The steam throttling control system for a steam turbine of a generator set according to claim 1, characterized in that: The regulating valve a (7) and the regulating valve b (8) are both high-pressure regulating valves.

3. The steam throttling control system for a steam turbine of a generator set according to claim 2, characterized in that: The nominal diameter of the regulating valve a7 (7) is larger than that of the regulating valve b (8).

4. A method for regulating steam throttling of a steam turbine of a generator set, characterized in that: The steam throttling regulation system for a steam turbine of a generator set according to any one of claims 2 to 3 is implemented specifically according to the following steps: Step 1: Obtain the unit load signal and determine the unit load operation stage; Step 2: When the unit is in the load-increasing stage, the openings of the regulating valve a (7) and the regulating valve b (8) are adjusted respectively to distribute the flow; Step 3: When the unit is in the load reduction stage, the openings of the regulating valve a (7) and the regulating valve b (8) are adjusted respectively to distribute the flow.

5. The method for regulating steam throttling of a steam turbine of a generator set according to claim 2, characterized in that: The step 2 is specifically as follows: Step 2.1: Set 40% load as the second threshold and 85% load as the first threshold to determine the load increase range of the unit. Step 2.2, when in the load increase stage in the range of 0%-40%, the steam inlet required by the steam turbine (9) is small, and the opening is independently adjusted by the regulating valve b (8). The heat exchange unit (1) generates high-temperature and high-pressure steam. After passing through the main steam valve 3, the high-temperature and high-pressure steam enters the steam turbine (9) through the regulating valve b (8). As the load increases, the opening of the regulating valve b (8) is adjusted from 0%-100%. The maximum flow rate of the regulating valve b (8) meets the steam inlet required by the steam turbine (9); the regulating valve a (7) is in the closed state; Step 2.3, when in the load increase stage in the range of 40%-85%, the steam inlet required by the steam turbine (9) increases, and the maximum flow rate of the regulating valve b (8) cannot meet the steam inlet required by the steam turbine (9), the regulating valve b (8) is fully opened, and the regulating valve a (7) takes over the regulation; the heat exchange unit (1) generates high-temperature and high-pressure steam, and after passing through the main steam valve 3, part of the high-temperature and high-pressure steam passes through the regulating valve b (8), and the other part passes through the regulating valve a (7), and then enters the steam turbine (9) after being converged. As the load increases, the opening of the regulating valve a (7) is adjusted from 0%-100%, and the regulating valve b (8) remains fully open; In step 2.4, when the load is increased in the range of 85%-100%, the steam inlet required by the steam turbine (9) is close to the steam inlet flow rate under rated operating conditions, and the regulating valve b (8) and the regulating valve a (7) are both fully opened. The heat exchange unit (1) generates high-temperature and high-pressure steam. After passing through the main steam valve 3, part of the high-temperature and high-pressure steam passes through the regulating valve b (8) and the other part passes through the regulating valve a (7). After converging, they enter the steam turbine (9). As the load increases, the regulating valve a (7) and the regulating valve b (8) are both kept in the fully open state.

6. The method for regulating steam throttling of a steam turbine of a generator set according to claim 5, characterized in that: The step 3 is specifically as follows: Step 3.1: Set 40% load as the second threshold and 85% load as the first threshold to determine the load reduction range of the unit. In step 3.2, when the load is reduced from 100% to 85%, the heat exchange unit (1) generates high-temperature and high-pressure steam. After passing through the main steam valve 3, part of the high-temperature and high-pressure steam passes through the regulating valve b (8), and the other part passes through the regulating valve a (7). After being converged, the regulating valve a (7) and the regulating valve b (8) are kept in a fully open state as the load decreases. Step 3.3, when the load is reduced from 85% to 40%, the heat exchange unit (1) generates high-temperature and high-pressure steam. After passing through the main steam valve 3, part of the high-temperature and high-pressure steam passes through the regulating valve b (8), and the other part passes through the regulating valve a (7). After being converged, it enters the steam turbine (9). As the load decreases, the opening of the regulating valve a (7) is adjusted from 100% to 0%, and the regulating valve b (8) remains fully open. In step 3.4, when the load is reduced from 40% to 0%, the heat exchange unit (1) generates high-temperature and high-pressure steam. After passing through the main steam valve 3, the high-temperature and high-pressure steam enters the turbine (9) through the regulating valve b (8). As the load decreases, the opening of the regulating valve b (8) is adjusted from 100% to 0%, and the regulating valve a (7) is in the closed state.

7. The method for regulating steam throttling of a steam turbine of a generator set according to claim 6, characterized in that: In step 3.3, when the regulating valve a (7) is adjusted in the load range of 40%-85%, the valve opening of the regulating valve a (7) is always greater than 25% of the critical anti-cavitation opening.

8. The method for regulating steam throttling of a steam turbine of a generator set according to claim 7, characterized in that: In step 3.4, when the regulating valve b (8) is adjusted below 40% load, the valve opening of the regulating valve b (8) is always greater than 25% of the critical anti-cavitation opening.

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