Frequency support method, device and control system for hybrid wind farm

Abstract

The present invention discloses a frequency support method, device and control system for a hybrid wind farm, which belongs to the technical field of grid-connected renewable energy power generation. In the frequency support process, the frequency support method first obtains the power interaction factor of each wind turbine according to the wind turbine type, and uses each wind turbine as a transmitting wind turbine and also as the receiving wind turbine to transmit and receive power interaction factors; each wind turbine uses the received multiple power interaction factors to calculate the compensation power in real time, and then adds the compensation power to the respective adjustment module according to the wind turbine type for frequency support; when the module switching conditions are met, the adjustment module switches to the recovery module to perform frequency and speed recovery. The present invention controls each wind turbine in the hybrid wind farm to coordinate the power distribution between wind turbines, which can improve the effect and stability of frequency support, and finally achieve the optimal frequency support of the hybrid wind farm within a wide range of power grid strength.

Description

Technical Field

[0001] The present invention belongs to the technical field of renewable energy power generation and grid connection, and more specifically, relates to a frequency support method, device and control system for a hybrid wind farm. Background Art

[0002] New energy sources represented by wind power have the advantages of being clean, renewable, and having low operation and maintenance costs. However, as the proportion of wind power access continues to rise, the inertia of the power grid and other characteristics are weakened, and frequency events have led to frequent large-scale power outages. The frequency support provided by wind farms is of great significance to the frequency security of the power system.

[0003] Wind turbines usually adopt grid-following control in engineering. However, grid-following wind turbines are unstable under weak grids. In order to improve this problem, grid-building wind turbines have been studied and significantly improved the stability under weak grids. However, the stability of grid-building wind turbines is poor under strong grids, while grid-building wind turbines have strong stability. Since the two have complementary grid strength compatibility, the construction of a hybrid wind farm that includes both grid-following and grid-building wind turbines can operate stably under wide grid strength. The frequency support of the grid-following wind turbine is based on the collected frequency as input to generate additional active power to be added to the reference value of the maximum power point tracking. The grid-building wind turbine establishes its own frequency by the active synchronization loop and has independent frequency support capabilities. The frequency support mechanism and control method of the grid-following wind turbine and the grid-building wind turbine are different, so the optimal frequency support of the hybrid wind farm is difficult to achieve.

[0004] The existing frequency support research of wind farms only discusses the frequency support control of wind farms composed of single grid-following or grid-forming wind turbines, and its control cannot be directly applied to hybrid wind farms. Secondly, the existing frequency support control is mostly designed to imitate the inertia and speed regulator of synchronous generators, which makes it impossible to utilize the optimal support capacity of wind turbines with flexible control. Summary of the invention

[0005] In view of the above defects or improvement needs of the prior art, the present invention provides a frequency support method, device and control system for a hybrid wind farm, which aims to solve the technical problem of how to flexibly and efficiently support the frequency of a hybrid wind farm including grid-following wind turbines and grid-forming wind turbines.

[0006] To achieve the above object, according to one aspect of the present invention, a frequency support method for a hybrid wind farm is provided, comprising:

[0007] S1: When the grid connection point frequency of the hybrid wind farm exceeds the dead zone threshold, a start-up frequency support signal is generated; the hybrid wind farm includes a grid-following wind turbine and a grid-forming wind turbine;

[0008] S2: when receiving the frequency support signal, obtaining a power interaction factor of each wind turbine according to the wind turbine type;

[0009] S3: each of the wind turbines is used as a sending wind turbine to transmit its own power interaction factor to a corresponding receiving wind turbine, and each of the wind turbines is used as a receiving wind turbine to receive the corresponding power interaction factors transmitted by the sending wind turbines;

[0010] S4: Calculating compensation power in real time using the multiple power interaction factors received by each of the wind turbines;

[0011] S5: adding the compensation power of each wind turbine to the adjustment module in its own frequency support control model to perform frequency support; the frequency support control model includes: the adjustment module and the recovery module; the frequency support control model of the grid-following wind turbine is a grid-following optimal frequency support control model, and the frequency support control model of the grid-forming wind turbine is a grid-forming optimal frequency support control model;

[0012] S6: When the module switching condition is met, each of the fans is controlled to switch from the frequency support by the regulating module to the frequency and speed recovery by the recovery module.

[0013] In one embodiment, S2 includes: if the current wind turbine is a grid-type wind turbine, determining the active power difference of the grid-type wind turbine P f,GFL Is it greater than the maximum capacity limit of the converter? P max If it is greater than P f,GFL - P max as the power interaction factor of the current wind turbine; if it is less than or equal to, the power interaction factor of the current wind turbine is recorded as 0.

[0014] In one embodiment, the S2 includes:

[0015] If the current wind turbine is a grid-type wind turbine, determine the active power difference of the grid-type wind turbine. P f,GFM and the initial value of active power for maximum power tracking control P MPPT0 Is the sum greater than the maximum capacity limit of the converter? P max ;

[0016] If it is greater than P f,GFM + P MPPT0 - P maxas the power interaction factor of the current wind turbine; if it is less than or equal to, the power interaction factor of the current wind turbine is recorded as 0.

[0017] In one embodiment, S4 includes: taking the average of the multiple power interaction factors received by each of the wind turbines as the compensation power.

[0018] In one embodiment, the S5 includes:

[0019] If the current wind turbine is a grid-following wind turbine, the calculated compensation power is added to the output of the adjustment module in the frequency support control model to obtain an active power reference value of the inner loop of the controller;

[0020] If the current wind turbine is a grid-type wind turbine, the calculated compensation power is added to the input of the adjustment module in the frequency support control model to obtain the phase angle of the inner loop of the controller.

[0021] In one embodiment, the transfer function of the regulating module of the grid-type fan is: Γ GFL,i (s)=-k wm,i +k wn,i / (1+sT w,i ); The transfer function of the regulating module of the grid-type fan is Λ GFM,i (s)=(1+sT w,i ) / (-k wm, i T w,i sk wm,i +k wn,i );in, k wm,i , k wn,i , T w,i are the control parameters of the current fan, i is the serial number of the current fan, and s is the Laplace factor;

[0022] The transfer function of the regulating module of the grid-type fan is Λ GFM,i (s) and the transfer function of the regulating module of the grid-type fan Γ GFL,i (s) satisfies the dual consistency condition: Λ GFM,i (s)=1 / Γ GFL,i (s).

[0023] In one embodiment, S5 includes: the transfer function of the recovery module of the grid-type wind turbine is ΛGFM,i (s)=1 / ( ω 0 Js );in, ω 0 is the reference angular frequency, J is the inertia coefficient.

[0024] According to another aspect of the present invention, there is provided a frequency support device for a hybrid wind farm, comprising:

[0025] A start-up module, used for generating a frequency support start-up signal when the grid connection point frequency of the hybrid wind farm exceeds the dead zone threshold; the hybrid wind farm includes a grid-following wind turbine and a grid-forming wind turbine;

[0026] An acquisition module, for acquiring a power interaction factor of each wind turbine according to the wind turbine type when a frequency support start signal is received;

[0027] A transmission module, used to use each of the wind turbines as a sending wind turbine to transmit its own power interaction factor to a corresponding receiving wind turbine, and at the same time use each of the wind turbines as a receiving wind turbine to receive the power interaction factors transmitted by the corresponding plurality of sending wind turbines;

[0028] A calculation module, used for controlling each of the wind turbines to calculate compensation power using the received multiple power interaction factors;

[0029] A support module, used for adding the compensation power of each wind turbine to the adjustment module in its own frequency support control model to perform frequency support; the frequency support control model includes: the adjustment module and the recovery module; the frequency support control model of the grid-following wind turbine is a grid-following optimal frequency support control model, and the frequency support control model of the grid-forming wind turbine is a grid-forming optimal frequency support control model;

[0030] The recovery module is used to control each of the fans to switch from frequency support by the regulating module to frequency and speed recovery by the recovery module when the module switching condition is met.

[0031] According to another aspect of the present invention, a control system for a hybrid wind farm is provided, comprising a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps of the above method when executing the computer program.

[0032] According to another aspect of the present invention, a computer-readable storage medium is provided, on which a computer program is stored, and when the computer program is executed by a processor, the steps of the above method are implemented.

[0033] In general, the above technical solutions conceived by the present invention can achieve the following beneficial effects compared with the prior art:

[0034] (1) This scheme provides a frequency support method for a hybrid wind farm. During the frequency support process, the power interaction factor of each wind turbine is first obtained according to the wind turbine type, and each wind turbine is used as a transmitting wind turbine and also as the receiving wind turbine to transmit and receive power interaction factors; each wind turbine uses the received multiple power interaction factors to calculate the compensation power in real time, and then adds the compensation power to its own adjustment module according to the wind turbine type for frequency support; when the module switching conditions are met, the adjustment module switches to the recovery module to perform frequency and speed recovery. The present invention controls each wind turbine in the hybrid wind farm to coordinate the power distribution between wind turbines, which can improve the effect and stability of frequency support, and ultimately achieve the optimal frequency support of the hybrid wind farm within a wide range of power grid strength.

[0035] (2) This solution considers that when the current wind turbine is a grid-following wind turbine, if the active power difference P f,GFL Greater than the maximum capacity limit of the converter P max Then P f,GFL - P max As the power interaction factor of the current wind turbine, otherwise the power interaction factor of the current wind turbine is recorded as 0; this method takes into account the expected output power of the grid-following wind turbine and the actual optimal output power limited by the converter capacity, and realizes the quantification of the over-limit power of the grid-following wind turbine into a power interaction factor, which is convenient for other wind turbines to make up for it.

[0036] (3) This scheme considers that when the current wind turbine is a grid-type wind turbine, if the active power difference P f,GFM and the initial value of active power for maximum power tracking control P MPPT0 The sum is greater than the maximum capacity limit of the converter P max Then P f,GFM + P MPPT0 - P max As the power interaction factor of the current wind turbine, otherwise the power interaction factor of the current wind turbine is recorded as 0; this method takes into account the expected output power of the grid-type wind turbine and the actual optimal output power limited by the converter capacity, and realizes the quantification of the over-limit power of the grid-type wind turbine into a power interaction factor, which is convenient for other wind turbines to make up for it.

[0037] (4) This scheme uses the average of multiple power interaction factors received by each wind turbine as the compensation power. For example, when one receiving wind turbine corresponds to two transmitting wind turbines, the compensation power Δ P x,i= ( x k + x j ) / 2, where Δ P x,i For the i Compensation power of typhoon generators; x k and x j For the sending unit ( k Typhoon and j Typhoon generator) to the receiving unit ( i This method interacts the power states of multiple wind turbines, so that the support power that cannot be generated by high-speed wind units due to wind turbine power limitations is compensated by other wind turbines, thereby avoiding additional frequency drops in high wind speed conditions and improving the overall frequency support capacity of the wind farm.

[0038] (5) In this scheme, if the current wind turbine is a grid-type wind turbine, the calculated compensation power is added to the output of the adjustment module in the frequency support control model; if the current wind turbine is a grid-forming wind turbine, the calculated compensation power is added to the input of the adjustment module in the frequency support control model; this method realizes the optimal frequency support for each type of wind turbine based on the difference in control structure between grid-type and grid-forming wind turbines.

[0039] (6) In this scheme, if the current wind turbine is a grid-type wind turbine, the transfer function of the regulation module of the optimal frequency support control is: Λ GFM,i (s)=(1+sT w,i ) / (-k wm,i T w,i sk wm,i +k wn,i ). The transfer function of the optimal frequency support adjustment module of the network-following type and the network-building type satisfies the dual consistency condition: Λ GFM,i (s)=1 / Γ GFL,i (s). Among them, k wm,i , k wn,i , T w,i All are i Control parameters of the typhoon; Λ GFM,i (s) is the transfer function of the grid-type fan regulation module. This method designs the response process of the grid-type fan to construct the frequency by power deviation, so as to realize the support frequency of the grid-type fan according to the optimal frequency lowest point response curve obtained by optimization.

[0040] (7) In this scheme, if the current wind turbine is a grid-type wind turbine, the transfer function of the recovery module of the optimal frequency support control is: Λ GFM,i (s)=1 / ( ω 0 Js ).in, ω 0 is the reference angular frequency, J This method avoids the secondary frequency drop that is easily caused in the initial stage of speed recovery, allowing the frequency and speed to recover quickly, thereby improving the wind farm's ability to cope with subsequent disturbances. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 This is a flow chart of a frequency support method for a hybrid wind farm provided by an embodiment of the present invention.

[0042] Figure 2a A schematic diagram of a frequency support method for a hybrid wind farm of a grid-following type and a grid-building type provided in one embodiment of the present invention.

[0043] Figure 2b A schematic diagram of the framework of a network-building type optimal frequency support control model and a network-following type optimal frequency support control model provided in one embodiment of the present invention.

[0044] Figure 3a This is a schematic diagram of the optimal frequency response of grid-following and grid-forming fans provided in one embodiment of the present invention.

[0045] Figure 3b A schematic diagram of power trajectory of grid-following and grid-forming wind turbines provided in one embodiment of the present invention.

[0046] Figure 4a This is a frequency support result of a hybrid wind farm grid-connected system after a disturbance in one embodiment of the present invention.

[0047] Figure 4b The output power of each wind turbine in the hybrid wind farm according to an embodiment of the present invention is shown in FIG.

[0048] Figure 4c The interaction factor results are issued for each wind turbine in the hybrid wind farm in one embodiment of the present invention. DETAILED DESCRIPTION

[0049] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0050] The actual hybrid wind farm parameters in a certain area are used as the example prototype. A hybrid wind farm access IEEE four-machine two-region model is built based on the Matlab / Simulink platform. The hybrid wind farm consists of 15 equivalent wind turbines, each of which is composed of 20 3.33MW direct-drive wind turbines. The wind power installed capacity penetration rate is 37.7%. The wind speed of the hybrid wind farm is set to 16.9m / s and the wind direction is positive to wind turbines 1~5. Due to the influence of the wake effect, the wind speed at wind turbines 6~15 is lower than this wind speed. t f = 5s, the system increases its active load by 500MW.

[0051] like Figure 1 As shown, a frequency support method for a hybrid wind farm is provided, which is applied to a hybrid wind farm including both grid-following type wind turbines and grid-forming type wind turbines. The frequency support method specifically includes:

[0052] S1: When the grid connection point frequency of the hybrid wind farm exceeds the dead zone threshold, a start-up frequency support signal is generated; the hybrid wind farm includes grid-following wind turbines and grid-forming wind turbines;

[0053] S2: when receiving the frequency support signal, obtaining the power interaction factor of each wind turbine according to the wind turbine type;

[0054] S3: each wind turbine is used as a sending wind turbine to transmit its own power interaction factor to the corresponding receiving wind turbine, and each wind turbine is used as a receiving wind turbine to receive the power interaction factors transmitted by the corresponding multiple sending wind turbines;

[0055] S4: Calculate the compensation power in real time using multiple power interaction factors received by each wind turbine;

[0056] S5: adding the compensation power of each wind turbine to the adjustment module in its own frequency support control model to perform frequency support; the frequency support control model includes: an adjustment module and a recovery module; the frequency support control model of the grid-following wind turbine is the grid-following optimal frequency support control model, and the frequency support control model of the grid-forming wind turbine is the grid-forming optimal frequency support control model;

[0057] S6: When the module switching conditions are met, each fan is controlled to switch from frequency support by the adjustment module to frequency and speed recovery by the recovery module.

[0058] See also Figure 1 and Figure 2a , the design method is as follows:

[0059] S1: When the frequency of the hybrid wind farm grid connection point exceeds the dead zone Δ f dbWhen , the hybrid wind farm starts the frequency support scheme of each wind turbine, where the hybrid wind farm that includes both grid-following wind turbines and grid-forming wind turbines is defined as a hybrid wind farm, the grid-following wind turbine is a unit synchronized by a phase-locked loop, and the grid-forming wind turbine is a unit synchronized by a power loop. Specifically, the dead zone Δ of the optimal frequency support scheme for starting the stratification f db The value is 0.02Hz. t =5.01s, the optimal frequency support scheme of the stratification is activated. In the hybrid wind farm, wind turbines 1 to 10 are grid-following wind turbines, and wind turbines 11 to 15 are grid-forming wind turbines.

[0060] S2: Control each fan to calculate the power interaction factor of each fan according to electromagnetic power, etc.

[0061] As an optional implementation, the calculation method of the wind turbine power interaction factor in S2 is:

[0062] For grid-following units, if P f,GFL > P max , the value of the interaction factor is P f,GFL - P max , otherwise the interaction factor is 0;

[0063] For grid-type fans, if P f,GFM + P MPPT0 > P max , the value of the interaction factor is P f,GFM + P MPPT0 - P max , otherwise the interaction factor is 0. Among them, P f,GFL and P f,GFM They are the active power differences between the grid-following wind turbine and the grid-building wind turbine respectively; P MPPT0 is the initial value of active power of the maximum power tracking control when the method is started; P max is the maximum capacity limit of the converter, which is taken as 1.2pu.

[0064] S3: Each wind turbine acts as a sending wind turbine and transmits its own power interaction factor to the corresponding receiving wind turbine based on the communication topology. At the same time, each wind turbine acts as a receiving wind turbine and receives the power interaction factors transmitted by the corresponding multiple sending wind turbines based on the communication topology.

[0065] S4: Each wind turbine calculates the compensation power using the received power interaction factor.

[0066] As an optional implementation, S4 includes: taking the mean of multiple power interaction factors received by each wind turbine as the compensation power; wherein, one receiving wind turbine corresponds to three, five, or ten sending wind turbines. If some of the wind turbines are unable to send power interaction factors, the mean of some of the received power interaction factors is still used to represent the compensation power. The mean after removing the maximum value and / or minimum value can also be considered to represent the compensation power. It should be noted that the variance, standard deviation, etc. of the received power interaction factors are also used to represent the compensation power.

[0067] As an optional implementation, for example, one receiving wind turbine corresponds to two sending wind turbines, and the calculation method of the wind turbine compensation power in S4 is: Δ P x,i = ( x k + x j ) / 2, where Δ P x,i For the i Compensation power of typhoon generators; x k and x j For the sending unit ( k Typhoon and j Typhoon generator) to the receiving unit ( i typhoon).

[0068] S5: Add the compensation power of each wind turbine to the adjustment module in its own frequency support control model to perform frequency support; the frequency support control model includes: an adjustment module and a recovery module; the frequency support control model of the grid-following wind turbine is the grid-following optimal frequency support control model, and the frequency support control model of the grid-forming wind turbine is the grid-forming optimal frequency support control model; wherein, Figure 2b The schematic diagram of the framework of the network-based optimal frequency support control model and the network-based optimal frequency support control model is shown in Figure 1. is the reactive power output by the wind turbine, is the reactive power reference value, For mesh type fans, is the phase angle of the grid-type fan, For the The terminal voltage of the wind turbine, It is the voltage reference value of grid-type wind turbine.

[0069] As an optional implementation, the adjustment module of the frequency support control model:

[0070] For grid-type fans, the transfer function of the regulation module can be Γ GFL,i (s)=-k wm,i +k wn,i / (1+sT w,i ); For the grid-type wind turbine, the transfer function of the regulation module is Λ GFM,i (s)=(1+sT w,i ) / (-k wm,i T w,i sk wm,i +k wn,i ); The transfer function of the adjustment module in the network-following and network-building frequency support models satisfies the dual consistency condition as follows: Λ GFM,i (s)=1 / Γ GFL,i (s). Among them, k wm,i , k wn,i , T w,i All are i Control parameters of the typhoon.

[0071] S6: When the module switching conditions are met, each fan is controlled to switch from frequency support by the adjustment module to frequency and speed recovery by the recovery module.

[0072] As an optional implementation, the recovery module of the frequency support control model: For a grid-connected wind turbine, the output of the recovery module is P ref = P MPPT ; For the grid-type wind turbine, the transfer function of the recovery module is ;in, P MPPT is the active power of the maximum power tracking control, ω 0 is the reference angular frequency, J is the inertia coefficient.

[0073] As an optional implementation, the switching condition in S6 may be: the electromagnetic power output by the fan is lower than the maximum power tracking power or the speed of the fan is lower than the minimum speed limit, that is, P e < P MPPT or ω < ω min .in, P e is the electromagnetic power output by the fan, ω minis the minimum speed limit, which is 0.7pu. Specifically, fans 11-15, 6-10, and 1-5 are t =24.22s, t =31.25s, t =38.94s, the switching condition is met and the control is switched to the recovery module.

[0074] As an optional implementation, both controls contain their own adjustment modules and recovery modules. Figure 3a and Figure 3b As shown, the regulating module first takes effect, causing the frequency to drop and remain stable at the lowest point for a long time. The electromagnetic power curve of the fan is O 1 - K - M - N .when t = t r When , the switching condition is met. At this time, the regulation phase switches to the recovery phase, the recovery module takes effect, the frequency and speed are restored, and the electromagnetic power curve is N - J .

[0075] The following is an explanation of the simulation data: The frequency support results after the hybrid wind farm is connected to the grid system disturbance are as follows: Figure 4a The output power of each fan is shown in Figure 4b As shown, the interaction factors of each fan are as follows Figure 4c As shown in the figure, when the hybrid wind farm does not participate in frequency support, the lowest frequency point is 48.15Hz. When the hybrid wind farm adopts comprehensive inertia control, the speed of a small number of wind turbines is lower than 0.7 at t=13.34s. They enter the speed protection. This leads to a secondary drop in frequency, and the lowest frequency point is 48.79Hz. When the optimal auxiliary control is adopted, the frequency cannot be maintained at the lowest point according to the expected characteristics, and the lowest frequency point is 48.92Hz.

[0076] When frequency support control is performed directly, the power of fans 1 to 5 is limited to t=5.92s reaches the maximum power limit. This results in part of the expected power not being emitted, and the lowest frequency point is 49.05Hz. When the complete frequency support method proposed in the present invention is adopted, the power that fans 1~5 fail to emit is compensated by fans 6~10 through the power interaction factor. This is because the medium wind speed unit has sufficient margin to stay away from the power and speed limitations. Fans 6~10 have increased power and better exerted the rotor kinetic energy, with the lowest speed being 0.702. This indirectly led to fans 1~5 also making better use of kinetic energy in the subsequent period, with the lowest speed being 0.748. Therefore, the lowest frequency point is increased to 49.11Hz, and the lowest frequency point is the highest, thereby achieving optimal frequency support.

[0077] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A frequency support method for a hybrid wind farm, It is characterized in that include: S1: When the grid connection point frequency of the hybrid wind farm exceeds the dead zone threshold, a start-up frequency support signal is generated; the hybrid wind farm includes a grid-following wind turbine and a grid-forming wind turbine; S2: when receiving the frequency support signal, obtaining a power interaction factor of each wind turbine according to the wind turbine type; S3: each of the wind turbines is used as a sending wind turbine to transmit its own power interaction factor to a corresponding receiving wind turbine, and each of the wind turbines is used as a receiving wind turbine to receive the corresponding power interaction factors transmitted by the sending wind turbines; S4: Calculating compensation power in real time using the multiple power interaction factors received by each of the wind turbines; S5: adding the compensation power of each wind turbine to the adjustment module in its own frequency support control model to perform frequency support; the frequency support control model includes: the adjustment module and the recovery module; the frequency support control model of the grid-following wind turbine is a grid-following optimal frequency support control model, and the frequency support control model of the grid-forming wind turbine is a grid-forming optimal frequency support control model; S6: When the module switching condition is met, control each of the fans to switch from the frequency support by the regulating module to the frequency and speed recovery by the recovery module; The S2 includes: if the current wind turbine is a grid-type wind turbine, determining the active power difference of the grid-type wind turbine; P f,GFL Is it greater than the maximum capacity limit of the converter? P max If it is greater than P f,GFL - P max as the power interaction factor of the current wind turbine; if it is less than or equal to, the power interaction factor of the current wind turbine is recorded as 0; if the current wind turbine is a grid-type wind turbine, the active power difference of the grid-type wind turbine is determined P f,GFM and the initial value of active power for maximum power tracking control P MPPT0 Is the sum greater than the maximum capacity limit of the converter? P max If it is greater than, P f,GFM + P MPPT0 - P max as the power interaction factor of the current wind turbine; if it is less than or equal to, the power interaction factor of the current wind turbine is recorded as 0.

2. The frequency support method of a hybrid wind farm according to claim 1, It is characterized in that The S4 includes: taking the average value of the multiple power interaction factors received by each of the wind turbines as compensation power.

3. The frequency support method of a hybrid wind farm according to claim 1, It is characterized in that The S5 includes: If the current wind turbine is a grid-following wind turbine, the calculated compensation power is added to the output of the adjustment module in the frequency support control model to obtain an active power reference value of the controller inner loop; If the current wind turbine is a grid-type wind turbine, the calculated compensation power is added to the input of the adjustment module in the frequency support control model to obtain the phase angle of the inner loop of the controller.

4. The frequency support method of a hybrid wind farm according to claim 3, It is characterized in that The transfer function of the regulating module of the grid-type fan is: Γ GFL,i (s)=-k wm,i +k wn,i / (1+sT w,i ); The transfer function of the regulating module of the grid-type fan is Λ GFM,i (s)=(1+sT w,i ) / (-k wm,i T w,i sk wm,i +k wn,i ); in, k wm,i , k wn,i , T w,i are the control parameters of the current fan, i is the serial number of the current fan, and s is the Laplace factor; The transfer function of the regulating module of the grid-type fan is Λ GFM,i (s) and the transfer function of the regulating module of the grid-type fan Γ GFL,i (s) satisfies the dual consistency condition: Λ GFM,i (s)=1 / Γ GFL,i (s).

5. The frequency support method of a hybrid wind farm according to claim 4, It is characterized in that The transfer function of the recovery module of the grid-type wind turbine is: Λ GFM,i (s)=1 / ( ω 0 Js ); in, ω 0 is the reference angular frequency, J is the inertia coefficient.

6. A frequency support device for a hybrid wind farm, It is characterized in that A frequency support method for a hybrid wind farm according to any one of claims 1 to 5, comprising: A start-up module, used for generating a frequency support start-up signal when the grid connection point frequency of the hybrid wind farm exceeds the dead zone threshold; the hybrid wind farm includes a grid-following wind turbine and a grid-forming wind turbine; An acquisition module, for acquiring a power interaction factor of each wind turbine according to the wind turbine type when a frequency support start signal is received; A transmission module, used to use each of the wind turbines as a sending wind turbine to transmit its own power interaction factor to a corresponding receiving wind turbine, and at the same time use each of the wind turbines as a receiving wind turbine to receive the power interaction factors transmitted by the corresponding plurality of sending wind turbines; A calculation module, used for controlling each of the wind turbines to calculate compensation power using the received multiple power interaction factors; A support module, used for adding the compensation power of each wind turbine to the adjustment module in its own frequency support control model to perform frequency support; the frequency support control model includes: the adjustment module and the recovery module; the frequency support control model of the grid-following wind turbine is a grid-following optimal frequency support control model, and the frequency support control model of the grid-forming wind turbine is a grid-forming optimal frequency support control model; The recovery module is used to control each of the fans to switch from frequency support by the regulating module to frequency and speed recovery by the recovery module when the module switching condition is met.

7. A control system for a hybrid wind farm, comprising a memory and a processor, wherein the memory stores a computer program, It is characterized in that When the processor executes the computer program, the steps of the method according to any one of claims 1 to 5 are implemented.

8. A computer-readable storage medium having a computer program stored thereon, It is characterized in that When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 5 are implemented.

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