Coal-fired unit model primary frequency modulation performance improvement method considering boiler characteristics

Abstract

The invention discloses a coal-fired unit model primary frequency modulation performance improvement method considering boiler characteristics. The method comprises the following steps: modeling a coal-fired unit; simplifying the unit dynamic model in the coal-fired unit; under the boundary working condition, coordinated optimization frequency modulation is carried out on the unit. By increasing operation characteristics and boundary conditions of a research unit, a frequency modulation model under a boundary working condition is constructed, and factor analysis that the frequency modulation capability of the unit is limited under the boundary working condition is completed. A multimode and self-stabilization frequency modulation comprehensive optimization technology is provided for boundary working conditions such as the operation output limit working condition and the maximum frequency difference disturbance of the thermal power generating unit; the method has an obvious effect of improving the frequency modulation capability of the thermal power generating unit under the boundary working condition.

Description

Technical Field

[0001] The present invention relates to the technical field of primary frequency regulation of coal-fired unit models, and in particular to a method for improving the performance of primary frequency regulation of coal-fired unit models taking boiler characteristics into consideration. Background Art

[0002] With the advancement of the construction of a new power system, higher requirements are placed on the regulation support capabilities of thermal power units. Restricted by multiple factors such as safety boundaries and unit performance, the frequency regulation boundaries of units under extremely deep working conditions are significantly limited after flexibility transformation and heating transformation. It is necessary to improve the frequency regulation capabilities of units under unit boundary conditions to achieve more effective support for the grid frequency.

[0003] In recent years, the operating characteristics of thermal power units have changed a lot, and the large and rapid fluctuations in the grid frequency have led to frequent low-frequency oscillation accidents, endangering the safety of the units and the power grid. The frequency regulation capability improvement technology under the boundary conditions of thermal power units is based on the characteristics of thermal power units, fully tapping the grid-related support potential of thermal power units, focusing on solving the coordination problems between grid frequency safety and unit equipment safety, grid frequency regulation needs and unit operation stability, and maximizing the grid-related support capabilities of units under the premise of ensuring the inherent safety of operation, meeting the urgent needs of the power system for frequency regulation resources, which has important practical significance. Summary of the invention

[0004] In view of the above-mentioned problems, the present invention is proposed.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions: a method for improving the primary frequency regulation performance of a coal-fired unit model considering boiler characteristics, comprising:

[0006] Modeling of coal-fired units;

[0007] Simplify the unit dynamic model in the coal-fired unit;

[0008] Under boundary conditions, the units are coordinated and optimized for frequency regulation.

[0009] As a preferred solution of the method for improving the primary frequency regulation performance of the coal-fired unit model considering boiler characteristics described in the present invention, wherein: the modeling of the coal-fired unit includes dividing the energy conversion process of the coal-fired unit into combustion and heat transfer in the furnace, steam heat exchange and transfer, and turbine work process according to the thermal process;

[0010] The material balance, energy balance and momentum balance equations of each process are obtained through modeling.

[0011] As a preferred solution of the method for improving the primary frequency regulation performance of the coal-fired unit model considering boiler characteristics of the present invention, wherein: the simplified form of the unit unit dynamic model includes considering the boiler and the main steam pipeline as a concentrated heat storage volume;

[0012] As a typical dual-input and dual-output system, the unit coordination system is based on a simplified nonlinear model of the unit.

[0013] As a preferred solution of the method for improving the primary frequency regulation performance of the coal-fired unit model considering boiler characteristics described in the present invention, wherein: the coordinated optimization of the frequency regulation of the unit includes canceling the inertia link of the primary frequency regulation power instruction and increasing the change speed of the instruction;

[0014] Increasing the limit of the main steam pressure control loop prevents the high pressure regulating valve from reversely adjusting due to the main steam pressure deviation exceeding the limit when the unit power has not yet reached the target value;

[0015] Reduce the inertia time constant of the feedwater command, improve the feedwater response speed, and increase the short-term output of the unit by increasing the feedwater to release the heat stored in the deaerator and metal pipes;

[0016] During the primary frequency modulation operation, by increasing the set value of the primary air main pipe pressure, the coal powder inside the coal mill is quickly blown into the furnace, increasing the combustion intensity of the furnace, and making full use of the residual powder of the coal mill to speed up the load response speed;

[0017] Set the primary frequency modulation priority to shield the AGC instructions that are opposite to the primary frequency modulation action, and prevent the AGC from having a reverse modulation effect on the primary frequency modulation.

[0018] As a preferred solution of the method for improving the primary frequency regulation performance of a coal-fired unit model considering boiler characteristics described in the present invention, the combustion and heat transfer process in the furnace specifically includes:

[0019] The combustion and heat transfer process in the furnace can be expressed as an inertial link with pure time delay:

[0020]

[0021] Among them, τ1 represents the combustion delay in the furnace, T1 represents the combustion time constant in the furnace, T2 represents the boiler heat transfer time constant, k1 represents the combustion gain in the furnace, ΔB represents the pulverized coal feed rate, ΔF represents the heat release of combustion, and ΔD Q Indicates the boiler heat transfer steam flow rate;

[0022] Thermal power units all use a direct-blowing pulverizing system. Add a description of the pulverizing system before the fuel quantity:

[0023]

[0024] Among them, B0 is the amount of raw coal entering the pulverizing system, V1 is the primary air volume, Q M is the raw coal loading capacity of the coal mill, T M is the time constant of the inertia link of the coal mill;

[0025] Separating the heat storage capacity of the boiler and the steam pipe, the heat storage capacity of the boiler is:

[0026]

[0027] Among them, v b is the heat storage coefficient of the boiler, which can be determined by experiment, P D is the boiler pressure, D D is the pipeline steam flow rate;

[0028] The steam heat exchange and transfer includes:

[0029] Considering the main steam pipeline as a concentrated parameter system, its heat storage can be expressed as:

[0030]

[0031] In the formula, c n is the heat storage coefficient of the steam pipe; Q n V is the steam volume in the main steam pipeline; n is the steam pipe volume; γ n is the steam gravity coefficient;

[0032] Main steam pressure P T The calculation table method is to use the relationship between the pressure drop at both ends of the steam pipe and the steam flow rate in the pipe:

[0033] P D --P T =kD D 2 (7)

[0034] Where, k is the resistance coefficient of the steam pipe;

[0035] The pressure before the machine is the main steam pressure P T and steam inlet volume D T There are the following relationships between them:

[0036] P T =(R V +R T )D T (8)

[0037] Among them, R V and R T They are the resistance of the main steam regulating valve and the resistance along the turbine respectively;

[0038] The opening of the main steam regulating valve is defined as:

[0039]

[0040] Substituting formula (9) into formula (8), we get:

[0041] D T =μP T (10)

[0042] The steam turbine model includes:

[0043] T SC High-pressure regulating valve steam chamber steam volume time constant; T RH Reheater time constant; T CO Steam volume time constant of medium pressure cylinder and low pressure connecting pipe; F DHP 、F DIP 、F DLP The percentage of power of the three cylinders, high, medium and low, in the whole machine; F DHP +F DIP +F DLP =1;

[0044] Take the power ratio coefficient F of the medium pressure cylinder DIP +F DLP =F DLP The output power of the steam turbine can be approximately equivalent to the sum of the output power of the high-pressure cylinder and the combined output power of the medium- and low-pressure cylinders:

[0045] N=N H +N L (11)

[0046] In static conditions:

[0047]

[0048] Among them, α is the proportion of the high-pressure cylinder output power of the turbine in the total output power, α=F DHP ; k2 is the turbine gain adjustment coefficient;

[0049] Under dynamic conditions, considering the volume and resistance of the reheater, the relationship between the steam flow rate and the output power of the medium and low pressure cylinders is expressed as:

[0050]

[0051] Among them, T t is the time constant τ of the steam volume in the high pressure regulating valve steam chamber DHP , T3 is the time constant τ of the intermediate reheater DIP ;

[0052]

[0053] Formula (14) can be further simplified as:

[0054]

[0055] As a preferred solution of the method for improving the primary frequency regulation performance of the coal-fired unit model considering the boiler characteristics of the present invention, wherein: the boiler and the main steam pipeline are regarded as a centralized heat storage volume: Formulas (4) and (5) can be combined into:

[0056]

[0057] Where c is the heat storage coefficient of the boiler and the main steam pipe;

[0058] The relationship between the pressure drop at both ends of the steam pipe and the steam flow rate entering the turbine is:

[0059]

[0060] Among them, k T is the resistance coefficient of the steam pipe and the main steam regulating valve.

[0061] As a preferred solution of the method for improving the primary frequency regulation performance of the coal-fired unit model considering the boiler characteristics described in the present invention, the simplified form of the unit unit dynamic model also includes that the unit coordination system is a typical dual-input dual-output system. In order to correspond to the actual unit control system, the simplified nonlinear model of the unit unit is used as the basis, and the simplified model is derived in the form of a transfer function matrix as follows:

[0062]

[0063] M(s) is the turbine dynamic process, and N(s) is the fuel dynamic process, which are:

[0064]

[0065] G0(s) reflects the coupling relationship within the system and is the core part of the unit model;

[0066] It can be concluded that the dynamic model of the Deyuan unit suitable for the actual control system is:

[0067]

[0068] in, are the transfer functions between fuel and main steam pressure and unit power respectively; They are the transfer functions between the turbine regulating valve and the main steam pressure and the unit power respectively.

[0069] A system for improving the primary frequency regulation performance of a coal-fired unit model taking into account boiler characteristics using any method described in the present invention, characterized in that:

[0070] The model building unit models the coal-fired unit and simplifies the unit dynamic model in the coal-fired unit;

[0071] Optimize the frequency regulation unit and coordinate and optimize the frequency regulation of the units under boundary conditions.

[0072] A computer device comprises: a memory and a processor; the memory stores a computer program, wherein: the processor implements the steps of any one of the methods of the present invention when executing the computer program.

[0073] A computer-readable storage medium stores a computer program, wherein: when the computer program is executed by a processor, the steps of any one of the methods of the present invention are implemented.

[0074] Beneficial effects of the invention: The method for improving the primary frequency regulation performance of the coal-fired unit model considering the boiler characteristics provided by the invention constructs a frequency regulation model under boundary conditions by increasing the operating characteristics and boundary conditions of the unit, and completes the analysis of the factors that limit the frequency regulation capability of the unit under boundary conditions. For boundary conditions such as the output limit of the thermal power unit and the maximum frequency difference disturbance, a multi-mode, self-stabilizing frequency regulation comprehensive optimization technology is proposed; it has a significant effect on improving the frequency regulation capability of the thermal power unit under boundary conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0075] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0076] Figure 1 An overall flow chart of a method for improving the primary frequency regulation performance of a coal-fired unit model taking into account boiler characteristics provided by the first embodiment of the present invention;

[0077] Figure 2 A model structure of the energy conversion process of a coal-fired unit in a method for improving the primary frequency regulation performance of a coal-fired unit model taking into account boiler characteristics provided by the first embodiment of the present invention;

[0078] Figure 3 A combustion and heat transfer process model structure in a furnace of a method for improving the primary frequency modulation performance of a coal-fired unit model taking into account boiler characteristics provided in the first embodiment of the present invention;

[0079] Figure 4 A steam heat exchange and transfer model structure of a method for improving the primary frequency regulation performance of a coal-fired unit model considering boiler characteristics provided in the first embodiment of the present invention;

[0080] Figure 5 The TB model structure of the steam turbine in the speed regulation model of the method for improving the primary frequency regulation performance of a coal-fired unit model considering boiler characteristics provided by the first embodiment of the present invention;

[0081] Figure 6 A simplified unit unit dynamic characteristic structure diagram in a method for improving the primary frequency regulation performance of a coal-fired unit model taking into account boiler characteristics provided by the first embodiment of the present invention;

[0082] Figure 7 A CCS and DEH control strategy for a method for improving the primary frequency regulation performance of a coal-fired unit model considering boiler characteristics provided in the first embodiment of the present invention;

[0083] Figure 8 A locked AGC or CCS reverse regulation loop of a method for improving the primary frequency regulation performance of a coal-fired unit model considering boiler characteristics provided by a second embodiment of the present invention;

[0084] Fig. 9 A fast-acting slow-return technology for improving the primary frequency regulation performance of a coal-fired unit model considering boiler characteristics provided in the second embodiment of the present invention;

[0085] Fig.10 A DCS-side pressure-pullback prevention loop of a method for improving the primary frequency regulation performance of a coal-fired unit model taking boiler characteristics into consideration is provided in accordance with a second embodiment of the present invention. DETAILED DESCRIPTION

[0086] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the drawings of the specification. Obviously, the described embodiments are part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary persons in the art without creative work should fall within the scope of protection of the present invention.

[0087] Example 1, reference Figure 1-Figure 7 , which is an embodiment of the present invention, provides a method for improving the primary frequency regulation performance of a coal-fired unit model considering boiler characteristics, comprising:

[0088] S1: Coal-fired unit modeling.

[0089] According to the thermal process, the energy conversion process of coal-fired units is divided into furnace (combustion and heat transfer in the furnace), boiler (steam heat exchange and transfer), and turbine (steam turbine work). Figure 2 ) On this basis, write the material balance, energy balance and momentum balance equations for each process.

[0090] Combustion and heat transfer process in the furnace:

[0091] The combustion and heat transfer process in the furnace can be represented as an inertia link with pure time delay.

[0092]

[0093] Among them, τ1 represents the combustion delay in the furnace, T1 represents the combustion time constant in the furnace, T2 represents the boiler heat transfer time constant, k1 represents the combustion gain in the furnace, ΔB represents the pulverized coal feed rate, ΔF represents the combustion heat release, and ΔD Q Indicates the boiler heat transfer steam flow rate.

[0094] At present, most of the thermal power units in the country use direct-blowing pulverizing systems. The description of the pulverizing system should be added before the fuel quantity:

[0095]

[0096] B0 is the amount of raw coal entering the pulverizing system, V1 is the primary air volume, Q M is the raw coal loading capacity of the coal mill, T M is the time constant of the inertia link of the coal mill.

[0097] Separating the heat storage capacity of the boiler and the steam pipe, the heat storage capacity of the boiler is:

[0098]

[0099] In the formula, c b is the heat storage coefficient of the boiler, which can be determined by experiment, P D is the boiler pressure, D D is the pipeline steam flow rate.

[0100] Finally, the combustion and heat transfer model in the furnace is obtained as follows Figure 3 .

[0101] Steam heat exchange and transfer:

[0102] Considering the main steam pipeline as a concentrated parameter system, its heat storage can be expressed as:

[0103]

[0104] In the formula, c n is the heat storage coefficient of the steam pipe; Q n V is the steam volume in the main steam pipeline; n is the steam pipe volume; γ n is the steam weight coefficient.

[0105] The main steam pressure P T The calculation table method is to use the relationship between the pressure drop at both ends of the steam pipeline and the pipeline steam flow rate:

[0106] P D -P T =kDD 2 (7)

[0107] In formula (7), k is the resistance coefficient of the steam pipe.

[0108] The pressure before the machine is the main steam pressure P T and steam inlet volume D T There are the following relationships between them:

[0109] P T =(R V +R T )D T (8)

[0110] In formula (8), R V and R T They are the resistance of the main steam regulating valve and the along-the-path resistance of the steam turbine respectively.

[0111] The opening of the main steam regulating valve is defined as:

[0112]

[0113] Substituting formula (9) into formula (8), we get:

[0114] D T =μP T (10)

[0115] The final steam heat transfer model is: Figure 4 .

[0116] Steam turbine model:

[0117] T SC High-pressure regulating valve steam chamber steam volume time constant; T RH Reheater time constant; T CO Steam volume time constant of medium pressure cylinder and low pressure connecting pipe; F DHP 、F DIP 、F DLP The percentage of power of the high, medium and low cylinders in the whole machine, also known as the power coefficient (F DHP +F DIP +F DLP =1), such as Figure 5 .

[0118] In general, the dynamic process of the steam turbine is very fast compared to that of the boiler. In the simplified model, DT The relationship between the unit output power N can be approximated by a high-order inertia process, and the inertia time is generally between 10s and 20s. Generally speaking, the low-pressure connecting pipe volume time constant τ DLP and the reheater volume time constant τ DIP Compared with the above, it is very small, so in practice, the model of medium and low pressure combined cylinder can be adopted, that is, the power ratio coefficient F of the medium pressure cylinder is taken. DIP +F DLP =F DLP The output power of the steam turbine can be approximately equivalent to the sum of the output power of the high-pressure cylinder and the combined output power of the medium- and low-pressure cylinders:

[0119] N=N H +N L (11)

[0120] In static conditions:

[0121]

[0122] α is the proportion of the turbine high-pressure cylinder output power in the total output power, α = F DHP , k2 is the turbine gain adjustment coefficient, which is given by F DIP , F DLP and λ are calculated equivalently.

[0123] Under dynamic conditions, considering the volume and resistance of the reheater, the relationship between the steam flow rate and the output power of the medium and low pressure cylinders is expressed as:

[0124]

[0125] In formula (13), T t is the time constant τ of the steam volume in the high pressure regulating valve steam chamber DHP , T3 is the time constant τ of the intermediate reheater DIP .

[0126]

[0127] Considering that the time from the change of combustion rate to the change of main steam flow rate of thermal power units is often as long as 60-150 seconds,

[0128] T1 is relatively small, so equation (14) can be further simplified as:

[0129]

[0130] S2: Simplified form of the unit plant dynamic model.

[0131] Based on the above analysis, if we further simplify and regard the boiler and the main steam pipeline as a centralized heat storage volume, then the above equations (4) and (5) can be combined into:

[0132]

[0133] Where c is the heat storage coefficient of the boiler and the main steam pipe.

[0134] The relationship between the pressure drop at both ends of the steam pipe and the steam flow rate entering the turbine is:

[0135]

[0136] In formula (17), k T is the resistance coefficient of the steam pipeline and the main steam regulating valve. The corresponding system structure diagram is also simplified to Figure 6 The form shown.

[0137] As a typical dual-input dual-output system, the unit coordination system is based on the simplified nonlinear model of the unit unit in order to correspond to the actual unit control system. The simplified model is derived in the form of a transfer function matrix:

[0138]

[0139] M(s) is the turbine dynamic process, N(s) is the fuel dynamic process, respectively

[0140]

[0141]

[0142] G0(s) reflects the coupling relationship within the system and is the core part of the unit model. It can be concluded that the dynamic model of the Deyuan unit suitable for the actual control system is:

[0143]

[0144] are the transfer functions between fuel and main steam pressure and unit power respectively; They are the transfer functions between the turbine regulating valve and the main steam pressure and the unit power respectively.

[0145] S3: Coordinated optimization of frequency regulation improvement technology under boundary conditions.

[0146] In order to solve the problems of unit primary frequency regulation reverse adjustment, frequency regulation response speed and insufficient duration, we can start from the coordinated control side and improve the unit primary frequency regulation performance through a series of optimization adjustments. However, the frequency regulation characteristics of boundary conditions such as full load operation, deep peak operation, and large frequency difference disturbance of the unit are significantly different from those of conventional conditions. Therefore, it is also necessary to characterize the parameters according to the characteristics of the operating conditions. The optimization content mainly includes:

[0147] (1) Cancel the inertia link of the primary frequency modulation power command and increase the speed of command change, thereby speeding up the response speed of the turbine regulating valve and boiler side.

[0148] (2) While ensuring the safe operation of the unit, the limit of the main steam pressure control loop is appropriately increased to prevent the high-pressure regulating valve from reversely adjusting due to the main steam pressure deviation exceeding the limit when the unit power has not yet reached the target value.

[0149] (3) Reduce the inertia time constant of the water supply command, improve the water supply response speed, and increase the short-term output of the unit by increasing the water supply to release the heat stored in the deaerator and metal pipes.

[0150] (4) During the primary frequency modulation operation, by increasing the set value of the primary air main pipe pressure, the coal powder inside the coal mill is quickly blown into the furnace, increasing the combustion intensity in the furnace and making full use of the residual powder in the coal mill to accelerate the load response speed.

[0151] (5) Set the primary frequency modulation priority to shield the AGC instructions that are opposite to the primary frequency modulation action, and prevent the AGC from having a reverse modulation effect on the primary frequency modulation.

[0152] If the above functions are implemented in the form of software functional units and sold or used as independent products, they 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 the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk and other media that can store program codes.

[0153] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as an ordered list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by an instruction execution system, device or apparatus (such as a computer-based system, a system including a processor, or other system that can fetch instructions from an instruction execution system, device or apparatus and execute instructions), or in conjunction with such instruction execution systems, devices or apparatuses. For the purposes of this specification, "computer-readable medium" can be any device that can contain, store, communicate, propagate or transmit a program for use by an instruction execution system, device or apparatus, or in conjunction with such instruction execution systems, devices or apparatuses.

[0154] More specific examples of computer-readable media (a non-exhaustive list) include the following: an electrical connection with one or more wires (electronic device), a portable computer disk case (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disk read-only memory (CDROM). In addition, the computer-readable medium may even be a paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, deciphering or, if necessary, processing in another suitable manner, and then stored in a computer memory.

[0155] It should be understood that the various parts of the present invention can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, a plurality of steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0156] Example 2, reference Figure 8-Figure 10 , which is an embodiment of the present invention, provides a method for improving the primary frequency regulation performance of a coal-fired unit model considering boiler characteristics. The specific optimization scheme is as follows Figure 8 , 9 , as shown in Figure 10. The optimized control loop is shown.

[0157] Embodiment 3 is an embodiment of the present invention, which provides a system for improving the primary frequency regulation performance of a coal-fired unit model taking into account boiler characteristics.

[0158] The model building unit models the coal-fired unit and simplifies the unit dynamic model in the coal-fired unit.

[0159] Optimize the frequency regulation unit and coordinate and optimize the frequency regulation of the units under boundary conditions.

[0160] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A method for improving the primary frequency regulation performance of a coal-fired unit model considering boiler characteristics, characterized in that: include: Modeling of coal-fired units; Simplify the unit dynamic model in the coal-fired unit; Under boundary conditions, the units are coordinated and optimized for frequency regulation.

2. The method for improving the primary frequency regulation performance of a coal-fired unit model considering boiler characteristics according to claim 1, characterized in that: The modeling of the coal-fired unit includes dividing the energy conversion process of the coal-fired unit into combustion and heat transfer in the furnace, steam heat exchange and transfer, and turbine work process according to the thermal process; The material balance, energy balance and momentum balance equations of each process are obtained through modeling.

3. The method for improving the primary frequency regulation performance of a coal-fired unit model considering boiler characteristics as claimed in claim 2, characterized in that: The simplified form of the unit dynamic model includes treating the boiler and the main steam pipeline as a centralized heat storage volume; As a typical dual-input and dual-output system, the unit coordination system is based on a simplified nonlinear model of the unit.

4. The method for improving the primary frequency regulation performance of a coal-fired unit model considering boiler characteristics as claimed in claim 3, characterized in that: The coordinated optimization of the frequency regulation of the units includes canceling the inertia link of the primary frequency regulation power instruction and increasing the speed of change of the instruction; Increasing the limit of the main steam pressure control loop prevents the high pressure regulating valve from reversely adjusting due to the main steam pressure deviation exceeding the limit when the unit power has not yet reached the target value; Reduce the inertia time constant of the feedwater command, improve the feedwater response speed, and increase the short-term output of the unit by increasing the feedwater to release the heat stored in the deaerator and metal pipes; During the primary frequency modulation operation, by increasing the set value of the primary air main pipe pressure, the coal powder inside the coal mill is quickly blown into the furnace, increasing the combustion intensity of the furnace, and making full use of the residual powder of the coal mill to speed up the load response speed; Set the primary frequency modulation priority to shield the AGC instructions that are opposite to the primary frequency modulation action, and prevent the AGC from having a reverse modulation effect on the primary frequency modulation.

5. The method for improving the primary frequency regulation performance of a coal-fired unit model considering boiler characteristics as claimed in claim 4, characterized in that: The process of combustion and heat transfer in the furnace specifically includes: The combustion and heat transfer process in the furnace can be expressed as an inertial link with pure time delay: Among them, τ1 represents the combustion delay in the furnace, T1 represents the combustion time constant in the furnace, T2 represents the boiler heat transfer time constant, k1 represents the combustion gain in the furnace, ΔB represents the pulverized coal feed rate, ΔF represents the combustion heat release, and ΔD Q Indicates the boiler heat transfer steam flow rate; Thermal power units all use a direct-blowing pulverizing system. Add a description of the pulverizing system before the fuel quantity: Among them, B0 is the amount of raw coal entering the pulverizing system, V1 is the primary air volume, Q M is the raw coal loading capacity of the coal mill, T M is the time constant of the inertia link of the coal mill; Separating the heat storage capacity of the boiler and the steam pipe, the heat storage capacity of the boiler is: Among them, c b is the heat storage coefficient of the boiler, which can be determined by experiment, P D is the boiler pressure, D D is the pipeline steam flow rate; The steam heat exchange and transfer includes: Considering the main steam pipeline as a concentrated parameter system, its heat storage can be expressed as: In the formula, c n is the heat storage coefficient of the steam pipe; Q n V is the steam volume in the main steam pipeline; n is the steam pipe volume; γ n is the steam gravity coefficient; Main steam pressure P T The calculation table method is to use the relationship between the pressure drop at both ends of the steam pipe and the steam flow rate in the pipe: P D -P T =kD D 2 (7) Where, k is the resistance coefficient of the steam pipe; The pressure before the machine is the main steam pressure P T and steam inlet volume D T There are the following relationships between them: P T =(R V +R T )D T (8) Among them, R V and R T They are the resistance of the main steam regulating valve and the resistance along the turbine respectively; The opening of the main steam regulating valve is defined as: Substituting formula (9) into formula (8), we get: D T =μP T (10) The steam turbine model includes: T SC High-pressure regulating valve steam chamber steam volume time constant; T RH Reheater time constant; T CO Steam volume time constant of medium pressure cylinder and low pressure connecting pipe; F DHP 、F DIP 、F DLP The percentage of power of the three cylinders, high, medium and low, in the whole machine; F DHP +F DIP +F DLP =1; Take the power ratio coefficient F of the medium pressure cylinder DIP +F DLP =F DLP The output power of the steam turbine can be approximately equivalent to the sum of the output power of the high-pressure cylinder and the combined output power of the medium- and low-pressure cylinders: N=N H +N L (11) In static conditions: Among them, α is the proportion of the high-pressure cylinder output power of the turbine in the total output power, α=F DHP ; k2 is the turbine gain adjustment coefficient; Under dynamic conditions, considering the volume and resistance of the reheater, the relationship between the steam flow rate and the output power of the medium and low pressure cylinders is expressed as: Among them, T t is the time constant τ of the steam volume in the high pressure regulating valve steam chamber DHP , T3 is the time constant τ of the intermediate reheater DIP ; Formula (14) can be further simplified as:

6. The method for improving the primary frequency regulation performance of a coal-fired unit model considering boiler characteristics as claimed in claim 5, characterized in that: The boiler and the main steam pipe are considered as a centralized heat storage volume. Specifically, equations (4) and (5) can be combined into: Where c is the heat storage coefficient of the boiler and the main steam pipe; The relationship between the pressure drop at both ends of the steam pipe and the steam flow rate entering the turbine is: Among them, k T is the resistance coefficient of the steam pipe and the main steam regulating valve.

7. The method for improving the primary frequency regulation performance of a coal-fired unit model considering boiler characteristics as claimed in claim 6, characterized in that: The simplified form of the unit unit dynamic model also includes that the unit coordination system is a typical dual-input dual-output system. In order to correspond to the actual unit control system, the simplified model is derived based on the simplified nonlinear model of the unit unit in the form of a transfer function matrix: M(s) is the turbine dynamic process, and N(s) is the fuel dynamic process, which are: G0(s) reflects the coupling relationship within the system and is the core part of the unit model; It can be concluded that the dynamic model of the Deyuan unit suitable for the actual control system is: in, are the transfer functions between fuel and main steam pressure and unit power respectively; They are the transfer functions between the turbine regulating valve and the main steam pressure and the unit power respectively.

8. A system for improving the primary frequency regulation performance of a coal-fired unit model taking into account boiler characteristics using the method as described in any one of claims 1 to 7, characterized in that: The model building unit models the coal-fired unit and simplifies the unit dynamic model in the coal-fired unit; Optimize the frequency regulation unit and coordinate and optimize the frequency regulation of the units under boundary conditions.

9. A computer device comprising: Memory and processor; The memory stores a computer program, characterized in that: when the processor executes the computer program, the steps of a method for improving the primary frequency regulation performance of a coal-fired unit model taking into account boiler characteristics are implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of a method for improving the primary frequency regulation performance of a coal-fired unit model taking into account boiler characteristics are implemented.

Images