Power grid frequency modulation method and system considering carbon dioxide energy storage dynamic characteristics

Abstract

The invention discloses a power grid frequency modulation method and system considering carbon dioxide energy storage dynamic characteristics. The method comprises the following steps: establishing a power model of a carbon dioxide energy storage system; constructing membership functions of input variables and output variables of the frequency modulation control system; formulating a frequency modulation rule according to the fuzzy level; obtaining a dynamic frequency response model of the carbon dioxide energy storage system based on the power model of the carbon dioxide energy storage system; obtaining a power grid dynamic frequency response model by combining the balance relationship between the output power change of a steam turbine in the power grid, the output power fluctuation of a wind turbine generator and the output power change of the carbon dioxide energy storage and the power grid load; and performing power grid frequency modulation based on the power grid dynamic frequency response model. The real-time change of the power grid frequency can be effectively responded, the uncertainty and complexity in the power grid frequency change can be effectively processed, and the stability of the power grid frequency is maintained.

Description

Technical Field

[0001] The present invention relates to the technical field of power systems, and in particular to a power grid frequency regulation method and system taking into account the dynamic characteristics of carbon dioxide energy storage. Background Art

[0002] Globally, with the profound changes in energy structure and the increasing proportion of renewable energy, the power system is undergoing a historic transformation from traditional fossil energy to clean energy. The core challenge of this transformation is how to effectively integrate renewable energy with strong volatility and intermittency, such as wind and solar energy, to ensure the stable operation of the power grid. In this context, energy storage technology has become one of the key technologies to support the stability of the power grid. Carbon dioxide energy storage technology has great potential due to its environmental friendliness and good compatibility with renewable energy.

[0003] In traditional power systems, the stability of grid frequency mainly depends on the rapid response of thermal power units. However, with the increase in the proportion of renewable energy, these units often find it difficult to respond quickly and accurately to small changes in frequency. The carbon dioxide energy storage system provides inertial support for the system by quickly absorbing or releasing energy, which can effectively smooth out fluctuations in grid frequency and improve the frequency quality of the grid. However, in practical applications, changes in grid frequency are random and uncertain, and the dynamic characteristics of charging and discharging of carbon dioxide energy storage systems involve complex physical processes. Traditional control methods often find it difficult to cope with these challenges. Therefore, it is urgent to develop a grid frequency regulation method that takes into account the dynamic characteristics of carbon dioxide energy storage. Summary of the invention

[0004] (I) Purpose of the invention

[0005] The purpose of the present invention is to provide a grid frequency regulation method and system taking into account the dynamic characteristics of carbon dioxide energy storage. By introducing carbon dioxide energy storage and designing frequency regulation rules to participate in grid frequency regulation, it is possible to effectively respond to real-time changes in grid frequency, and at the same time effectively handle the uncertainty and complexity in grid frequency changes to maintain the stability of grid frequency.

[0006] (II) Technical solution

[0007] In order to solve the above problems, a first aspect of the present invention provides a grid frequency regulation method considering the dynamic characteristics of carbon dioxide energy storage, the method comprising:

[0008] S1, establish a power model of the CO2 energy storage system;

[0009] S2, constructing a membership function of an input variable and an output variable of a frequency modulation control system, wherein the membership function divides the input variable and the output variable into different fuzzy levels respectively;

[0010] S3, formulating frequency modulation rules according to the fuzzy level;

[0011] S4, based on the power model of the carbon dioxide energy storage system, obtaining a dynamic frequency response model of the carbon dioxide energy storage system; the dynamic frequency response model of the carbon dioxide energy storage system outputs corresponding output variables according to the frequency modulation rule, and the output variables cause the output power of the carbon dioxide energy storage to change;

[0012] S5, combining the output power change of the steam turbine in the power grid, the output power fluctuation of the wind turbine and the balance relationship between the output power change of the carbon dioxide energy storage and the power grid load, to obtain a power grid dynamic frequency response model;

[0013] S6, performing grid frequency regulation based on the grid dynamic frequency response model.

[0014] Furthermore, the S1 includes: obtaining a power model of the carbon dioxide energy storage system according to the inherent physical mechanism of the carbon dioxide energy storage system and the interaction and functional coupling between the internal components of the carbon dioxide energy storage system.

[0015] Furthermore, the calculation formula of the power model of the carbon dioxide energy storage system is as follows:

[0016]

[0017]

[0018] In the formula, are the j-th compressor power and the k-th turbine power respectively; are the compression ratio of the j-th compressor and the turbine expansion ratio of the k-th turbine respectively; κ is the adiabatic index of carbon dioxide; are the isentropic efficiency of the j-th compressor and the isentropic efficiency of the k-th turbine respectively; is the mass flow rate of carbon dioxide in the compressor, is the mass flow rate of carbon dioxide in the turbine; C p is the specific heat capacity of carbon dioxide at constant pressure; are the inlet temperature of the j-th stage compressor and the inlet temperature of the k-th stage turbine respectively; are the mechanical efficiency of the compressor and the mechanical efficiency of the turbine respectively; P c ,P t are the total power of the compressor and the total power of the turbine respectively; c and t are the total number of compressor stages and the total number of turbine stages respectively.

[0019] Furthermore, S2 includes: constructing membership functions of input variables and output variables of the frequency regulation control system according to the dynamic response characteristics of the carbon dioxide energy storage and the frequency deviation range of the power grid.

[0020] Furthermore, the input variables include carbon dioxide flow and grid frequency deviation, and the membership function divides the input variables into 4 or 5 fuzzy levels, and different fuzzy levels correspond to different values.

[0021] Furthermore, the output variable is the carbon dioxide energy storage feedback amount, and the membership function divides the output variable into five fuzzy levels.

[0022] Further, the S3 includes:

[0023] If the grid frequency deviation is near 0, the carbon dioxide energy storage feedback amount is near 0;

[0024] If the grid frequency deviation is not near 0, the output power change of the carbon dioxide energy storage is positively correlated with the carbon dioxide energy storage feedback amount.

[0025] Further, if the grid frequency deviation is not near 0, the output power change of the carbon dioxide energy storage is positively correlated with the carbon dioxide energy storage feedback amount, including: if the grid frequency deviation is the same, the carbon dioxide flow rate and the carbon dioxide energy storage feedback amount are negatively correlated.

[0026] Furthermore, the calculation formula of the dynamic frequency response model of the carbon dioxide energy storage system is as follows:

[0027]

[0028] Where F is the frequency modulation rule mapping relationship between input variables and output variables; ΔP out is the controller output; ΔP ref K is the total change of CO2 energy storage reference power; G is the gain coefficient of primary frequency modulation; K S is the gain coefficient of secondary frequency modulation; Δf is the grid frequency deviation; is the carbon dioxide flow rate; t is time, t0 is the starting time; Δf(t) is the frequency deviation value at time t; is the integral of the frequency deviation.

[0029] Another aspect of the present invention provides a power grid frequency regulation system considering the dynamic characteristics of carbon dioxide energy storage, the system comprising:

[0030] Establishing a module for establishing a power model of a CO2 energy storage system;

[0031] A construction module, used to construct a membership function of an input variable and an output variable of a frequency modulation control system, wherein the membership function divides the input variable and the output variable into different fuzzy levels respectively;

[0032] A rule formulation module, used for formulating frequency modulation rules according to the fuzzy level;

[0033] A first dynamic frequency response model module is used to obtain a dynamic frequency response model of the carbon dioxide energy storage system based on the power model of the carbon dioxide energy storage system; the dynamic frequency response model of the carbon dioxide energy storage system outputs corresponding output variables according to the frequency modulation rule, and the output variables cause the output power of the carbon dioxide energy storage to change;

[0034] The second dynamic response module is used to combine the output power changes of other elements in the power grid and the balance relationship between the output power changes of the carbon dioxide energy storage and the power grid load to obtain a power grid dynamic frequency response model.

[0035] The frequency modulation module is used to perform power grid frequency modulation based on the power grid dynamic frequency response model.

[0036] (III) Beneficial effects

[0037] The above technical scheme of the present invention has the following beneficial technical effects: the present invention provides a power grid frequency modulation method and system considering the dynamic characteristics of carbon dioxide energy storage, the power grid frequency modulation method participates in power grid frequency modulation by introducing carbon dioxide energy storage and designing frequency modulation rules, can effectively respond to real-time changes in power grid frequency, and reduce power grid frequency fluctuations, the specific process is as follows: by constructing the membership function of the input variable and output variable of the frequency modulation control system, and dividing the input variable and the output variable into different fuzzy levels through the membership function, and then formulating frequency modulation rules according to the fuzzy levels, the dynamic frequency response model of the carbon dioxide energy storage system outputs the corresponding output variable according to the frequency modulation rule, and the output variable will cause the output power of the carbon dioxide energy storage to change; finally, combining the output power change of the steam turbine in the power grid, the output power fluctuation of the wind turbine unit and the balance relationship between the output power change of the carbon dioxide energy storage and the power grid load, the power grid dynamic frequency response model is obtained, and the power grid frequency is modulated based on the power grid dynamic frequency response model. The present invention can effectively reduce the fluctuation of power grid frequency, can flexibly deal with uncertain factors in power grid operation, and enhance the ability of the power grid to deal with emergencies. The method proposed in the present invention can flexibly respond to various uncertainties in the operation of the power grid, and improve the ability of the power grid to respond to emergencies; at the same time, the use of carbon dioxide energy storage technology is also environmentally friendly, which helps to promote the green transformation of the power system. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 is a flow chart of a power grid frequency regulation method considering the dynamic characteristics of carbon dioxide energy storage based on the present invention;

[0039] Figure 2 is a schematic diagram of a power grid frequency regulation system considering the dynamic characteristics of carbon dioxide energy storage based on the present invention;

[0040] Figure 3 A comparison diagram of frequency modulation effects of a power grid frequency modulation method considering the dynamic characteristics of carbon dioxide energy storage in an embodiment of the present invention. DETAILED DESCRIPTION

[0041] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings. It should be understood that these descriptions are only exemplary and are not intended to limit the scope of the present invention. In addition, in the following description, the description of well-known structures and technologies is omitted to avoid unnecessary confusion of the concept of the present invention.

[0042] like Figure 1 As shown, the present invention provides a power grid frequency regulation method considering the dynamic characteristics of carbon dioxide energy storage, including:

[0043] S1, establish a power model of the CO2 energy storage system;

[0044] S2, constructing a membership function of an input variable and an output variable of a frequency modulation control system, wherein the membership function divides the input variable and the output variable into different fuzzy levels respectively;

[0045] S3, formulating frequency modulation rules according to the fuzzy level;

[0046] S4, based on the power model of the carbon dioxide energy storage system, obtaining a dynamic frequency response model of the carbon dioxide energy storage system; the dynamic frequency response model of the carbon dioxide energy storage system outputs corresponding output variables according to the frequency modulation rule, and the output variables cause the output power of the carbon dioxide energy storage to change;

[0047] S5, combining the output power change of the steam turbine in the power grid, the output power fluctuation of the wind turbine and the balance relationship between the output power change of the carbon dioxide energy storage and the power grid load, to obtain a power grid dynamic frequency response model;

[0048] S6, performing grid frequency regulation based on the grid dynamic frequency response model.

[0049] Furthermore, S1 includes: obtaining a power model of the carbon dioxide energy storage system according to the inherent physical mechanism of the carbon dioxide energy storage system, as well as the interaction and functional coupling between the internal components of the carbon dioxide energy storage system. The inherent physical mechanism of the carbon dioxide energy storage system specifically includes: the core of the inherent physical mechanism of the carbon dioxide energy storage system is to use carbon dioxide as a medium to achieve energy conversion. In the compression energy storage stage, the carbon dioxide energy storage system applies external force to the carbon dioxide gas through the compressor, forcing it to undergo multi-stage compression, and the pressure and temperature rise sharply. In this process, electrical energy is converted into the internal energy of carbon dioxide. In the energy release stage, the carbon dioxide in the high-pressure container undergoes an adiabatic expansion process under the action of the turbine. The turbine uses the mechanical energy released during this expansion process to efficiently convert it into rotational kinetic energy, thereby driving the generator to generate electricity and feed it back to the power grid. Through an in-depth analysis of the inherent physical mechanism of the system, a power model of the carbon dioxide energy storage system is constructed. Then, the interaction and functional coupling between the internal components are comprehensively considered to obtain the power model of the carbon dioxide energy storage system. The calculation formula is as follows:

[0050]

[0051] In formulas (1) to (4), are the j-th compressor power and the k-th turbine power respectively; are the compression ratio of the j-th compressor and the turbine expansion ratio of the k-th turbine respectively; κ is the adiabatic index of carbon dioxide; are the isentropic efficiency of the j-th compressor and the isentropic efficiency of the k-th turbine respectively; is the mass flow rate of carbon dioxide in the compressor, is the mass flow rate of carbon dioxide in the turbine; C p is the specific heat capacity of carbon dioxide at constant pressure; are the inlet temperature of the j-th stage compressor and the inlet temperature of the k-th stage turbine respectively; are the mechanical efficiency of the compressor and the mechanical efficiency of the turbine respectively; P c ,P t are the total power of the compressor and the total power of the turbine respectively; c and t are the total number of compressor stages and the total number of turbine stages respectively.

[0052] Furthermore, S2 includes: constructing a membership function of the input variables and output variables of the frequency modulation control system according to the dynamic response characteristics of the carbon dioxide energy storage and the grid frequency deviation range. The input variables include the carbon dioxide flow rate (carbon dioxide mass flow rate) and the grid frequency deviation. It is a key parameter that reflects its dynamic response characteristics. When the system is started or adjusted, the flow changes rapidly, which intuitively shows the operating characteristics of the system. By monitoring the flow, we can not only understand the real-time operation of carbon dioxide, but also accurately judge the state and response speed of the system. In the power system, the frequency deviation Δf refers to the difference between the actual frequency and the rated frequency, which is a key indicator for measuring the stability of the system. The existence of frequency deviation may indicate that there is an imbalance between supply and demand in the system, or that other interference factors affect the normal operation of the system. In order to ensure the stable operation of the power system, the frequency deviation must be closely monitored and corresponding control measures must be taken to maintain the system frequency within the allowable range. The membership function divides the input variable into 4 or 5 fuzzy levels, and different fuzzy levels correspond to different values, so as to more finely describe the system state. The output variable is the carbon dioxide energy storage feedback amount, and the output of the controller is used to adjust the reference power of the energy storage system. The output variable of the controller only includes the carbon dioxide energy storage feedback amount. The membership function divides the output variable into 5 fuzzy levels. The membership function is usually used to describe the strength of the relationship between a variable and a fuzzy set. It is a value from 0 to 1, indicating the degree to which the variable belongs to the fuzzy set, and is used to determine the proportion of the input variable or output variable belonging to a certain region. The composite membership function is designed, and the linear membership function and Gaussian membership function are used to construct a variable description framework with clear boundaries and smooth transitions.

[0054]

[0055] In formulas (5)-(8), μ linear (Δf) is the membership of the input variable (grid frequency deviation) in the fuzzy set using the linear membership function, μ gaussian (Δf) is the membership of the input variable (grid frequency deviation) in the fuzzy set using the Gaussian membership function; is the membership of the input variable (CO2 flow) in the fuzzy set under the linear membership function, is the membership degree f of the input variable (carbon dioxide flow) in the fuzzy set under the Gaussian membership function a ,f b ,f c ,f d ,m a ,m b ,m c ,m d are all constants, related to the designed membership function area, and e is a natural constant.

[0056] Furthermore, the principle of formulating the frequency modulation rule according to the fuzzy level in S3 is that different fuzzy levels correspond to different value sizes. The frequency modulation rule specifies the fuzzy level of the corresponding output variable by combining the fuzzy levels of the two input variables to achieve control, which is reflected in the value size as a positive correlation or negative correlation. S3 specifically includes:

[0057] If the grid frequency deviation is near 0, the carbon dioxide energy storage feedback amount is near 0;

[0058] If the grid frequency deviation is not near 0, the output power change of the carbon dioxide energy storage is positively correlated with the carbon dioxide energy storage feedback amount. This situation includes: if the grid frequency deviation is the same, the carbon dioxide flow rate and the carbon dioxide energy storage feedback amount are negatively correlated. Step S3 is specifically: for the two input quantities of carbon dioxide flow rate and grid frequency deviation, a series of frequency modulation rules are formulated to describe the relationship between input and control output. For the grid frequency deviation, when it is near 0, regardless of the size of the carbon dioxide flow rate, the frequency modulation rules are designed to make the output feedback (carbon dioxide energy storage feedback amount) near 0, reflecting the system's tolerance for slight frequency fluctuations. When the grid frequency deviation is large, the amplitude of the frequency fluctuation is positively correlated with the feedback intensity of the output (carbon dioxide energy storage feedback amount). This means that when the system detects an increase in frequency fluctuations, in order to suppress this instability, the controller will enhance the output feedback to balance the system state and reduce the impact of fluctuations. As for the carbon dioxide flow rate, it reflects to a certain extent the role of carbon dioxide energy storage in the active power balance of the system. Under the same frequency deviation, the larger the carbon dioxide flow rate, the greater the role of the carbon dioxide energy storage system. To prevent the system from overloading, the output feedback (carbon dioxide energy storage feedback amount) should be reduced accordingly to ensure the stability of the carbon dioxide energy storage system.

[0059] Furthermore, the calculation formula of the dynamic frequency response model of the carbon dioxide energy storage system is as follows:

[0060]

[0061] Where F is the frequency modulation rule mapping relationship between input variables and output variables; ΔP out is the controller output; ΔP ref K is the total change of CO2 energy storage reference power; G is the gain coefficient of primary frequency modulation; K S is the gain coefficient of the secondary frequency modulation. F is the frequency modulation rule mapping relationship between input and output; ΔP out is the controller output; ΔP ref K is the total change of CO2 energy storage reference power; Gis the gain coefficient of primary frequency modulation, reflecting the rapid response of the system to frequency; K S is the gain coefficient of secondary frequency regulation, reflecting the system's correction of long-term frequency deviation, and Δf is the grid frequency deviation; is the carbon dioxide flow rate; t is time, t0 is the starting time; Δf(t) is the frequency deviation value at time t; is the integral of the frequency deviation.

[0062] Furthermore, in S5, the dynamic frequency response model of the power grid is obtained by combining the output power change of the steam turbine in the power grid, the output power fluctuation of the wind turbine, and the output power change of the carbon dioxide energy storage with the power grid load; wherein the balance relationship between the steam turbine, the wind turbine, the carbon dioxide energy storage and the load refers to,

[0063] ΔP T +ΔP W +ΔP CCES +ΔP L =0; (11)

[0064] In formula (11), ΔP T is the output power change of the steam turbine (power fluctuation of the steam turbine); ΔP W is the output power fluctuation of the wind turbine (power fluctuation of the wind turbine); ΔP CCES is the output power change of CO2 energy storage (power fluctuation of CO2 energy storage); ΔP L The power fluctuation of the load.

[0065] The power grid dynamic frequency response model refers to:

[0066]

[0067] In formula (12), H T is the inertia constant of the steam turbine; H W is the inertia constant of the wind turbine; H CCES is the inertia constant of carbon dioxide energy storage; D is the damping coefficient; is the rate of change of grid frequency f with time t.

[0068] In a specific implementation of the embodiment of the present invention, the optional values ​​of the above parameters are as follows:

[0069] κ=1.29,c=4,C p =0.82 kJ / kg·K, t = 4,

[0070] H T =3.17s, H W =3s, HCCES =3s.

[0071] Rated power P of steam turbine in power grid T =20MW, wind turbine rated power P W =10MW, load rated power P L =25MW, rated power of carbon dioxide energy storage P CCES =10MW.

[0072] As attached Figure 2 As shown in the figure, the impact of load fluctuation on the grid frequency and the effect of different frequency regulation control strategies are simulated. Figure 2 It can be seen that the frequency modulation method proposed in the present invention can adapt to the dynamic changes of the power grid more accurately, thereby greatly reducing frequency fluctuations and enhancing the frequency regulation capability and overall stability of the power grid.

[0073] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

[0074] On the other hand Figure 3 As shown, the present invention also provides a power grid frequency regulation system considering the dynamic characteristics of carbon dioxide energy storage, including:

[0075] Establishing module 201, for establishing a power model of a carbon dioxide energy storage system;

[0076] A construction module 202 is used to construct a membership function of an input variable and an output variable of a frequency modulation control system, wherein the membership function divides the input variable and the output variable into different fuzzy levels respectively;

[0077] A rule formulation module 203, for formulating frequency modulation rules according to the fuzzy level;

[0078] A first dynamic frequency response model module 204 is used to obtain a dynamic frequency response model of the carbon dioxide energy storage system based on the power model of the carbon dioxide energy storage system; the dynamic frequency response model of the carbon dioxide energy storage system outputs corresponding output variables according to the frequency modulation rule, and the output variables cause the output power of the carbon dioxide energy storage to change;

[0079] The second dynamic response module 205 is used to combine the output power changes of other components in the power grid and the balance relationship between the output power changes of the carbon dioxide energy storage and the power grid load to obtain a power grid dynamic frequency response model;

[0080] The frequency regulation module 206 is used to perform power grid frequency regulation based on the power grid dynamic frequency response model.

[0081] The present invention provides a power grid frequency regulation method and system considering the dynamic characteristics of carbon dioxide energy storage. The method introduces carbon dioxide energy storage and designs frequency regulation rules to participate in power grid frequency regulation, which can effectively respond to real-time changes in power grid frequency, reduce power grid frequency fluctuations, and improve the frequency control effect of the entire power grid; and the proposed method can flexibly respond to various uncertainties in power grid operation, improve the power grid's ability to respond to emergencies, enhance the flexibility and adaptability of frequency regulation control, effectively handle the uncertainty and complexity in power grid frequency changes, and maintain the stability of power grid frequency; at the same time, the use of carbon dioxide energy storage technology is also environmentally friendly, which helps to promote the green transformation of the power system.

Claims

1. A method for power grid frequency regulation considering the dynamic characteristics of carbon dioxide energy storage, characterized in that: include: S1, establish a power model of the CO2 energy storage system; S2, constructing a membership function of an input variable and an output variable of a frequency modulation control system, wherein the membership function divides the input variable and the output variable into different fuzzy levels respectively; S3, formulating frequency modulation rules according to the fuzzy level; S4, based on the power model of the carbon dioxide energy storage system, obtaining a dynamic frequency response model of the carbon dioxide energy storage system; the dynamic frequency response model of the carbon dioxide energy storage system outputs corresponding output variables according to the frequency modulation rule, and the output variables cause the output power of the carbon dioxide energy storage to change; S5, combining the output power change of the steam turbine in the power grid, the output power fluctuation of the wind turbine and the balance relationship between the output power change of the carbon dioxide energy storage and the power grid load, to obtain a power grid dynamic frequency response model; S6, performing grid frequency regulation based on the grid dynamic frequency response model.

2. The method for power grid frequency modulation considering the dynamic characteristics of carbon dioxide energy storage according to claim 1, characterized in that: The S1 includes: obtaining a power model of the carbon dioxide energy storage system according to the physical mechanism inherent in the carbon dioxide energy storage system and the interaction and functional coupling between the components inside the carbon dioxide energy storage system.

3. The method for power grid frequency modulation considering the dynamic characteristics of carbon dioxide energy storage according to claim 2 is characterized in that: The calculation formula of the power model of the carbon dioxide energy storage system is as follows: In the formula, are the j-th compressor power and the k-th turbine power respectively; are the compression ratio of the j-th compressor and the turbine expansion ratio of the k-th turbine respectively; κ is the adiabatic index of carbon dioxide; are the isentropic efficiency of the j-th compressor and the isentropic efficiency of the k-th turbine respectively; is the mass flow rate of carbon dioxide in the compressor, is the mass flow rate of carbon dioxide in the turbine; C p is the specific heat capacity of carbon dioxide at constant pressure; are the inlet temperature of the j-th stage compressor and the inlet temperature of the k-th stage turbine respectively; are the mechanical efficiency of the compressor and the mechanical efficiency of the turbine respectively; P c ,P t are the total power of the compressor and the total power of the turbine respectively; c and t are the total number of compressor stages and the total number of turbine stages respectively.

4. The method for power grid frequency modulation considering the dynamic characteristics of carbon dioxide energy storage according to claim 1, characterized in that: The S2 includes: constructing a membership function of the input variable and the output variable of the frequency modulation control system according to the dynamic response characteristics of the carbon dioxide energy storage and the frequency deviation range of the power grid.

5. The method for power grid frequency regulation considering the dynamic characteristics of carbon dioxide energy storage according to claim 4, characterized in that: The input variables include carbon dioxide flow and grid frequency deviation, and the membership function divides the input variables into 4 or 5 fuzzy levels, and different fuzzy levels correspond to different values.

6. The method for power grid frequency regulation considering the dynamic characteristics of carbon dioxide energy storage according to claim 4, characterized in that: The output variable is the carbon dioxide energy storage feedback amount, and the membership function divides the output variable into five fuzzy levels.

7. The method for power grid frequency regulation considering the dynamic characteristics of carbon dioxide energy storage according to claim 6, characterized in that: The S3 includes: If the grid frequency deviation is near 0, the carbon dioxide energy storage feedback amount is near 0; If the grid frequency deviation is not near 0, the output power change of the carbon dioxide energy storage is positively correlated with the carbon dioxide energy storage feedback amount.

8. The method for power grid frequency regulation considering the dynamic characteristics of carbon dioxide energy storage according to claim 6, characterized in that: If the grid frequency deviation is not near 0, the output power change of the carbon dioxide energy storage is positively correlated with the carbon dioxide energy storage feedback amount, including: if the grid frequency deviation is the same, the carbon dioxide flow rate and the carbon dioxide energy storage feedback amount are negatively correlated.

9. The method for power grid frequency modulation considering the dynamic characteristics of carbon dioxide energy storage according to claim 1, characterized in that: The calculation formula of the dynamic frequency response model of the carbon dioxide energy storage system is as follows: Where F is the frequency modulation rule mapping relationship between input variables and output variables; ΔP out is the controller output; ΔP ref K is the total change of CO2 energy storage reference power; G is the gain coefficient of primary frequency modulation; K S is the gain coefficient of secondary frequency modulation; Δf is the grid frequency deviation; is the carbon dioxide flow rate; t is time, t0 is the starting time; Δf(t) is the frequency deviation value at time t; is the integral of the frequency deviation.

10. A power grid frequency modulation system considering the dynamic characteristics of carbon dioxide energy storage, characterized in that: include: Establishing a module for establishing a power model of a CO2 energy storage system; A construction module, used to construct a membership function of an input variable and an output variable of a frequency modulation control system, wherein the membership function divides the input variable and the output variable into different fuzzy levels respectively; A rule formulation module, used for formulating frequency modulation rules according to the fuzzy level; A first dynamic frequency response model module is used to obtain a dynamic frequency response model of the carbon dioxide energy storage system based on the power model of the carbon dioxide energy storage system; the dynamic frequency response model of the carbon dioxide energy storage system outputs corresponding output variables according to the frequency modulation rule, and the output variables cause the output power of the carbon dioxide energy storage to change; A second dynamic response module is used to combine the output power changes of other components in the power grid and the balance relationship between the output power changes of the carbon dioxide energy storage and the power grid load to obtain a dynamic frequency response model of the power grid; The frequency modulation module is used to perform power grid frequency modulation based on the power grid dynamic frequency response model.

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