A coordinated control method and system for an external steam supply mode of a supercritical thermal power unit

Abstract

The application discloses a kind of supercritical thermal power unit external steam supply mode under coordination control method and system, belong to the intelligent control field of thermal power unit, including first parameter module, second parameter module, first function module, first multiplication module, third parameter module, fourth parameter module, second function module, second multiplication module, fifth parameter module, sixth parameter module, third function module, third multiplication module and first addition module;The application is based on high-pressure industrial steam extraction flow fluctuation, constructs high-pressure industrial steam conversion boiler main control feedforward loop, through relative flow proportion correction boiler output mode, realizes the quick response of boiler main control instruction change with high-pressure industrial steam extraction flow fluctuation.Based on low-pressure industrial steam extraction and heating steam extraction flow fluctuation, constructs low-pressure and heating industrial steam conversion boiler main control feedforward loop, through relative flow proportion correction boiler output mode, realizes the quick response of boiler main control instruction change with low-pressure and industrial steam extraction flow fluctuation.

Description

Technical Field

[0001] This invention belongs to the field of intelligent control of thermal power units, specifically relating to a coordinated control method and system for supercritical thermal power units under external steam supply mode. Background Technology

[0002] Supercritical thermal power units, relative to drum boilers, generally employ indirect energy balance as their coordinated control strategy. The boiler main control typically consists of a unit load command conversion reference function and a PID correction loop for main steam pressure deviation. This strategy works well under pure condensing conditions. However, if the unit has multiple energy grades of external steam supply or significant fluctuations in external steam flow, the turbine will passively change its steam intake to maintain a constant power demand from the grid, leading to large fluctuations in the boiler's main steam pressure. This passive response to main steam pressure fluctuations in the boiler main control command fails to meet the grid's requirements for precise unit power regulation and stable boiler steam parameters, resulting in losses in grid power deviation assessments and external steam quality deviations.

[0003] To mitigate the impact of external steam flow fluctuations on the accuracy of unit load regulation, an external steam flow enthalpy drop correction loop is added to the boiler main control loop, and a pressure function for calculating the unit load from external steam is added to the main steam pressure setting loop. The total pressure is dynamically corrected based on the change in the current value of the turbine's comprehensive flow command, achieving direct energy balance between boiler output and turbine electrical power and the power calculated from external steam. Minor deviations between the two are gradually eliminated by the main steam pressure, achieving the coordinated control objective of stable power and rapid response to external steam demand.

[0004] Because the extraction pressure varies depending on the external steam supply demand, the extraction points are located in different extraction sections of the steam turbine. The closer to the upstream of the steam turbine extraction point, the greater the energy loss after extraction, and the more supplementary commands to the boiler main control system are required. At the same time, the extraction flow rate of the external steam supply and its proportion of the overall boiler evaporation also affect the boiler pressure fluctuation. Therefore, the higher its proportion, the greater the feedforward compensation required for the boiler main control system.

[0005] This control method and system predicts boiler main control changes in advance based on the flow and pressure of different extraction sections of externally supplied steam, as well as the changes in their relative proportions. Using the unit load command and the converted load demand of externally supplied steam as the basic main steam pressure function, the system dynamically corrects the basic main steam pressure function based on the current state of the turbine's comprehensive flow command changes, ultimately achieving a turbine comprehensive flow command at an appropriate opening and the actual boiler main steam pressure near the desired design pressure. After fluctuations in externally supplied steam flow or changes in unit load command, the boiler main control feedforward rapidly adjusts the boiler output and sets it according to the changed main steam pressure, achieving a new energy balance between the boiler and turbine. Specifically: 1. After the external steam supply flow rate changes, the required boiler main control feedforward is calculated based on the difference between the enthalpy of the medium-pressure inlet steam and the enthalpy of the low-pressure cylinder exhaust steam for high-pressure industrial extraction. The required boiler main control feedforward is calculated based on the difference between the enthalpy of the steam in the extraction section and the enthalpy of the exhaust steam for low-pressure cylinder for low-pressure industrial extraction and heating extraction. The boiler main control feedforwards calculated separately for high-pressure industrial extraction, low-pressure industrial extraction, and heating extraction are then corrected for the proportion of boiler evaporation and used as the final boiler main control feedforward, directly affecting the corresponding water, coal, and air circuits of the boiler main control system.

[0006] 2. The final boiler main control feedforward signal is synchronously sent to the main steam pressure correction loop, which synchronously changes the boiler-side main steam pressure setpoint to achieve energy balance between boiler output and desired main steam pressure.

[0007] 3. The turbine's comprehensive flow command is calculated based on the boiler's evaporation rate to determine the desired opening value. When the actual comprehensive flow command deviates from the desired value, the turbine automatically adjusts the sliding pressure curve to achieve precise power regulation and automatic optimization of unit energy consumption. Summary of the Invention

[0008] To address the aforementioned problems, the present invention aims to provide a coordinated control method and system for supercritical thermal power units under external steam supply mode. Its main functions include: constructing a feedforward loop for boiler main control based on high-pressure industrial steam extraction flow fluctuations, and correcting the boiler output mode through relative flow ratio adjustments to achieve rapid response of boiler main control commands to fluctuations in high-pressure industrial steam extraction flow; constructing feedforward loops for boiler main control based on low-pressure and heating industrial steam extraction flow fluctuations, and correcting the boiler output mode through relative flow ratio adjustments to achieve rapid response of boiler main control commands to fluctuations in low-pressure and heating industrial steam extraction flow; and adding a correction for main steam pressure based on turbine comprehensive flow changes to achieve rapid response of turbine comprehensive flow commands to grid power changes.

[0009] To achieve the above objectives, the present invention adopts the following technical solution: A coordinated control system for a supercritical thermal power unit under external steam supply mode includes a first parameter module, a second parameter module, a first function module, a first multiplication module, a third parameter module, a fourth parameter module, a second function module, a second multiplication module, a fifth parameter module, a sixth parameter module, a third function module, a third multiplication module, and a first addition module; The second parameter module is connected to the first function module; the outputs of the first parameter module and the first function module are respectively connected to the first multiplication module; the fourth parameter module is connected to the second function module; the outputs of the third parameter module and the second function module are respectively connected to the second multiplication module; the sixth parameter module is connected to the third function module; the outputs of the fifth parameter module and the third function module are respectively connected to the third multiplication module; the outputs of the first multiplication module, the second multiplication module, and the third multiplication module are respectively connected to the first addition module.

[0010] A further improvement of the present invention is that the output of the first addition module is connected to the boiler main control feedforward.

[0011] A further improvement of the present invention is that it also includes a second addition module, a fourth function module, a first subtraction module, a first PID module, a first constraint module, a third multiplication module, and a fifth function module; The output of the fourth function module is connected to the first subtraction module; the output of the first subtraction module is connected to the first PID module; the output of the first PID module is connected to the first limit module; the outputs of the second addition module and the first limit module are respectively connected to the third multiplication module; the output of the third multiplication module is connected to the fifth function module; and the output of the fifth function module is connected to the main steam pressure setting.

[0012] A further improvement of the present invention is that the boiler main control feedforward and the rate afterload command are respectively connected to the second addition module.

[0013] A further improvement of the present invention is that the rate afterload command is connected to the fourth function module.

[0014] A further improvement of the present invention is that the turbine flow command is connected to the first subtraction module.

[0015] A further improvement of the present invention is that it also includes a sixth function module, a first rate module, a seventh function module, an eighth function module, a fourth multiplication module, a first inertia function, a second inertia function, a first coefficient function, a third inertia function, and a second coefficient function; The output of the sixth function module is connected to the first rate module; the outputs of the seventh and eighth function modules are respectively connected to the fourth multiplication module; the outputs of the first rate module and the fourth multiplication module are respectively connected to the first inertial function; the output of the fourth multiplication module is connected to the first coefficient function; the outputs of the first coefficient function and the first inertial function are respectively connected to the second inertial function; the output of the fourth multiplication module is connected to the second coefficient function; the outputs of the second inertial function and the second coefficient function are respectively connected to the third inertial function; the output of the third inertial function is connected to the main steam pressure setting after the rate.

[0016] A further improvement of the present invention is that the variable load rate is connected to the sixth function module; the furnace feedforward differential is connected to the seventh function module; and the rate-afterload command is connected to the eighth function module.

[0017] A further improvement of the present invention is that the main steam pressure setting is connected to the first rate module.

[0018] A coordinated control method for supercritical thermal power units under external steam supply mode includes: The system collects key parameters in real time, including unit load commands, high-pressure industrial steam extraction flow rate and enthalpy h1, low-pressure industrial steam extraction flow rate and enthalpy h2, heating steam extraction flow rate and enthalpy h3, and low-pressure cylinder exhaust steam enthalpy h4. Each steam extraction flow rate and its corresponding enthalpy drop are fed into the first, third, and fifth parameter modules for calculation to obtain the uncorrected boiler energy demand. Simultaneously, the ratio of each steam extraction flow rate to the total evaporation is fed into the second, fourth, and sixth parameter modules for calculation. The energy demand value is then nonlinearly corrected by the first, second, and third function modules, multiplied by the corresponding first, second, and third multiplication modules, and summed in the first addition module, ultimately outputting the total boiler main control feedforward command. The obtained boiler main control feedforward is superimposed on the load command after rate limitation in the second addition module as the basic correction amount for the main steam pressure setting; at the same time, the load command after rate limitation is converted into the expected value of turbine flow by the fourth function module, and compared with the actual turbine flow command in the first subtraction module. The deviation is adjusted by the first PID module and limited by the first limiting module, and then multiplied with the aforementioned basic correction amount in the third multiplication module, and then converted by the fifth function module to generate the initial main steam pressure setting value. The initial main steam pressure setpoint and the variable load rate corrected by the sixth function module work together in the first rate module to form the pressure setpoint change trend. The differential of the boiler main control feedforward is processed by the seventh function module, and the load command after the rate is processed by the eighth function module. The two are multiplied in the fourth multiplication module, and the output is used as a dynamic correction factor. This dynamic correction factor is applied to the first inertial function, the second inertial function, and the third inertial function. The output of the first inertial function is directly used as the input of the second inertial function, and the dynamic correction factor is scaled by the first coefficient function and the second coefficient function, respectively, and used as the inertial time of the second inertial function and the third inertial function. Finally, the output of the third inertial function is the main steam pressure setpoint after dynamic correction and adaptation to changes in external steam supply and load.

[0019] Compared with the prior art, the present invention has at least the following beneficial technical effects: This invention provides a coordinated control system for supercritical thermal power units under external steam supply mode. This method relies on a coordinated control system of boiler main control and turbine integrated flow command. The system integrates a data acquisition unit, a logic operation unit, an execution control unit and a safety monitoring unit. The functions of each unit work together to ensure the accurate execution of the control logic.

[0020] This invention provides a coordinated control method for supercritical thermal power units under external steam supply mode. Based on key parameters such as unit load command, external steam supply flow (high-pressure industrial steam extraction, low-pressure industrial steam extraction, heating steam extraction), boiler evaporation rate, main steam pressure, and turbine comprehensive flow command, it achieves precise and dynamic adjustment of boiler main control feedforward and main steam pressure setting, maintaining stable unit power and steam parameter quality.

[0021] In summary, the coordinated control method and system for supercritical thermal power units under external steam supply mode described in this invention calculates and corrects the boiler main control feedforward based on the external steam supply flow rate and its enthalpy drop characteristics; dynamically corrects the main steam pressure setting based on the external steam supply converted load and unit load command; and performs a secondary dynamic correction of the main steam pressure setting based on the real-time status of the turbine's comprehensive flow command. This enables the rapid establishment of a new boiler-turbine energy balance when the external steam supply flow rate fluctuates or the grid load command changes, ensuring the accuracy of power regulation and the stability of the main steam pressure. Attached Figure Description

[0022] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of a coordinated control system for a supercritical thermal power unit under external steam supply mode.

[0024] Figure 2 This is a schematic diagram of a coordinated control system for a supercritical thermal power unit under external steam supply mode.

[0025] Figure 3 This is a schematic diagram of a coordinated control system for a supercritical thermal power unit under external steam supply mode.

[0026] Figure 4 This is a schematic diagram of a coordinated control system for a supercritical thermal power unit under external steam supply mode.

[0027] Figure 5 This is a rendering of an embodiment of the present invention.

[0028] Explanation of reference numerals in the attached figures: 001. Main Steam; 002. High-Pressure Cylinder; 003. High-Pressure Industrial Steam Extraction Flow Rate; 004. Reheater; 005. Enthalpy h1; 006. Intermediate-Pressure Cylinder; 007. Enthalpy h2; 008. Low-Pressure Industrial Steam Extraction Flow Rate; 009. Enthalpy h3; 010. Residential Heating Steam Extraction Flow Rate; 011. First Low-Pressure Cylinder; 012. Second Low-Pressure Cylinder; 013. Enthalpy h4; 014. Condenser; 015. First Parameter Number module; 016, Second parameter module; 017, First function module; 018, First multiplication module; 019, Third parameter module; 020, Fourth parameter module; 021, Second function module; 022, Second multiplication module; 023, Fifth parameter module; 024, Sixth parameter module; 025, Third function module; 026, Third multiplication module; 027, First addition module; 028, Boiler 029. Boiler main control feedforward; 030. Rate-followed load command; 031. Second addition module; 032. Fourth function module; 033. Steam turbine flow command; 034. First subtraction module; 035. First PID module; 036. First limit module; 037. Third multiplication module; 038. Fifth function module; 039. Main steam pressure setting; 040. Variable load rate; 041. Sixth function module; 042. First rate module; 043. Boiler feedforward differential; 044. Seventh function module; 045. Rate-followed load command; 046. Eighth function module; 047. Fourth multiplication module; 048. First inertia function; 049. Second inertia function; 050. First coefficient function; 051. Third inertia function; 052. Second coefficient function; 053. Rate-followed main steam pressure setting. Detailed Implementation

[0029] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope of the invention. Therefore, the drawings and description are considered to be exemplary in nature and not restrictive.

[0030] In the description of this invention, 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," "axial," "radial," and "circumferential" 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 invention 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 invention.

[0031] 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 indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0032] In this invention, unless otherwise explicitly 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 part; they can refer to a mechanical connection, an electrical connection, or a communication connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0033] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0034] It should be understood that, when used in this specification and the appended claims, the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0035] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0036] It should also be further understood that the term "and / or" as used in this specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0037] The accompanying drawings illustrate various structural schematic diagrams according to embodiments disclosed in this invention. These drawings are not to scale, and some details have been enlarged for clarity, and some details may have been omitted. The shapes of the various regions and layers shown in the drawings, as well as their relative sizes and positional relationships, are merely exemplary and may deviate from reality due to manufacturing tolerances or technical limitations. Furthermore, those skilled in the art can design regions / layers with different shapes, sizes, and relative positions as needed.

[0038] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0039] Example 1 This invention provides a coordinated control system for a supercritical thermal power unit under external steam supply mode, comprising: The Figure 1 This is a system schematic diagram of a coordinated control system for a supercritical thermal power unit under external steam supply mode according to the present invention.

[0040] Specifically, it includes: main steam 001, high-pressure cylinder 002, high-pressure industrial steam extraction flow 003, reheater 004, enthalpy h1005, intermediate-pressure cylinder 006, enthalpy h2007, low-pressure industrial steam extraction flow 008, enthalpy h3009, residential heating steam extraction flow 010, first low-pressure cylinder 011, second low-pressure cylinder 012, enthalpy h4013, and condenser 014.

[0041] The Figure 2 This is a schematic diagram of the feedforward circuit for the main control of a high-pressure industrial steam extraction boiler.

[0042] Specifically, it includes: First parameter module 015, Second parameter module 016, First function module 017, First multiplication module 018, Third parameter module 019, Fourth parameter module 020, Second function module 021, Second multiplication module 022, Fifth parameter module 023, Sixth parameter module 024, Third function module 025, Third multiplication module 026, First addition module 027, and Boiler main control feedforward 028.

[0043] The Figure 3 This is a schematic diagram of the feedforward circuit for the main control of a boiler, calculated for low-pressure and heating steam extraction.

[0044] Specifically, it includes: boiler main control feedforward 029, rate afterload command 030, second addition module 031, fourth function module 032, steam turbine flow command 033, first subtraction module 034, first PID module 035, first limit module 036, third multiplication module 037, fifth function module 038, and main steam pressure setting 039.

[0045] The Figure 4Schematic diagram of the correction circuit for main steam pressure set according to the load of external steam supply.

[0046] Specifically, it includes: main steam pressure setting 039, variable load rate 040, sixth function module 041, first rate module 042, furnace front feed differential 043, seventh function module 044, rate-followed load command 045, eighth function module 046, fourth multiplication module 047, first inertia function 048, second inertia function 049, first coefficient function 050, third inertia function 051, second coefficient function 052, and rate-followed main steam pressure setting 053.

[0047] Figure 1 The system schematic diagram includes the following parts: based on Figure 1 The system includes main steam (001), high-pressure cylinder (002), high-pressure industrial steam extraction flow (003), reheater (004), enthalpy h1005, intermediate-pressure cylinder (006), enthalpy h2007, low-pressure industrial steam extraction flow (008), enthalpy h3009, residential heating steam extraction flow (010), first low-pressure cylinder (011), second low-pressure cylinder (012), enthalpy h4013, and condenser (014). This control method and system acquires external steam supply flow and enthalpy signals, calculates the boiler main control feedforward, combines the boiler main control feedforward, unit load command, and turbine flow-based load conversion, calculates the main steam pressure setpoint, and then performs inertial dynamic correction based on the boiler feedforward derivative and the real-time status of the rate-based load command to obtain the final main steam pressure setpoint. Through the coordinated adjustment of the boiler main control command and the turbine integrated flow command, stable control of the unit's electrical power and steam parameters is achieved under external steam supply conditions.

[0048] Figure 2 The control strategy logic diagram includes the following parts: The second parameter module 016 is connected to the first function module 017; the outputs of the first parameter module 015 and the first function module 017 are respectively connected to the first multiplication module 018; the fourth parameter module 020 is connected to the second function module 021; the outputs of the third parameter module 019 and the second function module 021 are respectively connected to the second multiplication module 022; the sixth parameter module 024 is connected to the third function module 025; the outputs of the fifth parameter module 023 and the third function module 025 are respectively connected to the third multiplication module 026; the outputs of the first multiplication module 018, the second multiplication module 022, and the third multiplication module 026 are respectively connected to the first addition module 027; the output of the first addition module 027 is connected to the boiler main control feedforward 028.

[0049] Figure 3 The control strategy logic diagram includes the following parts: The boiler main control feedforward 029 and the rate-afterload command 030 are respectively connected to the second adder module 031; the rate-afterload command 030 is connected to the fourth function module 032; the output of the fourth function module 032 and the turbine flow command 033 are respectively connected to the first subtractor module 034; the output of the first subtractor module 034 is connected to the first PID module 035; the output of the first PID module 035 is connected to the first limit module 036; the output of the second adder module 031 and the output of the first limit module 036 are respectively connected to the third multiplier module 037; the output of the third multiplier module 037 is connected to the fifth function module 038; the output of the fifth function module 038 is connected to the main steam pressure setting 039.

[0050] Figure 4 The control strategy logic diagram includes the following parts: The variable load rate 040 is connected to the sixth function module 041; the main steam pressure setting 039 and the output of the sixth function module 041 are respectively connected to the first rate module 042; the furnace feed differential 043 is connected to the seventh function module 044; the rate-followed load command 045 is connected to the eighth function module 046; the outputs of the seventh function module 044 and the eighth function module 046 are respectively connected to the fourth multiplication module 047; the outputs of the first rate module 042 and the fourth multiplication module 047 are respectively connected to the first inertial function 048; the output of the fourth multiplication module 047 is connected to the first coefficient function 050; the outputs of the first coefficient function 050 and the first inertial function 048 are respectively connected to the second inertial function 049; the output of the fourth multiplication module 047 is connected to the second coefficient function 052; the outputs of the second inertial function 049 and the second coefficient function 052 are respectively connected to the third inertial function 051; the output of the third inertial function 051 is connected to the rate-followed main steam pressure setting 053.

[0051] Example 2 The coordinated control method for supercritical thermal power units under external steam supply mode provided by this invention consists of the following steps: (1) Real-time acquisition of key parameters such as unit load command, high-pressure industrial steam extraction flow rate 003 and enthalpy h1, low-pressure industrial steam extraction flow rate 008 and enthalpy h2, heating steam extraction flow rate 010 and enthalpy h3, and low-pressure cylinder exhaust steam enthalpy h4. Each steam extraction flow rate and its corresponding enthalpy drop (h1-h4, h2-h4, h3-h4) are sent to the first parameter module 015, the third parameter module 019, and the fifth parameter module 023 for calculation to obtain the uncorrected boiler energy demand; at the same time, the ratio of each steam extraction flow rate to the total evaporation (Q1 / Q0, Q2 / Q0, Q3 / Q0) is sent to the second parameter module 016, the fourth parameter module 020, and the sixth parameter module 024 for calculation. The aforementioned energy demand values ​​are nonlinearly corrected by the first function module 017, the second function module 021, and the third function module 025, respectively. Then, they are multiplied by the corresponding first multiplication module 018, the second multiplication module 022, and the third multiplication module 026 and summarized into the first addition module 027, finally outputting the total boiler main control feedforward command 028.

[0052] (2) The boiler main control feedforward 029 obtained in step 1 is superimposed on the load command 030 after rate limitation in the second addition module 031 as the basic correction amount for the main steam pressure setting. At the same time, the load command 030 after rate limitation is converted into the expected value of the turbine flow rate by the fourth function module 032 and compared with the actual turbine flow rate command 033 in the first subtraction module 034. The deviation is adjusted by the first PID module 035 and limited by the first limiting module 036. Then, it is multiplied by the aforementioned basic correction amount in the third multiplication module 037 and converted by the fifth function module 038 to generate the initial main steam pressure setting value 039.

[0053] (3) The initial main steam pressure setpoint 039 and the variable load rate 040 corrected by the sixth function module 041 work together on the first rate module 042 to form a pressure setpoint change trend. The differential 043 of the boiler main control feedforward is processed by the seventh function module 044, and the rate-following load command 045 is processed by the eighth function module 046. The two are multiplied in the fourth multiplication module 047, and the output is used as a dynamic correction factor. This factor acts on the first inertia function 048, the second inertia function 049, and the third inertia function 051, respectively. The output of the first inertia function 048 is directly used as the input of the second inertia function 049, while the dynamic correction factor is scaled by the first coefficient function 050 and the second coefficient function 052, and is used as the inertia time of the second inertia function 049 and the third inertia function 051, respectively. Finally, the output of the third inertia function 051 is the main steam pressure setpoint 053 after dynamic correction and adaptation to changes in external steam supply and load.

[0054] The main functions of this invention are as follows: When the unit participates in external steam supply operation, the compensation energy required by the boiler is calculated in real time based on the external steam flow rate and enthalpy drop characteristics. The boiler output is then rapidly adjusted in a feedforward manner to offset the impact of external steam fluctuations on the main steam pressure. By converting the external steam supply into an equivalent load and incorporating it into the main steam pressure setting loop, the pressure setpoint is matched to the actual total energy demand. Real-time feedback from the turbine's integrated flow command provides secondary dynamic correction to the main steam pressure setting, ensuring that the turbine regulating mechanism operates within its efficient range. This achieves precise control of the unit's electrical power and a stable supply of external steam parameters.

[0055] Example 3 Through the implementation and application of the technology of this invention, within the simulation range and the time range from t0 to t8, the following functions can be achieved: 1. Based on the steam extraction flow rate of high-pressure industrial / low-pressure industrial / residential heating, a boiler main control feedforward control loop is constructed, and a dynamic correction method is adopted to realize the rapid response of the boiler feedforward with the external steam supply and extraction flow rate; 2. Based on the boiler main control feedforward, the main steam pressure setpoint is calculated, and through the dynamic correction of variable load rate and boiler feedforward differential, the main steam pressure setpoint is rapidly and unidirectionally increased after the rate, effectively offsetting the initial decline of the actual pressure, and achieving the stable control target of rapid response of the set pressure.

[0056] The results show that, after applying the control method described in this invention, when the external steam supply flow rate undergoes a step change, the dynamic response time of the boiler main control feedforward command is shortened, the maximum fluctuation amplitude of the main steam pressure is reduced, the unit power regulation accuracy fully meets the grid assessment requirements, and the external steam supply pressure remains stable. This effectively solves the problems of difficult coordinated control and large pressure and power fluctuations in supercritical thermal power units under external steam supply mode.

[0057] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the scope of the invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0058] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can be appropriately combined to form other embodiments that can be understood by those skilled in the art. The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A coordinated control system for a supercritical thermal power unit under external steam supply mode, characterized in that, It includes a first parameter module (015), a second parameter module (016), a first function module (017), a first multiplication module (018), a third parameter module (019), a fourth parameter module (020), a second function module (021), a second multiplication module (022), a fifth parameter module (023), a sixth parameter module (024), a third function module (025), a third multiplication module (026), and a first addition module (027); The second parameter module (016) is connected to the first function module (017); the output terminals of the first parameter module (015) and the first function module (017) are respectively connected to the first multiplication module (018); the fourth parameter module (020) is connected to the second function module (021); the output terminals of the third parameter module (019) and the second function module (021) are respectively connected to the second multiplication module (022); the sixth parameter module (024) is connected to the third function module (025); the output terminals of the fifth parameter module (023) and the third function module (025) are respectively connected to the third multiplication module (026); the output terminals of the first multiplication module (018), the second multiplication module (022), and the third multiplication module (026) are respectively connected to the first addition module (027).

2. The coordinated control system for a supercritical thermal power unit under external steam supply mode according to claim 1, characterized in that, The output of the first adder module (027) is connected to the boiler main control feedforward (028).

3. The coordinated control system for a supercritical thermal power unit under external steam supply mode according to claim 2, characterized in that, It also includes a second addition module (031), a fourth function module (032), a first subtraction module (034), a first PID module (035), a first limit module (036), a third multiplication module (037), and a fifth function module (038); The output of the fourth function module (032) is connected to the first subtraction module (034); the output of the first subtraction module (034) is connected to the first PID module (035); the output of the first PID module (035) is connected to the first limit module (036); the output of the second addition module (031) and the output of the first limit module (036) are respectively connected to the third multiplication module (037); the output of the third multiplication module (037) is connected to the fifth function module (038); the output of the fifth function module (038) is connected to the main steam pressure setting (039).

4. The coordinated control system for a supercritical thermal power unit under external steam supply mode according to claim 3, characterized in that, The boiler main control feedforward (029) and the rate afterload command (030) are respectively connected to the second adder module (031).

5. A coordinated control system for a supercritical thermal power unit under external steam supply mode according to claim 4, characterized in that, The rate afterload instruction (030) is connected to the fourth function module (032).

6. A coordinated control system for a supercritical thermal power unit under external steam supply mode according to claim 5, characterized in that, The turbine flow command (033) is connected to the first subtraction module (034).

7. A coordinated control system for a supercritical thermal power unit under external steam supply mode according to claim 6, characterized in that, It also includes the sixth function module (041), the first rate module (042), the seventh function module (044), the eighth function module (046), the fourth multiplication module (047), the first inertia function (048), the second inertia function (049), the first coefficient function (050), the third inertia function (051), and the second coefficient function (052); The output of the sixth function module (041) is connected to the first rate module (042); the outputs of the seventh function module (044) and the eighth function module (046) are respectively connected to the fourth multiplication module (047); the outputs of the first rate module (042) and the fourth multiplication module (047) are respectively connected to the first inertial function (048); the output of the fourth multiplication module (047) is connected to the first coefficient function (050); the outputs of the first coefficient function (050) and the first inertial function (048) are respectively connected to the second inertial function (049); the output of the fourth multiplication module (047) is connected to the second coefficient function (052); the outputs of the second inertial function (049) and the second coefficient function (052) are respectively connected to the third inertial function (051); the output of the third inertial function (051) is connected to the main steam pressure setting after the rate (053).

8. A coordinated control system for a supercritical thermal power unit under external steam supply mode according to claim 7, characterized in that, The variable load rate (040) is connected to the sixth function module (041); the furnace feed differential (043) is connected to the seventh function module (044); and the rate afterload command (045) is connected to the eighth function module (046).

9. A coordinated control system for a supercritical thermal power unit under external steam supply mode according to claim 8, characterized in that, The main steam pressure setting (039) is connected to the first rate module (042).

10. A coordinated control method for a supercritical thermal power unit under external steam supply mode, characterized in that, This method, based on the coordinated control system of a supercritical thermal power unit under external steam supply mode as described in claim 9, includes: Real-time acquisition of key parameters such as unit load command, high-pressure industrial steam extraction flow (003) and enthalpy h1, low-pressure industrial steam extraction flow (008) and enthalpy h2, heating steam extraction flow (010) and enthalpy h3, and low-pressure cylinder exhaust enthalpy h4; sending each steam extraction flow and its corresponding enthalpy drop to the first parameter module (015), the third parameter module (019), and the fifth parameter module (023) for calculation to obtain the uncorrected boiler energy demand; simultaneously, sending the ratio of each steam extraction flow to the total evaporation to the first parameter module (023). The two-parameter module (016), the fourth-parameter module (020), and the sixth-parameter module (024) are used for calculation; the energy demand value is nonlinearly corrected by the first function module (017), the second function module (021), and the third function module (025), and then multiplied by the corresponding first multiplication module (018), the second multiplication module (022), and the third multiplication module (026) and summarized to the first addition module (027), and finally outputs the total boiler main control feedforward command (028); The obtained boiler main control feedforward (029) and the load command (030) after rate limitation are superimposed in the second addition module (031) as the basic correction amount for the main steam pressure setting; at the same time, the load command (030) after rate limitation is converted into the expected value of the turbine flow rate by the fourth function module (032), and compared with the actual turbine flow rate command (033) in the first subtraction module (034). The deviation is adjusted by the first PID module (035) and limited by the first limiting module (036), and then multiplied by the aforementioned basic correction amount in the third multiplication module (037), and then converted by the fifth function module (038) to generate the initial main steam pressure setting value (039). The initial main steam pressure setpoint (039) and the variable load rate (040) corrected by the sixth function module (041) work together on the first rate module (042) to form the pressure setpoint change trend; the differential (043) of the boiler main control feedforward is processed by the seventh function module (044), and the rate-following load command (045) is processed by the eighth function module (046). The two are multiplied in the fourth multiplication module (047), and the output is used as a dynamic correction factor; this dynamic correction factor acts on the first inertia function (048), the second inertia function (049), the third inertia function (040), and the fourth inertia function (041). The two inertial functions (049) and the third inertial function (051) are used. The output of the first inertial function (048) is directly used as the input of the second inertial function (049). The dynamic correction factor is scaled by the first coefficient function (050) and the second coefficient function (052) and used as the inertial time of the second inertial function (049) and the third inertial function (051) respectively. Finally, the output of the third inertial function (051) is the main steam pressure setpoint (053) after dynamic correction and adaptation to the rate of external steam supply and load changes.

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