Feed pump turbine system suitable for deep peak regulation

Abstract

The utility model discloses a feed pump turbine system suitable for deep peak regulation, belongs to the technical field of thermal power generation, and mainly aims to guarantee efficient operation of a feed pump turbine under the working condition of deep peak regulation of a main turbine. According to the main technical scheme, the feed pump turbine system suitable for deep peak regulation comprises a feed pump turbine, a first low-pressure steam pipe and a second low-pressure steam pipe; the power adjusting range of the water feeding pump steam turbine at least covers the steam parameter change requirement of the load of the main steam turbine within the range of 30%-100% of the rated load; the first low-pressure steam pipe and the second low-pressure steam pipe are arranged in parallel, and the first low-pressure steam pipe and the second low-pressure steam pipe are configured as follows: when the load of the main steam turbine is less than 90% of the rated load, the feed pump steam turbine is communicated with the first low-pressure steam pipe; when the load of the main steam turbine exceeds 90% of the rated load, the feed pump steam turbine is communicated with the first low-pressure steam pipe and the second low-pressure steam pipe at the same time.

Description

Technical Field

[0001] This application belongs to the field of thermal power generation technology, specifically relating to a feedwater pump turbine system suitable for deep peak shaving. Background Technology

[0002] In modern thermal power generation systems, feedwater pumps are core equipment ensuring a stable supply of boiler feedwater, and the operating performance of their driving unit, the feedwater pump turbine, directly affects the overall efficiency and reliability of the unit. With the increasing demands for unit flexibility and economy in the power market, feedwater pump turbines need to operate efficiently across a wide load range to meet grid peak-shaving requirements and energy conservation and emission reduction goals.

[0003] Traditional feedwater pump turbine systems often employ a "high-pressure and low-pressure" steam inlet scheme, meaning the feedwater pump turbine is driven by a combination of high-pressure and low-pressure steam. This scheme presents a problem of turbine speed fluctuations when switching from a low-pressure steam source to a high-pressure steam source. Utility Model Content

[0004] In view of this, this application provides a feedwater pump turbine system suitable for deep peak shaving. The main purpose is to ensure that the feedwater pump turbine operates efficiently under the deep peak shaving conditions of the main turbine, while avoiding the problem of large fluctuations in the feedwater pump turbine speed caused by the switching of high-pressure steam source.

[0005] To achieve the above objectives, this application mainly provides the following technical solutions:

[0006] This application provides a feedwater pump turbine system suitable for deep peak shaving, comprising:

[0007] Feedwater pump turbine, first low-pressure steam pipe and second low-pressure steam pipe;

[0008] The power regulation range of the feedwater pump turbine shall at least cover the steam parameter variation requirements of the main turbine load within the range of 30% to 100% of the rated load;

[0009] The first low-pressure steam pipe and the second low-pressure steam pipe are connected in parallel and configured such that: when the load of the main steam turbine is below 90% of the rated load, the feedwater pump turbine is connected to the first low-pressure steam pipe; when the load of the main steam turbine exceeds 90% of the rated load, the feedwater pump turbine is connected to both the first low-pressure steam pipe and the second low-pressure steam pipe.

[0010] Optionally, the feedwater pump turbine system suitable for deep peak shaving further includes:

[0011] Low-pressure steam source;

[0012] The low-pressure steam source is a four-pipe steam system, which is connected to the first low-pressure steam system and the second low-pressure steam system, respectively.

[0013] Optionally, the four steam extraction pipes are equipped with an electric isolation valve.

[0014] Optionally, the first low-pressure steam pipe is provided with a first main steam valve and a first regulating valve.

[0015] Optionally, the first regulating valve is located downstream of the first main steam valve along the steam flow path.

[0016] Optionally, the second low-pressure steam pipe is provided with a second main steam valve and a second regulating valve.

[0017] Optionally, the second regulating valve is located downstream of the second main steam valve along the steam flow path.

[0018] Optionally, the feedwater pump turbine is provided with a first regulating stage nozzle connected to the outlet of the first low-pressure steam pipe, and the nozzle area of ​​the first regulating stage nozzle is adapted to the load of the main steam turbine in the range of 30% to 90% of the rated load.

[0019] Optionally, the feedwater pump turbine is further provided with a second regulating stage nozzle connected to the outlet of the second low-pressure steam pipe, and the nozzle area of ​​the second regulating stage nozzle is smaller than the nozzle area of ​​the first regulating stage nozzle.

[0020] Optionally, the feedwater pump turbine system suitable for deep peak shaving further includes:

[0021] Exhaust pipe;

[0022] The exhaust pipe is connected to the feedwater pump turbine.

[0023] By employing the above technical solution, this application has at least the following beneficial effects:

[0024] The feedwater pump turbine system for deep peak shaving provided in the embodiments of this application, through the parallel connection of the first and second low-pressure steam pipes and the flexible connection configuration according to the main turbine load, allows for efficient utilization of the energy of low-pressure steam and maintains the first regulating stage operating in the high-efficiency range when the main turbine load is low (below 90% of rated load). When the main turbine load is high (above 90% of rated load), both the first and second low-pressure steam pipes are simultaneously opened to increase the steam supply and meet the power demand of the feedwater pump turbine under high load. Therefore, this feedwater pump turbine system for deep peak shaving achieves wide-load, high-efficiency operation of the small turbine within the deep peak shaving range, thereby improving the overall economic efficiency of the unit. Meanwhile, it avoids the problem of feedwater pump turbine speed fluctuation when switching from low-pressure steam source to high-pressure steam source in the traditional "one high, one low" steam intake scheme. This allows the feedwater pump turbine to obtain the required steam smoothly under different loads, maintain stable speed and power output, improve the operational stability and reliability of feedwater pump turbine systems suitable for deep peak shaving, reduce equipment wear and failures that may be caused by speed fluctuations, extend equipment service life, and ensure the stable operation of the entire thermal power generation system. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of a feedwater pump turbine system suitable for deep peak shaving, which is an optional embodiment of this application.

[0026] The reference numerals in the attached figures are as follows:

[0027] 1. Feedwater pump turbine; 2. First low-pressure steam pipe; 3. Second low-pressure steam pipe; 4. Fourth extraction steam pipe; 5. Electric isolation valve; 6. First main steam valve; 7. First regulating valve; 8. Second main steam valve; 9. Second regulating valve; 10. Exhaust pipe. Detailed Implementation

[0028] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0029] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0030] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0031] The preferred embodiments of this application are described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit this application.

[0032] See Figure 1 As shown, according to an embodiment of this application, a feedwater pump turbine system suitable for deep peak shaving is provided, including a feedwater pump turbine 1, a first low-pressure steam pipe 2, and a second low-pressure steam pipe 3; the power regulation range of the feedwater pump turbine 1 at least covers the steam parameter variation requirements of the main turbine load within the range of 30% to 100% of the rated load; the first low-pressure steam pipe 2 and the second low-pressure steam pipe 3 are connected in parallel and configured such that: when the main turbine load is below 90% of the rated load, the feedwater pump turbine 1 is connected to the first low-pressure steam pipe 2; when the main turbine load exceeds 90% of the rated load, the feedwater pump turbine 1 is simultaneously connected to both the first low-pressure steam pipe 2 and the second low-pressure steam pipe 3.

[0033] The feedwater pump turbine system for deep peak shaving provided in this embodiment has a power regulation range of feedwater pump turbine 1 that covers at least 30% to 100% of the main turbine load at rated load. This can meet the steam parameter variation requirements of the main turbine under different operating conditions, enabling the feedwater pump turbine system for deep peak shaving to operate stably within a wide load range. This improves the unit's adaptability to different load conditions and better meets the needs of grid peak shaving and other requirements.

[0034] The feedwater pump turbine system for deep peak shaving provided in this embodiment, through the parallel connection of the first low-pressure steam pipe 2 and the second low-pressure steam pipe 3, and the flexible connection configuration according to the main turbine load, allows for efficient utilization of the low-pressure steam energy and ensures the first regulating stage operates in its high-efficiency range when the main turbine load is low (below 90% of rated load). When the main turbine load is high (above 90% of rated load), both the first low-pressure steam pipe 2 and the second low-pressure steam pipe 3 are simultaneously activated to increase the steam supply and meet the power demand of the feedwater pump turbine 1 under high load. Therefore, this feedwater pump turbine system for deep peak shaving achieves wide-load, high-efficiency operation of the small turbine within the deep peak shaving range, thereby improving the overall unit economy.

[0035] The feedwater pump turbine system for deep peak shaving provided in this embodiment avoids the problem of feedwater pump turbine 1 speed fluctuation when switching from low-pressure steam source to high-pressure steam source in the traditional "one high, one low" steam intake scheme by setting the first low-pressure steam pipe 2 and the second low-pressure steam pipe 3 in parallel and flexibly connecting them according to the main turbine load. This allows feedwater pump turbine 1 to obtain the required steam smoothly under different loads, maintain stable speed and power output, improve the operational stability and reliability of feedwater pump turbine system for deep peak shaving, reduce equipment wear and failures that may be caused by speed fluctuations, extend equipment service life, and ensure the stable operation of the entire thermal power generation system.

[0036] In thermal power generation systems, the feedwater pump turbine 1, as a key component driving the feedwater pump, is often referred to as a small turbine compared to the main turbine. Its core function is to drive the feedwater pump, continuously delivering water from the deaerator to the boiler, ensuring the stable operation of the power generation process.

[0037] In this embodiment, the feedwater pump turbine 1 has a wide power regulation capability, which can adapt to the changes in steam parameters of the main turbine under different load conditions. Specifically, its power regulation range covers at least 30% to 100% of the rated load of the main turbine, and can be extended to a wider load range such as 20% to 100%, 30% to 110%, or even 20% to 110%, to meet the operational needs of different power generation scenarios.

[0038] Furthermore, to achieve efficient and stable steam supply, the feedwater pump turbine system suitable for deep peak shaving is equipped with two parallel pipelines: a first low-pressure steam pipe 2 and a second low-pressure steam pipe 3. These two pipelines work together to respond to changes in the main turbine load and dynamically adjust the steam input. When the main turbine is under low load (90% or below rated load), only the first low-pressure steam pipe 2 is activated. The steam parameters output by this pipeline precisely match the power demand of the feedwater pump turbine 1 under this condition, avoiding the speed fluctuation problem caused by switching from a low-pressure steam source to a high-pressure steam source in the traditional "one high, one low" steam supply scheme. Taking the off-peak electricity demand period as an example, if the main turbine load drops to 50% of the rated load, the first low-pressure steam pipe 2 can independently supply enough steam to meet the demand, ensuring the stable operation of the feedwater pump turbine 1. When the main turbine load exceeds 90% of the rated load and enters a high-load condition, the system automatically activates the dual-pipeline parallel steam supply mode, with the first low-pressure steam pipe 2 and the second low-pressure steam pipe 3 operating synchronously, significantly increasing the steam supply. When the main steam turbine is running at full load during peak electricity demand, the two pipelines work together to deliver sufficient steam, ensuring that the feedwater pump turbine 1 can output enough power to drive the feedwater pump to maintain stable boiler feedwater pressure and flow, thus ensuring reliable operation of the unit under high load.

[0039] In some possible implementations disclosed in this application, see [link to relevant documentation]. Figure 1 As shown, the feedwater pump turbine system suitable for deep peak shaving also includes a low-pressure steam source; the low-pressure steam source is a four-extraction steam pipe 4, which is connected to the first low-pressure steam pipe 2 and the second low-pressure steam pipe 3 respectively.

[0040] In this embodiment, the fourth extraction steam pipe 4 is a steam pipe drawn from the fourth-stage extraction port of the main steam turbine, and its steam parameters are relatively stable. Using it as a low-pressure steam source, it is connected to the first low-pressure steam pipe 2 and the second low-pressure steam pipe 3, respectively, to provide a continuous and stable steam supply to the feedwater pump turbine 1. This ensures that the feedwater pump turbine 1 has a reliable power source under different main steam turbine loads, thereby improving the operational stability and reliability of the entire feedwater pump turbine system suitable for deep peak shaving.

[0041] Understandably, using the steam extracted from the fourth extraction stage of the main steam turbine as the gas source for the feedwater pump turbine 1 achieves cascade utilization of steam. Since the fourth extraction steam has already performed some work in the main steam turbine, introducing it into the feedwater pump turbine system, which is suitable for deep peak shaving, to drive feedwater pump turbine 1 allows for further utilization of the thermal energy of this steam. This avoids energy waste caused by direct steam discharge, improves the overall energy efficiency of the unit, and reduces energy consumption.

[0042] In some possible implementations disclosed in this application, see [link to relevant documentation]. Figure 1 As shown, an electric isolation valve 5 is installed on the four-extraction steam pipe 4.

[0043] Here, when it is necessary to inspect or maintain some equipment in the feedwater pump turbine system suitable for deep peak shaving (such as the first low-pressure steam pipe 2, the second low-pressure steam pipe 3, the feedwater pump turbine 1, etc.), the four-extraction steam pipe 4 can be isolated from other components by closing the electric isolation valve 5 to prevent steam leakage, provide a safe working environment for maintenance personnel, facilitate the inspection, repair and maintenance of related equipment, and improve the maintainability of the system.

[0044] Understandably, the electric isolation valve 5 can quickly cut off the steam supply in the event of abnormal conditions (such as pipeline rupture or equipment failure), preventing large-scale steam leakage that could lead to safety accidents, reducing safety risks, protecting equipment and personnel, and improving the overall safety of the feedwater pump turbine system suitable for deep peak shaving. Specifically, the electric isolation valve 5 can flexibly control the opening and closing of the four-stage steam pipe 4 according to actual operating needs. For example, during system startup or shutdown, the electric isolation valve 5 can be used to control the inflow and outflow of steam, ensuring smooth system startup and shutdown, and improving the system's operational flexibility and control precision.

[0045] In some possible implementations disclosed in this application, see [link to relevant documentation]. Figure 1 As shown, the first low-pressure steam pipe 2 is equipped with a first main steam valve 6 and a first regulating valve 7.

[0046] In this embodiment, the first main steam valve 6 is used to control the on / off state of steam. When the feedwater pump turbine system suitable for deep peak shaving starts up, stops, or malfunctions, closing the first main steam valve 6 can quickly cut off the steam supply to the first low-pressure steam pipe 2, ensuring system safety. The first regulating valve 7 can precisely adjust the steam flow rate according to the actual operating requirements of the feedwater pump turbine 1. When the main turbine load changes, the first regulating valve 7 can adjust its opening accordingly to match the amount of steam entering the feedwater pump turbine 1 with the unit's operating conditions, ensuring stable operation of the feedwater pump turbine 1 and outputting appropriate power to drive the feedwater pump, meeting the boiler's feedwater requirements.

[0047] Understandably, the combined use of the first main steam valve 6 and the first regulating valve 7 can improve the accuracy of steam flow regulation. The first main steam valve 6 can quickly cut off or connect the steam, while the first regulating valve 7 is responsible for fine flow regulation under steam flow conditions. This combination can more accurately control the steam flow under different operating conditions, especially under low load or frequent load changes, thereby improving the operating efficiency and stability of the feedwater pump turbine 1.

[0048] In the above embodiments, see Figure 1 As shown, the first regulating valve 7 is located downstream of the first main steam valve 6 along the steam flow path.

[0049] Here, the first main steam valve 6 can quickly cut off the steam supply when the feedwater pump turbine system, suitable for deep peak shaving, starts up, stops, or malfunctions. Since the first regulating valve 7 is located downstream of it, damage to the first regulating valve 7 caused by the impact and high pressure generated at the moment of steam on / off is avoided, extending the service life of the first regulating valve 7 and improving its operational reliability.

[0050] Understandably, when the first main steam valve 6 is closed, the upstream steam pressure is higher and relatively stable, while the downstream pressure is lower and fluctuates more. Placing the first regulating valve 7 on the downstream side allows it to regulate flow under a relatively stable pressure differential environment, which helps improve regulation accuracy and sensitivity, and more accurately controls the amount of steam entering the feedwater pump turbine 1, meeting the operating requirements under different working conditions.

[0051] In some possible implementations disclosed in this application, see [link to relevant documentation]. Figure 1 As shown, the second low-pressure steam pipe 3 is equipped with a second main steam valve 8 and a second regulating valve 9.

[0052] In this embodiment, the second main steam valve 8 can independently control the steam flow through the second low-pressure steam pipe 3. When the feedwater pump turbine system, suitable for deep peak shaving, requires separate operation of the second low-pressure steam pipe 3, the steam can be cut off by closing the second main steam valve 8 to ensure operational safety. Simultaneously, the second regulating valve 9 can precisely adjust the steam flow through the second low-pressure steam pipe 3 according to actual operating requirements. When the main turbine load increases, requiring the second low-pressure steam pipe 3 to participate in steam supply to meet the high-load operation of the feedwater pump turbine 1, the second regulating valve 9 can precisely control the steam flow, ensuring that the amount of steam entering the feedwater pump turbine 1 matches the required power.

[0053] Understandably, the second main steam valve 8 and the second regulating valve 9 on the second low-pressure steam pipe 3, in conjunction with the first main steam valve 6 and the first regulating valve 7 on the first low-pressure steam pipe 2, enable more flexible steam supply control. For example, under different main turbine load conditions, the steam supply method can be optimized by adjusting the main steam valves and regulating valves on the two pipes separately, making the operation of the feedwater pump turbine 1 more efficient. Under partial load conditions, steam supply may mainly rely on the first low-pressure steam pipe 2, with fine adjustment through the first regulating valve 7; while under high load conditions, in addition to the continued steam supply from the first low-pressure steam pipe 2, the steam supply from the second low-pressure steam pipe 3 can be adjusted by opening the second main steam valve 8 and using the second regulating valve 9, achieving coordinated steam supply from both pipes and flexibly meeting the steam demand of the feedwater pump turbine 1 under different operating conditions.

[0054] In the above embodiments, see Figure 1 As shown, the second regulating valve 9 is located downstream of the second main steam valve 8 along the steam flow path.

[0055] Here, the second regulating valve 9 is located downstream of the second main steam valve 8, which can prevent water hammer, high pressure impact and other damage to the regulating valve caused by the instantaneous steam switching, thereby extending the service life of the second regulating valve 9 and improving its working stability and reliability.

[0056] In some possible embodiments disclosed in this application, the feedwater pump turbine 1 is provided with a first regulating stage nozzle connected to the outlet of the first low-pressure steam pipe 2, and the nozzle area of ​​the first regulating stage nozzle is adapted to the main turbine load in the range of 30% to 90% of the rated load.

[0057] In this embodiment, the design of the first regulating stage nozzle eliminates the drawbacks of the traditional feedwater pump turbine 1 large flow margin design scheme (margin ≥ 30%). Its nozzle area is adapted to the operating conditions of the main turbine load in the range of 30% to 90% of the rated load, and can match the steam inlet flow of the first low-pressure steam pipe 2, thereby improving the operating efficiency of the feedwater pump turbine 1 and ensuring the efficient operation of the feedwater pump turbine 1 under deep peak shaving conditions.

[0058] Understandably, due to excessive design margins, the actual operating flow rate of the low-pressure steam source is far lower than the maximum capacity of the flow path design in traditional solutions, causing the feedwater pump turbine 1 to operate inefficiently for extended periods, with operating efficiency generally below 70%. However, in this embodiment, the first regulating stage nozzle can match the steam flow rate of the first low-pressure steam pipe 2, improving the operating efficiency of the feedwater pump turbine 1. This allows it to maintain efficient and stable operation even under deep peak-shaving conditions, effectively solving the long-standing inefficiency problem of traditional solutions and contributing to energy conservation, efficiency improvement, and stable operation of the entire thermal power generation system.

[0059] In the above embodiment, the feedwater pump turbine 1 is further provided with a second regulating stage nozzle that is connected to the outlet of the second low-pressure steam pipe 3. The nozzle area of ​​the second regulating stage nozzle is smaller than that of the first regulating stage nozzle.

[0060] Here, the second regulating stage nozzle has a smaller area, which, in conjunction with the first regulating stage nozzle, allows for better adaptation to changes in steam flow under different main turbine loads. When the main turbine load is between 30% and 90% of its rated load, the steam demand of the feedwater pump turbine 1 is primarily met by the first regulating stage nozzle in conjunction with the first low-pressure steam pipe 2. At this time, the first regulating stage nozzle has a larger area, allowing for a larger steam flow. When the main turbine load exceeds 90% of its rated load, the second low-pressure steam pipe 3 is put into use. Although the second regulating stage nozzle has a smaller area, it can accurately supplement an appropriate amount of steam according to the operating conditions at this time. Working together with the first regulating stage nozzle, it ensures that the feedwater pump turbine 1 can obtain a suitable amount of steam even under high loads, meeting the power output requirements.

[0061] In some possible implementations disclosed in this application, see [link to relevant documentation]. Figure 1 As shown, the feedwater pump turbine system suitable for deep peak shaving also includes an exhaust pipe 10; the exhaust pipe 10 is connected to the feedwater pump turbine 1.

[0062] In this embodiment, by setting up an exhaust pipe 10, a channel is provided for the steam discharged from the feedwater pump turbine 1 after it has done work, so that the steam can be discharged smoothly from the feedwater pump turbine 1 and the normal operation of the feedwater pump turbine 1 can be guaranteed.

[0063] Understandably, during the operation of the feedwater pump turbine 1, the energy of the steam decreases after driving the impeller to rotate, and it needs to be discharged in a timely manner to maintain the pressure balance and normal working cycle within the feedwater pump turbine 1. Discharging the steam through the exhaust pipe 10 prevents excessive pressure buildup inside the feedwater pump turbine 1, thus ensuring the stability and safety of the feedwater pump turbine 1 and the entire feedwater pump turbine system suitable for deep peak shaving, and preventing damage to the equipment from overpressure or other malfunctions.

[0064] It will be readily understood by those skilled in the art that the aforementioned advantageous methods can be freely combined and superimposed without conflict.

[0065] The above are merely preferred embodiments of this application and are not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application. The above are merely preferred embodiments of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of this application, and these improvements and modifications should also be considered within the protection scope of this application.

Claims

1. A feedwater pump turbine system suitable for deep peak shaving, characterized in that, include: Feedwater pump turbine (1), first low-pressure steam pipe (2), and second low-pressure steam pipe (3); The power regulation range of the feedwater pump turbine (1) shall at least cover the steam parameter variation requirements of the main turbine load within the range of 30% to 100% of the rated load; The first low-pressure steam pipe (2) and the second low-pressure steam pipe (3) are connected in parallel and configured such that: when the load of the main steam turbine is below 90% of the rated load, the feedwater pump turbine (1) is connected to the first low-pressure steam pipe (2); when the load of the main steam turbine exceeds 90% of the rated load, the feedwater pump turbine (1) is connected to both the first low-pressure steam pipe (2) and the second low-pressure steam pipe (3).

2. The feedwater pump turbine system suitable for deep peak shaving according to claim 1, characterized in that, Also includes: Low-pressure steam source; The low-pressure steam source is a four-extraction steam pipe (4), which is connected to the first low-pressure steam pipe (2) and the second low-pressure steam pipe (3) respectively.

3. The feedwater pump turbine system suitable for deep peak shaving according to claim 2, characterized in that, An electric isolation valve (5) is provided on the four steam extraction pipes (4).

4. The feedwater pump turbine system suitable for deep peak shaving according to claim 1, characterized in that, The first low-pressure steam pipe (2) is equipped with a first main steam valve (6) and a first regulating valve (7).

5. The feedwater pump turbine system suitable for deep peak shaving according to claim 4, characterized in that, The first regulating valve (7) is located downstream of the first main steam valve (6) along the steam flow path.

6. The feedwater pump turbine system suitable for deep peak shaving according to claim 1, characterized in that, The second low-pressure steam pipe (3) is equipped with a second main steam valve (8) and a second regulating valve (9).

7. The feedwater pump turbine system suitable for deep peak shaving according to claim 6, characterized in that, The second regulating valve (9) is located downstream of the second main steam valve (8) along the steam flow path.

8. The feedwater pump turbine system suitable for deep peak shaving according to claim 1, characterized in that, The feedwater pump turbine (1) is equipped with a first regulating stage nozzle that is connected to the outlet of the first low-pressure steam pipe (2). The nozzle area of ​​the first regulating stage nozzle is adapted to the load of the main steam turbine in the range of 30% to 90% of the rated load.

9. The feedwater pump turbine system suitable for deep peak shaving according to claim 8, characterized in that, The feedwater pump turbine (1) is also provided with a second regulating stage nozzle that is connected to the outlet of the second low-pressure steam pipe (3). The nozzle area of ​​the second regulating stage nozzle is smaller than that of the first regulating stage nozzle.

10. The feedwater pump turbine system suitable for deep peak shaving according to claim 1, characterized in that, Also includes: Exhaust pipe (10); The exhaust pipe (10) is connected to the feedwater pump turbine (1).

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