A supplementary steam regulating system for an intermediate pressure cylinder of a deep peak-regulating steam turbine and a running method thereof

Abstract

This invention discloses a deep peak-shaving steam turbine intermediate-pressure cylinder supplementary steam regulation system and its operation method, relating to the power plant field. It primarily addresses the problem of significantly increased heat rate during deep peak-shaving processes in power plants. The system mainly includes an intermediate-pressure cylinder, a steam turbine intermediate-pressure cylinder inlet regulating valve, and multi-stage steam turbine intermediate-pressure cylinder supplementary steam regulating valves. By adding multiple turbine stages before the existing intermediate-pressure cylinder and configuring multi-stage steam turbine intermediate-pressure cylinder supplementary steam regulating valves, the flow area of ​​the intermediate-pressure cylinder is variable, increasing the reheat steam pressure at the boiler outlet and achieving the optimal reheat steam pressure under different loads. This enables efficient operation and improved flexibility of the turbine unit at low loads. During high-load operation, opening the supplementary steam regulating valves can quickly reduce the reheat steam temperature, preventing overheating and ensuring safe operation of the turbine unit at high loads. This invention reduces the increase in unit heat rate caused by the decrease in reheat steam pressure at low loads, thus improving the unit's peak-shaving performance.

Description

Technical Field

[0001] This invention relates to the field of deep peak shaving technology in power plants, and in particular to a deep peak shaving turbine intermediate pressure cylinder steam injection regulation system and its operation method. Background Technology

[0002] With the continuous development of renewable energy, the proportion of power generation from renewable energy sources is also increasing. However, due to the intermittent and unstable nature of renewable energy, its grid connection will adversely affect the stability of the power grid. Therefore, peak shaving by power plants is necessary to improve grid stability. However, during deep peak shaving at power plants, the operating conditions deviate significantly from the design conditions, leading to a significant decrease in unit efficiency, increased heat rate, and reduced economic efficiency. Currently, when reducing load, units generally reduce the main steam pressure while simultaneously throttling the main steam valve. These methods all result in a significant decrease in turbine efficiency and an increased heat rate. Therefore, addressing the significant decrease in unit efficiency at low loads is a crucial way to improve the thermal economy of the units. Summary of the Invention

[0003] To overcome the shortcomings of existing technologies, the present invention aims to provide a deep peak-shaving steam turbine intermediate-pressure cylinder steam injection regulation system and operation method. By adding multiple turbine stages before the original intermediate-pressure cylinder and configuring multi-stage steam turbine intermediate-pressure cylinder steam injection regulation valves, the flow area of ​​the intermediate-pressure cylinder can be varied, thereby increasing the reheat steam pressure at the boiler outlet and enabling the reheat steam pressure to reach the optimal value under different loads. This achieves the effect of efficient operation and improved flexibility of the turbine unit at low loads, solving the problem of significantly reduced unit efficiency.

[0004] To achieve the above objectives, the present invention adopts the following technical solution.

[0005] A deep peak-shaving steam turbine intermediate-pressure cylinder supplementary steam regulation system is provided. The reheat steam outlet of boiler 1 is connected to the steam inlet I, steam inlet II, and steam outlet of intermediate-pressure cylinder 3 through steam turbine intermediate-pressure cylinder supplementary steam regulation valve I 14, steam turbine intermediate-pressure cylinder supplementary steam regulation valve II 15, and steam turbine intermediate-pressure cylinder inlet steam regulation valve 16, respectively. The steam outlet of intermediate-pressure cylinder 3 is connected to the steam inlet of low-pressure cylinder 4. A multi-stage steam turbine group is set between steam inlet I and steam inlet II of intermediate-pressure cylinder 3, and between steam inlet II and steam outlet of intermediate-pressure cylinder 3.

[0006] The aforementioned deep peak-shaving turbine intermediate-pressure cylinder supplementary steam regulation system, for a multi-stage turbine group between inlet I and inlet II of intermediate-pressure cylinder 3, has an inlet design steam temperature that is the reheat steam temperature of boiler 1 under rated operating conditions, a design steam flow rate that is 40% to 60% of the reheat steam flow rate of boiler 1 under rated operating conditions, and a design steam pressure that is the optimal reheat steam pressure when the turbine group reaches its design operating conditions, ranging from 20% to 30% of the main steam pressure, i.e., p rh = (0.2~0.3)p0; For the multi-stage turbine group between the steam inlet II of the intermediate pressure cylinder 3 and the steam inlet of the intermediate pressure cylinder 3, the inlet design steam temperature is the reheat steam temperature of boiler 1 under rated operating conditions, the design steam flow rate is 60%~80% of the reheat steam flow rate of boiler 1 under rated operating conditions, and the design steam pressure is the optimal reheat steam pressure when the turbine group reaches the design operating conditions, ranging from 20%~30% of the main steam pressure, i.e., p rh = (0.2~0.3)p0; For the turbine stage between the steam inlet of the intermediate pressure cylinder 3 and the steam outlet of the intermediate pressure cylinder 3, the inlet design steam pressure is the reheat steam pressure of boiler 1 under rated operating conditions, the design steam temperature is the reheat steam temperature of boiler 1 under rated operating conditions, and the design steam flow rate is the reheat steam flow rate of boiler 1 under rated operating conditions.

[0007] Preferably, the number of multi-stage turbine groups between steam inlet I and steam inlet II of intermediate pressure cylinder 3 is 2 to 4; the number of multi-stage turbine groups between steam inlet II and steam inlet III of intermediate pressure cylinder 3 is also 2 to 4. Using multi-stage turbines can greatly improve the turbine's cycle thermal efficiency and relative internal efficiency, but too many turbine stages will increase the number of components and correspondingly increase the overall cost. Therefore, 2 to 4 stages are most suitable.

[0008] The operation method of the intermediate-pressure cylinder steam injection regulating system of a deep peak-shaving steam turbine involves opening the intermediate-pressure cylinder steam injection regulating valve I14 and the intermediate-pressure cylinder inlet regulating valve 16 when the unit load is higher than 90%. The reheat steam temperature at the inlet of the intermediate-pressure cylinder 3 is controlled by the intermediate-pressure cylinder steam injection regulating valve I14, and the unit load is controlled by the high-pressure cylinder inlet regulating valve 13 for constant pressure operation. When the unit load is between 70% and 90%, the intermediate-pressure cylinder steam injection regulating valve II15 is opened. The steam temperature of the turbine stage between inlet I and inlet II of the intermediate-pressure cylinder 3 is controlled by the intermediate-pressure cylinder steam injection regulating valve I14, and the unit load is controlled by the high-pressure cylinder inlet regulating valve II15. The reheat steam temperature at the inlet of intermediate pressure cylinder 3 is controlled by the turbine high-pressure cylinder inlet steam regulating valve 13 to control the unit load, and the unit operates at constant pressure. When the unit load is 50% to 70%, the reheat steam pressure at the inlet of intermediate pressure cylinder 3 is controlled by the turbine intermediate pressure cylinder supplementary steam regulating valve II 15, the reheat steam temperature at the inlet of intermediate pressure cylinder 3 is controlled by the turbine intermediate pressure cylinder inlet steam regulating valve 16, and the unit load is controlled by the turbine high-pressure cylinder inlet steam regulating valve 13, and the unit operates at constant pressure. When the unit load is below 50%, the turbine intermediate pressure cylinder supplementary steam regulating valve II 15 and the turbine intermediate pressure cylinder inlet steam regulating valve 16 are closed, and the unit load is controlled by the turbine intermediate pressure cylinder supplementary steam regulating valve I 14, and the unit operates at sliding pressure.

[0009] Preferably, the inlet steam pressure of the turbine stage is the optimal reheat steam pressure under different loads, and the reheat steam temperature is controlled between 540℃ and 566℃.

[0010] Preferably, the minimum steam pressure at the inlet of the intermediate pressure cylinder 3 is 2 MPa.

[0011] Preferably, the difference between the make-up steam pressure of the intermediate pressure cylinder make-up steam regulating valve I14 and the pressure of the reheat steam should ensure that the flow rate of the turbine stage between the steam inlet I and the steam inlet II of the intermediate pressure cylinder 3 is not less than 80% to 90% of the design flow rate.

[0012] Preferably, the difference between the steam supply pressure of the intermediate pressure cylinder steam supply regulating valve II15 and the steam supply pressure of the intermediate pressure cylinder steam supply regulating valve I14 should ensure that the flow rate of the turbine stage group between the steam inlet II of the intermediate pressure cylinder 3 and the steam inlet of the intermediate pressure cylinder 3 is not less than 80% to 90% of the design flow rate.

[0013] Preferably, when the unit is above 90% load and the reheat steam temperature is greater than 566°C, the intermediate pressure cylinder steam injection regulating valve I14 of the steam turbine is fully opened.

[0014] Compared with the prior art, the present invention has the following advantages:

[0015] (1) This invention can increase the reheat steam pressure by adding multiple turbine stages before the original intermediate pressure cylinder and configuring multi-stage turbine intermediate pressure cylinder steam injection regulating valve during deep peak shaving, so that the reheat steam pressure is maintained at the optimal value under different loads, thereby improving the operating efficiency of the intermediate and low pressure cylinders and significantly reducing the problem of increased heat consumption rate. Compared with the means of regulating flue gas, its regulation performance is better.

[0016] (2) This invention can increase the reheat steam pressure and increase the heat storage of the reheater inside the boiler during deep peak shaving. When the unit load increases, the pressure and temperature of the reheat steam can be quickly increased to the set value, which further improves the flexibility of the unit.

[0017] (3) The present invention can fully open the steam injection regulating valve of the intermediate pressure cylinder of the steam turbine during high load operation, which can quickly reduce the reheat steam pressure, thereby reducing the reheat steam temperature, preventing overheating, and improving the safety of the unit. Attached Figure Description

[0018] Figure 1 A schematic diagram of the configuration of the deep peak-shaving steam turbine supplementary steam regulation system.

[0019] In the diagram: 1. Boiler, 2. High-pressure cylinder, 3. Intermediate-pressure cylinder, 4. Low-pressure cylinder, 5. Generator, 6. Condenser, 7. Low-pressure heater group, 8. Low-pressure heater, 9. Deaerator, 10. Feedwater pump, 11. High-pressure heater, 12. High-pressure heater group, 13. Steam inlet regulating valve for high-pressure cylinder of turbine, 14. Steam supplement regulating valve I for intermediate-pressure cylinder of turbine, 15. Steam supplement regulating valve II for intermediate-pressure cylinder of turbine, 16. Steam inlet regulating valve for intermediate-pressure cylinder of turbine, 17. Steam inlet valve for low-pressure heater group, 18. Steam inlet valve for low-pressure heater, 19. Steam inlet valve for deaerator, 20. Steam inlet valve for high-pressure heater, 21. Steam inlet valve for high-pressure heater group.

[0020] Figure 2 This is a graph showing the relationship between reheat steam pressure and cycle efficiency. Detailed Implementation

[0021] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0022] like Figure 1As shown, this invention discloses a deep peak-shaving steam turbine intermediate-pressure cylinder supplementary steam regulation system, including a boiler 1, a high-pressure cylinder 2, an intermediate-pressure cylinder 3, a low-pressure cylinder 4, a generator 5, a condenser 6, a low-pressure heater group 7, a low-pressure heater 8, a deaerator 9, a feedwater pump 10, a high-pressure heater 11, a high-pressure heater group 12, a steam turbine high-pressure cylinder inlet steam regulating valve 13, a steam turbine intermediate-pressure cylinder supplementary steam regulating valve I 14, a steam turbine intermediate-pressure cylinder supplementary steam regulating valve II 15, a steam turbine intermediate-pressure cylinder inlet steam regulating valve 16, a low-pressure heater group inlet steam valve 17, a low-pressure heater inlet steam valve 18, a deaerator inlet steam valve 19, a high-pressure heater inlet steam valve 20, and a high-pressure heater group inlet steam valve 21.

[0023] The main steam outlet of boiler 1 is connected to the steam inlet of high-pressure cylinder 2 via steam inlet regulating valve 13 of the high-pressure cylinder of the turbine. The steam outlet of high-pressure cylinder 2 is connected to the reheat steam inlet of boiler 1. The reheat steam outlet of boiler 1 is connected to the steam inlet I, steam inlet II, and steam outlet of intermediate-pressure cylinder 3 via steam inlet regulating valve I 14, steam inlet regulating valve II 15, and steam inlet regulating valve 16 of the intermediate-pressure cylinder of the turbine. The steam outlet of intermediate-pressure cylinder 3 is connected to the steam inlet of low-pressure cylinder 4. A multi-stage turbine group is set between steam inlet I and steam inlet II of intermediate-pressure cylinder 3. A multi-stage turbine group is set between steam inlet II and steam outlet of intermediate-pressure cylinder 3. The system is equipped with a multi-stage steam turbine group; the steam outlet of the low-pressure cylinder 4 is connected to the inlet of the condenser 6; the shafts of the high-pressure cylinder 2, intermediate-pressure cylinder 3 and low-pressure cylinder 4 are connected to the generator 5; the outlet of the condenser 6 is connected to the feedwater inlet of the low-pressure heater group 7; the feedwater outlet of the low-pressure heater group 7 is connected to the feedwater inlet of the low-pressure heater 8; the feedwater outlet of the low-pressure heater 8 is connected to the feedwater inlet of the deaerator 9; the feedwater outlet of the deaerator 9 is connected to the feedwater inlet of the high-pressure heater 11 through the feedwater pump 10; the feedwater outlet of the high-pressure heater 11 is connected to the feedwater inlet of the high-pressure heater group 12; and the feedwater outlet of the high-pressure heater group 12 is connected to the main steam inlet of the boiler 1.

[0024] The steam inlet of the low-pressure heater group 7 is connected to the extraction steam outlet of the low-pressure cylinder 4 through the low-pressure heater group steam inlet valve 17. The steam inlet of the low-pressure heater 8 is connected to the extraction steam outlet III of the intermediate-pressure cylinder 3 through the low-pressure heater steam inlet valve 18. The steam inlet of the deaerator 9 is connected to the extraction steam outlet II of the intermediate-pressure cylinder 3 through the deaerator steam inlet valve 19. The steam inlet of the high-pressure heater 11 is connected to the extraction steam outlet I of the intermediate-pressure cylinder 3 through the high-pressure heater steam inlet valve 20. The steam inlet of the high-pressure heater group 12 is connected to the extraction steam outlet of the high-pressure cylinder 2 through the high-pressure heater group steam inlet valve 21.

[0025] The aforementioned deep peak-shaving turbine intermediate-pressure cylinder supplementary steam regulation system, for a multi-stage turbine group between inlet I and inlet II of intermediate-pressure cylinder 3, has an inlet design steam temperature equal to the reheat steam temperature of boiler 1 under rated operating conditions, a design steam flow rate of 40% to 60% of the reheat steam flow rate of boiler 1 under rated operating conditions, and a design steam pressure equal to the optimal reheat steam pressure p when the turbine group reaches its design operating conditions. rh , Figure 2 For reheat steam pressure p rh Compared to ideal reheat cycle efficiency The relationship curve is shown, with the vertical axis representing the efficiency of the reheat cycle and the horizontal axis representing the ideal specific enthalpy drop H of the steam before reheat. 1a Compared with the ideal specific enthalpy drop H of the basic cycle steam a ratio. Depend on Figure 2 It can be seen that in H 1a / H a The reheat cycle efficiency is highest when the reheat steam pressure is around 30%, at which point the optimal reheat steam pressure is 20%–30% of the main steam pressure, i.e., p. rh = (0.2~0.3)p0, the number of turbine stages is 2~4; for multi-stage turbine stages between the inlet II of intermediate pressure cylinder 3 and the inlet of intermediate pressure cylinder 3, the inlet design steam temperature is the reheat steam temperature of boiler 1 under rated conditions, the design steam flow rate is 60%~80% of the reheat steam flow rate of boiler 1 under rated conditions, and the design steam pressure is the optimal reheat steam pressure p when the turbine stage reaches the design conditions. rh That is, the optimal reheat steam pressure is 20% to 30% of the main steam pressure, i.e., p rh = (0.2~0.3)p0, the number of turbine stages is 2~4 stages; for the turbine stage between the steam inlet of the intermediate pressure cylinder 3 and the steam outlet of the intermediate pressure cylinder 3, the inlet design steam pressure is the reheat steam pressure of boiler 1 under rated operating conditions, the design steam temperature is the reheat steam temperature of boiler 1 under rated operating conditions, and the design steam flow rate is the reheat steam flow rate of boiler 1 under rated operating conditions.

[0026] The operation method of the intermediate-pressure cylinder steam injection regulation system of a deep peak-shaving steam turbine, when the unit load is higher than 90%, mainly relies on the turbine stage between the inlet and outlet of the intermediate-pressure cylinder 3 for power generation. To avoid overheating of the reheat steam (temperature greater than 566℃), it is necessary to maintain a low steam flow rate between the inlet I and outlet of the intermediate-pressure cylinder 3. Therefore, the intermediate-pressure cylinder steam injection regulation valve I14 and the intermediate-pressure cylinder inlet steam regulation valve 16 are opened. The reheat steam temperature at the inlet of the intermediate-pressure cylinder 3 is controlled by the intermediate-pressure cylinder steam injection regulation valve I14, and the unit load is controlled by the high-pressure cylinder inlet steam regulation valve 13. Constant pressure operation; when the unit load is 70%–90%, in order to reduce the outlet steam flow of boiler 1 while maintaining the outlet steam pressure of boiler 1, the intermediate pressure cylinder steam supply regulating valve II15 of the turbine is opened. The steam temperature of the turbine stage between inlet I and inlet II of the intermediate pressure cylinder 3 is controlled by the intermediate pressure cylinder steam supply regulating valve I14. The reheat steam temperature at the inlet of the intermediate pressure cylinder 3 is controlled by the intermediate pressure cylinder steam supply regulating valve II15, with a temperature control range of 540℃–566℃. The unit load is controlled by the high pressure cylinder steam supply regulating valve 13. The steam supply pressure of the intermediate pressure cylinder steam supply regulating valve II15 is related to the turbine... The pressure difference between the supplementary steam pressure of the intermediate-pressure cylinder supplementary steam regulating valve I14 should ensure that the flow rate of the turbine stage unit between the steam inlet II and the steam inlet of intermediate-pressure cylinder 3 is not less than 80% to 90% of the design flow rate, and the unit operates at constant pressure. When the unit load is 50% to 70%, in order to maintain the steam pressure of intermediate-pressure cylinder 3 while further reducing the flow rate, the reheat steam pressure at the steam inlet of intermediate-pressure cylinder 3 is controlled by the turbine intermediate-pressure cylinder supplementary steam regulating valve II15. This pressure is the optimal reheat steam pressure under different loads, with a minimum of 2 MPa. The reheat steam temperature at the steam inlet of intermediate-pressure cylinder 3 is controlled by the turbine intermediate-pressure cylinder inlet steam regulating valve 16. The temperature range is 540℃~566℃. The unit load is controlled by the steam inlet regulating valve 13 of the high-pressure cylinder of the steam turbine. The difference between the steam supply pressure of the intermediate-pressure cylinder supplementary steam regulating valve I14 and the pressure of the reheat steam should ensure that the flow rate of the steam turbine stage between the steam inlet I and the steam inlet II of the intermediate-pressure cylinder 3 is not less than 80% to 90% of the design flow rate, and the unit operates at constant pressure. When the unit load is lower than 50%, the outlet steam flow rate of boiler 1 is significantly reduced. Therefore, the steam supply regulating valve II15 and the steam inlet regulating valve 16 of the intermediate-pressure cylinder of the steam turbine are closed, and the unit load is controlled by the steam supply regulating valve I14 of the intermediate-pressure cylinder of the steam turbine, and the unit operates at sliding pressure.

[0027] By using the system and method of this invention, multiple turbine stages are added before the existing intermediate-pressure cylinder, and multi-stage intermediate-pressure cylinder supplementary steam regulating valves are configured to achieve a variable flow area in the intermediate-pressure cylinder. This increases the reheat steam pressure at the boiler outlet, allowing it to reach the optimal value under different loads. This achieves efficient operation and improved flexibility of the turbine unit at low loads. During high-load operation, opening the supplementary steam regulating valves can quickly reduce the reheat steam temperature, preventing overheating and ensuring safe operation of the turbine unit at high loads. This invention reduces the increase in unit heat consumption rate caused by the decrease in reheat steam pressure at low loads, thus improving the unit's peak-shaving performance.

Claims

1. A method for operating a deep peak-shaving steam turbine intermediate-pressure cylinder steam injection regulation system, characterized in that, In the system, the reheat steam outlet of the boiler (1) is connected to the steam inlet I, steam inlet II, and steam inlet III of the intermediate pressure cylinder (3) via the intermediate pressure cylinder supplementary steam regulating valve I (14), the intermediate pressure cylinder supplementary steam regulating valve II (15), and the intermediate pressure cylinder inlet steam regulating valve (16). The steam outlet of the intermediate pressure cylinder (3) is connected to the steam inlet III of the low pressure cylinder (4). A multi-stage turbine group is set between the steam inlet I and the steam inlet II of the intermediate pressure cylinder (3). A multi-stage steam turbine group is set between steam inlet II and steam inlet III of intermediate pressure cylinder (3); the operation method is as follows: when the unit load is higher than 90%, the steam turbine intermediate pressure cylinder supplementary steam regulating valve I (14) and the steam turbine intermediate pressure cylinder inlet steam regulating valve (16) are opened, the reheat steam temperature of the intermediate pressure cylinder (3) inlet III is controlled by the steam turbine intermediate pressure cylinder supplementary steam regulating valve I (14), and the unit load is controlled by the steam turbine high pressure cylinder inlet steam regulating valve (13) for constant pressure operation; when the unit load is 70%~90%, the steam turbine intermediate pressure cylinder inlet steam regulating valve (13) is opened. The intermediate pressure cylinder steam supply regulating valve II (15) controls the steam temperature of the turbine stage between the steam inlet I and the steam inlet II of the intermediate pressure cylinder (3) through the intermediate pressure cylinder steam supply regulating valve I (14), controls the reheat steam temperature of the steam inlet III of the intermediate pressure cylinder (3) through the intermediate pressure cylinder steam supply regulating valve II (15), and controls the unit load through the high pressure cylinder steam supply regulating valve (13). The unit operates at constant pressure. When the unit load is 50%~70%, the intermediate pressure cylinder steam supply regulating valve II (15) controls the steam temperature of the turbine stage between the steam inlet I and the steam inlet II of the intermediate pressure cylinder (3). The reheat steam pressure at the inlet III of the intermediate pressure cylinder (3) is controlled by the inlet steam regulating valve (16) of the intermediate pressure cylinder of the turbine, and the unit load is controlled by the inlet steam regulating valve (13) of the high pressure cylinder of the turbine. The unit operates at constant pressure. When the unit load is less than 50%, the inlet steam regulating valve II (15) and the inlet steam regulating valve (16) of the intermediate pressure cylinder of the turbine are closed. The unit load is controlled by the inlet steam regulating valve I (14) of the intermediate pressure cylinder of the turbine, and the unit operates at sliding pressure.

2. The operating method of the intermediate-pressure cylinder steam injection regulation system for a deep peak-shaving steam turbine according to claim 1, characterized in that, For the multi-stage turbine group between the steam inlet I and the steam inlet II of the intermediate pressure cylinder (3), the inlet design steam temperature is the reheat steam temperature of the boiler (1) under rated operating conditions, the design steam flow rate is 40%~60% of the reheat steam flow rate of the boiler (1) under rated operating conditions, and the design steam pressure is the optimal reheat steam pressure when the turbine group reaches the design operating conditions, within the range of the main steam pressure. p 20%~30% of 0, that is p rh = (0.2~0.3) p 0; For the multi-stage turbine group between the steam inlet II and the steam inlet III of the intermediate pressure cylinder (3), the inlet design steam temperature is the reheat steam temperature of the boiler (1) under rated operating conditions, the design steam flow rate is 60%~80% of the reheat steam flow rate of the boiler (1) under rated operating conditions, and the design steam pressure is the optimal reheat steam pressure when the turbine group reaches the design operating conditions, within the range of the main steam pressure. p 20%~30% of 0, that is p rh = (0.2~0.3) p 0; For the turbine stage between the steam inlet Ⅲ of the intermediate pressure cylinder (3) and the steam outlet of the intermediate pressure cylinder (3), the inlet design steam pressure is the reheat steam pressure of the boiler (1) under rated operating conditions, the design steam temperature is the reheat steam temperature of the boiler (1) under rated operating conditions, and the design steam flow rate is the reheat steam flow rate of the boiler (1) under rated operating conditions.

3. The operating method of the intermediate-pressure cylinder steam injection regulation system for a deep peak-shaving steam turbine according to claim 1, characterized in that, The number of multi-stage turbine groups between the steam inlet I of the intermediate pressure cylinder (3) and the steam inlet II of the intermediate pressure cylinder (3) is 2 to 4; the number of multi-stage turbine groups between the steam inlet II of the intermediate pressure cylinder (3) and the steam inlet III of the intermediate pressure cylinder (3) is 2 to 4.

4. The operating method of the intermediate-pressure cylinder steam injection regulation system for a deep peak-shaving steam turbine according to claim 1, characterized in that, Open the intermediate pressure cylinder steam injection regulating valve I (14), the intermediate pressure cylinder steam injection regulating valve II (15), and the intermediate pressure cylinder steam inlet regulating valve (16) to control the inlet steam pressure of the intermediate turbine stage to the optimal reheat steam pressure under different loads, and control the reheat steam temperature between 540 ℃ and 566 ℃.

5. The operating method of the intermediate-pressure cylinder steam injection regulation system for a deep peak-shaving steam turbine according to claim 1, characterized in that, The minimum steam pressure at the inlet III of the intermediate pressure cylinder (3) is 2 MPa.

6. The operating method of the intermediate-pressure cylinder steam injection regulation system for a deep peak-shaving steam turbine according to claim 1, characterized in that, The difference between the make-up steam pressure of the intermediate pressure cylinder make-up steam regulating valve I (14) and the pressure of the reheat steam should ensure that the flow rate of the turbine stage between the steam inlet I and the steam inlet II of the intermediate pressure cylinder (3) is not less than 80% to 90% of the design flow rate.

7. The operating method of the intermediate-pressure cylinder steam injection regulation system for a deep peak-shaving steam turbine according to claim 1, characterized in that, The difference between the steam pressure of the intermediate pressure cylinder steam supply regulating valve II (15) and the steam pressure of the intermediate pressure cylinder steam supply regulating valve I (14) should ensure that the flow rate of the turbine stage group between the steam inlet II and the steam inlet III of the intermediate pressure cylinder (3) is not less than 80% to 90% of the design flow rate.

8. The operating method of the intermediate-pressure cylinder steam injection regulation system for a deep peak-shaving steam turbine according to claim 1, characterized in that, When the unit load is higher than 90% and the reheat steam temperature is greater than 566℃, the intermediate pressure cylinder steam injection regulating valve I (14) of the steam turbine is fully opened.

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