A high exhaust pressure control method and system for nuclear power heating transformation

Abstract

The present invention discloses a high exhaust pressure control method and system for nuclear power heating transformation, wherein the control method includes: when the operating load of the nuclear power unit exceeds a certain value, the operation of the steam extraction heating system is entered, the opening of multiple steam extraction regulating valves is adjusted, and the total actual steam extraction amount of the heating pipeline is controlled to approach the target steam extraction amount; in the operation of the steam extraction heating system, the main steam turbine control system synchronously adjusts the opening of multiple reheat regulating valves according to the actual pressure value of the high-pressure exhaust pressure measuring point P1, so that the pressure value of the high-pressure exhaust pressure measuring point P1 reaches the high exhaust pressure set value. The present invention is aimed at the heating transformation project of high-pressure cylinder exhaust pressure steam extraction heating, and by adjusting the opening of the reheat regulating valve, the extraction pressure and flow are adjusted to provide users with stable and reliable heating steam, and effectively protect the steam turbine.

Description

Technical Field

[0001] The present invention belongs to the field of nuclear power heating transformation unit control, and in particular relates to a nuclear power heating transformation high exhaust pressure control method and system. Background Art

[0002] At present, there are many locations for steam extraction transformation and heating in thermal power projects, which are divided into adjustable steam extraction and non-adjustable steam extraction.

[0003] The location of the steam extraction transformation for heating in thermal power projects, specific references: Economic analysis of different heating methods for 300MW units, "The 9th Academic Seminar on Energy Conservation and Emission Reduction of Electric Power Industry Enterprises (Jiangsu Section)", July 1, 2014.

[0004] Adjustable steam extraction and non-adjustable steam extraction, specific reference: Steam extraction modification plan and experimental analysis of heating units, "Huadian Technology" Vol. 40 No. 9, September 2018.

[0005] In reality, the steam extraction position of most heating transformation units is to open holes on the medium and low pressure connecting pipes, such as Figure 1 As shown, a heat extraction butterfly valve is set at the back, and the extraction steam pressure is controlled by adjusting the heat extraction butterfly valve. Some of the heat supply transformation units have holes opened on the reheating hot section pipeline, and a steam extraction regulating valve is set at the back. The heating pressure is adjusted by the heat supply regulating valve on the heating pipeline, such as Figure 1 Although medium pressure regulating valves are generally not involved in load regulation, they are capable of regulating flow within a larger lift range.

[0006] For the scheme of drilling holes in the reheating hot section pipe of the heating transformation unit, refer to the following documents: [3] Logic design of medium-pressure regulating valve for controlling heating pressure of large steam turbine, "2017 Power Plant Thermal Automation Technology Exchange Conference"; Medium-pressure regulating valve heating for large steam turbine units of Dongfang Steam Turbine - DEH control scheme, "Oriental Steam Turbine" February 2013.

[0007] In addition, some projects also use medium-pressure regulating valves to adjust heating. For specific references, please refer to: Research on Medium-Pressure Regulating Valve for Adjusting Heating of Large Steam Turbines, "Huadian Technology" Issue 3, 2018.

[0008] In the above existing technologies, none of them provides how to realize steam extraction heating in the absence of intermediate pressure cylinders in nuclear power heating reconstruction projects, and how to ensure the safety of the steam turbine after reconstruction. Summary of the invention

[0009] In view of the above problems, the present invention provides a method and system for controlling high exhaust pressure of nuclear power heating transformation to provide stable and reliable heating steam and effectively protect the steam turbine.

[0010] A method for controlling high exhaust pressure of nuclear power heating transformation comprises: when the operating load of the nuclear power unit exceeds a certain value, entering the operation state of the extraction steam heating system, adjusting the openings of multiple extraction steam regulating valves, and controlling the total actual steam extraction amount of the heating pipeline to approach the target steam extraction amount; in the operation state of the extraction steam heating system, the main steam turbine control system synchronously adjusts the openings of multiple reheat regulating valves according to the actual pressure value of the high-pressure exhaust pressure measuring point P1, so that the pressure value of the high-pressure exhaust pressure measuring point P1 reaches the high exhaust pressure set value.

[0011] Furthermore, multiple reheat regulating valves adopt a single valve control method.

[0012] Furthermore, during the operation of the extraction steam heating system during the startup process of the nuclear power unit, when the electric power of the nuclear power unit rises to the first set value, the main steam turbine control system stops increasing the generator power, and the main steam turbine control system stabilizes the power generation at the current value through the automatic load adjustment function. After the power generation is stable, the extraction steam heating system is put into operation, and the opening of the extraction steam regulating valve is gradually increased manually.

[0013] Furthermore, during the commissioning of the heating system and the stable operation of the heating system, the main steam turbine control system automatically adjusts the opening of the high-pressure regulating valve through the automatic load adjustment function to maintain the first set value of the unit generator power unchanged. The reactor power increases with the increase in the heating steam extraction volume, and multiple reheat regulating valves automatically adjust the high exhaust pressure to the set value.

[0014] Furthermore, in the operating condition of the extraction steam heating system being put into operation during the normal operation of the nuclear power unit, according to the control method of electrical and thermal separate control, the power of the nuclear power unit generator is first reduced to the second set value. During the power reduction process, the main steam turbine control system adjusts the opening of the high-pressure regulating valve according to the electrical power set value to gradually reduce the opening, and the reactor power decreases accordingly. After the power level stabilizes, the extraction steam heating system is put into operation, and the opening of the extraction steam regulating valve is gradually increased manually; wherein, during the opening of the extraction steam regulating valve, the opening of the reheat regulating valve is in the pressure control mode and gradually closed, and the high exhaust pressure is automatically maintained at the set value; the generator is in the power control mode, the opening of the high-pressure regulating valve gradually increases with the increase of the extraction steam amount, the opening of the reheat regulating valve is in the pressure control mode and gradually closed, and the reactor is in the reactor control mode and the power increases accordingly.

[0015] Furthermore, in the operating condition of shutting down the extraction steam heating system during the normal operation of the nuclear power unit, according to the control method of separate electrical and thermal control, the generator power remains unchanged at the second set value, and the nuclear power unit operates in the reactor-following mode; when the extraction steam regulating valve is closed, multiple reheat regulating valves are gradually opened according to the change of the high-pressure cylinder exhaust pressure, and when the extraction steam regulating valve is fully closed, multiple reheat regulating valves are fully opened, and the high-pressure regulating valve is gradually closed according to the electrical power setting value, the generator power remains unchanged, and the reactor power is in the reactor-following control mode and gradually decreases.

[0016] Furthermore, the control method also includes: setting minimum opening values ​​of multiple reheat control valves.

[0017] Furthermore, the control method also includes: setting the operating load of the nuclear power unit to be higher than the minimum load corresponding to the current steam extraction amount.

[0018] Furthermore, the control method also includes: when the nuclear power unit enters the load rejection condition, the extraction control valve is adjusted to close quickly, and the main steam turbine control system automatically controls multiple reheat control valves and high-pressure control valves to open quickly.

[0019] Furthermore, the control method also includes: when the heat load of the nuclear power unit is suddenly completely cut off, the main steam turbine control system closes the high-pressure regulating valve.

[0020] The present invention also provides a high exhaust pressure control system for nuclear power heating transformation, comprising: a main steam turbine control system, which is used to synchronously send adjustment instructions to multiple reheat regulating valves according to the actual pressure value of the high-pressure exhaust steam pressure measuring point P1, so that the pressure value of the high-pressure exhaust steam pressure measuring point P1 reaches the high exhaust pressure set value; multiple extraction steam regulating valves, which are used to adjust their own openings and control the actual steam extraction amount of the heating pipeline; and multiple reheat regulating valves, which are used to adjust their own openings according to the adjustment instructions of the main steam turbine control system and control the high-pressure exhaust steam pressure value.

[0021] Furthermore, the control system also includes a high-pressure cylinder, a high-pressure regulating valve, a first exhaust steam pipe, a steam-water separation reheater, a second exhaust steam pipe, a steam extraction main pipe and a low-pressure cylinder; wherein the main steam pipe is connected to the high-pressure cylinder, a high-pressure regulating valve is arranged on the main steam pipe, the high-pressure cylinder is connected to one end of the steam-water separation reheater through the first exhaust steam pipe, and the other end of the steam-water separation reheater is connected to multiple low-pressure cylinders through the second exhaust steam pipe; the high-pressure exhaust steam pressure measuring point P1 is arranged on the first exhaust steam pipe, and a reheat regulating valve is arranged between the air inlet on both sides of each low-pressure cylinder and the second exhaust pipe, and one end of the steam extraction main pipe is connected to the first exhaust steam pipe upstream of the high-pressure exhaust steam pressure measuring point P1.

[0022] Beneficial effects of the present invention:

[0023] 1. The present invention is aimed at the heating reconstruction project of high-pressure cylinder exhaust pressure extraction steam heating. By adjusting the opening of the reheat regulating valve, the extraction steam pressure and flow rate are adjusted to meet the user's demand for heating steam.

[0024] 2. The reheat regulating valve has the characteristic of high sensitivity in controlling the high exhaust pressure. When the reheat regulating valve is actuated, it directly affects the amount of steam entering the turbine, and the high exhaust pressure changes respond sensitively.

[0025] 3. To address the problem of a large number of reheat regulating valves, a single valve control method is adopted to reduce the complexity of control.

[0026] 4. When abnormal heating conditions cause a sudden change in high exhaust pressure, a variety of turbine protection measures are provided.

[0027] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures pointed out in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0029] Figure 1 The system flow of the reheating hot section heating transformation according to the prior art is shown;

[0030] Figure 2 A schematic diagram of heating control in which a reheat regulating valve controls high exhaust pressure according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] It should be noted that, due to the lack of intermediate pressure cylinders in some nuclear power units during the nuclear power heating transformation process, the high pressure cylinder exhaust steam extraction heating is quite different from the reheat cold section extraction of thermal power units. When extracting steam from the high pressure cylinder exhaust pipe for heating, the amount of steam extraction will cause changes in the high pressure cylinder exhaust pressure. An increase in the amount of steam extraction will cause the high pressure exhaust pressure to be too low and the high pressure cylinder pressure drop to be too large, threatening the safety of the steam turbine. Therefore, maintaining the high pressure exhaust pressure within an acceptable range is a key point for stable heating.

[0033] The embodiment of the present invention provides a method and system for controlling the exhaust steam pressure of a high-pressure cylinder of a nuclear power heating unit according to the matching of heating parameters during the nuclear power heating modification process, extracts steam from the exhaust steam pipe of the high-pressure cylinder (HP) for heating, adopts adjustable steam extraction, provides stable and reliable heating steam, and effectively protects the steam turbine.

[0034] See also Figure 2, Figure 2 A schematic diagram of heating control in which a reheat regulating valve controls high exhaust pressure according to an embodiment of the present invention is shown.

[0035] A high-exhaust pressure control system for nuclear power heating transformation comprises a high-pressure cylinder (HP), a high-pressure regulating valve (GV), a first exhaust steam pipeline, a moisture separator and heater (MSR), a second exhaust steam pipeline, a plurality of induction control valves (ICV), an extraction steam main pipeline, a plurality of extraction steam branch pipes, a plurality of extraction steam regulating valves, a plurality of heat network heaters, a low-pressure cylinder (LP), a heat supply system controller (Controller of Heat Supply System Heaters) and a main steam turbine control system (MTC).

[0036] The main steam pipeline is connected to the high-pressure cylinder, and a high-pressure regulating valve is arranged on the main steam pipeline. The high-pressure cylinder is connected to one end of the steam-water separation reheater through the first exhaust pipe, and the other end of the steam-water separation reheater is connected to multiple low-pressure cylinders through the second exhaust pipe.

[0037] The main steam of the nuclear power unit enters the high-pressure cylinder through the main steam pipe to expand and do work. The steam that has done the work enters the steam-water separation reheater through the first exhaust steam pipe. The steam treated by the steam-water separation reheater enters the low-pressure cylinder through the second exhaust steam pipe to continue expanding and doing work.

[0038] A high-pressure exhaust pressure measuring point P1 is provided on the first exhaust pipe. In the embodiment of the present invention, the number of low-pressure cylinders is 3, and a reheat regulating valve is provided between the air inlet on both sides of each low-pressure cylinder and the second exhaust pipe, that is, 6 reheat regulating valves are provided. Each reheat regulating valve is connected to the first EH hydraulic actuator (Electro hydraulic, E / H), and the first EH hydraulic actuator receives the command of the main turbine control system to adjust the opening of the reheat regulating valve.

[0039] One end of the steam extraction main pipeline is connected to the first steam exhaust pipeline upstream of the high-pressure exhaust pressure measuring point P1, and the other end of the steam extraction main pipeline is connected to multiple steam extraction branch pipes. Each steam extraction branch pipe is provided with a steam extraction regulating valve, and each steam extraction regulating valve is connected to the second EH hydraulic actuator. The opening of the steam extraction regulating valve is adjusted by the second EH hydraulic actuator.

[0040] Furthermore, a pneumatic check valve is provided upstream of each steam extraction regulating valve to prevent the turbine from overspeeding and water ingress. An electric valve is provided downstream of each steam extraction regulating valve. The electric valve is provided downstream of the steam extraction regulating valve to cut off the downstream when the steam extraction regulating valve fails and needs maintenance or replacement, so as to facilitate maintenance. Each electric valve is connected to the heating network heater through a heating pipeline.

[0041] The high-pressure regulating valve is connected to the third EH hydraulic actuator, and the third EH hydraulic actuator receives the GV valve position instruction of the main turbine control system to adjust the opening of the high-pressure regulating valve.

[0042] In an embodiment of the present invention, when the operating load of the nuclear power unit exceeds a certain value, the extraction steam heating system is put into operation. The main steam turbine control system is used to synchronously send adjustment instructions to multiple reheat regulating valves according to the actual pressure value of the high-pressure exhaust steam pressure measuring point P1, so that the pressure value of the high-pressure exhaust steam pressure measuring point P1 reaches the high exhaust pressure set value; multiple extraction steam regulating valves are used to adjust their own openings to control the actual steam extraction amount of the heating pipeline; multiple reheat regulating valves are used to adjust their own openings according to the adjustment instructions of the main steam turbine control system to control the high-pressure exhaust steam pressure value.

[0043] It should be noted that after the heating transformation, the heating steam pipeline is connected from the cold section. As the heating steam volume gradually increases, the high-discharge pressure will gradually decrease, and the pressure difference before and after the high-pressure final stage and the second final stage will increase at the same flow rate. If the high-discharge pressure is not controlled, when the heating steam volume increases to a certain amount, the further reduction of the high-discharge pressure will endanger the safety of the high-pressure blades. In order to ensure the safety of the high-pressure blades, the high-discharge pressure needs to be controlled after the heating transformation.

[0044] Based on the above-mentioned nuclear power heating transformation high exhaust pressure control system, the embodiment of the present invention also provides a nuclear power heating transformation high exhaust pressure control method, including the following steps:

[0045] S1. Set a high-pressure exhaust steam pressure measuring point P1 on the first exhaust steam pipe between the high-pressure cylinder and.

[0046] In one embodiment, the high-pressure exhaust steam pressure measuring point P1 adopts a triple-redundancy setting.

[0047] S2. When the operating load of the nuclear power unit exceeds a certain value, the extraction steam heating system is put into operation. When the extraction steam heating system is put into operation, the openings of multiple extraction steam regulating valves are manually adjusted to control the total actual extraction steam volume of the heating pipeline to approach the target extraction steam volume.

[0048] During specific implementation, the opening of one extraction steam regulating valve is manually changed (increased / decreased), and the high exhaust pressure automatically changes (decreases / increases). The six reheat regulating valves will automatically follow the change of the high exhaust pressure (decreases / increases), and adjust the opening of the reheat regulating valve (decreases / increases), thereby stabilizing the high exhaust pressure. To ensure the balance of steam flow entering the low-pressure cylinder, the six reheat regulating valves operate simultaneously.

[0049] Manually adjust the opening of multiple steam extraction regulating valves to correspond to the commissioning of multiple heating network heaters.

[0050] S3. When the extraction steam heating system is put into operation, the main steam turbine control system synchronously adjusts the openings of multiple reheat regulating valves according to the actual pressure value of the high-pressure exhaust steam pressure measuring point P1, so that the pressure value of the high-pressure exhaust steam pressure measuring point P1 reaches the high exhaust pressure set value.

[0051] The embodiment of the present invention adopts a reheat regulating valve to control the high exhaust pressure, which has the characteristic of high sensitivity. When the reheat regulating valve is actuated, it directly affects the steam intake into the steam turbine, and the high exhaust pressure changes respond sensitively.

[0052] During specific implementation, the operator manually adjusts the opening of the extraction regulating valve to control the steam extraction amount of the heating pipeline to the target extraction amount required by the heat load. At the same time, the main steam turbine control system automatically controls the high-pressure cylinder exhaust pressure. Multiple reheat regulating valves will slowly close or open, and the actual extraction pressure will increase or decrease accordingly, approaching the target extraction pressure.

[0053] In one embodiment, six reheat regulating valves are provided, and the six reheat regulating valves adopt a single valve control mode. Since there are six reheat regulating valves, when the sequential valve control mode is adopted, the response to the change of steam after the reheat regulating valve will be relatively slow; when the single valve control mode is adopted, the regulation change of the pressure change is dispersed to the six reheat regulating valves, and the sensitivity of the reheat regulating valve action is high, but the regulation range corresponding to a certain pressure change is narrow, reducing the complexity of the control.

[0054] It should be noted that the sequential valve control method refers to opening the valves in sequence according to a pre-set order; the single valve control method refers to the same valve opening method and the same opening degree of each valve.

[0055] After the high discharge pressure is controlled by the high discharge pressure control method for nuclear power heating transformation according to the embodiment of the present invention, the analysis of the parameter changes of the nuclear power unit under several typical working conditions is as follows:

[0056] In the operation condition of the extraction steam heating system during the startup process of the nuclear power unit, when the electric power of the nuclear power unit rises to the first set value, for example, the electric power can be 78%, the main steam turbine control system stops further increasing the generator power, and the main steam turbine control system stabilizes the power generation at the current value through the automatic load regulation function (ALR). After the power generation is stable, the extraction steam heating system is put into operation, and the opening of the extraction steam regulating valve is gradually increased manually.

[0057] During the specific implementation, when the steam extraction process is started for heating, the operator gradually and slowly increases the opening of the steam extraction regulating valve by manually operating the heating system controller to control the heating steam flow rate change rate to be lower than 10t / h / min.

[0058] During the operation of the heating system and the stable operation of the heating system, the main steam turbine control system automatically adjusts the opening of the high-pressure regulating valve through the automatic load regulation function to maintain the first set value of the unit generator power. In this process, the reactor power increases with the increase of the heating steam extraction volume, and multiple reheat regulating valves automatically adjust the high discharge pressure of the high-pressure cylinder to the set value.

[0059] In the operating condition of the extraction steam heating system in the normal operation of the nuclear power unit, according to the control mode of electric and thermal separate control, when the power of the nuclear power unit generator is first reduced to the second set value, for example, it can be 78%-90% (the value is determined by the current required heat load, if 100% extraction steam heat load is put into operation, the set value is not higher than 78%), during the power reduction process, the main steam turbine control system adjusts the opening of the high-pressure regulating valve to gradually reduce the second set value of the electric power, and the reactor power decreases accordingly. After the power level stabilizes, the extraction steam heating system is put into operation, and the opening of the extraction steam regulating valve is manually gradually increased.

[0060] In this working condition, the extraction steam regulating valve is remotely and manually controlled by the operator, and the extraction steam flow rate increase rate is not greater than 10t / h / min.

[0061] During the opening of the extraction steam regulating valve, the opening of the reheat regulating valve is in the pressure control mode and gradually closes, automatically maintaining the high-pressure cylinder exhaust pressure at the set value. The generator is in the power control mode, and the high-pressure regulating valve gradually opens with the increase of the extraction steam volume. The reheat regulating valve is in the pressure control mode and gradually closes. The reactor is in the reactor control mode and the power increases accordingly.

[0062] In the condition where the extraction steam heating system is shut down during the normal operation of the nuclear power unit, according to the control method of electrical and thermal separate control, the second set value of the generator power remains unchanged, and the nuclear power unit operates in the reactor-following mode. The operator manually closes the extraction steam regulating valve remotely until it is fully closed. As the extraction steam regulating valve is closed, multiple reheat regulating valves gradually open according to the change of the high-pressure cylinder exhaust pressure. When the extraction steam regulating valve is fully closed, multiple reheat regulating valves are fully opened, and the steam turbine high-pressure regulating valve gradually closes according to the second set value of the electric power. The generator power remains unchanged, and the reactor power gradually decreases in the reactor-following control mode. After stabilization, the generator power is set according to the grid dispatching instruction, and the unit resumes pure condensing steam operation. If the generator power can be increased with the consent of the grid dispatching after the shutdown, the unit power will be increased under the pure condensing steam condition after all the heating extraction steam is shut down.

[0063] After the high exhaust pressure is controlled by the high exhaust pressure control method for nuclear power heating transformation according to the embodiment of the present invention, changes in reactor power, high pressure cylinder power, low pressure cylinder power, extraction steam heat load, etc. are shown in Table 1.

[0064] Table 1 Unit parameter changes under various operating conditions

[0065]

[0066] It should be noted that, in the high-discharge pressure control method for nuclear power heating modification in an embodiment of the present invention, after the high-discharge pressure is controlled by the reheat regulating valve, when an abnormal condition in the heating system causes a sudden change in the high-discharge pressure of the steam turbine, the reheat regulating valve will quickly rise to respond to the change, and may cause damage to the low-pressure steam turbine due to the sudden change in the steam flow at the turbine inlet.

[0067] Based on the above situation, the embodiment of the present invention also establishes a steam turbine protection measure. Further, the high exhaust pressure control method for nuclear power heating transformation also includes the following steps:

[0068] S4. Set the minimum opening value of multiple reheat regulating valves to ensure the minimum flow rate of the low-pressure cylinder and realize the minimum flow protection of the low-pressure cylinder.

[0069] S5. Set the operating load of the nuclear power unit higher than the minimum load corresponding to the current steam extraction volume to prevent the exhaust steam from overheating due to the low-pressure final stage blast.

[0070] S6. When the nuclear power unit enters the load shedding condition, the extraction steam regulating valve closes quickly, and the main steam turbine control system automatically controls multiple reheat regulating valves and high-pressure regulating valves to open quickly to prevent the turbine from overspeeding.

[0071] The main steam turbine control system of the embodiment of the present invention adds the RB function of rapid heat rejection load, taking into account the instability of the electric power platform during rapid heat rejection load, while rejecting the heat load, the electric load is adjusted to the lower limit of the electric load operation under the heating condition.

[0072] S7. When the thermal load of the nuclear power unit is suddenly cut off, the main steam turbine control system closes the high-pressure regulating valve to prevent the load from changing too much or exceeding the design load.

[0073] The present invention is aimed at the heating reconstruction project of high-pressure cylinder exhaust pressure extraction steam heating. By adjusting the opening of the reheat regulating valve, the extraction steam pressure and flow rate are adjusted to meet the user's demand for heating steam. In addition, when the abnormal heating situation causes a sudden change in high exhaust pressure, a variety of steam turbine protection measures are provided.

[0074] Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent substitutions for some of the technical features therein; and these modifications or substitutions do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for controlling high exhaust pressure in nuclear power heating transformation, characterized in that: include: When the operating load of the nuclear power unit exceeds a certain value, the steam extraction heating system is put into operation, and the opening of multiple steam extraction regulating valves is adjusted to control the total actual steam extraction volume of the heating pipeline to approach the target steam extraction volume; When the extraction steam heating system is put into operation, the main steam turbine control system synchronously adjusts the opening of multiple reheat regulating valves according to the actual pressure value of the high-pressure exhaust steam pressure measuring point P1, so that the pressure value of the high-pressure exhaust steam pressure measuring point P1 reaches the high-exhaust pressure setting value; multiple reheat regulating valves adopt a single valve control method, and the specific single valve control method is: the valve opening method is the same, and the opening of each valve is the same; Among them, the high-pressure cylinder is connected to one end of the steam-water separation reheater through the first exhaust steam pipeline, and the other end of the steam-water separation reheater is connected to multiple low-pressure cylinders through the second exhaust steam pipeline; the high-pressure exhaust steam pressure measuring point P1 is set on the first exhaust steam pipeline, and a reheat regulating valve is set between the air inlet on both sides of each low-pressure cylinder and the second exhaust pipe. One end of the extraction steam main pipeline is connected to the first exhaust steam pipeline upstream of the high-pressure exhaust steam pressure measuring point P1; the other end of the extraction steam main pipeline is connected to multiple extraction steam branch pipes, and each extraction steam branch pipe is provided with an extraction steam regulating valve; In the operating condition of the extraction steam heating system being put into operation during the normal operation of the nuclear power unit, according to the control mode of electric and thermal separate control, the power of the nuclear power unit generator is first reduced to the second set value. During the power reduction process, the main steam turbine control system adjusts the opening of the high-pressure regulating valve according to the electric power set value and gradually closes it. The reactor power decreases accordingly. After the power level stabilizes, the extraction steam heating system is put into operation, and the opening of the extraction steam regulating valve is gradually increased manually; Among them, during the opening of the extraction steam regulating valve, the opening of the reheat regulating valve is in the pressure control mode and gradually closes, automatically maintaining the high exhaust pressure at the set value; the generator is in the power control mode, the opening of the high pressure regulating valve gradually increases with the increase of the extraction steam amount, the opening of the reheat regulating valve is in the pressure control mode and gradually closes, and the reactor is in the stack control mode and the power increases accordingly.

2. The method for controlling high exhaust pressure of nuclear power heating transformation according to claim 1, characterized in that: During the operation of the extraction steam heating system during the startup process of the nuclear power unit, when the electric power of the nuclear power unit rises to the first set value, the main steam turbine control system stops increasing the generator power, and the main steam turbine control system stabilizes the power generation at the current value through the automatic load adjustment function. After the power generation is stable, the extraction steam heating system is put into operation, and the opening of the extraction steam regulating valve is gradually increased manually.

3. The high exhaust pressure control method for nuclear power heating transformation according to claim 2 is characterized in that: During the commissioning of the heating system and the process of stable heating operation, the main steam turbine control system automatically adjusts the opening of the high-pressure regulating valve through the automatic load adjustment function to maintain the first set value of the unit generator power unchanged. The reactor power increases with the increase of heating steam extraction, and multiple reheat regulating valves automatically adjust the high exhaust pressure to the set value.

4. The high exhaust pressure control method for nuclear power heating transformation according to claim 1 is characterized in that: In the operating condition of shutting down the extraction steam heating system during the normal operation of the nuclear power unit, according to the control method of electrical and thermal separate control, the generator power remains unchanged at the second set value, and the nuclear power unit operates in the reactor-following mode; when the extraction steam regulating valve is closed, multiple reheat regulating valves are gradually opened according to the change of the high-pressure cylinder exhaust pressure, when the extraction steam regulating valve is fully closed, multiple reheat regulating valves are fully opened, and the high-pressure regulating valve is gradually closed according to the electrical power setting value, the generator power remains unchanged, and the reactor power is in the reactor-following control mode and gradually decreases.

5. The method for controlling high exhaust pressure of nuclear power heating transformation according to any one of claims 1 to 4, characterized in that: Also includes: Set the minimum opening value of multiple reheat control valves.

6. The high exhaust pressure control method for nuclear power heating transformation according to any one of claims 1 to 4, characterized in that: Also includes: The operating load of the nuclear power unit is set higher than the minimum load corresponding to the current steam extraction volume.

7. The method for controlling high exhaust pressure of nuclear power heating transformation according to any one of claims 1 to 4, characterized in that: Also includes: When the nuclear power unit enters the load rejection condition, the extraction steam regulating valve is adjusted to close quickly, and the main steam turbine control system automatically controls multiple reheat regulating valves and high-pressure regulating valves to open quickly.

8. The method for controlling high exhaust pressure of nuclear power heating transformation according to any one of claims 1 to 4, characterized in that: Also includes: When the heat load of the nuclear power unit is suddenly cut off, the main steam turbine control system closes the high-pressure regulating valve.

9. A high-pressure exhaust pressure control system for nuclear power heating transformation, characterized in that: The method for controlling high exhaust pressure of nuclear power heating transformation according to any one of claims 1 to 8 comprises: The main steam turbine control system is used to send adjustment instructions to multiple reheat control valves synchronously according to the actual pressure value of the high-pressure exhaust steam pressure measuring point P1, so that the pressure value of the high-pressure exhaust steam pressure measuring point P1 reaches the high exhaust pressure set value; Multiple steam extraction regulating valves are used to adjust their own openings and control the actual steam extraction volume of the heating pipeline; Multiple reheat regulating valves are used to adjust their own openings according to the regulation instructions of the main steam turbine control system and control the high-pressure exhaust steam pressure value.

10. The high exhaust pressure control system for nuclear power heating transformation according to claim 9, characterized in that: The main steam pipeline is connected to the high-pressure cylinder, and a high-pressure regulating valve is arranged on the main steam pipeline.

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