A method and device for frequency domain dynamic equivalence modeling of a doubly-fed wind farm based on real-time data

Abstract

This application proposes a frequency domain dynamic equivalent modeling method and apparatus for doubly-fed wind farms based on real-time data. The method includes: for a wind farm with k doubly-fed wind turbines, calculating the equivalent rotational speed coefficient η of the kth doubly-fed wind turbine. k ; Calculate the state coefficient STA of the k-th doubly-fed wind turbine. k According to the rotational speed equivalent coefficient η k and state coefficient STA k Calculate the equivalent impedance Z of the k-th doubly-fed wind turbine. Gk (s); based on the equivalent impedance Z Gk (s) The characteristics in the frequency domain are used to determine the stability of the wind farm in the frequency domain. This invention can efficiently and quickly obtain the equivalent impedance of a doubly-fed induction generator (DFIG) wind farm at various time periods, and the results provide an important basis for the analysis of the impact of wind farm grid connection.

Description

Technical Field

[0001] This invention relates to the field of power system analysis technology, and in particular to a method and apparatus for dynamic equivalent modeling of doubly fed wind farms in the frequency domain based on real-time data. Background Technology

[0002] With the successive completion of wind power bases with a capacity of tens of millions of kilowatts, the centralized grid connection of large-scale wind turbines poses a significant challenge to the safe and stable operation of the power system. Constructing equivalent models that accurately describe the overall characteristics of large-scale wind farms is fundamental to the study of the operation and control of high-proportion wind power systems. The equivalent modeling of detailed wind farm models is a crucial aspect of dynamic equivalent modeling of wind farms. Dynamic equivalent modeling of wind farms has become an important research method for analyzing the grid connection characteristics of large-scale wind farms. Currently, research on the characteristics of a single doubly-fed induction generator (DFIG) is extensive, but there is still little discussion on the overall characteristics of the wind farm. Due to the significant differences in operation between wind turbines, multi-machine equivalent models can more fully reflect the dynamic characteristics of wind farms. Summary of the Invention

[0003] The present invention aims to at least partially solve one of the technical problems in the related art.

[0004] Therefore, one objective of this invention is to propose a wind farm frequency domain dynamic equivalent modeling method based on real-time data. This method can efficiently and accurately obtain the impedance characteristics of wind power systems over a wide frequency range, providing an important basis for the impact analysis of large-scale wind turbine grid connection.

[0005] The second objective of this invention is to propose a frequency domain dynamic equivalent modeling of wind farms based on real-time data.

[0006] To achieve the above objectives, a first aspect of the present invention proposes a frequency domain dynamic equivalent modeling method for wind farms based on real-time data, comprising: for a wind farm with k doubly-fed induction generator (DFIG) wind turbines,

[0007] S1, calculate the equivalent speed coefficient of the k-th doubly-fed wind turbine generator, where the equivalent speed coefficient is η. k ;

[0008] S2, calculate the state coefficient of the k-th doubly-fed wind turbine, the state coefficient being STA. k ;

[0009] S3, based on the aforementioned rotational speed equivalent coefficient η k and the state coefficient STA k Calculate the equivalent impedance Z of the k-th doubly-fed wind turbine. Gk (s);

[0010] S4, based on the equivalent impedance Z Gk(s) Determine the stability of the wind farm in the frequency domain based on its characteristics; wherein, the equivalent impedance Z Gk (s) The features in the frequency domain include the equivalent real part and the equivalent imaginary part at different frequencies.

[0011] In addition, the wind farm frequency domain dynamic equivalent modeling method based on real-time data according to the above embodiments of the present invention may have the following additional technical features:

[0012] Furthermore, in one embodiment of the present invention, the rotational speed equivalent coefficient η k Calculated using the following formula:

[0013]

[0014] Among them, v k (t+Δt) represents the wind speed of the k-th wind turbine at time t+Δt, n represents the nth sampling, and i represents the i-th time.

[0015] Furthermore, in one embodiment of the present invention, the state coefficient STA k Calculated using the following formula:

[0016] At time t+Δt, STA k :

[0017]

[0018] in,

[0019]

[0020] When the wind turbine is connected to the grid at time t-gΔt, s(t-gΔt) = 1; when the wind turbine is disconnected at time t-gΔt, s(t-gΔt) = 0.

[0021] Furthermore, in one embodiment of the present invention, the equivalent impedance Z Gk (s) is calculated using the following formula:

[0022] Equivalent impedance of k wind turbines in the wind field:

[0023] Z eqk (s)=Z eq(k-1) (s) / / Z Gk (s)+Z Tk (s)+Z Lk (s);

[0024] Where, at time t+Δt

[0025]

[0026] Among them, ZTk (s)=R Tk (s)+jX Tk (s) represents the equivalent transformer impedance of the k-th wind turbine, R Tk (s) represents the real part of the equivalent box transformer impedance, X Tk (s) represents the imaginary part of the equivalent box transformer impedance; Z Lk (s)=R Lk (s)+jX Lk (s) represents the equivalent line impedance of the k-th wind turbine, R Lk (s) represents the real part of the equivalent line impedance, X Tk (s) represents the imaginary part of the equivalent line impedance.

[0027] Furthermore, in one embodiment of the present invention, the method further includes:

[0028] α(T) = [cos(2πfT),…,cos(2nπfT)] is a phasor matrix; θ k =[θ k1 … θ kn [ ] is the coefficient matrix to be fitted for k wind turbine units;

[0029] By solving θ k =[θ k1 … θ kn To find the minimum value of Q:

[0030]

[0031] Based on the solution θ k =[θ k1 … θ kn ],

[0032] Result: v k (t+Δt)=θ k α(t+Δt) T .

[0033] Furthermore, in one embodiment of the present invention, the equivalent impedance of the wind field for the k wind turbines is calculated using the following formula:

[0034] Let the equivalent impedance of the wind field for one wind turbine be:

[0035] Z eq1 (s)=Z G1 (s)+Z T1 (s)+Z L1 (s)

[0036] Equivalent impedance of the wind farm for 2 wind turbines:

[0037] Z eq2 (s)=Zeq1 (s) / / Z G2 (s)+Z T2 (s)+Z L2 (s)

[0038] Equivalent impedance of the wind farm for the 3 wind turbines:

[0039] Z eq3 (s)=Z eq2 (s) / / Z G2 (s)+Z T2 (s)+Z L2 (s)

[0040] The equivalent impedance of the wind field for the k wind turbines:

[0041] Z eqk (s)=Z eq(k-1) (s) / / Z Gk (s)+Z Tk (s)+Z Lk (s).

[0042] The frequency domain dynamic equivalent modeling method for doubly-fed induction generator (DFIG) wind farms based on real-time data in this embodiment of the invention calculates the equivalent rotational speed coefficient of the k-th DFIG wind turbine for a wind farm with k DFIG wind turbines; calculates the state coefficient of the k-th DFIG wind turbine; calculates the equivalent impedance of the k-th DFIG wind turbine based on the equivalent rotational speed coefficient and the state coefficient; and calculates the equivalent impedance Z based on the equivalent impedance Z. Gk (s) Determine the stability of the wind farm in the frequency domain based on its characteristics; where the equivalent impedance Z Gk (s) The frequency domain features include the equivalent real part and the equivalent imaginary part at different frequencies. This invention can efficiently and quickly obtain the equivalent impedance of a doubly-fed wind farm at various time periods, and the results provide an important basis for the impact analysis of wind farm grid connection.

[0043] To achieve the above objectives, a second aspect of the present invention provides a frequency domain dynamic equivalent modeling device for doubly-fed wind farms based on real-time data, comprising:

[0044] For a wind farm with k doubly fed wind turbine units

[0045] The rotational speed equivalent coefficient module is used to calculate the rotational speed equivalent coefficient of the k-th doubly-fed wind turbine, where the rotational speed equivalent coefficient is η. k ;

[0046] The state coefficient module is used to calculate the state coefficient of the k-th doubly-fed wind turbine, wherein the state coefficient is STA. k ;

[0047] The equivalent impedance module is used to determine the equivalent rotational speed coefficient η. kand the state coefficient STA k Calculate the equivalent impedance Z of the k-th doubly-fed wind turbine. Gk (s);

[0048] The judgment module is used to determine the equivalent impedance Z based on the given impedance Z. Gk (s) Determine the stability of the wind farm in the frequency domain based on its characteristics; wherein, the equivalent impedance Z Gk (s) The features in the frequency domain include the equivalent real part and the equivalent imaginary part at different frequencies.

[0049] The frequency domain dynamic equivalent modeling device for doubly-fed induction generator (DFIG) wind farms based on real-time data in this embodiment of the invention calculates the equivalent rotational speed coefficient of the k-th DFIG wind turbine for a wind farm with k DFIG wind turbines; calculates the state coefficient of the k-th DFIG wind turbine; calculates the equivalent impedance of the k-th DFIG wind turbine based on the equivalent rotational speed coefficient and the state coefficient; and a judgment module is used to determine the equivalent impedance Z. Gk (s) Determine the stability of the wind farm in the frequency domain based on its characteristics; where the equivalent impedance Z Gk (s) The frequency domain features include the equivalent real part and the equivalent imaginary part at different frequencies. This invention can efficiently and quickly obtain the equivalent impedance of a doubly-fed wind farm at various time periods, and the results provide an important basis for the impact analysis of wind farm grid connection.

[0050] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0051] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein:

[0052] Figure 1 This is a flowchart of a frequency domain dynamic equivalent modeling method for doubly fed wind farms based on real-time data, according to an embodiment of the present invention.

[0053] Figure 2 This is a schematic diagram of a doubly fed wind farm frequency domain dynamic equivalent modeling device based on real-time data according to an embodiment of the present invention. Detailed Implementation

[0054] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0055] The following describes, with reference to the accompanying drawings, a method and apparatus for dynamic equivalent modeling of doubly fed wind farms in the frequency domain based on real-time data, according to embodiments of the present invention.

[0056] The frequency domain dynamic equivalent modeling method for doubly fed wind farms based on real-time data in this application fully considers the real-time dynamic characteristics of a single generator, thereby forming an equivalent model of the entire wind farm. Compared with traditional methods, considering the huge differences in operation between wind turbines, the multi-machine equivalent model can more fully reflect the dynamic characteristics of the wind farm.

[0057] Figure 1 The flowchart illustrates a frequency domain dynamic equivalent modeling method for doubly fed wind farms based on real-time data, as provided in an embodiment of the present invention.

[0058] like Figure 1 As shown, the method includes: for a wind farm with k doubly-fed induction generators,

[0059] Step S1: Calculate the equivalent speed coefficient of the k-th doubly-fed wind turbine, where the equivalent speed coefficient is η. k .

[0060] Specifically, for a wind farm with k doubly-fed induction generator (DFIG) wind turbines, the equivalent speed coefficient η of the kth wind turbine is... k

[0061]

[0062] Where: v k (t+Δt) represents the wind speed of the k-th wind turbine at time t+Δt, n represents the nth sampling, and i represents the i-th time.

[0063] α(T) = [cos(2πfT),…,cos(2nπfT)] is a phasor matrix.

[0064] θ k =[θ k1 … θ kn ] is the coefficient matrix to be fitted for k wind turbine units.

[0065] By solving θ k =[θ k1 … θ kn To find the minimum value of Q:

[0066]

[0067] Based on the solution θ k =[θ k1 …θ kn ],

[0068] Result: v k (t+Δt)=θk α(t+Δt) T .

[0069] Step S2: Calculate the state coefficient of the k-th doubly-fed wind turbine, denoted as STA. k .

[0070] It is understandable that for a wind farm with k doubly-fed induction generator (DFIG) wind turbines, the state coefficient STA of the kth wind turbine is... k At time t+Δt, the state coefficient STA of the k-th wind turbine is... k :

[0071]

[0072] in,

[0073]

[0074] When the wind turbine is connected to the grid at time t-gΔt, s(t-gΔt) = 1; when the wind turbine is disconnected at time t-gΔt, s(t-gΔt) = 0.

[0075] Step S3, based on the rotational speed equivalent coefficient η k and state coefficient STA k Calculate the equivalent impedance Z of the k-th doubly-fed wind turbine. Gk (s).

[0076] Understandable,

[0077] Let the equivalent impedance of the wind field for one wind turbine be:

[0078] Z eq1 (s)=Z G1 (s)+Z T1 (s)+Z L1 (s)

[0079] Equivalent impedance of the wind farm for 2 wind turbines:

[0080] Z eq2 (s)=Z eq1 (s) / / Z G2 (s)+Z T2 (s)+Z L2 (s)

[0081] Equivalent impedance of the wind farm for the 3 wind turbines:

[0082] Z eq3 (s)=Z eq2 (s) / / Z G2 (s)+Z T2 (s)+Z L2 (s)

[0083] Equivalent impedance of k wind turbines in the wind field:

[0084] Z eqk (s)=Z eq(k-1) (s) / / Z Gk (s)+Z Tk (s)+Z Lk (s)

[0085] Wherein, at time t+Δt, the impedance formula for the k-th doubly-fed wind turbine is:

[0086]

[0087] Where s=jω, Z Gk (s) represents the equivalent impedance of the k-th wind turbine at time t+Δt; Z Tk (s)=R Tk (s)+jX Tk (s) represents the equivalent transformer impedance of the k-th wind turbine, R Tk (s) represents the real part of the equivalent box transformer impedance, X Tk (s) represents the imaginary part of the equivalent box transformer impedance; Z Lk (s)=R Lk (s)+jX Lk (s) represents the equivalent line impedance of the k-th wind turbine, R Lk (s) represents the real part of the equivalent line impedance, X Tk (s) represents the imaginary part of the equivalent line impedance.

[0088] Step S4, based on the equivalent impedance Z Gk (s) Characteristics in the frequency domain, to determine the stability of the wind farm in the frequency domain; where the equivalent impedance Z Gk (s) The features in the frequency domain include the equivalent real part and the equivalent imaginary part at different frequencies.

[0089] Understandably, equivalent impedance is an important component in wind farm stability analysis. Based on the characteristics of equivalent impedance in the frequency domain, including its equivalent real and equivalent imaginary parts at different frequencies, the stability of the wind farm at those frequencies can be determined. When the equivalent real part is greater than 0, it indicates that the wind farm is stable at that frequency; when the equivalent real part is less than 0, it indicates that the wind farm is unstable at that frequency.

[0090] This invention constructs an equivalent model that can accurately describe the overall characteristics of large-scale wind farms. It is the foundation for studying the operation and control of high-proportion wind power systems. The equivalent model of a detailed wind farm is an important part of the dynamic equivalent model of a wind farm.

[0091] This invention can be used for wind farm planning and wind turbine controller parameter design. When the equivalent modeling analysis of the wind farm under study indicates the presence of instability risks, it can provide a reference for the design.

[0092] According to the frequency domain dynamic equivalent modeling method for doubly-fed induction generator (DFIG) wind farms based on real-time data proposed in this embodiment of the invention, for a wind farm with k DFIG wind turbines, the method calculates the equivalent rotational speed coefficient of the kth DFIG wind turbine; calculates the state coefficient of the kth DFIG wind turbine; calculates the equivalent impedance of the kth DFIG wind turbine based on the equivalent rotational speed coefficient and the state coefficient; and calculates the equivalent impedance Z based on the equivalent impedance Z. Gk (s) Characteristics in the frequency domain, to determine the stability of the wind farm in the frequency domain; where the equivalent impedance Z Gk (s) The frequency domain features include the equivalent real part and the equivalent imaginary part at different frequencies. This invention can efficiently and quickly obtain the equivalent impedance of a doubly-fed wind farm at various time periods, and the results provide an important basis for the impact analysis of wind farm grid connection.

[0093] Figure 2 This is a schematic diagram of a doubly fed wind farm frequency domain dynamic equivalent modeling device based on real-time data according to an embodiment of the present invention.

[0094] like Figure 2 As shown, the device 10 includes:

[0095] The module includes a rotational speed equivalent coefficient module 100, a state coefficient module 200, an equivalent impedance module 300, and a judgment module 400.

[0096] The speed equivalent coefficient module 100 is used to calculate the speed equivalent coefficient of the k-th doubly-fed wind turbine, where the speed equivalent coefficient is η. k ;

[0097] State coefficient module 200 is used to calculate the state coefficient of the k-th doubly-fed wind turbine, where the state coefficient is STA. k ;

[0098] Equivalent impedance module 300, used to determine the equivalent impedance based on the rotational speed coefficient η k and state coefficient STA k Calculate the equivalent impedance Z of the k-th doubly-fed wind turbine. Gk (s);

[0099] The judgment module 400 is used to determine the equivalent impedance Z. Gk (s) Characteristics in the frequency domain, to determine the stability of the wind farm in the frequency domain; where the equivalent impedance Z Gk (s) The features in the frequency domain include the equivalent real part and the equivalent imaginary part at different frequencies.

[0100] Furthermore, the speed equivalent coefficient η of the aforementioned speed equivalent coefficient module 100 k Calculated using the following formula:

[0101]

[0102] Among them, v k (t+Δt) represents the wind speed of the k-th wind turbine at time t+Δt, n represents the nth sampling, and i represents the i-th time.

[0103] Furthermore, the state coefficient STA of the aforementioned state coefficient module 200 k Calculated using the following formula:

[0104] At time t+Δt, STA k :

[0105]

[0106] in,

[0107]

[0108] When the wind turbine is connected to the grid at time t-gΔt, s(t-gΔt) = 1; when the wind turbine is disconnected at time t-gΔt, s(t-gΔt) = 0.

[0109] Furthermore, the equivalent impedance Z of the aforementioned equivalent impedance module 300 Gk (s) is calculated using the following formula:

[0110] Equivalent impedance of k wind turbines in the wind field:

[0111] Z eqk (s)=Z eq(k-1) (s) / / Z Gk (s)+Z Tk (s)+Z Lk (s);

[0112] Where, at time t+Δt

[0113]

[0114] Among them, Z Tk (s)=R Tk (s)+jX Tk (s) represents the equivalent transformer impedance of the k-th wind turbine, R Tk (s) represents the real part of the equivalent box transformer impedance, X Tk (s) represents the imaginary part of the equivalent box transformer impedance; Z Lk (s)=R Lk (s)+jX Lk(s) represents the equivalent line impedance of the k-th wind turbine, R Lk (s) represents the real part of the equivalent line impedance, X Tk (s) represents the imaginary part of the equivalent line impedance.

[0115] The frequency domain dynamic equivalent modeling device for doubly-fed induction generator (DFIG) wind farms based on real-time data, proposed in this invention, calculates the equivalent rotational speed coefficient of the k-th DFIG wind turbine for a wind farm with k DFIG wind turbines; calculates the state coefficient of the k-th DFIG wind turbine; and calculates the equivalent impedance of the k-th DFIG wind turbine based on the equivalent rotational speed coefficient and the state coefficient. This invention can efficiently and quickly obtain the equivalent impedance of a DFIG wind farm at various time periods, and the results provide important basis for the impact analysis of wind farm grid connection.

[0116] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0117] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0118] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A frequency domain dynamic equivalent modeling method for doubly-fed wind farms based on real-time data, characterized in that, The method includes the following steps: For a wind farm with k doubly fed wind turbine units Calculate the equivalent speed coefficient of the k-th doubly-fed wind turbine, where the equivalent speed coefficient is η. k ; Calculate the state coefficient of the k-th doubly-fed wind turbine, where the state coefficient is STA. k ; According to the aforementioned rotational speed equivalent coefficient η k and the state coefficient STA k Calculate the equivalent impedance Z of the k-th doubly-fed wind turbine. Gk (s); According to the equivalent impedance Z Gk (s) Determine the stability of the wind farm in the frequency domain based on its characteristics; wherein, the equivalent impedance Z Gk (s) The features in the frequency domain include the equivalent real part and the equivalent imaginary part at different frequencies; The rotational speed equivalent coefficient η k Calculated using the following formula: Among them, v k (t+Δt) represents the wind speed of the kth wind turbine at time t+Δt, n represents the nth sampling, and i represents the i-th time. The state coefficient STA k Calculated using the following formula: At time t+Δt, STA k : in, When the wind turbine is connected to the grid at time t-gΔt, s(t-gΔt)=1; when the wind turbine is disconnected at time t-gΔt, s(t-gΔt)=0. The equivalent impedance Z Gk (s) is calculated using the following formula: Equivalent impedance of k wind turbines in the wind field: Z eqk (s)=Z eq(k-1) (s) / / Z Gk (s)+Z Tk (s)+Z Lk (s); Where, at time t+Δt Among them, Z Tk (s)=R Tk (s)+jX Tk (s) represents the equivalent transformer impedance of the k-th wind turbine, R Tk (s) represents the real part of the equivalent box transformer impedance, X Tk (s) represents the imaginary part of the equivalent box transformer impedance; Z Lk (s)=R Lk (s)+jX Lk (s) represents the equivalent line impedance of the k-th wind turbine, R Lk (s) represents the real part of the equivalent line impedance, X Tk (s) represents the imaginary part of the equivalent line impedance.

2. The frequency domain dynamic equivalent modeling method for doubly-fed wind farms based on real-time data according to claim 1, characterized in that, α(T) = [cos(2πfT),L,cos(2nπfT)] is a phasor matrix; θ k =[θ k1 Lθ kn [ ] is the coefficient matrix to be fitted for k wind turbine units; By solving θ k =[θ k1 Lθ kn To find the minimum value of Q: Based on the solution θ k =[θ k1 Lθ kn ], get: v k (t+Δt)=θ k α(t+Δt) T 。 3. The frequency domain dynamic equivalent modeling method for doubly-fed wind farms based on real-time data according to claim 2, characterized in that, The equivalent impedance of the wind field for the k wind turbines can be calculated using the following formula: Let the equivalent impedance of the wind field for one wind turbine be: Z eq1 (s)=Z G1 (s)+Z T1 (s)+Z L1 (s) Equivalent impedance of the wind farm for 2 wind turbines: Z eq2 (s)=Z eq1 (s) / / Z G2 (s)+Z T2 (s)+Z L2 (s) Equivalent impedance of the wind farm for the 3 wind turbines: Z eq3 (s)=Z eq2 (s) / / Z G2 (s)+Z T2 (s)+Z L2 (s) The equivalent impedance of the wind field for the k wind turbines: Z eqk (s)=Z eq(k-1) (s) / / Z Gk (s)+Z Tk (s)+Z Lk (s)。 4. A frequency domain dynamic equivalent modeling device for doubly-fed wind farms based on real-time data, characterized in that, include: For a wind farm with k doubly fed wind turbine units The rotational speed equivalent coefficient module is used to calculate the rotational speed equivalent coefficient of the k-th doubly-fed wind turbine, where the rotational speed equivalent coefficient is η. k ; The state coefficient module is used to calculate the state coefficient of the k-th doubly-fed wind turbine, wherein the state coefficient is STA. k ; The equivalent impedance module is used to determine the equivalent rotational speed coefficient η. k and the state coefficient STA k Calculate the equivalent impedance Z of the k-th doubly-fed wind turbine. Gk (s); The judgment module is used to determine the equivalent impedance Z based on the given impedance Z. Gk (s) Determine the stability of the wind farm in the frequency domain based on its characteristics; wherein, the equivalent impedance Z Gk (s) The features in the frequency domain include the equivalent real part and the equivalent imaginary part at different frequencies; The rotational speed equivalent coefficient module has a rotational speed equivalent coefficient η. k Calculated using the following formula: Among them, v k (t+Δt) represents the wind speed of the kth wind turbine at time t+Δt, n represents the nth sampling, and i represents the i-th time. The state coefficient STA of the state coefficient module k Calculated using the following formula: At time t+Δt, STA k : in, When the wind turbine is connected to the grid at time t-gΔt, s(t-gΔt)=1; when the wind turbine is disconnected at time t-gΔt, s(t-gΔt)=0. The equivalent impedance Z of the equivalent impedance module Gk (s) is calculated using the following formula: Equivalent impedance of k wind turbines in the wind field: Z eqk (s)=Z eq(k-1) (s) / / Z Gk (s)+Z Tk (s)+Z Lk (s); Where, at time t+Δt Among them, Z Tk (s)=R Tk (s)+jX Tk (s) represents the equivalent transformer impedance of the k-th wind turbine, R Tk (s) represents the real part of the equivalent box transformer impedance, X Tk (s) represents the imaginary part of the equivalent box transformer impedance; Z Lk (s)=R Lk (s)+jX Lk (s) represents the equivalent line impedance of the k-th wind turbine, R Lk (s) represents the real part of the equivalent line impedance, X Tk (s) represents the imaginary part of the equivalent line impedance.

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