A 200MW series ultra-high pressure three-cylinder three-exhaust flexible steam turbine

Abstract

A 200MW series ultra-high pressure three-cylinder three-exhaust flexible transformation steam turbine, which relates to the technical field of steam turbines. The present invention is to solve the problem that the heating capacity needs to be increased due to the continuous increase in the heating area in winter, and the unit needs to have a more flexible peak-shaving capacity in summer, which increases the difficulty of transformation for the three-cylinder three-exhaust ultra-high pressure steam turbine unit. The present invention includes a medium-pressure cylinder, a single-flow low-pressure cylinder and a double-flow low-pressure cylinder. One side of the connecting pipe is connected to the exhaust interface of the medium-pressure cylinder, and the other side of the connecting pipe is connected to the low-pressure steam inlet in the middle of the upper part of the double-flow low-pressure cylinder; a heating steam extraction pipe is provided on the medium-pressure side of the connecting pipe, and the heating steam extraction pipe is connected to the heating steam extraction system, and a cooling steam medium-pressure side pipe is arranged on the heating steam extraction pipe; a cooling steam low-pressure side pipe is provided on the low-pressure side of the connecting pipe, and a cooling steam system is connected between the cooling steam medium-pressure side pipe and the cooling steam low-pressure side pipe. The present invention is used for steam work.

Description

Technical Field

[0001] The invention relates to the technical field of steam turbines, and in particular to a 200MW series ultra-high pressure three-cylinder three-exhaust flexible modified steam turbine. Background Art

[0002] At present, energy conservation and consumption reduction are the core content of the national energy policy. Improving unit efficiency and reducing unit heat consumption have become the main work goals of power generation companies. At present, the cycle efficiency of some in-service units is low, the heat consumption value and coal consumption are high, and the peak-shaving capacity is insufficient, and it is impossible to achieve the cascade utilization of energy. In order to ensure the flexible peak-shaving of the unit while increasing the heating capacity of the unit, simply drilling holes in a steam extraction pipe of the turbine to extract steam or high back pressure modification cannot meet the actual needs. Especially for the transformation of old three-cylinder and three-exhaust units, combined with the special structure of the unit, the transformation is more difficult. Summary of the invention

[0003] In order to solve the problem that the heating capacity needs to be increased due to the continuous increase in heating area in winter, and the unit needs to have more flexible peak-shaving capability in summer, for the three-cylinder three-exhaust ultra-high pressure steam turbine unit, the difficulty of transformation increases due to the particularity of the structure. Therefore, a 200MW series ultra-high pressure three-cylinder three-exhaust flexible transformation steam turbine is proposed.

[0004] The technical solution adopted by the present invention to solve the above technical problems is:

[0005] A 200MW series ultra-high pressure three-cylinder three-exhaust flexible modified steam turbine comprises an intermediate pressure cylinder, a single-flow low pressure cylinder and a double-flow low pressure cylinder, which are fixedly connected in sequence from front to back, the intermediate pressure cylinder and the single-flow low pressure cylinder are combined into a cylinder, connecting pipes are arranged in parallel, one side of the connecting pipe is connected to the exhaust interface of the intermediate pressure cylinder, and the other side of the connecting pipe is connected to the low-pressure steam inlet in the middle of the upper part of the double-flow low pressure cylinder; a heating steam extraction pipe is provided on the intermediate pressure side of the connecting pipe, the heating steam extraction pipe is connected to the heating steam extraction system, and a cooling steam intermediate pressure side pipe is arranged on the heating steam extraction pipe; a cooling steam low pressure side pipe is provided on the low pressure side of the connecting pipe, and a cooling steam system is connected between the cooling steam intermediate pressure side pipe and the cooling steam low pressure side pipe.

[0006] Furthermore, the cooling steam system includes an electric gate valve, a pressure regulating valve, a temperature reducing valve group and a cooling steam pipeline. The exhaust end of the cooling steam medium-pressure side pipe is connected to the steam inlet end of the cooling steam pipeline, and the exhaust end of the cooling steam pipeline is connected to the steam inlet end of the cooling steam low-pressure side pipe. The cooling steam pipeline is sequentially connected with an electric gate valve, a pressure regulating valve and a temperature reducing valve group from the steam inlet direction to the steam exhaust direction. The exhaust end of the cooling steam pipeline is provided with temperature and pressure measuring points. Two drain pipelines are connected to the cooling steam pipeline, one drain pipeline is provided between the electric gate valve and the pressure regulating valve, and the other drain pipeline is provided between the temperature reducing valve group and the temperature and pressure measuring points. A valve is provided on the drain pipeline.

[0007] Furthermore, the exhaust end of the cooling steam medium-pressure side pipe and the steam inlet end of the cooling steam pipeline are connected via a cooling steam medium-pressure side flange assembly, and the exhaust end of the cooling steam pipeline and the steam inlet end of the cooling steam low-pressure side pipe are connected via a cooling steam low-pressure side flange assembly.

[0008] Furthermore, the heating steam extraction system includes a safety valve, a check valve, a quick-closing regulating valve, a stop valve and a heating steam extraction pipeline. The exhaust end of the heating steam extraction pipe is connected to the steam inlet end of the heating steam extraction pipeline. The heating steam extraction pipeline is sequentially connected with a safety valve, a check valve, a quick-closing regulating valve and a stop valve from the steam inlet direction to the steam exhaust direction.

[0009] Furthermore, the exhaust end of the heating steam extraction pipe is connected to the steam inlet end of the heating steam extraction pipeline via a heating steam extraction flange assembly.

[0010] Furthermore, four second-stage steam temperature measuring points are set on the lower half of the cylinder body behind the forward and reverse second-stage moving blades of the double-split low-pressure cylinder, and four last-stage steam temperature measuring points are set on the lower half of the cylinder body behind the forward and reverse last-stage moving blades of the double-split low-pressure cylinder.

[0011] Furthermore, the four secondary and final stage steam temperature measuring points are symmetrically arranged along the center line of the double-divided low-pressure cylinder, and the four final stage steam temperature measuring points are symmetrically arranged along the center line of the double-divided low-pressure cylinder.

[0012] Furthermore, a dual-path water spray system is symmetrically arranged along the center line of the dual-flow low-pressure cylinder.

[0013] Furthermore, the dual-path water spray system includes a first water spray pipeline and a second water spray pipeline, the water inlet ends of the first water spray pipeline and the second water spray pipeline are respectively connected to the condensate inlet, the water outlet end of the first water spray pipeline is connected to the water inlet end of the first nozzle, the electrical end and the adjustment end of the double-divided low-pressure cylinder body are respectively symmetrically provided with a plurality of atomizing nozzles, the water outlet end of the second water spray pipeline is connected to the water inlet end of the second nozzle, and the water outlet ends of the first nozzle and the second nozzle are respectively connected to the atomizing nozzles.

[0014] Furthermore, the atomizing nozzles at each side end include two groups of atomizing nozzles, an inner group and an outer group. The inner group of atomizing nozzles is connected to the water outlet end of the first nozzle, and the outer group of atomizing nozzles is connected to the water outlet end of the second nozzle.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] The high and medium pressure flow, front, middle and rear bearing boxes and bearings, valve positions, and the positions of various pipeline interfaces remain unchanged. The old rotor is used for transformation, the low-pressure forward and reverse final stage impellers and moving blades are removed, and new low-pressure forward and reverse final stage impellers are installed. At the same time, new reinforced final blades are used, and low-pressure final and sub-final temperature measuring elements are added. The connecting pipe uses a corrugated expansion joint connecting pipe (curved pipe pressure balance chamber), a butterfly valve is installed, the connecting pipe elevation is appropriately raised, and holes are punched for steam extraction.

[0017] After the transformation, the unit can be flexibly switched between pure condensing, extraction condensing, and pure back pressure conditions according to the actual operation of the unit to meet the unit's flexible peak-shaving capabilities. When the unit is operating under flexible cylinder-cutting conditions, the steam flow entering the No. 2 low-pressure cylinder is small, which causes friction and blast heating when the low-pressure rotor rotates at high speed. If no effective cooling method is adopted, it will cause problems such as rotor deformation and shaft elevation changes. In severe cases, it can cause dynamic and static friction, unit shaft vibration, and low-pressure cylinder dynamic and static expansion difference. In severe cases, it can cause the unit to shut down. Since the condenser of the ultra-high-pressure steam turbine unit does not stop, steam cooling is used after the transformation.

[0018] Since this is an old renovation project, after theoretical calculations, the strength of the low-pressure impellers at all levels and the stability of the shaft system meet the design requirements after the renovation, which can ensure the safe and stable operation of the unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a longitudinal section view of the intermediate pressure cylinder 1 and the single-flow low-pressure cylinder 2 before transformation of the present invention;

[0020] Figure 2 It is a longitudinal section view of the double-divided low-pressure cylinder 6 before transformation of the present invention;

[0021] Figure 3 It is a longitudinal section view of the double-divided low-pressure cylinder 6 after the modification of the present invention;

[0022] Figure 4 It is a schematic diagram of the structure of the connecting pipe 15 in the present invention;

[0023] Figure 5 yes Figure 4 A-direction view in the figure;

[0024] Figure 6 yes Figure 4 B view in the figure;

[0025] Figure 7 yes Figure 4 C-direction view in;

[0026] Figure 8 It is a diagram of the cooling steam system in the present invention;

[0027] Fig. 9 It is a diagram of the heating steam extraction system in the present invention;

[0028] Fig.10 It is a steam temperature measuring point position diagram of the double-divided low-pressure cylinder 6 in the present invention;

[0029] Fig.11 It is a diagram of a dual-path water spraying system of a dual-divided low-pressure cylinder 6 in the present invention. DETAILED DESCRIPTION

[0030] Specific implementation method 1: Combination Figures 1 to 11 The present embodiment is described. The present embodiment describes a 200MW series ultra-high pressure three-cylinder three-exhaust flexible modified steam turbine comprising an intermediate pressure cylinder 1, a single-flow low pressure cylinder 2 and a double-flow low pressure cylinder 6. The intermediate pressure cylinder 1, the single-flow low pressure cylinder 2 and the double-flow low pressure cylinder 6 are fixedly connected in sequence from front to back. The intermediate pressure cylinder 1 is combined with the single-flow low pressure cylinder 2. A connecting pipe 15 is arranged in parallel. One side of the connecting pipe 15 is connected to the exhaust interface of the intermediate pressure cylinder 1, and the other side of the connecting pipe 15 is connected to the low-pressure steam inlet in the middle of the upper part of the double-flow low pressure cylinder 6. A heating steam extraction pipe 17 is provided on the intermediate pressure side of the connecting pipe 15. The heating steam extraction pipe 17 is connected to the heating steam extraction system. A cooling steam intermediate pressure side pipe 18 is arranged on the heating steam extraction pipe 17. A cooling steam low pressure side pipe 19 is provided on the low pressure side of the connecting pipe 15. A cooling steam system is connected between the cooling steam intermediate pressure side pipe 18 and the cooling steam low pressure side pipe 19.

[0031] The 200MW series ultra-high pressure three-cylinder three-exhaust flexible steam turbine transformation is embodied in that the high and medium pressure flow, front, middle and rear bearing boxes and bearings, valve positions, and pipeline interface positions of the original unit remain unchanged, and the double-divided low-pressure cylinder 6 flow is transformed and modified based on the principle of reusing the old:

[0032] 1. Remove the final baffle plate and final impeller (including moving blades) of the double-divided low-pressure cylinder 6, and install new final baffle plates and final impeller (including moving blades) of the double-divided low-pressure cylinder 6 (see attached Figure 3 ) to ensure unit safety during flexible operation;

[0033] 2. Optimize the structure of the connecting pipe 15, adopt a hot-pressed elbow structure, install a fully sealed butterfly valve 16, and reserve a heating steam extraction pipe 17 and cooling steam pipes 18 and 19 (see Figure 4-7 );

[0034] 3. Add new heating steam extraction system pipelines (including flanges and connectors) and valves to ensure the heating steam volume under winter conditions (see Fig. 9 );

[0035] 4. Add cooling steam system pipelines (including flanges and connectors) and valves to ensure that the blast heat in the double-divided low-pressure cylinder 6 can be effectively removed during flexible operation (see Figure 8 );

[0036] 5. Install temperature measuring points after the last stage and the second last stage of the double-divided low-pressure cylinder 6 to effectively monitor the exhaust temperature of the unit, and more reasonably invest in water spray to ensure the safety of the unit (see Fig.10 );

[0037] 6. Optimize the water spray system of the unit to make the water spray system more intelligent (see Fig.11 ).

[0038] After this renovation, while ensuring the safe, flexible and stable operation of the unit, the peak-shaving capacity of the unit has been increased and the heating capacity during the heating season has been increased.

[0039] Figure 1 Before the transformation, there is an intermediate pressure cylinder 1, a single-flow low-pressure cylinder 2, a partition 3 in the single-flow low-pressure cylinder (a total of 5 stages), a moving blade 4 in the single-flow low-pressure cylinder (a total of 5 stages), a moving blade impeller 5 in the single-flow low-pressure cylinder (a total of 5 stages), and an intermediate and low-pressure rotor 10 in the single-flow low-pressure cylinder;

[0040] Figure 2 Before the middle transformation, there are double-split low-pressure cylinder 6, last-stage partition plate 7 in the double-split low-pressure cylinder (1 stage each for forward and reverse directions), last-stage moving blades 8 in the double-split low-pressure cylinder (1 stage each for forward and reverse directions), last-stage moving blade impeller 9 in the double-split low-pressure cylinder (1 stage each for forward and reverse directions), and low-pressure rotor 11 in the double-split low-pressure cylinder.

[0041] Figure 3 After the transformation, under the premise of ensuring the stability of the shaft system, the final stage partition 7 (1 stage each in the forward and reverse directions), the final stage moving blades 8 (1 stage each in the forward and reverse directions) and the final stage moving blade impeller 9 (1 stage each in the forward and reverse directions) in the double-divided low-pressure cylinder are removed, and replaced with new final stage partitions 12 (1 stage each in the forward and reverse directions), new final stage moving blades 13 (1 stage each in the forward and reverse directions) and new final stage moving blade impeller 14 (1 stage each in the forward and reverse directions) in the double-divided low-pressure cylinder. The final stage partitions 12, the final stage moving blades 13 and the final stage moving blade impeller 14 in the new double-divided low-pressure cylinder are all new profile structures to meet the unit safety during flexible operation.

[0042] The principle of reusing old steam is adopted to carry out flexibility transformation of the unit. After the transformation, the new steam enters the high and medium pressure cylinders to do work, and a part of the medium pressure exhaust steam (the heat recovery extraction steam of the low pressure heater is cut off) enters the single-flow low pressure cylinder 2 to do work, and the rest of the steam all enters the heat network heater for heating.

[0043] When operating in flexible conditions, part of the medium-pressure exhaust steam enters the single-flow low-pressure cylinder 2 to perform work, and the rest of the exhaust steam enters the connecting pipe 15. Most of the steam enters the heating steam extraction system through the heating steam extraction pipe 17 and then enters the heat network. There is also a 10-20t / h steam cooling steam system.

[0044] A connecting pipe butterfly valve 16 is arranged on the connecting pipe 15 .

[0045] Specific implementation method 2: Combination Figures 1 to 11 This embodiment is described. The cooling steam system described in this embodiment includes an electric gate valve 23, a pressure regulating valve 24, a temperature reducing valve group 25 and a cooling steam pipeline 27. The exhaust end of the cooling steam medium-pressure side pipe 18 is connected to the steam inlet end of the cooling steam pipeline 27, and the exhaust end of the cooling steam pipeline 27 is connected to the steam inlet end of the cooling steam low-pressure side pipe 19. The cooling steam pipeline 27 is sequentially connected with the electric gate valve 23, the pressure regulating valve 24 and the temperature reducing valve group 25 from the steam inlet direction to the steam exhaust direction. The exhaust end of the cooling steam pipeline 27 is provided with a temperature and pressure measuring point 28. Two drain pipes are connected to the cooling steam pipeline 27, one drain pipe is provided between the electric gate valve 23 and the pressure regulating valve 24, and the other drain pipe is provided between the temperature reducing valve group 25 and the temperature and pressure measuring point 28. A valve 26 is provided on the drain pipe. Other components and connection methods are the same as those of the first embodiment.

[0046] When the flexible working condition is in operation, the electric gate valve 23 is in the open state, and the steam flow entering the single-flow low-pressure cylinder 2 is controlled and regulated by the pressure regulating valve 25. The temperature of the cooling steam entering the low pressure is reduced to the design temperature by the temperature reducing valve group 26. The temperature and pressure measuring points 28 are arranged on the cooling steam pipeline 27 to monitor the cooling steam parameters. When the flexible working condition is cut off, the electric gate valve 23 and the pressure regulating valve 24 are both in the closed state. The low-pressure cooling steam system is equipped with a drain pipe and valve 26. Due to the low temperature parameters of the cooling steam, the drain pipe and valve 26 are always in the open state when the low-pressure cooling steam system is put into operation.

[0047] Specific implementation method three: Combination Figures 1 to 11 To explain this embodiment, the exhaust end of the cooling steam medium-pressure side pipe 18 and the steam inlet end of the cooling steam pipeline 27 are connected via a cooling steam medium-pressure side flange assembly 22, and the exhaust end of the cooling steam pipeline 27 and the steam inlet end of the cooling steam low-pressure side pipe 19 are connected via a cooling steam low-pressure side flange assembly 21. Other components and connection methods are the same as those of the second embodiment.

[0048] Specific implementation method four: Combination Figures 1 to 11 This embodiment is described. The heating steam extraction system of this embodiment includes a safety valve 29, a check valve 30, a fast closing regulating valve 31, a stop valve 32 and a heating steam extraction pipeline 33. The exhaust end of the heating steam extraction pipe 17 is connected to the steam inlet end of the heating steam extraction pipeline 33. The heating steam extraction pipeline 33 is sequentially connected with the safety valve 29, the check valve 30, the fast closing regulating valve 31 and the stop valve 32 from the steam inlet direction to the steam exhaust direction. Other components and connection methods are the same as those of the first embodiment.

[0049] When the system is operating under normal pressure, the safety valve is in a closed state; when overpressure occurs, the safety valve 29 automatically opens to discharge steam to the outside, protecting the steam extraction pipeline 33 and the turbine main equipment to prevent damage; the steam extraction check valve 30 is installed in the heating steam extraction pipeline 33 to prevent steam backflow. The fast-closing regulating valve 31 is installed in the heating steam extraction pipeline 33, which is used to quickly close the steam extraction pipeline in abnormal conditions to protect the steam turbine. The stop valve 32 is installed in the heating steam extraction pipeline 33 to shut off the steam extraction pipeline.

[0050] Specific implementation method five: Combination Figures 1 to 11 To explain this embodiment, the exhaust end of the heating steam extraction pipe 17 in this embodiment is connected to the steam inlet end of the heating steam extraction pipe 33 via a heating steam extraction flange assembly 20. Other components and connection methods are the same as those of the fourth embodiment.

[0051] Specific implementation method six: Combination Figures 1 to 11 To explain this embodiment, four steam temperature measuring points 34 after the next-to-last stage are set on the lower half of the cylinder body behind the forward and reverse next-to-last stage moving blades of the double-divided low-pressure cylinder 6 in this embodiment, and four steam temperature measuring points 35 after the last stage are set on the lower half of the cylinder body behind the forward and reverse last stage moving blades of the double-divided low-pressure cylinder 6. Other components and connection methods are the same as those in the first embodiment.

[0052] According to the actual situation of flexibility transformation, it is necessary to add the measurement point 34 for measuring the low-pressure forward and reverse secondary last stage steam temperature and the steam temperature measurement point 35 after the last stage to monitor the exhaust steam temperature of the last two low-pressure stages.

[0053] According to the actual situation on site, the outer cylinder of the double-divided low-pressure cylinder 6 is supplemented with processing, namely, drilling holes on site, welding the lead connector for the thermocouple, installing the protective cone sleeve, cone sleeve gasket, and thermocouple, and leading the signal to the main control room.

[0054] Specific implementation method seven: Combination Figures 1 to 11To explain this embodiment, the four secondary and final stage steam temperature measuring points 34 of this embodiment are symmetrically arranged along the center line of the double-divided low-pressure cylinder 6, and the four final stage steam temperature measuring points 35 are symmetrically arranged along the center line of the double-divided low-pressure cylinder 6. Other components and connection methods are the same as those of the sixth embodiment.

[0055] Specific implementation method eight: Combination Figures 1 to 11 To explain this embodiment, a dual-path water spray system is symmetrically arranged along the center line of the dual-flow low-pressure cylinder 6. Other components and connection methods are the same as those of the first embodiment.

[0056] Specific implementation method nine: Combination Figures 1 to 11 To explain this embodiment, the dual-channel water spray system of this embodiment includes a first channel water spray pipeline 36 and a second channel water spray pipeline 37. The water inlet ends of the first channel water spray pipeline 36 and the second channel water spray pipeline 37 are respectively connected to the condensate inlet, the water outlet end of the first channel water spray pipeline 36 is connected to the water inlet end of the first channel nozzle 39, the electric end and the regulating end of the double-divided low-pressure cylinder 6 are symmetrically provided with a plurality of atomizing nozzles 40, the water outlet end of the second channel water spray pipeline 37 is connected to the water inlet end of the second channel nozzle 38, and the water outlet ends of the first channel nozzle 39 and the second channel nozzle 38 are respectively connected to the atomizing nozzle 40. Other components and connection methods are the same as those of the specific embodiment eight.

[0057] Specific implementation method ten: Combination Figures 1 to 11 To explain this embodiment, the atomizing nozzles 40 at each side end of this embodiment include two groups of atomizing nozzles 40, one inside and one outside. The atomizing nozzles 40 at the inside are connected to the water outlet end of the first nozzle 39, and the atomizing nozzles 40 at the outside are connected to the water outlet end of the second nozzle 38. Other components and connection methods are the same as those of the ninth embodiment.

[0058] During the flexible operation, the flow in the double-divided low-pressure cylinder 6 does not do work, and the blast heat generated by the high-speed rotation of the rotor can cause the cylinder to deform, resulting in changes in the bearing elevation and dynamic and static friction; there is a risk of excessive static stress on the blades; and there is a risk that the dynamic frequency of the blades falls into the resonance point.

[0059] In order to avoid the above problems, in addition to adding a cooling steam system and adding low-pressure final stage and sub-final stage temperature measurement points, the double-divided low-pressure cylinder 6 water spray system also needs to be optimized. The original low-pressure cylinder water spray system is retained and defined as the first water spray pipeline 36. A new low-pressure cylinder water spray system is added, defined as the second water spray pipeline 37. The water spray pipeline in the double-divided low-pressure cylinder 6 is optimized, and all stainless steel products are used to ensure stable operation of the system; an excellent atomizing nozzle 40 is used to ensure the cooling effect of water spraying; a two-way water spray system, namely the first water spray pipeline 36 and the second water spray pipeline 37, is used and put into use in stages to ensure the cooling effect and avoid excessive water spraying; the water spray angle is optimized to reduce the water erosion of the blades caused by the backflow of cooling water.

[0060] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0061] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0062] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A 200MW series ultra-high pressure three-cylinder three-exhaust flexible steam turbine, characterized by: It comprises a medium-pressure cylinder (1), a single-flow low-pressure cylinder (2) and a double-flow low-pressure cylinder (6). The medium-pressure cylinder (1), the single-flow low-pressure cylinder (2) and the double-flow low-pressure cylinder (6) are fixedly connected in sequence from front to back. The medium-pressure cylinder (1) and the single-flow low-pressure cylinder (2) are combined into a cylinder. A connecting pipe (15) is arranged in parallel. One side of the connecting pipe (15) is connected to the exhaust interface of the medium-pressure cylinder (1), and the other side of the connecting pipe (15) is connected to the low-pressure steam inlet in the middle of the upper part of the double-flow low-pressure cylinder (6). A heating steam extraction pipe (17) is arranged on the medium-pressure side of the connecting pipe (15). The heating steam extraction pipe (17) is connected to the heating steam extraction system. A cooling steam medium-pressure side pipe (18) is arranged on the heating steam extraction pipe (17). A cooling steam low-pressure side pipe (19) is arranged on the low-pressure side of the connecting pipe (15). A cooling steam system is connected between the cooling steam medium-pressure side pipe (18) and the cooling steam low-pressure side pipe (19). Four steam temperature measuring points (34) after the second-last stage are arranged on the lower half of the cylinder body at the rear side of the forward and reverse second-last stage moving blades of the double-split low-pressure cylinder (6), and four steam temperature measuring points (35) after the final stage are arranged on the lower half of the cylinder body at the rear side of the forward and reverse final stage moving blades of the double-split low-pressure cylinder (6); The four secondary and final stage steam temperature measuring points (34) are symmetrically arranged along the center line of the double-divided low-pressure cylinder (6), and the four final stage steam temperature measuring points (35) are symmetrically arranged along the center line of the double-divided low-pressure cylinder (6); A dual-channel water spray system is symmetrically arranged along the center line of the dual-flow low-pressure cylinder (6); The dual-path water spraying system comprises a first water spraying pipeline (36) and a second water spraying pipeline (37); the water inlet ends of the first water spraying pipeline (36) and the second water spraying pipeline (37) are respectively connected to the condensate inlet; the water outlet end of the first water spraying pipeline (36) is connected to the water inlet end of the first nozzle (39); the electric end and the regulating end of the cylinder body of the dual-flow low-pressure cylinder (6) are respectively symmetrically provided with a plurality of atomizing nozzles (40); the water outlet end of the second water spraying pipeline (37) is connected to the water inlet end of the second nozzle (38); and the water outlet ends of the first nozzle (39) and the second nozzle (38) are respectively connected to the atomizing nozzles (40).

2. A 200MW series ultra-high pressure three-cylinder three-exhaust flexible steam turbine according to claim 1, characterized in that: The cooling steam system comprises an electric gate valve (23), a pressure regulating valve (24), a temperature reducing valve group (25) and a cooling steam pipeline (27); the exhaust end of the cooling steam medium-pressure side pipe (18) is connected to the steam inlet end of the cooling steam pipeline (27); the exhaust end of the cooling steam pipeline (27) is connected to the steam inlet end of the cooling steam low-pressure side pipe (19); the electric gate valve (23), the pressure regulating valve (24) and the temperature reducing valve group (25) are sequentially connected to the cooling steam pipeline (27) from the steam inlet direction to the steam exhaust direction; the exhaust end of the cooling steam pipeline (27) is provided with a temperature and pressure measuring point (28); two drain pipelines are connected to the cooling steam pipeline (27); one drain pipeline is provided between the electric gate valve (23) and the pressure regulating valve (24); the other drain pipeline is provided between the temperature reducing valve group (25) and the temperature and pressure measuring point (28); a valve (26) is provided on the drain pipeline.

3. A 200MW series ultra-high pressure three-cylinder three-exhaust flexible steam turbine according to claim 2, characterized in that: The exhaust end of the cooling steam medium-pressure side pipe (18) is connected to the steam inlet end of the cooling steam pipeline (27) via a cooling steam medium-pressure side flange assembly (22), and the exhaust end of the cooling steam pipeline (27) is connected to the steam inlet end of the cooling steam low-pressure side pipe (19) via a cooling steam low-pressure side flange assembly (21).

4. According to claim 1, a 200MW series ultra-high pressure three-cylinder three-exhaust flexible steam turbine is characterized by: The heating steam extraction system comprises a safety valve (29), a check valve (30), a quick-closing regulating valve (31), a stop valve (32) and a heating steam extraction pipeline (33); the exhaust end of the heating steam extraction pipe (17) is connected to the inlet end of the heating steam extraction pipeline (33); the safety valve (29), the check valve (30), the quick-closing regulating valve (31) and the stop valve (32) are sequentially connected to the heating steam extraction pipeline (33) from the steam inlet direction to the steam exhaust direction.

5. A 200MW series ultra-high pressure three-cylinder three-exhaust flexible steam turbine according to claim 4, characterized in that: The exhaust end of the heating steam extraction pipe (17) is connected to the steam inlet end of the heating steam extraction pipeline (33) via a heating steam extraction flange assembly (20).

6. According to claim 1, a 200MW series ultra-high pressure three-cylinder three-exhaust flexible steam turbine is characterized by: The atomizing nozzles (40) at each side end include two groups of atomizing nozzles (40), an inner group and an outer group. The inner group of atomizing nozzles (40) are connected to the water outlet end of the first nozzle (39), and the outer group of atomizing nozzles (40) are connected to the water outlet end of the second nozzle (38).

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