An inertia estimation method suitable for large-scale wind farms

Abstract

The application discloses an inertia estimation method suitable for large-scale wind farms, comprising the following steps: obtaining virtual synchronous generator (VSG) operation parameters corresponding to each wind turbine in the wind farm and alternating current (AC) power transmission network parameters, performing power flow calculation to obtain the voltage of each wind turbine VSG and the coupling node of the AC power transmission network; calculating the admittance matrix of the AC power transmission network according to the AC power transmission line parameters, and calculating the eigenvalue of the admittance matrix according to the admittance matrix; and determining the inertia of the entire wind farm according to the eigenvalue of the admittance matrix and the inertia constant of the VSG. The application considers the coupling effect of the AC network of the wind farm to calculate the inertia of the entire wind farm under the VSG control mode, thereby reducing the inertia calculation error of the wind farm, especially the large-scale wind farm.

Description

Technical Field

[0001] This invention relates to the field of wind turbine grid connection technology, and in particular to an inertia estimation method applicable to large-scale wind farms. Background Technology

[0002] With the vigorous development of clean energy, sustainable development strategic resources, mainly wind power and photovoltaics, are being utilized. As a result, wind farms are rapidly expanding in scale to connect to the power system with greater capacity. The large number of wind turbines will lead to the grid-connected operation of a large number of power electronic devices. If the grid-connected wind turbine VSC adopts traditional droop control, it cannot provide rotational inertia for the power system. The wind farm will greatly reduce the inertia of the power system and weaken the frequency stability of the power system.

[0003] Currently, numerous studies have shown that using virtual synchronous generators (VSGs) for grid-connected wind turbine control (VSCs) will increase the inertia of wind turbines, thereby providing voltage and frequency support. However, current research typically calculates the inertia of individual VSGs, rather than simply summing the inertia of the entire wind farm, leading to significant errors in the wind farm's inertia calculation. Summary of the Invention

[0004] The purpose of this invention is to provide an inertia estimation method suitable for large-scale wind farms. This method considers the coupling effect of the wind farm's AC network when calculating the inertia of the entire wind farm under VSG control mode, thereby reducing the inertia calculation error, especially for large-scale wind farms. The technical solution adopted by this invention is as follows.

[0005] On the one hand, the present invention provides an inertia estimation method applicable to large-scale wind farms, comprising:

[0006] Obtain the virtual synchronous machine (VSG) operating parameters and AC transmission network parameters for each wind turbine in the wind farm;

[0007] Power flow calculations are performed based on the VSG operating parameters and AC transmission network parameters to obtain the voltage of the VSG and AC transmission network coupling node corresponding to each wind turbine.

[0008] Calculate the AC transmission network susceptance matrix based on the AC transmission line parameters;

[0009] Calculate the eigenvalues ​​of the susceptance matrix based on the susceptance matrix of the AC transmission network;

[0010] The inertia of the entire wind farm is determined based on the eigenvalues ​​of the susceptance matrix and the inertia constant of the VSG.

[0011] Optionally, the VSG operating parameters include the wind turbine output power and the VSG inertia constant, and the AC transmission network parameters include the reactance parameters of the AC transmission line and the coupling point voltage between the AC transmission network and the external power grid.

[0012] The process of calculating power flow based on VSG operating parameters and AC transmission network parameters to obtain the voltage of the VSG-AC transmission network coupling node corresponding to each wind turbine includes:

[0013] Based on the wind turbine output power, VSG inertia constant, AC transmission line reactance parameters, and coupling point voltage between the AC transmission network and the external power grid, the Newton-Layer method is used for power flow calculation to obtain the voltage of the coupling node between the VSG and the AC transmission network for each wind turbine. The VSG employs constant power control; based on this control method and the acquired data, the Newton-Layer method for power flow calculation can refer to existing technologies.

[0014] Optionally, calculating the AC transmission network susceptance matrix based on the AC transmission line parameters includes:

[0015] Substituting the reactances of each transmission line in the AC transmission network, as well as the reactances of the coupling lines between the AC transmission network and the external power grid, into the following formula, we obtain the AC transmission network susceptance matrix Y:

[0016]

[0017] In the formula: N is the number of VSG wind turbines in the wind farm, x1-x N Let x be the reactance of N transmission lines in an AC transmission network. L Reactance on the coupling line between the AC transmission network and the external power grid.

[0018] Optionally, the eigenvalues ​​of the susceptance matrix are calculated based on the susceptance matrix Y of the AC transmission network, according to the following formula:

[0019] P -1 YP = diag(ρ) i )

[0020] In the formula, ρ i Let represent the eigenvalue of the susceptance matrix corresponding to the i-th transmission line, diag(·) denotes a diagonal matrix, and P is an orthogonal matrix.

[0021] Optionally, the step of using the eigenvalue ρ of the susceptance matrix... i Calculate the inertia constant H of the VSG and the inertia J of the entire wind farm. all ,include:

[0022] Based on the voltage of the coupling node between the VSG and the AC transmission network corresponding to each wind turbine, determine the amplitude V of the voltage at the output port of each VSG.k0 ;

[0023] According to ρ i H and V k0 The inertia of the entire wind farm can be calculated using the following formula:

[0024]

[0025] In the formula, ω0=2πf represents the power frequency angular velocity, and f is the power frequency of the AC power grid.

[0026] Secondly, the present invention discloses an inertia estimation device suitable for large-scale wind farms, comprising:

[0027] The data acquisition module is configured to acquire the operating parameters of the virtual synchronous generator (VSG) for each wind turbine in the wind farm, as well as the parameters of the AC transmission network.

[0028] The VSG output voltage calculation module is configured to perform power flow calculations based on the VSG operating parameters and AC transmission network parameters to obtain the voltage of the VSG and AC transmission network coupling node corresponding to each wind turbine.

[0029] The susceptance matrix calculation module is configured to calculate the AC transmission network susceptance matrix based on the AC transmission line parameters;

[0030] The susceptance matrix eigenvalue calculation module is configured to calculate the eigenvalues ​​of the susceptance matrix based on the susceptance matrix of the AC transmission network.

[0031] In addition, an inertia determination module is configured to determine the inertia of the entire wind farm based on the eigenvalues ​​of the susceptance matrix and the inertia constant of the VSG.

[0032] Optionally, the susceptance matrix calculation module calculates the AC transmission network susceptance matrix based on the AC transmission line parameters, including:

[0033] Substituting the reactances of each transmission line in the AC transmission network, as well as the reactances of the coupling lines between the AC transmission network and the external power grid, into the following formula, we obtain the AC transmission network susceptance matrix Y:

[0034]

[0035] In the formula: N is the number of VSG wind turbines in the wind farm, x1-x N Let x be the reactance of N transmission lines in an AC transmission network. L Reactance on the coupling line between the AC transmission network and the external power grid.

[0036] Optionally, the susceptance matrix eigenvalue calculation module calculates the susceptance matrix eigenvalues ​​based on the AC transmission network susceptance matrix Y using the following formula:

[0037] P -1 YP = diag(ρ) i )

[0038] In the formula, ρ i Let represent the eigenvalue of the susceptance matrix corresponding to the i-th transmission line, diag(·) denotes a diagonal matrix, and P is an orthogonal matrix.

[0039] Optionally, the inertia determination module determines the inertia based on the eigenvalue ρ of the susceptance matrix. i Calculate the inertia constant H of the VSG and the inertia J of the entire wind farm. all ,include:

[0040] Based on the voltage of the coupling node between the VSG and the AC transmission network corresponding to each wind turbine, determine the amplitude V of the voltage at the output port of each VSG. k0 ;

[0041] According to ρ i H and V k0 The inertia of the entire wind farm can be calculated using the following formula:

[0042]

[0043] In the formula, ω0=2πf represents the power frequency angular velocity, and f is the power frequency of the AC power grid.

[0044] Thirdly, the present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements an inertia estimation method applicable to large-scale wind farms as described in the first aspect.

[0045] Beneficial effects

[0046] The inertia estimation method for large-scale wind farms of this invention can calculate the inertia of the entire wind farm containing multiple wind turbines. Furthermore, this invention considers the coupling effect of the wind farm's AC network, extracting the susceptance matrix eigenvalues ​​from the AC transmission network at the VSG outlet of the wind turbines. Based on the extracted susceptance matrix eigenvalues, the inertia constant of the VSG, the amplitude of the VSG output port voltage, and the power frequency angular velocity, the inertia corresponding to each wind turbine is calculated. Then, the inertia of the entire wind farm under VSG control mode is determined by summation. This reduces the inertia calculation error of wind farms, especially large-scale wind farms, providing reliable data references for precise VSG control, thereby improving the control reliability of the virtual synchronous machine VSG and enhancing the stability of the wind turbine grid-connected system. Attached Figure Description

[0047] Figure 1 The diagram shown is a schematic of the wind farm grid connection system.

[0048] Figure 2 The diagram shows the equivalent structure of a wind farm grid-connected system containing three VSGs.

[0049] Figure 3 The diagram shown is a schematic of the VSG control model.

[0050] Figure 4 The diagram shown is a flowchart illustrating an inertia estimation method applicable to large-scale wind farms in one embodiment of the present invention. Detailed Implementation

[0051] The technical solution will be described below with reference to the accompanying drawings and specific embodiments.

[0052] The technical concept of this invention is as follows: considering the coupling effect of the AC network of the wind farm, the characteristic value of the susceptance matrix is ​​extracted from the AC transmission network of the VSG outlet of the wind turbine, and the inertia corresponding to each wind turbine is determined based on the characteristic value of the susceptance matrix. Then, the inertia of the entire wind farm under the VSG control mode is calculated to reduce the inertia calculation error of the wind farm.

[0053] Example 1

[0054] This embodiment introduces an inertia estimation method applicable to large-scale wind farms. Figure 1 and Figure 2 The diagram shows a wind farm grid connection system. This system includes N wind farms with VSG output power; VSG stands for DC / DC converter.

[0055] refer to Figure 4 As shown, the method in this embodiment includes:

[0056] Obtain the virtual synchronous machine (VSG) operating parameters and AC transmission network parameters for each wind turbine in the wind farm;

[0057] Power flow calculations are performed based on the VSG operating parameters and AC transmission network parameters to obtain the voltage of the VSG and AC transmission network coupling node corresponding to each wind turbine.

[0058] Calculate the AC transmission network susceptance matrix based on the AC transmission line parameters;

[0059] Calculate the eigenvalues ​​of the susceptance matrix based on the susceptance matrix of the AC transmission network;

[0060] The inertia of the entire wind farm is determined based on the eigenvalues ​​of the susceptance matrix and the inertia constant of the VSG.

[0061] The method in this embodiment specifically involves the following contents.

[0062] To better analyze the influencing factors of the inertia of the entire wind farm, this embodiment first... Figure 1The AC transmission network in the grid-connected system shown is equivalent to: Figure 2 As shown, here it is assumed Figure 1 N is 3. Figure 1 In the middle, P k For the output power of the k-th wind turbine, VSG uses constant power control, based on P k The reactance parameters of each transmission line in the equivalent AC transmission network are then used to calculate the power flow using the Newton-Laurel method, yielding the voltage at each VSG coupling node with the AC system. The amplitude can be directly used to calculate the inertia of a wind farm; reference Figure 2 , For wind farms via transmission line x L Coupling point with external power system.

[0063] like Figure 3 The control model of VSG is given, for Figure 1 The kth VSG in the series: VSG reactive and active baseline values; P k Q k For the active and reactive power output of VSG; ω pk ω0 represents the frequency of the VSG equivalent internal potential and the AC power grid reference frequency; θ k denoted as VSG voltage phase angle; H and D are the inertia constant and damping coefficient of the virtual synchronous machine, respectively; and K is the gain coefficient of the reactive power controller.

[0064] Due to the reactive power Q output of the wind turbine k If ≈0, and the impact of reactive power on frequency is ignored, then the control model for the k-th VSG is:

[0065]

[0066] The relationship between output power and voltage / current is as follows:

[0067]

[0068] In equation (2), V xk V yk with I xk I yk Let V represent the output voltage and current of the VSG in the xy coordinate system. Since the influence of reactive power is neglected, the dynamic change of the VSG output voltage ΔV is... k =0.

[0069] Linearizing equations (1) and (2) yields the state-space model of the k-th VSG:

[0070]

[0071] In equation (3), △Vk =[△V xk △V yk ] T , △I k =[△I xk △I yk ] T , △X k =[△ω pk △θ k ] T △ represents the incremental change of the variable.

[0072] Where the matrix is: The subscript 0 indicates the steady-state value.

[0073] When calculating the inertia of a wind farm, it can be assumed that the differences between the various wind turbine models are relatively small, that is:

[0074]

[0075] In the formula: A s B s C s These represent the state matrix, input matrix, and output matrix of the baseline model for all wind turbines. Furthermore, the state matrix, input matrix, and output matrix are identical across different wind turbine baseline models, all being A. s B s C s .

[0076] The linearized spatial model of the entire wind farm is obtained from equations (3) and (4) above, as follows:

[0077]

[0078] In the formula: △X p , △V p , △I p Let these represent the state changes of the entire wind farm, the voltage changes of all VSG coupling nodes with the AC transmission network, and the current changes, respectively, and we have:

[0079]

[0080] In the formula, diag[·] represents a diagonal matrix.

[0081] Ignoring the resistance of the AC transmission network of the wind farm, the following relationship exists based on the susceptance matrix:

[0082]

[0083] In the formula: The product of Kronecker; Y is the susceptance matrix of the wind farm. The susceptance matrix Y is a real symmetric matrix. Define an orthogonal matrix P, then the eigenvalues ​​of the susceptance matrix are:

[0084] P -1 YP = diag(ρ) i (7)

[0085] In the formula, diag(·) represents a diagonal matrix, ρ i Let be the element in the diagonal matrix, representing the eigenvalue of the susceptance matrix corresponding to the i-th transmission line.

[0086] Substituting equations (6) and (7) into equation (5), the wind farm is equivalent to N subsystems. For the i-th subsystem A... wi , can be represented as:

[0087]

[0088] In the formula, V k0 The amplitude of the voltage at each VSG output port can be determined based on the voltage VG at the coupling node between the VSG of each wind turbine and the AC transmission network. k It is confirmed that the fundamentals will remain unchanged.

[0089] Equation (8) only performs a linear transformation on the original wind farm, without changing the calculation of its inertia. Equation (8) can be transformed into a second-order expression as follows:

[0090]

[0091] In the formula, s represents the Laplace operator.

[0092] Therefore, equation (9) can be simplified to:

[0093]

[0094] In traditional wind farm inertia calculations, A is directly used s The calculation, its second-order expression is:

[0095] 2Hs 2 +Ds=0 (11)

[0096] Comparing formula (10) derived from the technical concept of this invention with the traditional formula (11), the differences can be seen. Traditional inertia calculations ignore this difference, which leads to errors in inertia calculation. This invention takes this difference into account to compensate for the shortcomings of traditional inertia calculations.

[0097] According to equation (7), it can be seen that changes in the AC transmission network of the wind farm will alter ρ. iThis changes the inertia of the VSG. Therefore, in this embodiment, the inertia of the entire wind farm is calculated by adding the inertia of the N equivalent systems in equation (10), as follows:

[0098]

[0099] In the formula, ω0=2πf represents the power frequency angular velocity, and f is the power frequency of the AC power grid.

[0100] In this embodiment, according to equation (7), the calculation of the eigenvalues ​​of the susceptance matrix first requires calculating the susceptance matrix of the AC transmission network. Based on the AC transmission line parameters, the reactance of each transmission line in the AC transmission network and the reactance on the coupling line between the AC transmission network and the external power grid are substituted into the following formula to obtain the AC transmission network susceptance matrix Y:

[0101]

[0102] In the formula: N is the number of VSG wind turbines in the wind farm, x1-x N Let x be the reactance of N transmission lines in an AC transmission network. L Reactance on the coupling line between the AC transmission network and the external power grid.

[0103] for Figure 2 The grid-connected structure of the wind farm, which includes 3 VSG wind turbines, has the following AC transmission network susceptance matrix:

[0104]

[0105] After substituting the reactance parameters of each line into the susceptance matrix Y of the AC transmission network, the eigenvalue ρ of the susceptance matrix corresponding to each transmission line can be obtained according to equation (7). i That is, ρ1~ρ N Then ρ1~ρ N Substituting the inertia constant H of VSG into formula (12), the inertia J of the entire wind farm can be calculated. all .

[0106] for Figure 2 The grid connection mechanism of the wind turbine shown assumes that the line reactance parameters of the AC transmission network, ignoring resistance, are: x1 = 0.02, x2 = 0.024, x3 = 0.015, x... L =0.05; The external power system coupling node is: This is the system's equilibrium node. The output power of each of the three VSGs is P = 0.4 pu, the inertia constant of each VSG is H = 3, and the damping coefficient is D = 1.

[0107] First, based on the Newton-Layer power flow calculation, the voltages at each VSG output port can be obtained:

[0108] Substituting the line reactance parameters into equation (13), the susceptance matrix Y of the AC transmission network is obtained as follows:

[0109]

[0110] Based on Y, the eigenvalues ​​of the susceptance matrix are calculated using equation (7): ρ1 = 58.79, ρ2 = 44.97, ρ3 ​​= 5.89. Substituting these values ​​into equation (12), the inertia of the entire wind farm is calculated as follows:

[0111]

[0112] In summary, the inertia estimation method of this invention can be used to quickly calculate the inertia of large-scale wind farms under VSG control mode, reduce the inertia calculation error of wind farms, especially large-scale wind farms, provide reliable data for wind farm inertia detection, and further improve the control reliability of virtual synchronous machines (VSGs) and the stability of wind turbine grid connection system operation.

[0113] Example 2

[0114] Based on the same inventive concept as Embodiment 1, this embodiment introduces an inertia estimation device suitable for large-scale wind farms, comprising:

[0115] The data acquisition module is configured to acquire the operating parameters of the virtual synchronous generator (VSG) for each wind turbine in the wind farm, as well as the parameters of the AC transmission network.

[0116] The VSG output voltage calculation module is configured to perform power flow calculations based on the VSG operating parameters and AC transmission network parameters to obtain the voltage of the VSG and AC transmission network coupling node corresponding to each wind turbine.

[0117] The susceptance matrix calculation module is configured to calculate the AC transmission network susceptance matrix based on the AC transmission line parameters;

[0118] The susceptance matrix eigenvalue calculation module is configured to calculate the eigenvalues ​​of the susceptance matrix based on the susceptance matrix of the AC transmission network.

[0119] In addition, an inertia determination module is configured to determine the inertia of the entire wind farm based on the eigenvalues ​​of the susceptance matrix and the inertia constant of the VSG.

[0120] The specific implementation of each of the above functional modules is described in reference to the relevant content of Implementation Example 1, and will not be repeated here.

[0121] Example 3

[0122] Based on the same inventive concept as Embodiments 1 and 2, this embodiment introduces a computer-readable storage medium storing a computer program that, when executed by a processor, implements a virtual inertial control method for a permanent magnet synchronous wind turbine as described in Embodiment 1.

[0123] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application 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.

[0124] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. 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... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0125] 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.

[0126] 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.

[0127] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims. All of these forms are within the protection scope of the present invention.

Claims

1. A method for estimating the inertia of large-scale wind farms, characterized in that, include: Obtain the virtual synchronous machine (VSG) operating parameters and AC transmission network parameters for each wind turbine in the wind farm; Power flow calculations are performed based on the VSG operating parameters and AC transmission network parameters to obtain the voltage of the VSG and AC transmission network coupling node corresponding to each wind turbine. Calculate the AC transmission network susceptance matrix based on the AC transmission network parameters; Calculate the eigenvalues ​​of the susceptance matrix based on the susceptance matrix of the AC transmission network; Based on the eigenvalues ​​of the susceptance matrix, the inertia constant of the VSG, and the voltage of the coupling node between the VSG and the AC transmission network for each wind turbine, the inertia of the entire wind farm is determined, including: Based on the voltage of the coupling node between the VSG and the AC transmission network corresponding to each wind turbine, determine the amplitude of the voltage at the output port of each VSG. ; Based on the eigenvalues ​​of the susceptance matrix The inertia constant of VSG and The inertia of the entire wind farm can be calculated using the following formula: In the formula, Let represent the power frequency angular velocity, and N be the number of VSGs (Variable Sensing Grids) for wind turbines in the wind farm. Then, the number of equivalent subsystems in the wind farm, divided according to the VSGs of the wind turbines, is N. It is the power frequency of the AC power grid.

2. The method according to claim 1, characterized in that, The VSG operating parameters include the wind turbine output power and the VSG inertia constant, and the AC transmission network parameters include the reactance parameters of the AC transmission lines and the coupling point voltage between the AC transmission network and the external power grid. The process of calculating power flow based on VSG operating parameters and AC transmission network parameters to obtain the voltage of the VSG-AC transmission network coupling node corresponding to each wind turbine includes: Based on the wind turbine output power, VSG inertia constant, AC transmission line reactance parameters, and coupling point voltage between the AC transmission network and the external power grid, the Newton-Layer method is used to perform power flow calculations to obtain the voltage of the VSG coupling node between each wind turbine and the AC transmission network.

3. The method according to claim 1, characterized in that, Calculating the AC transmission network susceptance matrix based on the AC transmission network parameters includes: Substituting the reactances of each transmission line in the AC transmission network, as well as the reactances of the coupling lines between the AC transmission network and the external power grid, into the following formula, we obtain the susceptance matrix of the AC transmission network. : In the formula: - Let N be the reactances of N transmission lines in an AC transmission network. Reactance on the coupling line between the AC transmission network and the external power grid.

4. The method according to claim 1, characterized in that, The susceptance matrix of the AC transmission network Calculate the eigenvalues ​​of the susceptance matrix using the following formula: In the formula, Indicates the first The eigenvalues ​​of the susceptance matrix corresponding to each transmission line. Represents a diagonal matrix. It is an orthogonal matrix.

5. An inertia estimation device suitable for large-scale wind farms, characterized in that, include: The data acquisition module is configured to acquire the operating parameters of the virtual synchronous generator (VSG) for each wind turbine in the wind farm, as well as the parameters of the AC transmission network. The VSG output voltage calculation module is configured to perform power flow calculations based on the VSG operating parameters and AC transmission network parameters to obtain the voltage of the VSG and AC transmission network coupling node corresponding to each wind turbine. The susceptance matrix calculation module is configured to calculate the AC transmission network susceptance matrix based on the AC transmission network parameters; The susceptance matrix eigenvalue calculation module is configured to calculate the eigenvalues ​​of the susceptance matrix based on the susceptance matrix of the AC transmission network. And, an inertia determination module is configured to determine the inertia of the entire wind farm based on the eigenvalues ​​of the susceptance matrix, the inertia constant of the VSG, and the voltage of the coupling node between the VSG and the AC transmission network for each wind turbine, including: Based on the voltage of the coupling node between the VSG and the AC transmission network corresponding to each wind turbine, determine the amplitude of the voltage at the output port of each VSG. ; Based on the eigenvalues ​​of the susceptance matrix The inertia constant of VSG and The inertia of the entire wind farm can be calculated using the following formula: In the formula, Let represent the power frequency angular velocity, and N be the number of VSGs (Variable Sensing Grids) for wind turbines in the wind farm. Then, the number of equivalent subsystems in the wind farm, divided according to the VSGs of the wind turbines, is N. It is the power frequency of the AC power grid.

6. The inertia estimation device for large-scale wind farms according to claim 5, characterized in that, The susceptance matrix calculation module calculates the AC transmission network susceptance matrix based on the AC transmission network parameters, including: Substituting the reactances of each transmission line in the AC transmission network, as well as the reactances of the coupling lines between the AC transmission network and the external power grid, into the following formula, we obtain the susceptance matrix of the AC transmission network. : In the formula: - Let N be the reactances of N transmission lines in an AC transmission network. Reactance on the coupling line between the AC transmission network and the external power grid.

7. The inertia estimation device for large-scale wind farms according to claim 5, characterized in that, The susceptance matrix eigenvalue calculation module calculates the susceptance matrix of the AC transmission network. The eigenvalues ​​of the susceptance matrix are calculated using the following formula: In the formula, Indicates the first The eigenvalues ​​of the susceptance matrix corresponding to each transmission line. Represents a diagonal matrix. It is an orthogonal matrix.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that, When executed by a processor, the computer program implements an inertia estimation method applicable to large-scale wind farms as described in any one of claims 1-4.

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