Soft measurement method for frequency modulation initial state parameters of supercritical unit based on variable interface

Abstract

The invention provides a supercritical unit frequency modulation initial state parameter soft measurement method based on a variable interface, and the method comprises the steps: dividing a once-through boiler of a supercritical unit into a supercooling section and a supercritical state section, or dividing the once-through boiler into a supercooling section, a steam-water coexistence section and an overheating section; based on the mass conservation law, the energy conservation law, the momentum conservation law and the heat exchange process of the steam-water working medium, models corresponding to all the segments are built; constructing a segmented boiler model corresponding to the once-through boiler based on the model corresponding to each segment and the steam-water working medium characteristics, wherein the segmented boiler model is a variable interface dynamic model in which the volume and the length of each segment change along with time; and determining operation state parameters of the once-through boiler in the unit frequency modulation initial state based on the segmented boiler model. The method provides a frequency modulation initial state parameter soft measurement scheme for the supercritical unit once-through boiler, can be used for identifying the initial state of the once-through boiler in power simulation, and accurately describes the unit operation state before the frequency modulation action of the supercritical unit.

Description

Technical Field

[0001] This invention relates to the field of thermal system analysis technology, and in particular to a soft measurement method for initial state parameters of frequency regulation in supercritical units based on variable interfaces. Background Technology

[0002] In order to accurately reflect the actual operating state of the unit before frequency regulation in frequency regulation simulation and operation analysis, it is necessary to reasonably model and identify the phase change process, heat transfer distribution and flow resistance inside the boiler.

[0003] Traditional methods often employ empirical formulas, simplified whole-unit models, or treat the boiler as several equivalent integral components, such as the finite difference method and the finite volume method. However, these methods are all interface-defined, treating the boiler as a whole without distinguishing interfaces. This makes it difficult to accurately reflect the impact of saturated / superheated boundaries on flow and enthalpy. The accuracy of initial state identification decreases under changing operating conditions (such as frequency regulation), and the initial parameters obtained from simplified models often have systematic deviations from the actual operating conditions, resulting in inaccurate final operating parameters. Furthermore, in terms of application, current power grid assessments of unit regulation capabilities primarily rely on boiler-free BPA (Bulk Power System Analysis) models, which cannot reflect changes in unit operating conditions, making it difficult to grasp the true regulation capabilities of thermal power units, and even more difficult to accurately quantify the system's regulation capacity gap.

[0004] Since the dynamic model of the variable interface, which shows how the volume length of different aggregate states changes over time, is more accurate than the fixed interface scheme, it can solve the problem of the difficult-to-solve interface changes between the liquid and supercritical states in a once-through boiler of a supercritical unit. Therefore, at least one of the above problems can be solved based on the variable interface scheme. Summary of the Invention

[0005] To address the aforementioned problems, this invention provides a soft measurement method for initial state parameters of frequency regulation in supercritical units based on variable interface.

[0006] This invention provides a soft measurement method for initial state parameters of frequency regulation in supercritical units based on variable interface, comprising: The once-through boiler of the supercritical unit is divided into a subcooled section and a supercritical section, or the once-through boiler is divided into a subcooled section, a steam-water coexistence section and a superheated section. Based on the laws of conservation of mass, energy, and momentum of the working fluid and the heat transfer process, models corresponding to each segment are constructed. Based on the models and steam-water working fluid characteristics corresponding to each segment, a segmented boiler model corresponding to the once-through boiler is constructed. The segmented boiler model is a dynamic model of the variable interface where the volume and length of each segment change over time. Based on the segmented boiler model, the operating parameters of the once-through boiler under the initial frequency regulation state of the supercritical unit are determined.

[0007] According to the present invention, a soft measurement method for initial state parameters of frequency regulation of a supercritical unit based on a variable interface is provided. The method for determining the operating state parameters of the once-through boiler under the initial state of frequency regulation of the supercritical unit, based on the segmented boiler model, includes: Obtain known operating parameters, including the cross-sectional area of ​​the heat exchange equivalent pipe corresponding to the DC boiler, the length of the heat exchange equivalent pipe, the average flue gas temperature on the furnace heat exchanger wall, the boiler inlet steam and water working fluid temperature, the boiler inlet steam and water working fluid pressure, the boiler outlet steam and water working fluid temperature, the boiler outlet steam and water working fluid pressure, and the steam and water working fluid flow rate. The operating parameters are input into the segmented boiler model for processing to obtain the operating status parameters of the once-through boiler under the initial frequency regulation state of the supercritical unit. The operating status parameters include at least the length and heat exchange of each segment.

[0008] According to the present invention, a soft measurement method for initial state parameters of frequency regulation of a supercritical unit based on a variable interface is provided. When the once-through boiler is divided into a subcooled section, a steam-water coexistence section, and a superheated section, the method constructs models corresponding to each section based on the laws of conservation of mass, energy, and momentum of the steam-water working fluid and the heat transfer process, including: Based on the law of conservation of mass, the law of conservation of energy, the law of conservation of momentum, and the heat transfer process, a model corresponding to the subcooled section is constructed. The model corresponding to the subcooled section includes the first mass conservation formula, the first energy conservation formula, the first momentum conservation formula, and the first heat transfer formula corresponding to the subcooled section. Based on the law of conservation of mass, the law of conservation of energy, and the heat transfer process, a model corresponding to the steam-water coexistence section is constructed. The model corresponding to the steam-water coexistence section includes the second mass conservation formula, the second energy conservation formula, and the second heat transfer formula corresponding to the steam-water coexistence section. Based on the law of conservation of mass, the law of conservation of energy, the law of conservation of momentum, and the heat transfer process, a model corresponding to the superheated section is constructed. The model corresponding to the superheated section includes the third mass conservation formula, the third energy conservation formula, the second momentum conservation formula, and the third heat transfer formula corresponding to the superheated section.

[0009] According to the present invention, a soft measurement method for initial state parameters of frequency regulation of a supercritical unit based on a variable interface is provided. The method involves constructing a segmented boiler model corresponding to the once-through boiler based on the model corresponding to each segment and the characteristics of the steam-water working fluid, including: Based on the initial state characteristics of frequency modulation, the models corresponding to each segment are simplified to obtain simplified models corresponding to each segment. The initial state characteristics of frequency modulation indicate that the unsteady term is zero in the initial state of frequency modulation. The simplified models corresponding to each segment and the steam-water working fluid models corresponding to the characteristics of the steam-water working fluid are combined and deformed to obtain the segmented boiler model.

[0010] According to the present invention, a soft measurement method for initial state parameters of frequency regulation of a supercritical unit based on a variable interface is provided, wherein the model corresponding to the subcooled section is: in, S ww Let be the equivalent cross-sectional area of ​​the pipe inside the DC boiler. t For time, l 13 The equivalent pipe length of the subcooled section is given. r 2 represents the density of the steam-water working fluid in the subcooling section. D 1 represents the mass flow rate of the steam-water working fluid at the inlet of the subcooling section. D 3 represents the mass flow rate of the steam-water working fluid at the outlet of the subcooling section. r 3 represents the density of the steam-water working fluid at the outlet of the subcooling section. u 2 represents the internal energy of the steam-water working fluid in the subcooling section. H 1 represents the specific enthalpy of the steam-water working fluid at the inlet of the subcooling section. H 3 represents the specific enthalpy of the steam-water working fluid at the outlet of the subcooling section. Q 2 represents the heat exchange between the steam-water working fluid and the flue gas in the subcooling section. p 1 represents the pressure of the steam-water working fluid at the inlet of the subcooling section. p 3 represents the pressure of the steam-water working fluid at the outlet of the subcooling section. g 13 The resistance coefficient of the steam-water working fluid in the subcooling section is given. D 2 represents the mass flow rate of the steam-water working fluid in the subcooling section. k 2 represents the heat transfer coefficient between the subcooled section's steam-water working fluid and the flue gas. t 2 represents the temperature of the steam-water working fluid in the subcooling section. t f This is the average temperature of the flue gas on the furnace heat exchanger wall. The simplified model corresponding to the subcooled section is: in, D 2 represents the mass flow rate of the steam-water working fluid in the subcooling section. t 1 represents the inlet temperature of the subcooling section's steam-water working fluid. t 3 represents the temperature of the steam-water working fluid at the outlet of the subcooling section.f ρ Let be a density property function of water. f H Let be the specific enthalpy property function of water.

[0011] According to the present invention, a soft measurement method for initial state parameters of frequency regulation of a supercritical unit based on a variable interface is provided. When the once-through boiler is divided into a subcooled section, a steam-water coexistence section, and a superheated section, the model corresponding to the steam-water coexistence section is as follows: in, S ww Let be the equivalent cross-sectional area of ​​the pipe inside the DC boiler. t For time, l 35 The equivalent pipe length of the soda-water coexistence section. r 4 represents the density of the working fluid in the gas-water coexistence section. D 3 represents the mass flow rate of the working fluid at the inlet of the steam-water coexistence section. D 5 represents the mass flow rate of the working fluid at the outlet of the steam-water coexistence section. r 3 represents the density of the working fluid at the inlet of the gas-water coexistence section. l 13 The equivalent pipe length of the subcooled section is given. r 5 represents the density of the working fluid at the outlet of the gas-water coexistence section. l 15 The equivalent pipe length for the subcooling section and the steam-water coexistence section. u 4 represents the internal energy of the working fluid in the gas-water coexistence section. H 3 represents the specific enthalpy of the working fluid at the inlet of the gas-water coexistence section. H 5 represents the specific enthalpy of the working fluid at the outlet of the gas-water coexistence section. Q 4 represents the heat exchange between the steam / water working medium and the flue gas in the steam / water coexistence section. k 4 represents the heat transfer coefficient between the steam-water working fluid and the flue gas in the steam-water coexistence section. t 4 represents the temperature of the working fluid in the gas-water coexistence section. t f This is the average temperature of the flue gas on the furnace heat exchanger wall. The simplified model corresponding to the soda-water coexistence section is: in, t 3 represents the temperature of the steam-water working fluid at the inlet of the phase-changing section. t 5 represents the temperature of the steam-water working fluid at the outlet of the phase-changing section. p 3 represents the pressure of the working fluid at the inlet of the steam-water coexistence section. p4 represents the pressure of the working fluid in the steam-water coexistence section. p 5 represents the pressure of the working fluid at the outlet of the steam-water coexistence section. f H1 Let be the specific enthalpy property function of saturated vapor. f H0 is the specific enthalpy property function of saturated water.

[0012] According to the present invention, a soft measurement method for initial state parameters of frequency regulation of a supercritical unit based on a variable interface is provided. When the once-through boiler is divided into a subcooled section, a steam-water coexistence section, and a superheated section, the model corresponding to the superheated section is as follows: in, S ww Let be the equivalent cross-sectional area of ​​the pipe inside the DC boiler. t For time, l 57 The equivalent pipe length of the superheated section is given. r 6 represents the density of the steam-water working fluid in the superheated section. D 5 represents the mass flow rate of the steam-water working fluid at the inlet of the superheated section. D 7 represents the mass flow rate of the steam-water working fluid at the outlet of the superheated section. r 5 represents the density of the steam-water working fluid at the inlet of the superheated section. l 57 The equivalent pipe length of the superheated section is given. r 6 represents the density of the steam-water working fluid in the superheated section. u 6 represents the internal energy of the steam-water working fluid within the superheated section. H 5 represents the specific enthalpy of the steam-water working fluid at the inlet of the superheated section. H 7 represents the specific enthalpy of the steam-water working fluid at the outlet of the superheated section. Q 6 represents the heat exchange between the steam-water working fluid and the flue gas in the superheated section. p 5 represents the pressure of the steam-water working fluid at the inlet of the superheated section. p 7 represents the pressure of the steam-water working fluid at the outlet of the superheated section. g 57 The resistance coefficient of the steam-water working fluid in the superheated section is given. D 6 represents the mass flow rate of the steam-water working fluid within the superheated section. k 6 represents the heat transfer coefficient between the steam-water working fluid and the flue gas in the superheated section. t 6 represents the temperature of the steam-water working fluid within the superheated section. t f This is the average temperature of the flue gas on the furnace heat exchanger wall. The simplified model corresponding to the superheated section is: in,D 5 represents the mass flow rate of the steam-water working fluid in the superheated section. t 5 represents the inlet temperature of the steam-water working fluid in the superheated section. t 7 represents the temperature of the steam-water working fluid at the outlet of the superheated section. f ρ Let be a density property function of water. f H Let be the specific enthalpy property function of water.

[0013] According to the present invention, a soft measurement method for initial state parameters of frequency regulation of a supercritical unit based on a variable interface is provided. When the once-through boiler is divided into a subcooled section, a steam-water coexistence section, and a superheated section, the steam-water working fluid model is as follows: in, l 17 This is the total length of the equivalent pipe. l 13 The equivalent pipe length of the subcooled section is given. l 35 The equivalent pipe length of the soda-water coexistence section. l 57 The equivalent pipe length of the superheated section is given. k 2 represents the heat transfer coefficient between the subcooled section's steam-water working fluid and the flue gas. k 4 represents the heat transfer coefficient between the steam-water working fluid and the flue gas in the steam-water coexistence section. k 6 represents the heat transfer coefficient between the steam-water working fluid and the flue gas in the superheated section. g 13 The resistance coefficient of the steam-water working fluid in the subcooling section is given. g 57 The resistance coefficient of the steam-water working fluid in the superheated section is given.

[0014] The present invention also provides a soft measurement device for initial state parameters of frequency regulation of a supercritical unit based on a variable interface, comprising: The partitioning module is configured to partition the once-through boiler of the supercritical unit into a subcooled section and a supercritical section, or to partition the once-through boiler into the subcooled section, a steam-water coexistence section, and a superheated section. The first building module is configured to construct models corresponding to each segment based on the laws of conservation of mass, energy, and momentum of the working fluid and the heat transfer process. The second construction module is configured to construct a segmented boiler model corresponding to the once-through boiler based on the model and steam-water working fluid characteristics corresponding to each segment. The segmented boiler model is a dynamic interface model in which the volume and length of each segment change over time. The determination module is configured to determine the operating status parameters of the DC boiler in the initial state of frequency regulation of the supercritical unit based on the segmented boiler model.

[0015] The present invention also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the soft measurement method for initial state parameters of frequency regulation of supercritical units based on variable interface as described above.

[0016] The present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the soft measurement method for initial state parameters of frequency regulation of supercritical units based on variable interface as described above.

[0017] The present invention also provides a computer program product, including a computer program that, when executed by a processor, implements the soft measurement method for initial state parameters of frequency regulation of supercritical units based on variable interface as described above.

[0018] This invention provides a soft measurement method for the initial state parameters of frequency regulation in supercritical units based on variable interface. The method divides the once-through boiler of a supercritical unit into a subcooled section and a supercritical section, or into a subcooled section, a steam-water coexistence section, and a superheated section. Based on the laws of conservation of mass, energy, and momentum of the steam-water working fluid and the heat transfer process, models corresponding to each section are constructed. Based on the models corresponding to each section and the characteristics of the steam-water working fluid, a segmented boiler model corresponding to the once-through boiler is constructed. The segmented boiler model is a dynamic model of the variable interface, showing the volume and length of each section changing over time. Based on the segmented boiler model, the operating state parameters of the once-through boiler under the initial state of frequency regulation in the supercritical unit are determined. This invention provides an easily solvable soft measurement scheme for the initial state parameters of frequency regulation in the once-through boiler of a supercritical unit, which can be used for the initial state identification of the once-through boiler in power simulation, accurately describing the unit's operating state before frequency regulation.

[0019] Furthermore, the soft measurement method for initial state parameters of supercritical units based on variable interface frequency regulation provided by this invention fully characterizes the boundary positions of each segment and the changes in thermodynamic properties within each segment, accurately reflecting the influence of saturated / superheated boundaries on flow rate and enthalpy. Considering the spatial distribution of flow resistance and local heat transfer coefficients, it can accurately identify initial state parameters under changing operating conditions (such as frequency regulation). When used for dynamic simulation of power systems (e.g., setting initial conditions for frequency regulation), the systematic deviation between the initial operating parameters obtained from the segmented boiler model and the actual operating state is small, improving the reliability of simulation results and control strategies. Moreover, this invention does not rely on the BPA model, can reflect changes in the unit's operating conditions, grasp the true regulation capability of thermal power units, and accurately quantify the system's regulation capability gap. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0021] Figure 1 This is one of the flowcharts of the soft measurement method for initial state parameters of frequency regulation of supercritical units based on variable interface provided by the present invention.

[0022] Figure 2 This is a schematic diagram of the DC boiler provided by the present invention.

[0023] Figure 3 This is the second flowchart of the soft measurement method for initial state parameters of frequency regulation of supercritical units based on variable interface provided by the present invention.

[0024] Figure 4 This is a schematic diagram of the structure of the soft measurement device for initial state parameters of frequency regulation of supercritical units based on variable interface provided by the present invention.

[0025] Figure 5 This is a schematic diagram of the structure of the electronic device provided by the present invention. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0027] First, a brief description of the relevant content involved in this invention will be given.

[0028] Currently, research on power plant models mainly focuses on model building and parameter identification. Based on the varying degrees of understanding of the thermal system mechanism, modeling methods can be categorized into three types: white-box models, black-box models, and gray-box models. White-box models, in particular, are models of power plants built based on fundamental physical laws.

[0029] Generally, white-box models often divide the power plant's thermal system into multiple components, such as boilers and regenerators, and perform mathematical modeling on each component separately, often equating them to heat exchanger models. The modeling process generally involves writing equations for thermal parameters such as temperature and pressure within the thermal components based on certain assumptions and fundamental laws such as energy conservation and mass conservation. In supercritical units, due to operating pressures and temperatures approaching or exceeding the critical point, the steam-water working fluid exhibits significant phase transitions and segmented characteristics within the boiler tubes. Its working fluid density, specific enthalpy, and heat transfer characteristics vary significantly with location and operating conditions, posing a significant challenge to accurately describing the transient and steady-state initial conditions within the boiler.

[0030] To accurately reflect the unit's true operating state before frequency regulation in frequency regulation simulation and operation analysis, it is necessary to reasonably model and identify the phase change process, heat transfer distribution, and flow resistance inside the boiler. Traditional methods commonly include using empirical formulas, simplified whole-section models, or treating the boiler as several equivalent integral components.

[0031] However, these methods often have the following shortcomings: First, they do not adequately characterize the boundary positions and thermodynamic property changes within the steam-water coexistence section and the non-steam-water coexistence section (subcooled, phase change, superheated), making it difficult to accurately reflect the influence of the saturated / superheated boundary on flow rate and enthalpy; second, they neglect or simplify the spatial distribution of flow resistance and local heat transfer coefficients, leading to a decrease in the accuracy of initial state identification under changing operating conditions (such as frequency regulation); third, when used for dynamic simulation of power systems (such as setting initial conditions for frequency regulation), the initial parameters obtained from the simplified model often have systematic deviations from the actual operating conditions, thus affecting the reliability of simulation results and control strategies. Since the location and length of the phase change zone in a supercritical single-pass boiler have a significant impact on the overall thermodynamic characteristics, the above problems are particularly prominent in supercritical single-pass boilers.

[0032] In terms of applications, the frequency problem of the power grid is becoming increasingly prominent due to the large-scale integration of high-proportion renewable energy sources into the power system. Thermal power generation, as an important supporting power source, has a wide range of applications in the new power system. Under the policy of coordinated reform of power generation, energy conservation, and environmental protection, large-scale flexibility upgrades have been carried out on thermal power units, resulting in significant changes to unit structure and steam control. After these upgrades, the operating conditions of thermal power units have been greatly expanded, allowing them to operate from rated power to deep-regulation conditions (as low as 20% in some provinces). This exacerbates the changes in unit state parameters with operating conditions, making it difficult for the power grid to accurately grasp the initial state parameter values ​​for unit frequency regulation and further assess the unit's current regulation capability.

[0033] Currently, the power grid's assessment of unit regulation capacity relies primarily on the boiler-less BPA model, which fails to reflect changes in unit operating conditions, makes it difficult to grasp the true regulation capacity of thermal power units, and cannot accurately quantify the system's regulation capacity gap. To overcome these shortcomings, a soft measurement method is needed that can fully consider the phase change and segmented heat transfer characteristics of the steam-water working fluid, and can stably solve for the initial parameters of each boiler segment under given limited measurable boundary conditions.

[0034] A dynamic interface model considering the time-varying volume length of different aggregate states was established, which can effectively solve the problem of excessively drastic changes in the interface between the liquid and supercritical states in a supercritical unit once-through boiler and the difficulty in solving the problem. Therefore, this invention provides a soft measurement method for initial state parameters of frequency regulation in supercritical units based on variable interface. It employs the moving boundary method to establish boiler equations and solve the heat transfer equations. By combining the mass, energy, and momentum conservation of a once-through boiler, a once-through boiler model can be obtained. Furthermore, based on physical mechanisms, this invention establishes a segmented one-dimensional heat transfer model (subcooled section and supercritical section, or subcooled section, steam-water coexistence section, and superheated section). The model simultaneously considers mass, energy, momentum conservation, and the heat transfer process. Under measurable or known operating conditions, such as the equivalent cross-sectional area and length of the heat transfer equivalent pipes, the average flue gas temperature at the furnace heat exchanger wall, and the temperature / pressure and flow rate at the boiler inlet and outlet, the length, heat transfer within each segment, thermodynamic properties within each segment, and equivalent resistance parameters are directly solved, thus providing an accurate initial state for frequency regulation simulation. This method retains the ability to describe key physical processes (phase change and heat transfer distribution) and has good solvability and engineering applicability under actual engineering boundary conditions. It can significantly improve the accuracy and reliability of initial state setting in power simulation and dispatch control, and meet the power system's demand for refined frequency regulation simulation of thermal power units.

[0035] The following is combined with Figure 1-Figure 5 This invention describes a soft measurement method for initial state parameters of frequency regulation in supercritical units based on variable interface.

[0036] Figure 1This is one of the flowcharts illustrating the soft measurement method for initial state parameters of frequency regulation in supercritical units based on variable interface provided by this invention, such as... Figure 1 As shown, the method includes the following: Step 101: Divide the once-through boiler of the supercritical unit into a subcooled section and a supercritical section, or divide the once-through boiler into the subcooled section, a steam-water coexistence section and a superheated section; Step 102: Based on the laws of conservation of mass, energy, and momentum of the working fluid and the heat transfer process, construct models corresponding to each segment. Step 103: Based on the models and steam-water working fluid characteristics corresponding to each segment, construct the segmented boiler model corresponding to the once-through boiler; Step 104: Based on the segmented boiler model, determine the operating state parameters of the once-through boiler under the initial frequency regulation state of the supercritical unit.

[0037] It should be noted that the soft measurement method for initial state parameters of frequency regulation of supercritical units based on variable interface provided by this invention can be applied to scenarios where a once-through boiler is divided into two segments: a subcooled segment and a supercritical segment, as well as scenarios where a once-through boiler is divided into three segments: a subcooled segment, a steam-water coexistence segment, and a superheated segment. The processing procedure provided by this invention is similar for both scenarios with two segments. Furthermore, the soft measurement method for initial state parameters of frequency regulation of supercritical units based on variable interface provided by this invention is mostly applied to scenarios with two segments: a subcooled segment and a supercritical segment.

[0038] Specifically, the segmented boiler model is a dynamic model of the changing interface, in which the volume and length of each segment vary over time.

[0039] Specifically, when the operating conditions of a once-through boiler are below the critical pressure, there are only subcooled and supercritical states. Therefore, the once-through boiler of a supercritical unit can be divided into two sections: a subcooled section and a supercritical section. When the operating conditions of a once-through boiler are above the critical pressure, there can be subcooled, steam-water coexistence, and superheated states. Therefore, the once-through boiler of a supercritical unit can be divided into three sections: a subcooled section, a steam-water coexistence section, and a superheated section.

[0040] For example, see Figure 2 , Figure 2 This is a schematic diagram of the once-through boiler provided by the present invention: The once-through boiler of the supercritical unit is divided into a subcooling section, a steam-water coexistence section, and a superheating section, which can be represented by nodes 1 to 7. Node 1 represents the inlet of the subcooling section, node 2 represents the interior of the subcooling section, node 3 represents the outlet of the subcooling section or the inlet of the steam-water coexistence section, node 4 represents the interior of the steam-water coexistence section, node 5 represents the outlet of the steam-water coexistence section or the inlet of the superheating section, node 6 represents the interior of the superheating section, and node 7 represents the outlet of the superheating section.

[0041] It should be noted that, since the subcooling section is connected to the steam-water coexistence section, the outlet of the subcooling section is also the inlet of the steam-water coexistence section; and since the steam-water coexistence section is connected to the superheating section, the outlet of the steam-water coexistence section is also the inlet of the superheating section.

[0042] Specifically, the operating status parameters include at least the length of each segment and the heat exchange capacity.

[0043] When a once-through boiler is divided into a subcooled section and a supercritical section, the operating parameters include the length of the subcooled section, the heat exchange of the subcooled section (i.e., the heat exchange between the steam-water working medium and the flue gas in the subcooled section), the length of the supercritical section, and the heat exchange of the supercritical section (i.e., the heat exchange between the steam-water working medium and the flue gas in the supercritical section).

[0044] When the once-through boiler is divided into a subcooling section, a steam-water coexistence section, and a superheating section, the operating status parameters include the length of the subcooling section, the heat exchange of the subcooling section (i.e., the heat exchange between the steam-water working medium and the flue gas in the subcooling section), the length of the steam-water coexistence section, the heat exchange of the steam-water coexistence section (i.e., the heat exchange between the steam-water working medium and the flue gas in the steam-water coexistence section), the length of the superheating section, and the heat exchange of the superheating section (i.e., the heat exchange between the steam-water working medium and the flue gas in the superheating section). Furthermore, when the once-through boiler is divided into a subcooling section, a steam-water coexistence section, and a superheating section, the operating parameters may also include the specific enthalpy of the steam-water working medium at the inlet of the subcooling section, the specific enthalpy of the steam-water working medium at the outlet of the subcooling section, the specific enthalpy of the steam-water working medium at the outlet of the steam-water coexistence section, the specific enthalpy of the steam-water working medium at the outlet of the superheating section, the heat transfer coefficient of the superheating section, the heat transfer coefficient of the steam-water coexistence section, the heat transfer coefficient of the superheating section, the saturation temperature of the steam-water coexistence section (i.e., the temperature of the steam-water working medium in the steam-water coexistence section), the density of the steam-water working medium in the steam-water coexistence section, the resistance coefficient of the steam-water working medium in the subcooling section, the resistance coefficient of the steam-water working medium in the superheating section, the density of the steam-water working medium in the subcooling section, and the density of the steam-water working medium in the superheating section.

[0045] Specifically, the characteristics of the steam-water working fluid can be described by three hypothetical models: a structural model, a heat transfer coefficient model, and a resistance coefficient model. The structural model represents the length of the once-through boiler as the sum of the lengths of the subcooling section, the steam-water coexistence section, and the superheated section. The heat transfer coefficient model is used to set the proportions of the heat transfer systems in the subcooling, steam-water coexistence, and superheated sections. The resistance coefficient model is used to determine the proportions of the resistance systems in the subcooling and superheated sections. The segmented boiler model can be a one-dimensional heat exchanger model.

[0046] In practical applications, a segmented boiler model of the phase change process of the steam-water working fluid can be established by using the moving boundary method based on mechanism analysis.

[0047] When a once-through boiler is divided into a subcooled section and a supercritical section, models are constructed to describe the mass, energy, momentum, and heat transfer processes of the steam-water working fluid in the subcooled section, and a model is also constructed to describe the mass, energy, momentum, and heat transfer processes of the steam-water working fluid in the supercritical section. These two models, along with the characteristics of the steam-water working fluid, are then fused to obtain a segmented boiler model of the phase change process of the steam-water working fluid. When a once-through boiler is divided into a subcooling section, a steam-water coexistence section, and a superheating section, models are constructed to describe the mass conservation, energy conservation, momentum conservation, and heat transfer processes of the steam-water working fluid in the subcooling section, the steam-water coexistence section, and the superheating section. These three models, along with the characteristics of the steam-water working fluid, are then integrated to obtain a segmented boiler model of the steam-water working fluid phase change process.

[0048] Furthermore, based on the segmented boiler model, the operating parameters under the initial frequency regulation state can be calculated.

[0049] The present invention provides a soft measurement method for initial state parameters of frequency regulation in supercritical units based on variable interface. This method offers an easily solvable soft measurement scheme for the initial state parameters of frequency regulation in once-through boilers of supercritical units. It can be used for initial state identification of once-through boilers in power simulations, accurately describing the unit's operating state before frequency regulation. It can fully characterize the boundary positions of each segment and the changes in thermodynamic properties within each segment, accurately reflecting the influence of saturated / superheated boundaries on flow rate and enthalpy. Considering the spatial distribution of flow resistance and local heat transfer coefficients, it can accurately identify initial state parameters under changing operating conditions (such as frequency regulation). When used for dynamic simulation of power systems (e.g., setting initial conditions for frequency regulation), the systematic deviation between the initial operating parameters obtained from the segmented boiler model and the actual operating state is small, improving the reliability of simulation results and control strategies. Furthermore, this invention does not rely on a BPA model, can reflect changes in the unit's operating conditions, grasp the true regulation capability of thermal power units, and accurately quantify the system's regulation capability gap.

[0050] Optionally, determining the operating state parameters of the once-through boiler based on the segmented boiler model under the initial frequency regulation state of the supercritical unit includes: Obtain known operating parameters; The operating parameters are input into the segmented boiler model for processing to obtain the operating status parameters of the once-through boiler under the initial frequency regulation state of the supercritical unit. The operating status parameters include at least the length and heat exchange of each segment.

[0051] Specifically, known operating parameters refer to parameters that are measurable or known under operating conditions. These operating parameters include the cross-sectional area of ​​the heat exchange equivalent pipe corresponding to the once-through boiler, the length of the heat exchange equivalent pipe, the average flue gas temperature on the furnace heat exchanger wall, the boiler inlet steam-water working fluid temperature, the boiler inlet steam-water working fluid pressure, the boiler outlet steam-water working fluid temperature, the boiler outlet steam-water working fluid pressure, and the steam-water working fluid flow rate.

[0052] In practical applications, the cross-sectional area of ​​the heat exchange equivalent pipe, the length of the heat exchange equivalent pipe, the average flue gas temperature at the furnace heat exchanger wall, the boiler inlet steam-water working fluid temperature, the boiler inlet steam-water working fluid pressure, the boiler outlet steam-water working fluid temperature, the boiler outlet steam-water working fluid pressure, and the steam-water working fluid flow rate can be obtained. Then, these parameters can be substituted into the segmented boiler model for solution, thus obtaining the operating state parameters of the supercritical unit under the initial state of frequency regulation.

[0053] In this embodiment of the invention, by inputting known operating parameters into the segmented boiler model, the operating state parameters of the supercritical unit under the initial state of frequency regulation can be obtained, thereby improving the efficiency and accuracy of obtaining the operating state parameters of the supercritical unit under the initial state of frequency regulation.

[0054] Optionally, when the once-through boiler is divided into the subcooling section, the steam-water coexistence section, and the superheating section, the model corresponding to each section is constructed based on the laws of conservation of mass, energy, and momentum of the steam-water working fluid and the heat transfer process, including: Based on the law of conservation of mass, the law of conservation of energy, the law of conservation of momentum, and the heat transfer process, a model corresponding to the subcooled section is constructed. The model corresponding to the subcooled section includes the first mass conservation formula, the first energy conservation formula, the first momentum conservation formula, and the first heat transfer formula corresponding to the subcooled section. Based on the law of conservation of mass, the law of conservation of energy, and the heat transfer process, a model corresponding to the steam-water coexistence section is constructed. The model corresponding to the steam-water coexistence section includes the second mass conservation formula, the second energy conservation formula, and the second heat transfer formula corresponding to the steam-water coexistence section. Based on the law of conservation of mass, the law of conservation of energy, the law of conservation of momentum, and the heat transfer process, a model corresponding to the superheated section is constructed. The model corresponding to the superheated section includes the third mass conservation formula, the third energy conservation formula, the second momentum conservation formula, and the third heat transfer formula corresponding to the superheated section.

[0055] In practical applications, based on the law of conservation of mass, a first mass conservation formula can be constructed for the supercooled section; based on the law of conservation of energy, a first energy conservation formula can be constructed for the supercooled section; based on the law of conservation of momentum, a first momentum conservation formula can be constructed for the supercooled section; and based on the heat transfer process, a first heat transfer formula can be constructed for the supercooled section. Then, by combining the third mass conservation formula, the third energy conservation formula, the second momentum conservation formula, and the third heat transfer formula, a model corresponding to the superheated section can be obtained.

[0056] The first mass conservation formula is: The first law of conservation of energy is: The first law of conservation of energy is: The first heat exchange formula is: The model corresponding to the superheated section is: Among them, see Figure 2 , S ww Let be the equivalent cross-sectional area of ​​the pipe inside the DC boiler. t For time, l 13 The equivalent pipe length of the subcooled section is given. r 2 represents the density of the steam-water working fluid in the subcooling section. D 1 represents the mass flow rate of the steam-water working fluid at the inlet of the subcooling section. D 3 represents the mass flow rate of the steam-water working fluid at the outlet of the subcooling section. r 3 represents the density of the steam-water working fluid at the outlet of the subcooling section. u 2 represents the internal energy of the steam-water working fluid in the subcooling section. H 1 represents the specific enthalpy of the steam-water working fluid at the inlet of the subcooling section. H 3 represents the specific enthalpy of the steam-water working fluid at the outlet of the subcooling section. Q 2 represents the heat exchange between the steam-water working fluid and the flue gas in the subcooling section. p 1 represents the pressure of the steam-water working fluid at the inlet of the subcooling section. p 3 represents the pressure of the steam-water working fluid at the outlet of the subcooling section. g 13 The resistance coefficient of the steam-water working fluid in the subcooling section is given. D 2 represents the mass flow rate of the steam-water working fluid in the subcooling section. k 2 represents the heat transfer coefficient between the subcooled section's steam-water working fluid and the flue gas. t 2 represents the temperature of the steam-water working fluid in the subcooling section.t f This is the average temperature of the flue gas on the furnace heat exchanger wall.

[0057] Similarly, based on the law of conservation of mass, a second mass conservation formula can be constructed for the gas-water coexistence section; based on the law of conservation of energy, a second energy conservation formula can be constructed for the gas-water coexistence section; and based on the heat transfer process, a second heat transfer formula can be constructed for the gas-water coexistence section. Then, by combining the third mass conservation formula, the third energy conservation formula, and the third heat transfer formula, a model corresponding to the gas-water coexistence section can be obtained.

[0058] The second mass conservation formula is: The second energy conservation formula is: The second heat exchange formula is: The model corresponding to the soda-water coexistence section is: Among them, see Figure 2 , S ww Let be the equivalent cross-sectional area of ​​the pipe inside the DC boiler. t For time, l 35 The equivalent pipe length of the soda-water coexistence section. r 4 represents the density of the working fluid in the gas-water coexistence section. D 3 represents the mass flow rate of the working fluid at the inlet of the steam-water coexistence section. D 5 represents the mass flow rate of the working fluid at the outlet of the steam-water coexistence section. r 3 represents the density of the working fluid at the inlet of the gas-water coexistence section. l 13 The equivalent pipe length of the subcooled section is given. r 5 represents the density of the working fluid at the outlet of the gas-water coexistence section. l 15 The equivalent pipe length for the subcooling section and the steam-water coexistence section. u 4 represents the internal energy of the working fluid in the gas-water coexistence section. H 3 represents the specific enthalpy of the working fluid at the inlet of the gas-water coexistence section. H 5 represents the specific enthalpy of the working fluid at the outlet of the gas-water coexistence section. Q 4 represents the heat exchange between the steam / water working medium and the flue gas in the steam / water coexistence section. k 4 represents the heat transfer coefficient between the steam-water working fluid and the flue gas in the steam-water coexistence section. t 4 represents the temperature of the working fluid in the gas-water coexistence section.t f This is the average temperature of the flue gas on the furnace heat exchanger wall.

[0059] Similarly, based on the law of conservation of mass, a third mass conservation formula can be constructed for the superheated section; based on the law of conservation of energy, a third energy conservation formula can be constructed for the superheated section; based on the law of conservation of momentum, a third momentum conservation formula can be constructed for the superheated section; and based on the heat transfer process, a third heat transfer formula can be constructed for the superheated section. Then, by combining the third mass conservation formula, the third energy conservation formula, the second momentum conservation formula, and the third heat transfer formula, the model corresponding to the superheated section can be obtained.

[0060] The third mass conservation formula is: The third energy conservation formula is: The third energy conservation formula is: The third heat exchange formula is: The model corresponding to the superheated section is: Among them, see Figure 2 , S ww Let be the equivalent cross-sectional area of ​​the pipe inside the DC boiler. t For time, l 57 The equivalent pipe length of the superheated section is given. r 6 represents the density of the steam-water working fluid in the superheated section. D 5 represents the mass flow rate of the steam-water working fluid at the inlet of the superheated section. D 7 represents the mass flow rate of the steam-water working fluid at the outlet of the superheated section. r 5 represents the density of the steam-water working fluid at the inlet of the superheated section. l 57 The equivalent pipe length of the superheated section is given. r 6 represents the density of the steam-water working fluid in the superheated section. u 6 represents the internal energy of the steam-water working fluid within the superheated section. H 5 represents the specific enthalpy of the steam-water working fluid at the inlet of the superheated section. H 7 represents the specific enthalpy of the steam-water working fluid at the outlet of the superheated section. Q 6 represents the heat exchange between the steam-water working fluid and the flue gas in the superheated section. p 5 represents the pressure of the steam-water working fluid at the inlet of the superheated section. p 7 represents the pressure of the steam-water working fluid at the outlet of the superheated section. g 57 The resistance coefficient of the steam-water working fluid in the superheated section is given. D 6 represents the mass flow rate of the steam-water working fluid within the superheated section. k 6 represents the heat transfer coefficient between the steam-water working fluid and the flue gas in the superheated section. t 6 represents the temperature of the steam-water working fluid within the superheated section. t f This is the average temperature of the flue gas on the furnace heat exchanger wall.

[0061] In this embodiment of the invention, by constructing models corresponding to the subcooled section, the steam-water coexistence section, and the superheated section from multiple dimensions such as mass conservation, energy conservation, momentum conservation, and heat exchange process, the accuracy and reliability of the models are improved.

[0062] Optionally, the step of constructing the segmented boiler model corresponding to the once-through boiler based on the model and steam-water working fluid characteristics corresponding to each segment includes: Based on the initial state characteristics of frequency modulation, the models corresponding to each segment are simplified to obtain simplified models corresponding to each segment. The initial state characteristics of frequency modulation indicate that the unsteady term is zero in the initial state of frequency modulation. The simplified models corresponding to each segment and the steam-water working fluid models corresponding to the characteristics of the steam-water working fluid are combined and deformed to obtain the segmented boiler model.

[0063] In practical applications, since the unsteady-state term is 0 in the initial state of unit frequency regulation, the model corresponding to each segment can be simplified to obtain the simplified model corresponding to each segment.

[0064] Specifically, the simplified model corresponding to the subcooled section is: Among them, see Figure 2 , D 2 represents the mass flow rate of the steam-water working fluid in the subcooling section. t 1 represents the inlet temperature of the subcooling section's steam-water working fluid. t 3 represents the temperature of the steam-water working fluid at the outlet of the subcooling section. f ρ Let be a density property function of water. f H Let be the specific enthalpy property function of water.

[0065] Specifically, when the once-through boiler is divided into a subcooling section, a steam-water coexistence section, and a superheating section, the simplified model corresponding to the steam-water coexistence section is as follows: Among them, see Figure 2 , t3 represents the temperature of the steam-water working fluid at the inlet of the phase-changing section. t 5 represents the temperature of the steam-water working fluid at the outlet of the phase-changing section. p 3 represents the pressure of the working fluid at the inlet of the steam-water coexistence section. p 4 represents the pressure of the working fluid in the steam-water coexistence section. p 5 represents the pressure of the working fluid at the outlet of the steam-water coexistence section. f H1 Let be the specific enthalpy property function of saturated vapor. f H0 is the specific enthalpy property function of saturated water.

[0066] Specifically, when the once-through boiler is divided into a subcooling section, a steam-water coexistence section, and a superheating section, the simplified model corresponding to the superheating section is as follows: Among them, see Figure 2 , D 5 represents the mass flow rate of the steam-water working fluid in the superheated section. t 5 represents the inlet temperature of the steam-water working fluid in the superheated section. t 7 represents the temperature of the steam-water working fluid at the outlet of the superheated section. f ρ Let be a density property function of water. f H Let be the specific enthalpy property function of water.

[0067] When the once-through boiler is divided into a subcooling section, a steam-water coexistence section, and a superheating section, three additional models are needed to make the final one-dimensional heat exchanger model, i.e., the segmented boiler model, solvable. Therefore, based on the characteristics of the steam-water working fluid, assumptions are made, and a steam-water working fluid model is given, including a structural model, a heat transfer coefficient model, and a drag coefficient model.

[0068] The structural model is as follows: The heat transfer coefficient model is as follows: The drag coefficient model is as follows: The working fluid model is as follows: in, l 17 This is the total length of the equivalent pipe. l 13 The equivalent pipe length of the subcooled section is given. l 35 The equivalent pipe length of the soda-water coexistence section.l 57 The equivalent pipe length of the superheated section is given. k 2 represents the heat transfer coefficient between the subcooled section's steam-water working fluid and the flue gas. k 4 represents the heat transfer coefficient between the steam-water working fluid and the flue gas in the steam-water coexistence section. k 6 represents the heat transfer coefficient between the steam-water working fluid and the flue gas in the superheated section. g 13 The resistance coefficient of the steam-water working fluid in the subcooling section is given. g 57 The resistance coefficient of the steam-water working fluid in the superheated section is given.

[0069] Furthermore, by combining the steam-water working fluid model corresponding to the characteristics of the steam-water working fluid with the simplified model corresponding to the subcooled section, the model corresponding to the superheated section, and the simplified model corresponding to the superheated section, and then deforming them, a segmented boiler model can be obtained.

[0070] The segmented boiler model is as follows: The following detailed description of the soft measurement method for initial state parameters of frequency regulation of supercritical units based on variable interface will further illustrate the present invention with reference to specific embodiments.

[0071] Figure 3 This is the second flowchart illustrating the soft measurement method for initial state parameters of frequency regulation in supercritical units based on variable interface provided by this invention. Figure 3 As shown, the method includes the following: Step 301: Divide the once-through boiler into a subcooling section, a steam-water coexistence section, and a superheating section.

[0072] Step 302: Using the moving boundary method, considering the conservation of mass, energy, momentum, and heat transfer of the working fluid, establish the first model corresponding to the subcooled section, the second model corresponding to the coexistence of steam and water, and the third model corresponding to the superheated section.

[0073] Step 303: Based on the fact that the unsteady term is 0 when the unit is in the initial state of frequency regulation, the first model, the second model and the third model are simplified respectively to obtain the first simplified model, the second simplified model and the third simplified model.

[0074] Step 304: Given a model of the working fluid in a soda-water mixture.

[0075] Step 305: Combine and simplify the first simplified model, the second simplified model, the third simplified model and the steam-water working fluid model to obtain the complete segmented boiler model.

[0076] Among them, the segmented boiler model is a dynamic model of the variable interface based on the change of volume length of different aggregate states over time.

[0077] Step 306: Obtain the known operating parameters and input them into the segmented boiler model to obtain the operating state parameters of the supercritical unit under the initial state of frequency regulation.

[0078] The operating parameters include: the cross-sectional area of ​​the heat exchange equivalent pipe corresponding to the once-through boiler, the length of the heat exchange equivalent pipe, the average temperature of flue gas on the furnace heat exchanger wall, the temperature of the steam and water working medium at the boiler inlet, the pressure of the steam and water working medium at the boiler inlet, the temperature of the steam and water working medium at the boiler outlet, the pressure of the steam and water working medium at the boiler outlet, and the flow rate of the steam and water working medium. Operating parameters include the length of the subcooling section, the heat exchange capacity of the subcooling section, the length of the steam-water coexistence section, the heat exchange capacity of the steam-water coexistence section, the length of the superheated section, the heat exchange capacity of the superheated section, the specific enthalpy of the steam-water working medium at the inlet of the subcooling section, the specific enthalpy of the steam-water working medium at the outlet of the subcooling section, the specific enthalpy of the steam-water working medium at the outlet of the steam-water coexistence section, the specific enthalpy of the steam-water working medium at the outlet of the superheated section, the heat transfer coefficient of the superheated section, the heat transfer coefficient of the steam-water coexistence section, the heat transfer coefficient of the superheated section, the saturation temperature of the steam-water coexistence section, the density of the steam-water working medium in the steam-water coexistence section, the resistance coefficient of the steam-water working medium in the subcooling section, the resistance coefficient of the steam-water working medium in the superheated section, the density of the steam-water working medium in the subcooling section, and the density of the steam-water working medium in the superheated section.

[0079] This invention provides an easy-to-solve soft measurement scheme for the initial state parameters of frequency regulation for DC boilers in supercritical units. It can be used for the initial state identification of DC boilers in power simulation and accurately describes the operating state of the supercritical unit before frequency regulation.

[0080] The following describes the soft measurement device for initial state parameters of frequency regulation of supercritical units based on variable interface provided by the present invention. The soft measurement device for initial state parameters of frequency regulation of supercritical units based on variable interface described below can be referred to in correspondence with the soft measurement method for initial state parameters of frequency regulation of supercritical units based on variable interface described above.

[0081] Figure 4 This is a schematic diagram of the soft measurement device for initial state parameters of frequency regulation of a supercritical unit based on a variable interface, provided by the present invention. Figure 4 As shown, the device includes the following: The partitioning module 401 is configured to partition the once-through boiler of the supercritical unit into a subcooled section and a supercritical section, or to partition the once-through boiler into the subcooled section, a steam-water coexistence section, and a superheated section. The first building module 402 is configured to build models corresponding to each segment based on the laws of conservation of mass, energy, and momentum of the steam-water working fluid and the heat transfer process. The second construction module 403 is configured to construct a segmented boiler model corresponding to the once-through boiler based on the model and steam-water working fluid characteristics corresponding to each segment. The segmented boiler model is a dynamic model of the variable interface where the volume and length of each segment change over time. The determination module 404 is configured to determine the operating status parameters of the DC boiler in the initial state of frequency regulation of the supercritical unit based on the segmented boiler model.

[0082] The present invention provides a soft measurement device for initial state parameters of frequency regulation in supercritical units based on variable interface. This device offers an easily solvable soft measurement scheme for the initial state parameters of frequency regulation in DC boilers of supercritical units. It can be used for initial state identification of DC boilers in power simulations, accurately describing the unit's operating state before frequency regulation. It can fully characterize the boundary positions of each segment and the changes in thermodynamic properties within each segment, accurately reflecting the influence of saturated / superheated boundaries on flow rate and enthalpy. Considering the spatial distribution of flow resistance and local heat transfer coefficients, it can accurately identify initial state parameters under changing operating conditions (such as frequency regulation). When used for dynamic simulation of power systems (e.g., setting initial conditions for frequency regulation), the systematic deviation between the initial operating parameters obtained from the segmented boiler model and the actual operating state is small, improving the reliability of simulation results and control strategies. Furthermore, this invention does not rely on a BPA model, can reflect changes in the unit's operating conditions, grasp the true regulation capability of thermal power units, and accurately quantify the system's regulation capability gap.

[0083] Optionally, the determining module 404 is specifically configured as follows: Obtain known operating parameters, including the cross-sectional area of ​​the heat exchange equivalent pipe corresponding to the DC boiler, the length of the heat exchange equivalent pipe, the average flue gas temperature on the furnace heat exchanger wall, the boiler inlet steam and water working fluid temperature, the boiler inlet steam and water working fluid pressure, the boiler outlet steam and water working fluid temperature, the boiler outlet steam and water working fluid pressure, and the steam and water working fluid flow rate. The operating parameters are input into the segmented boiler model for processing to obtain the operating status parameters of the once-through boiler under the initial frequency regulation state of the supercritical unit. The operating status parameters include at least the length and heat exchange of each segment.

[0084] Optionally, when the once-through boiler is divided into the subcooling section, the steam-water coexistence section, and the superheating section, the first construction module 402 is specifically configured as follows: Based on the law of conservation of mass, the law of conservation of energy, the law of conservation of momentum, and the heat transfer process, a model corresponding to the subcooled section is constructed. The model corresponding to the subcooled section includes the first mass conservation formula, the first energy conservation formula, the first momentum conservation formula, and the first heat transfer formula corresponding to the subcooled section. Based on the law of conservation of mass, the law of conservation of energy, and the heat transfer process, a model corresponding to the steam-water coexistence section is constructed. The model corresponding to the steam-water coexistence section includes the second mass conservation formula, the second energy conservation formula, and the second heat transfer formula corresponding to the steam-water coexistence section. Based on the law of conservation of mass, the law of conservation of energy, the law of conservation of momentum, and the heat transfer process, a model corresponding to the superheated section is constructed. The model corresponding to the superheated section includes the third mass conservation formula, the third energy conservation formula, the second momentum conservation formula, and the third heat transfer formula corresponding to the superheated section.

[0085] Optionally, the second building module 403 is specifically configured as follows: Based on the initial state characteristics of frequency modulation, the models corresponding to each segment are simplified to obtain simplified models corresponding to each segment. The initial state characteristics of frequency modulation indicate that the unsteady term is zero in the initial state of frequency modulation. The simplified models corresponding to each segment and the steam-water working fluid models corresponding to the characteristics of the steam-water working fluid are combined and deformed to obtain the segmented boiler model.

[0086] Optionally, the model corresponding to the subcooled section is: in, S ww Let be the equivalent cross-sectional area of ​​the pipe inside the DC boiler. t For time, l 13 The equivalent pipe length of the subcooled section is given. r 2 represents the density of the steam-water working fluid in the subcooling section. D 1 represents the mass flow rate of the steam-water working fluid at the inlet of the subcooling section. D 3 represents the mass flow rate of the steam-water working fluid at the outlet of the subcooling section. r 3 represents the density of the steam-water working fluid at the outlet of the subcooling section. u 2 represents the internal energy of the steam-water working fluid in the subcooling section. H 1 represents the specific enthalpy of the steam-water working fluid at the inlet of the subcooling section. H 3 represents the specific enthalpy of the steam-water working fluid at the outlet of the subcooling section. Q 2 represents the heat exchange between the steam-water working fluid and the flue gas in the subcooling section. p 1 represents the pressure of the steam-water working fluid at the inlet of the subcooling section. p 3 represents the pressure of the steam-water working fluid at the outlet of the subcooling section. g 13 The resistance coefficient of the steam-water working fluid in the subcooling section is given. D 2 represents the mass flow rate of the steam-water working fluid in the subcooling section. k 2 represents the heat transfer coefficient between the subcooled section's steam-water working fluid and the flue gas. t 2 represents the temperature of the steam-water working fluid in the subcooling section. t f This is the average temperature of the flue gas on the furnace heat exchanger wall. The simplified model corresponding to the subcooled section is: in, D 2 represents the mass flow rate of the steam-water working fluid in the subcooling section. t 1 represents the inlet temperature of the subcooling section's steam-water working fluid. t 3 represents the temperature of the steam-water working fluid at the outlet of the subcooling section. f ρ Let be a density property function of water. f H Let be the specific enthalpy property function of water.

[0087] Optionally, when the once-through boiler is divided into a subcooling section, a steam-water coexistence section, and a superheating section, the model corresponding to the steam-water coexistence section is: in, S ww Let be the equivalent cross-sectional area of ​​the pipe inside the DC boiler. t For time, l 35 The equivalent pipe length of the soda-water coexistence section. r 4 represents the density of the working fluid in the gas-water coexistence section. D 3 represents the mass flow rate of the working fluid at the inlet of the steam-water coexistence section. D 5 represents the mass flow rate of the working fluid at the outlet of the steam-water coexistence section. r 3 represents the density of the working fluid at the inlet of the gas-water coexistence section. l 13 The equivalent pipe length of the subcooled section is given. r 5 represents the density of the working fluid at the outlet of the gas-water coexistence section. l 15 The equivalent pipe length for the subcooling section and the steam-water coexistence section. u 4 represents the internal energy of the working fluid in the gas-water coexistence section. H 3 represents the specific enthalpy of the working fluid at the inlet of the gas-water coexistence section. H 5 represents the specific enthalpy of the working fluid at the outlet of the gas-water coexistence section. Q 4 represents the heat exchange between the steam / water working medium and the flue gas in the steam / water coexistence section. k 4 represents the heat transfer coefficient between the steam-water working fluid and the flue gas in the steam-water coexistence section. t 4 represents the temperature of the working fluid in the gas-water coexistence section. t f This is the average temperature of the flue gas on the furnace heat exchanger wall. The simplified model corresponding to the soda-water coexistence section is: in, t 3 represents the temperature of the steam-water working fluid at the inlet of the phase-changing section. t 5 represents the temperature of the steam-water working fluid at the outlet of the phase-changing section. p 3 represents the pressure of the working fluid at the inlet of the steam-water coexistence section. p 4 represents the pressure of the working fluid in the steam-water coexistence section. p 5 represents the pressure of the working fluid at the outlet of the steam-water coexistence section. f H1 Let be the specific enthalpy property function of saturated vapor. f H0 is the specific enthalpy property function of saturated water.

[0088] Optionally, when the once-through boiler is divided into a subcooling section, a steam-water coexistence section, and a superheating section, the model corresponding to the superheating section is: in, S ww Let be the equivalent cross-sectional area of ​​the pipe inside the DC boiler. t For time, l 57 The equivalent pipe length of the superheated section is given. r 6 represents the density of the steam-water working fluid in the superheated section. D 5 represents the mass flow rate of the steam-water working fluid at the inlet of the superheated section. D 7 represents the mass flow rate of the steam-water working fluid at the outlet of the superheated section. r 5 represents the density of the steam-water working fluid at the inlet of the superheated section. l 57 The equivalent pipe length of the superheated section is given. r 6 represents the density of the steam-water working fluid in the superheated section. u 6 represents the internal energy of the steam-water working fluid within the superheated section. H 5 represents the specific enthalpy of the steam-water working fluid at the inlet of the superheated section. H 7 represents the specific enthalpy of the steam-water working fluid at the outlet of the superheated section. Q 6 represents the heat exchange between the steam-water working fluid and the flue gas in the superheated section. p 5 represents the pressure of the steam-water working fluid at the inlet of the superheated section. p 7 represents the pressure of the steam-water working fluid at the outlet of the superheated section. g 57 The resistance coefficient of the steam-water working fluid in the superheated section is given. D 6 represents the mass flow rate of the steam-water working fluid within the superheated section. k 6 represents the heat transfer coefficient between the steam-water working fluid and the flue gas in the superheated section. t 6 represents the temperature of the steam-water working fluid within the superheated section. t fThis is the average temperature of the flue gas on the furnace heat exchanger wall. The model corresponding to the superheated section is: in, D 5 represents the mass flow rate of the steam-water working fluid in the superheated section. t 5 represents the inlet temperature of the steam-water working fluid in the superheated section. t 7 represents the temperature of the steam-water working fluid at the outlet of the superheated section. f ρ Let be a density property function of water. f H Let be the specific enthalpy property function of water.

[0089] Optionally, when the once-through boiler is divided into a subcooling section, a steam-water coexistence section, and a superheating section, the steam-water working fluid model is as follows: in, l 17 This is the total length of the equivalent pipe. l 13 The equivalent pipe length of the subcooled section is given. l 35 The equivalent pipe length of the soda-water coexistence section. l 57 The equivalent pipe length of the superheated section is given. k 2 represents the heat transfer coefficient between the subcooled section's steam-water working fluid and the flue gas. k 4 represents the heat transfer coefficient between the steam-water working fluid and the flue gas in the steam-water coexistence section. k 6 represents the heat transfer coefficient between the steam-water working fluid and the flue gas in the superheated section. g 13 The resistance coefficient of the steam-water working fluid in the subcooling section is given. g 57 The resistance coefficient of the steam-water working fluid in the superheated section is given.

[0090] Figure 5 This is a schematic diagram of the structure of the electronic device provided by the present invention, such as... Figure 5As shown, the electronic device may include: a processor 510, a communications interface 520, a memory 530, and a communications bus 540, wherein the processor 510, the communications interface 520, and the memory 530 communicate with each other through the communications bus 540. Processor 510 can call logic instructions in memory 530 to execute a soft measurement method for initial state parameters of frequency regulation of a supercritical unit based on a variable interface. This method includes: dividing the once-through boiler of the supercritical unit into a subcooled section and a supercritical state section, or dividing the once-through boiler into the subcooled section, a steam-water coexistence section, and a superheated section; constructing models corresponding to each section based on the laws of conservation of mass, energy, and momentum of the steam-water working fluid and the heat transfer process; constructing a segmented boiler model corresponding to the once-through boiler based on the models corresponding to each section and the characteristics of the steam-water working fluid, wherein the segmented boiler model is a dynamic model of the variable interface where the volume and length of each section change over time; and determining the operating state parameters of the once-through boiler in the initial state of frequency regulation of the supercritical unit based on the segmented boiler model.

[0091] Furthermore, the logical instructions in the aforementioned memory 530 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0092] On the other hand, the present invention also provides a computer program product, which includes a computer program that can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer can execute the soft measurement method for initial state parameters of frequency regulation of supercritical units based on variable interface provided by the above methods. The method includes: dividing the once-through boiler of the supercritical unit into a subcooled section and a supercritical state section, or dividing the once-through boiler into the subcooled section, a steam-water coexistence section, and a superheated section; constructing models corresponding to each section based on the mass conservation law, energy conservation law, momentum conservation law, and heat transfer process of the steam-water working fluid; constructing a segmented boiler model corresponding to the once-through boiler based on the models corresponding to each section and the characteristics of the steam-water working fluid, wherein the segmented boiler model is a variable interface dynamic model of the volume and length of each section changing with time; and determining the operating state parameters of the once-through boiler in the initial state of frequency regulation of the supercritical unit based on the segmented boiler model.

[0093] In another aspect, the present invention also provides a non-transitory computer-readable storage medium storing a computer program thereon. When executed by a processor, the computer program implements a soft measurement method for initial state parameters of a supercritical unit based on variable interface frequency regulation, as provided by the methods described above. This method includes: dividing the once-through boiler of the supercritical unit into a subcooled section and a supercritical state section, or dividing the once-through boiler into the subcooled section, a steam-water coexistence section, and a superheated section; constructing models corresponding to each section based on the laws of conservation of mass, energy, and momentum of the steam-water working fluid and the heat transfer process; constructing a segmented boiler model corresponding to the once-through boiler based on the models corresponding to each section and the characteristics of the steam-water working fluid, wherein the segmented boiler model is a dynamic model of the variable interface where the volume and length of each section change over time; and determining the operating state parameters of the once-through boiler in the initial state of frequency regulation of the supercritical unit based on the segmented boiler model.

[0094] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0095] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0096] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A soft measurement method for initial state parameters of frequency modulation of a supercritical unit based on a variable interface, characterized in that, The application relates to a method for determining the running state parameters of a supercritical once-through boiler under the initial state of frequency modulation of a supercritical unit. The once-through boiler of the supercritical unit is divided into a supercooling section and a supercritical section, or the once-through boiler is divided into the supercooling section, a steam-water coexistence section and a superheating section; Based on the mass conservation law, the energy conservation law, the momentum conservation law and the heat exchange process of steam-water working medium, a model corresponding to each section is constructed; Based on the model corresponding to each section and the characteristics of steam-water working medium, a section boiler model corresponding to the once-through boiler is constructed, and the section boiler model is a variable-interface dynamic model of the volume and length of each section changing over time; Based on the section boiler model, the running state parameters of the once-through boiler under the initial state of frequency modulation of the supercritical unit are determined.

2. The soft measurement method of the initial state parameters of the variable boundary based supercritical unit frequency modulation according to claim 1, characterized in that, The method comprises the following steps: Known working condition parameters are acquired, and the working condition parameters comprise the cross-sectional area of a heat exchange equivalent pipeline corresponding to the once-through boiler, the length of the heat exchange equivalent pipeline, the average temperature of flue gas on the wall surface of a furnace heat exchanger, the temperature of steam-water working medium at the inlet of the boiler, the pressure of steam-water working medium at the inlet of the boiler, the temperature of steam-water working medium at the outlet of the boiler, the pressure of steam-water working medium at the outlet of the boiler and the flow of steam-water working medium; The working condition parameters are input into the section boiler model for processing, and the running state parameters of the once-through boiler under the initial state of frequency modulation of the supercritical unit are obtained, wherein the running state parameters at least comprise the length and the heat exchange amount of each section.

3. The variable boundary based supercritical unit frequency modulation initial state parameter soft measurement method according to claim 1, characterized in that, In the case that the once-through boiler is divided into the supercooling section, the steam-water coexistence section and the superheating section, the method of constructing the model corresponding to each section based on the mass conservation law, the energy conservation law, the momentum conservation law and the heat exchange process of steam-water working medium comprises the following steps: Based on the mass conservation law, the energy conservation law, the momentum conservation law and the heat exchange process, a model corresponding to the supercooling section is constructed, and the model corresponding to the supercooling section comprises a first mass conservation formula, a first energy conservation formula, a first momentum conservation formula and a first heat exchange formula corresponding to the supercooling section; Based on the mass conservation law, the energy conservation law and the heat exchange process, a model corresponding to the steam-water coexistence section is constructed, and the model corresponding to the steam-water coexistence section comprises a second mass conservation formula, a second energy conservation formula and a second heat exchange formula corresponding to the steam-water coexistence section; Based on the mass conservation law, the energy conservation law, the momentum conservation law and the heat exchange process, a model corresponding to the superheating section is constructed, and the model corresponding to the superheating section comprises a third mass conservation formula, a third energy conservation formula, a second momentum conservation formula and a third heat exchange formula corresponding to the superheating section.

4. The soft measurement method of the initial state parameters of the variable boundary face-based supercritical unit frequency modulation according to any one of claims 1-3, characterized in that, The method of constructing the section boiler model corresponding to the once-through boiler based on the model corresponding to each section and the characteristics of steam-water working medium comprises the following steps: Based on the characteristics of the initial state of frequency modulation, the model corresponding to each section is simplified to obtain a simplified model corresponding to each section, and the characteristics of the initial state of frequency modulation indicate that the non-steady-state term is zero under the initial state of frequency modulation. The subsegment boiler model is obtained by combining and deforming the simplified model corresponding to each of the subsegments and the steam-water working medium model corresponding to the steam-water working medium characteristics.

5. The variable boundary based supercritical unit frequency modulation initial state parameter soft measurement method according to claim 4, characterized in that, The model corresponding to the supercooling segment is: wherein, S ww Ae is the equivalent pipe cross-sectional area of the drum, τ t is time, l 13 Le is the equivalent pipe length of the subcooled section, ρ 2 is the density of the steam-water mixture in the subcooled section, D 1 is the mass flow rate of the steam-water mixture at the inlet of the subcooled section, D 3 is the mass flow rate of the steam-water mixture at the outlet of the subcooled section, ρ 3 is the density of the steam-water mixture at the outlet of the subcooled section, u 2 is the internal energy of the steam-water mixture in the subcooled section, H 1 is the specific enthalpy of the steam-water mixture at the inlet of the subcooled section, H 3 is the specific enthalpy of the steam-water mixture at the outlet of the subcooled section, Q 2 is the heat exchange amount between the steam-water mixture and the flue gas in the subcooled section, p 1 is the pressure of the steam-water mixture at the inlet of the subcooled section, p 3 is the pressure of the steam-water mixture at the outlet of the subcooled section, ζ 13 Cf is the resistance coefficient of the steam-water mixture in the subcooled section, D 2 is the mass flow rate of the steam-water mixture in the subcooled section, k 2 is the heat exchange coefficient between the steam-water mixture and the flue gas in the subcooled section, t 2 is the temperature of the steam-water mixture in the subcooled section, t f Tf is the average temperature of the flue gas on the wall of the furnace heat exchanger; The simplified model corresponding to the supercooling segment is: wherein, D 2 is the mass flow rate of the steam-water mixture in the subcooling section, t 1 is the temperature of the steam-water mixture at the inlet of the subcooling section, t 3 is the temperature of the steam-water mixture at the outlet of the subcooling section, f ρ is a density property function of water, f H is a specific enthalpy property function of water.

6. The variable boundary based supercritical unit frequency modulation initial state parameter soft measurement method according to claim 4, characterized in that, In the case where the once-through boiler is divided into the supercooling segment, the steam-water coexistence segment and the superheating segment, the model corresponding to the steam-water coexistence segment is: wherein, S ww Ae is the equivalent pipe cross-sectional area of the drum, τ t is time, l 35 Le is the equivalent pipe length of the subcooled section, ρ 4 is the density of the steam-water mixture in the steam-water coexistence section, D 3 is the mass flow rate of the steam-water mixture at the inlet of the steam-water coexistence section, D 5 is the mass flow rate of the steam-water mixture at the outlet of the steam-water coexistence section, ρ 3 is the density of the steam-water mixture at the inlet of the steam-water coexistence section, l 13 Le is the equivalent pipe length of the subcooled section, ρ 5 is the density of the steam-water mixture at the outlet of the steam-water coexistence section, l 15 Le is the equivalent pipe length of the subcooled section and the steam-water coexistence section, u 4 is the internal energy of the steam-water mixture in the steam-water coexistence section, H 3 is the specific enthalpy of the steam-water mixture at the inlet of the steam-water coexistence section, H 5 is the specific enthalpy of the steam-water mixture at the outlet of the steam-water coexistence section, Q 4 is the heat exchange amount between the steam-water mixture and the flue gas in the steam-water coexistence section, k 4 is the heat exchange coefficient between the steam-water mixture and the flue gas in the steam-water coexistence section, t 4 is the temperature of the steam-water mixture in the steam-water coexistence section, t f Tf is the average temperature of the flue gas on the wall surface of the furnace heat exchanger; The simplified model corresponding to the steam-water coexistence segment is: wherein, t 3 is the temperature of the steam-water working medium at the inlet of the phase change section, t 5 is the temperature of the steam-water working medium at the outlet of the phase change section, p 3 is the pressure of the steam-water working medium at the inlet of the steam-water coexistence section, p 4 is the pressure of the steam-water working medium in the steam-water coexistence section, p 5 is the pressure of the steam-water working medium at the outlet of the steam-water coexistence section, f H1 is the specific enthalpy property function of saturated steam, f H0 is the specific enthalpy property function of saturated water.

7. The variable boundary based supercritical unit frequency modulation initial state parameter soft measurement method according to claim 4, characterized in that, In the case where the once-through boiler is divided into the supercooling segment, the steam-water coexistence segment and the superheating segment, the model corresponding to the superheating segment is: wherein, S ww Ae is the equivalent pipe cross-sectional area of the drum, τ t is time, l 57 Le is the equivalent pipe length of the superheating section, ρ 6 is the density of the steam-water mixture in the superheating section, D 5 is the mass flow rate of the steam-water mixture at the inlet of the superheating section, D 7 is the mass flow rate of the steam-water mixture at the outlet of the superheating section, ρ 5 is the density of the steam-water mixture at the inlet of the superheating section, l 57 Le is the equivalent pipe length of the superheating section, ρ 6 is the density of the steam-water mixture in the superheating section, u 6 is the internal energy of the steam-water mixture in the superheating section, H 5 is the specific enthalpy of the steam-water mixture at the inlet of the superheating section, H 7 is the specific enthalpy of the steam-water mixture at the outlet of the superheating section, Q 6 is the heat exchange amount between the steam-water mixture and the flue gas in the superheating section, p 5 is the pressure of the steam-water mixture at the inlet of the superheating section, p 7 is the pressure of the steam-water mixture at the outlet of the superheating section, ζ 57 Cf is the resistance coefficient of the steam-water mixture in the superheating section, D 6 is the mass flow rate of the steam-water mixture in the superheating section, k 6 is the heat exchange coefficient between the steam-water mixture and the flue gas in the superheating section, t 6 is the temperature of the steam-water mixture in the superheating section, t f Tf is the average temperature of the flue gas on the wall surface of the furnace heat exchanger; The simplified model corresponding to the superheating segment is: wherein, D 5 is the mass flow of the steam-water mixture in the superheating section, t 5 is the temperature of the steam-water mixture at the inlet of the superheating section, t 7 is the temperature of the steam-water mixture at the outlet of the superheating section, f ρ is the density property function of water, f H is the specific enthalpy property function of water.

8. The variable boundary based supercritical unit frequency modulation initial state parameter soft measurement method according to claim 4, characterized in that, In the case where the once-through boiler is divided into the supercooling segment, the steam-water coexistence segment and the superheating segment, the steam-water working medium model is: wherein, l 17 Lp is the total length of the equivalent pipe, l 13 Lp is the equivalent pipe length of the supercooling section, l 35 Lp is the equivalent pipe length of the two-phase section, l 57 Lp is the equivalent pipe length of the superheating section, k 2Lp is the heat transfer coefficient of the supercooling section between the steam-water working medium and the flue gas, k 4Lp is the heat transfer coefficient of the two-phase section between the steam-water working medium and the flue gas, k 6Lp is the heat transfer coefficient of the superheating section between the steam-water working medium and the flue gas, ζ 13 Lp is the resistance coefficient of the steam-water working medium in the supercooling section, ζ 57 Lp is the resistance coefficient of the steam-water working medium in the superheating section.

9. A soft measurement device for initial state parameters of frequency modulation of a supercritical unit based on a variable interface, characterized in that, The method comprises the following steps: The division module is configured to divide the once-through boiler of the supercritical unit into a supercooling segment and a supercritical state segment, or divide the once-through boiler into the supercooling segment, a steam-water coexistence segment and a superheating segment; The first construction module is configured to construct a model corresponding to each of the subsegments based on the mass conservation law, the energy conservation law, the momentum conservation law and the heat exchange process of the steam-water working medium; The second construction module is configured to construct a subsegment boiler model corresponding to the once-through boiler based on the model corresponding to each of the subsegments and the steam-water working medium characteristics, the subsegment boiler model being a variable boundary dynamic model with the volume and length of each of the subsegments changing over time; The determination module is configured to determine the operating state parameter of the once-through boiler in the initial state of the frequency modulation of the supercritical unit based on the subsegment boiler model.

10. An electronic device comprising a memory, a processor, and a computer program stored on the memory and running on the processor, characterized in that, The processor implements the supercritical unit frequency modulation initial state parameter soft measurement method based on the variable boundary surface according to any one of claims 1 to 8 when executing the computer program.

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