Direct current boiler frequency modulation simulation method and device considering heat distribution and storage characteristics

Abstract

The invention belongs to the technical field of power grid frequency analysis, and particularly relates to a once-through boiler frequency modulation simulation method and device considering heat distribution and storage characteristics. The method comprises the steps that the steady-state distribution condition of physical property parameters along the height of a hearth is calculated based on heat load distribution nonuniformity, and a dynamic heat exchange model is constructed; aiming at the dynamic heat exchange model, building a thermodynamic system dynamic simulation model of the boiler; based on a thermodynamic system dynamic simulation model, the method is embedded into a traditional primary frequency modulation model of a power system for simulation verification and comparison. According to the method, the boiler model is built by using the heat flow method, the mismatching relation between complex fluctuation and large delay of a power plant boiler thermodynamic system in power grid frequency modulation is revealed, and under the working condition of long-term power shortage or low load, the frequency modulation capability prediction precision is higher, and the prediction accuracy is higher. And optimization of a power grid frequency modulation scheduling instruction and stability control of the power grid frequency under high-proportion new energy grid connection are facilitated.

Description

Technical Field

[0001] This invention belongs to the field of power grid frequency analysis technology, and particularly relates to a DC boiler frequency regulation simulation method and device that takes into account heat distribution and storage characteristics. It is applicable to the optimization method of heat and mass transfer model of thermal power plant boiler part and traditional primary frequency regulation model for power grid frequency regulation. Background Technology

[0002] The proportion of renewable energy has increased significantly, and the inherent randomness and volatility of new energy sources have led to an increase in the frequency of power disturbance events. The high proportion of renewable energy, primarily powered by power electronic devices, connected to the grid makes it difficult to provide sufficient inertia support. Therefore, coal-fired power plants, as the "ballast" of the modern power system, bear a significant burden of regulation. However, in existing frequency regulation simulation models, the current power system's prediction of overall grid frequency stability characteristics is overly optimistic when facing large power shortages, necessitating an improvement in the accuracy of the assessment of overall grid frequency regulation actions.

[0003] Due to the complex coupling relationships and nonlinear dynamic characteristics within the boiler system of thermal power units, the boiler system is often simplified to an overly idealized linear model, focusing on optimizing the turbine model parameters. There is a lack of research exploring the constraints of the boiler system on frequency regulation capabilities. Furthermore, a common problem in current research is the assumption of constant main steam pressure, which ignores the crucial impact of boiler heat storage levels on the regulation capability of thermal power units. Therefore, it is necessary to establish a simulation model of primary frequency regulation in the power grid that takes into account boiler dynamics.

[0004] In recent years, the heat flow method has been proposed in existing technologies. By redefining the thermal resistance in the heat exchange process, it is used to analyze the heat transfer process of heat exchangers. Based on the heat flow model, the dynamic heat transfer characteristics of the system can be accurately described without introducing intermediate variables. This method reveals the heat transfer characteristics at the system level and provides a novel approach for constructing overall constraints for boiler dynamics.

[0005] Therefore, based on the heat flow method, the frequency regulation capability of existing thermal power units under primary frequency regulation can be further improved through technical updates. Summary of the Invention

[0006] To address the shortcomings of the existing technology, this invention provides a method and apparatus for frequency regulation simulation of a DC boiler that takes into account heat distribution and storage characteristics. Its purpose is to achieve the objectives of the invention.

[0007] The technical solution adopted by the present invention to achieve the above objectives is as follows:

[0008] A simulation method for frequency regulation of a DC boiler that takes into account heat distribution and storage characteristics includes:

[0009] Based on the uneven distribution of heat load, the steady-state distribution of physical properties along the furnace height is calculated, and a dynamic heat transfer model is constructed.

[0010] For the boiler heat exchange model, a dynamic simulation model of the boiler's thermal system is built;

[0011] Based on the dynamic simulation model of the thermal system, simulation verification and comparison are performed by embedding it into the traditional primary frequency regulation model of the power system.

[0012] Furthermore, the dynamic heat transfer model is constructed by calculating the steady-state distribution of physical properties along the furnace height based on the non-uniformity of heat load distribution; including:

[0013] The uneven distribution of boiler heat load along the furnace height was calculated based on steady-state boundary conditions, and a dynamic heat transfer model of furnace-water-cooled wall-working fluid in tubes was constructed in the form of heat flow source.

[0014] A two-layer iterative calculation was constructed to determine the distribution of heat transfer, Darcy friction coefficient, and physical property parameters along the furnace.

[0015] Furthermore, the method for calculating the non-uniform distribution of boiler heat load along the furnace height based on steady-state boundary conditions includes:

[0016] Starting from the uneven distribution of heat load in the furnace, the radiative heat transfer and convective heat transfer that are difficult to solve and separate inside the furnace are integrated into the model as heat flow sources.

[0017] A two-layer iterative calculation was constructed to determine the heat transfer, Darcy friction coefficient, and distribution of physical properties along the furnace.

[0018] Furthermore, starting from the uneven distribution of heat load in the furnace, the radiative heat transfer and convective heat transfer that are difficult to solve and separate inside the furnace are integrated into the model as heat flow sources.

[0019] The calculation of the heat load non-uniformity coefficient is shown below:

[0020]

[0021]

[0022] in: The coefficient of non-uniformity, The first of the coefficient matrix One element, The current highly normalized version Power;

[0023] For a perimeter of For a heat transfer element of height dx, the heat transfer equation can be obtained as follows:

[0024]

[0025] Where, q x The heat load distribution of the water-cooled wall at height x;

[0026] Integrating both sides of the above equation, we get:

[0027]

[0028] Therefore, the specific enthalpy of the working fluid at height x can be obtained as follows:

[0029]

[0030] in: The average heat load of the boiler, For the working fluid mass flow rate, The total height of the furnace. and These are the specific enthalpy of the working fluid at the inlet and outlet, respectively, which can be obtained from the physical property parameter table;

[0031] The method involves constructing a two-layer iterative calculation to determine the heat transfer, Darcy friction coefficient, and physical property parameters distributed along the furnace. For supercritical steam-water working fluid flow, the Darcy friction coefficient and the correction value of the heat transfer during the steady-state process need to be confirmed. A two-layer iterative solution is employed, assuming the Darcy friction coefficient and the correction value of the heat transfer, and providing upper and lower boundaries. The qualitative temperature and pressure of the first segment are assumed to be the inlet temperature and pressure. The outlet parameters are calculated, and the qualitative temperature and pressure are compared with the average inlet and outlet temperatures until convergence. This process is repeated segment by segment until the outlet side is reached, comparing the outlet physical properties with the actual measured values. The Darcy friction coefficient and the correction value of the heat transfer are corrected using a bisection method until the inlet and outlet temperatures are consistent with the measured parameters of the discrete control system.

[0032] Furthermore, the dynamic heat exchange model for the boiler's thermal system is constructed by establishing a dynamic heat flow model for the heat exchange section from the perspective of capacitive operation of the thermal system components under varying operating conditions. A delayed thermodynamic potential is added to characterize the flow process to account for the time delay of the working fluid flow.

[0033] Furthermore, from the perspective of capacitive operation of thermodynamic system components under varying operating conditions, a dynamic heat flow model of the heat exchange section is established. Considering the time delay of the working fluid flow, a delayed thermodynamic potential is added to characterize the flow process, including:

[0034] The relevant dynamic equations are shown below:

[0035]

[0036]

[0037]

[0038]

[0039] in, To address the furnace heat load, it is integrated into a heat flow source. For pipe wall temperature, The characteristic temperature of the working fluid. For heat exchange thermal resistance, For the heat capacity of the pipe wall, Darcy's coefficient of friction The characteristic temperature of the working fluid. The average velocity of the working fluid within a single segment. For the length of the heat exchanger, For heat exchanger diameter, subscript The number of segments is indicated by S, the cross-sectional area of ​​the heat exchanger is S, g is the acceleration due to gravity, and ΔP is the pressure loss of a single segment of the heat exchanger.

[0040] A DC boiler frequency modulation simulation device considering heat distribution and storage characteristics, comprising:

[0041] The calculation module is used to calculate the steady-state distribution of physical property parameters along the furnace height based on the non-uniformity of heat load distribution, and to build a dynamic heat transfer model;

[0042] The module for building a dynamic simulation model of the boiler's thermal system is used to build a dynamic simulation model of the boiler's thermal system based on a dynamic heat transfer model.

[0043] The verification and comparison module was used to perform simulation verification and comparison based on the dynamic simulation model of the thermal system and embedded in the traditional primary frequency regulation model of the power system.

[0044] Furthermore, the computing module also includes:

[0045] The uneven distribution of boiler heat load along the furnace height was calculated based on steady-state boundary conditions, and a heat load distribution and dynamic heat transfer model was constructed in the form of heat flow sources.

[0046] A two-layer iterative calculation was constructed to determine the distribution of heat transfer, Darcy friction coefficient, and physical property parameters along the furnace.

[0047] A computer device includes a storage medium, a processor, and a computer program stored on the storage medium and executable on the processor, wherein the processor executes the computer program to implement the steps of a DC boiler frequency regulation simulation method considering heat distribution and storage characteristics as described in any one of the claims.

[0048] A computer storage medium storing a computer program, wherein when the computer program is executed by a processor, the steps of a DC boiler frequency modulation simulation method considering heat distribution and storage characteristics as described in any one of the claims are implemented.

[0049] The present invention has the following beneficial effects and advantages:

[0050] The boiler model for thermal power plants and the optimized primary frequency regulation simulation model for power systems provided by this invention calculate the time-domain response characteristics of the boiler under low-load conditions based on the heat flow method of the heat transfer process. This model improves the accuracy of primary frequency regulation simulation for power grids, which is helpful for the generation and allocation of system dispatching and automatic generation control commands.

[0051] This invention can establish a heat transfer model of the boiler part of a thermal power unit based on the heat flow method and embed it into the existing primary frequency regulation simulation model of the power system, thereby enabling a more accurate evaluation of the frequency regulation capability of the thermal power unit under primary frequency regulation.

[0052] The method of this invention utilizes a boiler model built using the heat flow method to reveal the mismatch between complex fluctuations in power grid frequency regulation and the large delays in the thermal system of power plant boilers. Under long-term power deficit or low load conditions, the prediction frequency regulation capability is more accurate, which helps to optimize power grid frequency regulation dispatch instructions and stabilize the power grid frequency under high proportion of new energy grid connection.

[0053] Because this invention incorporates thermal components such as boilers, water-cooled walls, and superheaters into the traditional primary frequency regulation simulation model, and utilizes the heat flow method to achieve efficient solution of the heat exchange dynamic process, the constructed primary frequency regulation dynamic simulation model has higher accuracy in new power systems with lower thermal power output compared to the current linear simplification of thermal power units. Attached Figure Description

[0054] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0055] Figure 1 This is a schematic diagram of the uneven distribution of furnace heat load along the furnace height calculated according to an embodiment of the present invention;

[0056] Figure 2 This is a schematic diagram of the two-layer iterative process for steady-state calculation according to an embodiment of the present invention;

[0057] Figure 3This is a graph showing the steady-state temperature variation along the furnace height, calculated for a certain supercritical once-through boiler according to an embodiment of the present invention.

[0058] Figure 4 This is a graph showing the steady-state pressure variation along the furnace height calculated for a certain supercritical once-through boiler according to an embodiment of the present invention;

[0059] Figure 5 This is a single-stage heat exchange dynamic model of a thermal power plant boiler constructed according to an embodiment of the present invention;

[0060] Figure 6 This is a modular representation of the mathematical model in the embodiments of the present invention;

[0061] Figure 7 This is a schematic diagram comparing the improved primary frequency modulation model of this invention with the traditional model;

[0062] Figure 8 This is a comparison chart of simulation results between the frequency modulation model built according to the embodiments of the present invention and the traditional model;

[0063] Figure 9 This is a schematic diagram of the structure of an electronic device provided in an embodiment of the present invention.

[0064] In the diagram: 1201 processor, 1202 memory, 1203 bus. Detailed Implementation

[0065] To better understand the above-mentioned objectives, features, and advantages of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, unless otherwise specified, the embodiments of the present invention and the features thereof can be combined with each other.

[0066] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and therefore the scope of protection of the invention is not limited to the specific embodiments disclosed below.

[0067] The following reference Figures 1-9 The technical solutions of some embodiments of the present invention are described below.

[0068] Example 1

[0069] This invention provides an embodiment of a frequency modulation simulation method for a DC boiler that takes into account heat distribution and storage characteristics, comprising:

[0070] Step 1. Equivalently treat the boiler water-cooled wall and superheater section as a single-stage heat exchanger, determine the equivalent structural parameters, and establish the equivalent model of the heat exchanger;

[0071] Step 2. Using the inlet and outlet physical property parameters as boundary conditions, calculate the heat transfer distribution along the furnace height based on the heat load distribution non-uniformity coefficient, and convert it into an equivalent heat flow source to establish a heat load heat flow source model.

[0072] (1) The equivalent model and the heat load heat flow source model are processed in segments, including:

[0073] The furnace is divided into uniform segments along its height, and the equivalent heat flow models are cascaded.

[0074] Based on the cascaded heat flow model, the relevant structural parameters of the model are determined;

[0075] (2) Using the equivalent model and equivalent structural parameters from step 1, calculate the heat transfer and flow process of each heat exchanger section, specifically including:

[0076] S1: Given inlet parameters, Darcy friction coefficient, and heat transfer correction factor;

[0077] S2: Assuming the inlet temperature pressure is the qualitative temperature pressure of this segment, calculate the outlet temperature pressure, compare the average inlet and outlet temperature pressures with the qualitative temperature pressure until convergence, and use the outlet temperature pressure as the temperature pressure of the next segment.

[0078] S3: Proceed step by step to the outlet side, compare the outlet side temperature and pressure with the actual measured values. If the error is greater than the given value, correct the Darcy friction coefficient and heat exchange correction coefficient using the dichotomy method, and jump back to S2.

[0079] S4: If the error is less than the given value, output the Darcy friction coefficient, heat exchange correction coefficient, and qualitative temperature and pressure for each segment.

[0080] The heat transfer and flow calculations for each heat exchanger section are used to solve for the working fluid properties at the outlet, mainly the main steam pressure and temperature, which are used to describe the nonlinear characteristics of the boiler output power.

[0081] Step 3. Based on the equivalent model and the iterative solution model, dynamic simulation was performed to verify and compare the results. A modular model was proposed, with the input being the heat load ratio and valve opening, and the output being the main steam flow rate.

[0082] Example 2

[0083] This invention provides an embodiment of a frequency regulation simulation method for a DC boiler that takes into account heat distribution and storage characteristics.

[0084] This invention, based on the heat flow method of the heat transfer process, calculates the time-domain response characteristics of a boiler under low-load conditions for frequency regulation. This model improves the accuracy of primary frequency regulation simulation in power grids, contributing to system scheduling and command generation and allocation. The specific method of this invention includes the following steps:

[0085] Step 1. Calculate the steady-state distribution of physical property parameters along the furnace height based on the non-uniformity of heat load distribution, and construct a dynamic heat transfer model.

[0086] Specifically, it includes:

[0087] Step (1) The uneven distribution of boiler heat load along the furnace height was calculated based on steady-state boundary conditions, and a dynamic heat transfer model was constructed in the form of heat flow sources;

[0088] Specifically, for a given boundary condition of a power plant boiler, considering the uneven heat load, the thermoelectric analogy is adopted to establish the electrical characterization of the thermodynamic system from the boiler water-cooled wall inlet to the turbine, and to calculate the distribution characteristics of physical property parameters along the furnace height under steady-state conditions.

[0089] Step (2) Construct a two-layer iterative calculation to determine the distribution of heat exchange, Darcy friction coefficient, and physical property parameters along the furnace.

[0090] Step 2. Based on the resistance and capacitance characteristics exhibited by each component during the boiler heat exchange process, a dynamic simulation model of the boiler's thermal system is built.

[0091] Specifically, from the perspective of capacitive behavior of components in a thermodynamic system under varying operating conditions, a dynamic heat flow model of the heat exchange section is established, and a delayed thermodynamic potential is added to characterize the flow process in response to the time delay of the working fluid flow.

[0092] Step 3. Based on the dynamic simulation model of the thermal system, embed the traditional primary frequency regulation model of the power system for simulation verification and comparison.

[0093] Specifically, this method addresses the insufficient accuracy of existing power system primary frequency regulation simulation models under low-load power plant operation. It modularizes the model and embeds it between the hydraulic actuators and turbines in existing frequency regulation models to describe the property changes caused by valve opening variations, which in turn lead to a decrease in frequency regulation capability. This method utilizes a boiler model built using the heat flow method and reveals the mismatch between complex fluctuations in grid frequency regulation and the large delays in the power plant boiler thermal system. Under long-term power deficit or low-load conditions, it achieves higher accuracy in predicting frequency regulation capability, contributing to the optimization of grid frequency regulation dispatch commands and the stability control of grid frequency under high-proportion renewable energy grid integration.

[0094] In step 1, the non-uniform distribution of boiler heat load along the furnace height was calculated based on steady-state boundary conditions, such as... Figure 1 As shown, Figure 1 This is a schematic diagram of the uneven distribution of furnace heat load along the furnace height calculated according to an embodiment of the present invention. The method for solving the heat transfer and flow includes:

[0095] S101. Starting from the uneven distribution of heat load in the furnace, the radiative heat transfer and convective heat transfer that are difficult to solve and separate inside the furnace are integrated into the model as heat flow sources.

[0096] The heat load distribution non-uniformity coefficient involved in S101 is derived from the boiler design manual. Based on the inlet and outlet boundary conditions under steady-state heat transfer, the distribution of heat load at each height under steady-state operating conditions is calculated, representing the current coal consumption of the boiler.

[0097] The calculation of the heat load non-uniformity coefficient is shown below:

[0098]

[0099]

[0100] in: The coefficient of non-uniformity, The first of the coefficient matrix One element, The current highly normalized version Power of 1.

[0101] For a perimeter of For a heat transfer element of height dx, the heat transfer equation can be obtained as follows:

[0102]

[0103] Where, q x The heat load distribution at height x is given.

[0104] Integrating both sides of the above equation, we get:

[0105]

[0106] Therefore, the specific enthalpy of the working fluid at height x can be obtained as follows:

[0107]

[0108] in: The average heat load of the boiler, For the working fluid mass flow rate, The total height of the furnace. and These are the inlet and outlet enthalpies of the working fluid, respectively, which can be obtained from the physical property parameter table.

[0109] S102. A two-layer iterative calculation was constructed to determine the heat transfer, Darcy friction coefficient, and distribution of physical properties along the furnace.

[0110] For supercritical water-gas flow, the Darcy friction coefficient and the correction value for heat transfer during the steady-state process need to be determined. Therefore, a two-level iterative solution is adopted. The idea is to assume the Darcy friction coefficient and the correction value for heat transfer, and give the upper and lower boundaries. Assume that the qualitative temperature and pressure of the first segment are the inlet temperature and pressure. Calculate the outlet parameters, compare the qualitative temperature and pressure with the average inlet and outlet temperatures until convergence, and then iterate segment by segment to the outlet side, comparing the outlet properties with the actual measured values. The Darcy friction coefficient and the correction value for heat transfer are corrected using a bisection method until the inlet and outlet temperatures are consistent with the measured parameters of the discrete control system.

[0111] Figure 2 This is a schematic diagram of the steady-state calculation two-layer iterative process according to an embodiment of the present invention. The obtained Darcy friction coefficient and heat transfer correction value can be used for dynamic calculation. Boiler parameters are shown in Table 1.

[0112] physical quantity value physical quantity value Total mass of heat exchanger <![CDATA[1.57141×10 ^5 kg]]> Inlet working fluid temperature 595K pipe wall heat capacity <![CDATA[6.76×10 ^8 kJ / K]]> Inlet working fluid pressure 31.2MPa heat exchanger diameter 0.3424m outlet working fluid temperature 844K Heat exchanger length 215.48m Export working fluid pressure 29.4MPa Flow cross-sectional area <![CDATA[0.3593m 2 ]]> mass flow 736.7 kg / s

[0113] The Darcy friction coefficient and the heat transfer correction coefficient can be obtained as follows:

[0114]

[0115] Figure 3 This is a graph showing the steady-state temperature variation along the furnace height, calculated for a certain supercritical once-through boiler according to an embodiment of the present invention. Figure 4 This is a graph showing the steady-state pressure variation along the furnace height calculated for a certain supercritical once-through boiler according to an embodiment of the present invention.

[0116] In step 2, this invention establishes a single-stage dynamic heat exchange model for a thermal power plant boiler, based on the resistive and capacitive characteristics exhibited by various components during the boiler heat exchange process. Figure 5 As shown.

[0117] Using the concept of thermoelectric analogy, the heat exchange process is analogous to the potential difference, the heat exchange flow to the current, and the capacitive property of the tube wall during the dynamic process to the capacitor. The heat exchange resistance is redefined, and the nonlinear characteristics of the heat exchange resistance, which is traditionally characterized by the logarithmic average temperature difference, are constrained in the thermal resistance element.

[0118] For the working fluid flow process, thermodynamic potential is used to characterize the temperature rise of the working fluid during the flow process, while delayed thermodynamic potential is used to characterize the temperature drop caused by the flow.

[0119] The relevant dynamic equations are shown below:

[0120]

[0121]

[0122]

[0123]

[0124] in, To address the furnace heat load, it is integrated into a heat flow source. For pipe wall temperature, The characteristic temperature of the working fluid. For heat exchange thermal resistance, For the heat capacity of the pipe wall, Darcy's coefficient of friction The characteristic temperature of the working fluid. The average velocity of the working fluid within a single segment. For the length of the heat exchanger, For heat exchanger diameter, subscript The number of segments is represented by S, the cross-sectional area of ​​the heat exchanger is S, d is the differential symbol, g is the acceleration due to gravity, and ΔP is the frictional resistance loss of a single segment.

[0125] The developed heat exchanger model for thermal power plant boilers solves the problem from both heat transfer and flow perspectives. The model provides an electrified representation of the thermodynamic system, allowing Kirchhoff's laws to separate topological and component constraints for easier overall solution. This concept originates from Chen Qun's team's work on the heat method and hierarchical divide-and-conquer approach for solving thermodynamic systems.

[0126] In step 3, the present invention modularized the constructed model and embedded it into an existing frequency modulation simulation model, comparing the simulation results with those of the traditional model. Figure 6 This is a modular model of the aforementioned boiler heat flow model, which can dynamically solve for changes in the physical properties of the working fluid.

[0127] Figure 7 Compared to the traditional primary frequency regulation model, this invention improves upon it by embedding the boiler model between the electro-hydraulic servo system and the turbine in the traditional model. It calculates changes in physical parameters by varying valve openings, thereby characterizing turbine power. This overcomes the inaccuracy caused by the traditional model treating main steam pressure as a constant value and relying solely on the linear characterization of turbine power by valve openings.

[0128] like Figure 8 As shown, Figure 8This is a comparison chart of simulation results between the frequency regulation model built according to the embodiments of the present invention and the traditional model. When the boiler is operating under low load conditions for a long time, its frequency regulation capability does not remain in an ideal state, but shows a trend of gradually decreasing over time. This reflects the problem that if the valve opening is changed without correspondingly increasing the amount of fuel and water, the boiler's heat storage will gradually be released while the water storage level is insufficient. This reflects the influencing factors of the boiler's heat storage level on its frequency regulation capability.

[0129] like Figure 9 As shown, Figure 9 This is a schematic diagram of the structure of an electronic device provided in an embodiment of the present invention. The electronic device includes a processor 1201, a memory 1202, and a bus 1203. The processor 1201 and the memory 1202 communicate with each other via the bus 1203. The processor 1201 is used to call program instructions in the memory 1202 to execute the methods provided in the above-described method embodiments, such as: based on the process structure of a thermal power plant boiler, introducing thermal resistance, thermodynamic potential, and / or energy sources to construct equivalent energy flow models of each independent component of the thermal system; by analyzing the pressure change characteristics of the working fluid flowing through each heat exchange section of the boiler, establishing pressure change equations for the working fluid flow process in the heat exchange model; by analyzing the coupling relationship between the working fluid flow process and the heat transfer and conversion process, establishing a set of constraint equations between working fluid pressure and temperature; and simultaneously establishing the control equations, the dynamic resistance balance equations, and the constraint equations between working fluid pressure and temperature to construct a physical model of the thermal system.

[0130] Example 3

[0131] The present invention provides another embodiment of a DC boiler frequency modulation simulation device that takes into account heat distribution and storage characteristics, comprising:

[0132] The calculation module is used to calculate the steady-state distribution of physical property parameters along the furnace height based on the non-uniformity of heat load distribution, and to build a dynamic heat transfer model;

[0133] The module for building a dynamic simulation model of the boiler's thermal system is used to build a dynamic simulation model of the boiler's thermal system based on a dynamic heat transfer model.

[0134] The verification and comparison module was used to perform simulation verification and comparison based on the dynamic simulation model of the thermal system, which was embedded in the traditional primary frequency regulation model of the power system.

[0135] The calculation module is used to calculate the steady-state distribution of physical properties along the furnace height based on the non-uniformity of heat load distribution.

[0136] The calculation module also includes:

[0137] The uneven distribution of boiler heat load along the furnace height was calculated based on steady-state boundary conditions, and a dynamic heat transfer and flow model of the boiler was constructed in the form of a heat flow source.

[0138] A two-layer iterative calculation was constructed to determine the distribution of heat transfer, Darcy friction coefficient, and physical property parameters along the furnace.

[0139] The DC boiler frequency modulation simulation device that takes into account heat distribution and storage characteristics described in this embodiment is used to implement the DC boiler frequency modulation simulation method that takes into account heat distribution and storage characteristics described in Embodiment 1.

[0140] Example 4

[0141] Based on the same inventive concept, this invention also provides a computer device, including a storage medium, a processor, and a computer program stored on the storage medium and executable on the processor. When the processor executes the computer program, it implements the steps of the DC boiler frequency modulation simulation method considering heat distribution and storage characteristics described in Embodiment 1.

[0142] More specifically, the computer program product disclosed in the embodiments of the present invention includes a computer program stored on a non-transitory computer-readable storage medium. The computer program includes program instructions, which, when executed by a computer, enable the computer to perform the methods provided in the above-described method embodiments. For example, this includes: constructing equivalent energy flow models of each independent component of the thermodynamic system based on the system's flow structure, by introducing thermal resistance, thermodynamic potential, and / or energy sources; connecting the equivalent energy flow models of each independent component through corresponding isothermal points to construct an overall equivalent energy flow model of the thermodynamic system; and, based on the overall equivalent energy flow model, utilizing Kirchhoff's... The energy flow model governing equations are established using the law of Fischer. By analyzing the pressure change characteristics of the working fluid flowing through each independent component of the thermodynamic system, including the functional relationship between the pressure change of the working fluid after flowing through each dynamic and / or resistance component and the mass flow rate of the working fluid, a dynamic resistance balance equation set for the working fluid flow process of the thermodynamic system is established. By analyzing the coupling relationship between the flow process of the working fluid and the heat transfer and conversion process, a constraint equation set between the working fluid pressure and temperature is established. By simultaneously establishing the energy flow model governing equation set, the dynamic resistance balance equation set, and the constraint equation set between the working fluid pressure and temperature, the physical model of the thermodynamic system is constructed.

[0143] Example 5

[0144] Based on the same inventive concept, this embodiment of the invention also provides a computer storage medium storing a computer program, which, when executed by a processor, implements the steps of any one of the DC boiler frequency modulation simulation methods considering heat distribution and storage characteristics described in Embodiment 1 or 2.

[0145] More specifically, in this embodiment of the invention, a non-transitory computer-readable storage medium stores computer instructions, which instruct the computer to execute the methods provided in the above-described method embodiments. These instructions include, for example,: based on the flow structure of the thermodynamic system, introducing thermal resistance, thermodynamic potential, and / or energy sources to construct equivalent energy flow models for each independent component of the thermodynamic system; connecting the equivalent energy flow models of each independent component through corresponding isothermal points to construct an overall equivalent energy flow model of the thermodynamic system; establishing a set of governing equations for the energy flow model based on the overall equivalent energy flow model using Kirchhoff's laws; and further... The pressure change characteristics of the working fluid flowing through each independent component of the thermodynamic system are analyzed. These pressure change characteristics include the functional relationship between the pressure change of the working fluid after flowing through each dynamic and / or resistance component and the mass flow rate of the working fluid. A set of dynamic and resistance balance equations for the working fluid flow process of the thermodynamic system is established. By analyzing the coupling relationship between the flow process of the working fluid and the heat transfer and conversion process, a set of constraint equations between the working fluid pressure and temperature is established. The energy flow model control equations, the dynamic and resistance balance equations, and the constraint equations between the working fluid pressure and temperature are combined to construct the physical model of the thermodynamic system.

[0146] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0147] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0148] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0149] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0150] 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 it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A simulation method for frequency regulation of a DC boiler that takes into account heat distribution and storage characteristics, characterized in that: include: Based on the uneven distribution of heat load, the steady-state distribution of physical properties along the furnace height is calculated, and a dynamic heat transfer model is constructed. For the dynamic heat transfer model, a dynamic simulation model of the boiler's thermal system is built; Based on the dynamic simulation model of the thermal system, simulation verification and comparison are performed by embedding it into the traditional primary frequency regulation model of the power system.

2. The DC boiler frequency modulation simulation method considering heat distribution and storage characteristics according to claim 1, characterized in that: The dynamic heat transfer model is constructed by calculating the steady-state distribution of physical properties along the furnace height based on the non-uniformity of heat load distribution; including: The uneven distribution of boiler heat load along the furnace height was calculated based on steady-state boundary conditions, and a dynamic heat transfer model of furnace-water-cooled wall-working fluid in tubes was constructed in the form of heat flow source. A two-layer iterative calculation was constructed to determine the distribution of heat transfer, Darcy friction coefficient, and physical property parameters along the furnace.

3. The DC boiler frequency modulation simulation method considering heat distribution and storage characteristics according to claim 2, characterized in that: The method for calculating the non-uniform distribution of boiler heat load along the furnace height based on steady-state boundary conditions includes: Starting from the uneven distribution of heat load in the furnace, the radiative heat transfer and convective heat transfer that are difficult to solve and separate inside the furnace are integrated into the model as heat flow sources. A two-layer iterative calculation was constructed to determine the heat transfer, Darcy friction coefficient, and distribution of physical properties along the furnace.

4. The DC boiler frequency modulation simulation method considering heat distribution and storage characteristics according to claim 3, characterized in that: Starting from the uneven distribution of heat load in the furnace, the radiative heat transfer and convective heat transfer that are difficult to solve and separate inside the furnace are integrated into the model as heat flow sources. The calculation of the heat load non-uniformity coefficient is shown below: ； ； in: The coefficient of non-uniformity, The first of the coefficient matrix One element, The current highly normalized version Power; For a perimeter of For a heat transfer element of height dx, the heat transfer equation can be obtained as follows: ； Where, q x The heat load distribution of the water-cooled wall at height x; Integrating both sides of the above equation, we get: ； Therefore, the specific enthalpy of the working fluid at height x can be obtained as follows: ； in: The average heat load of the boiler, For the working fluid mass flow rate, The total height of the furnace. and These are the specific enthalpy of the working fluid at the inlet and outlet, respectively, which can be obtained from the physical property parameter table; The method involves constructing a two-layer iterative calculation to determine the heat transfer, Darcy friction coefficient, and physical property parameters distributed along the furnace. For supercritical steam-water working fluid flow, the Darcy friction coefficient and the correction value of the heat transfer during the steady-state process need to be confirmed. A two-layer iterative solution is employed, assuming the Darcy friction coefficient and the correction value of the heat transfer, and providing upper and lower boundaries. The qualitative temperature and pressure of the first segment are assumed to be the inlet temperature and pressure. The outlet parameters are calculated, and the qualitative temperature and pressure are compared with the average inlet and outlet temperatures until convergence. This process is repeated segment by segment until the outlet side is reached, comparing the outlet physical properties with the actual measured values. The Darcy friction coefficient and the correction value of the heat transfer are corrected using a bisection method until the inlet and outlet temperatures are consistent with the measured parameters of the discrete control system.

5. The DC boiler frequency modulation simulation method considering heat distribution and storage characteristics according to claim 1, characterized in that: The aforementioned dynamic heat exchange model, which establishes a dynamic simulation model of the boiler's thermal system, is based on the capacitive nature of the thermal system components under varying operating conditions. It establishes a dynamic heat flow model for the heat exchange section and adds a delayed thermodynamic potential to characterize the flow process, taking into account the time delay of the working fluid flow.

6. The DC boiler frequency modulation simulation method considering heat distribution and storage characteristics according to claim 5, characterized in that: From the perspective of capacitive operation of components in a thermodynamic system under varying operating conditions, a dynamic heat flow model of the heat exchange section is established. Considering the time delay in the working fluid flow, a delayed thermodynamic potential is added to characterize the flow process, including: The relevant dynamic equations are shown below: ； ； ； ； in, To address the furnace heat load, it is integrated into a heat flow source. For pipe wall temperature, The characteristic temperature of the working fluid. For heat exchange thermal resistance, For the heat capacity of the pipe wall, Darcy's coefficient of friction The characteristic temperature of the working fluid. The average velocity of the working fluid within a single segment. For the length of the heat exchanger, For heat exchanger diameter, subscript The number of segments is indicated by S, the cross-sectional area of ​​the heat exchanger is S, g is the acceleration due to gravity, and ΔP is the pressure loss of a single segment of the heat exchanger.

7. A DC boiler frequency modulation simulation device considering heat distribution and storage characteristics, characterized in that: include: The calculation module is used to calculate the steady-state distribution of physical property parameters along the furnace height based on the non-uniformity of heat load distribution, and to build a dynamic heat transfer model; The module for building a dynamic simulation model of the boiler's thermal system is used to build a dynamic simulation model of the boiler's thermal system based on a dynamic heat transfer model. The verification and comparison module was used to perform simulation verification and comparison based on the dynamic simulation model of the thermal system and embedded in the traditional primary frequency regulation model of the power system.

8. The DC boiler frequency modulation simulation device considering heat distribution and storage characteristics according to claim 7, characterized in that: The computing module also includes: The uneven distribution of boiler heat load along the furnace height was calculated based on steady-state boundary conditions, and a heat load distribution and dynamic heat transfer model was constructed in the form of heat flow sources. A two-layer iterative calculation was constructed to determine the distribution of heat transfer, Darcy friction coefficient, and physical property parameters along the furnace.

9. A computer device, comprising a storage medium, a processor, and a computer program stored on the storage medium and executable on the processor, characterized in that, When the processor executes the computer program, it implements the steps of the DC boiler frequency modulation simulation method that takes into account heat distribution and storage characteristics as described in any one of claims 1-6.

10. A computer storage medium, characterized in that: The computer storage medium contains a computer program, which, when executed by a processor, implements the steps of a DC boiler frequency modulation simulation method considering heat distribution and storage characteristics as described in any one of claims 1-6.

Images