Frequency active support control method, system, equipment and medium for new energy collection station

Abstract

The present invention provides a method, system, device and medium for actively supporting and controlling the frequency of a new energy collection station. The method is to obtain the DC support inertia and the fan support damping and generate a first primary frequency modulation control strategy based on the coupling relationship between the DC voltage reference value and the AC frequency established based on the principle of maximizing the power support of the receiving end converter and the coupling relationship between the fan power and the DC voltage based on the preset fan control principle, and generate a second primary frequency modulation control strategy based on the energy storage support inertia and the energy storage support damping obtained based on the principle of maximizing the energy storage output power to cope with the maximum frequency change rate and the maximum frequency deviation. Frequency modulation is performed according to the primary frequency modulation strategy, and after completion, secondary frequency modulation control is performed according to the preset energy storage power control model and the preset fan power control model. The present invention can coordinate multiple resources in the collection station for power grid frequency modulation, and achieve low-cost, efficient and reliable AC frequency stability control effect.

Description

Technical Field

[0001] The present invention relates to the technical field of power systems, and in particular to a method, system, equipment and medium for actively supporting and controlling the frequency of a new energy collection station. Background Art

[0002] With the accelerated advancement of the construction of new power systems, the capacity of new energy grid connection has gradually increased, and the frequency stability problem of the AC system has gradually become prominent. On the one hand, the overall inertia level of the AC power grid has decreased due to the excessive proportion of new energy, and the randomness, intermittency and volatility of new energy will cause frequent power disturbances in the AC system, affecting the frequency stability; on the other hand, the frequency of the new energy connected to the flexible direct current grid is decoupled from the frequency of the receiving AC system. When the system has frequency fluctuations, the new energy cannot directly adjust its output to participate in the system frequency regulation, and the frequency regulation task can only be undertaken by the synchronous machine in the AC system.

[0003] In order to cope with the problem of insufficient frequency regulation capacity of the power grid caused by large-scale new energy grid connection, existing scholars have proposed that the new power system can configure energy storage in the new energy collection station, and use the fast charging and discharging ability of the energy storage system to adjust the frequency of the power surplus of the power grid to actively support the control method, so as to provide frequency regulation capability for the power grid. However, the high cost, limited capacity and short cycle life of energy storage materials limit the possibility of large-scale application. Therefore, it is urgent to provide a control method that can use multiple frequency regulation resources in the new energy collection station to coordinately provide active support for the frequency stability of the AC power grid. Summary of the invention

[0004] The purpose of the present invention is to provide a method for active frequency support and control of a new energy collection station. By establishing a coupling relationship between the DC voltage of a receiving-end converter and the frequency of a commutation bus and the power of an offshore wind turbine, a primary frequency regulation strategy for a new energy collection station is generated in combination with the principle of using energy storage to respond to the maximum frequency change rate and the maximum frequency deviation of the system with maximum output power. In addition, a secondary frequency regulation strategy is generated based on the collaborative support of the energy storage system and the wind turbine while considering the recovery of the operating state. This method can coordinate various resources in the collection station for grid frequency regulation without increasing additional control costs, thereby achieving a low-cost, efficient and reliable AC frequency stability control effect.

[0005] In order to achieve the above objectives, it is necessary to provide a new energy collection station frequency active support control method, system, equipment and medium in response to the above technical problems.

[0006] In a first aspect, an embodiment of the present invention provides a method for actively supporting and controlling the frequency of a new energy collection station, the method comprising the following steps:

[0007] Based on the principle of maximizing the power support of the receiving-end converter, a first coupling relationship model between the DC voltage reference value and the AC frequency of the receiving-end converter is established;

[0008] According to the preset wind turbine control principle, a second coupling relationship model between the wind turbine power and the DC voltage of the receiving-end converter is established;

[0009] According to the first coupling relationship model and the second coupling relationship model, a DC support inertia and a fan support damping are obtained, and according to the DC support inertia and the fan support damping, a first primary frequency modulation control strategy is generated;

[0010] Based on the principle of maximizing the energy storage output power to cope with the maximum frequency change rate of the system and the maximum frequency deviation of the system, the energy storage support inertia and the energy storage support damping are obtained, and according to the energy storage support inertia and the energy storage support damping, a second primary frequency modulation control strategy is generated;

[0011] According to the first primary frequency regulation control strategy and the second primary frequency regulation control strategy, performing primary frequency regulation control of the new energy collection station;

[0012] In response to the completion of the primary frequency regulation control, the secondary frequency regulation control of the new energy collection station is performed according to the preset energy storage power control model and the preset wind turbine power control model.

[0013] Furthermore, the step of establishing a first coupling relationship model between the DC voltage reference value and the AC frequency of the receiving-end converter based on the receiving-end converter power support maximization principle includes:

[0014] According to the minimum operating value of the DC voltage and the rated DC voltage of the receiving-end converter, a model of the maximum energy allowed to be released by the converter is established;

[0015] The first coupling relationship model is established according to the maximum energy release model allowed by the converter, the rated frequency of the AC power grid, the minimum allowable frequency of the AC power grid, the instantaneous frequency of the commutation bus and the rated DC voltage, based on the principle of maximizing the power support of the receiving-end converter.

[0016] Furthermore, the first coupling relationship model is expressed as:

[0017]

[0018] In the formula,

[0019]

[0020] in, , and They respectively represent the DC voltage reference value, rated DC voltage and minimum operating DC voltage of the receiving-end converter; Indicates the maximum energy that the receiving-end converter is allowed to release; It represents the lumped capacitance parameter of the receiving-end converter; and Respectively represent the rated frequency of the AC power grid and the minimum permissible frequency of the AC power grid; Indicates the instantaneous frequency of the commutation bus.

[0021] Furthermore, the preset fan control principle is that the fan adopts overspeed control and the fan power adopts a droop control method coupled with the DC voltage of the receiving-end converter; the second coupling relationship model is expressed as:

[0022]

[0023] In the formula,

[0024]

[0025] in, Indicates the fan reference power, Indicates the initial operating power of the fan; Indicates the fan power control droop coefficient; , and They respectively represent the operating DC voltage, rated DC voltage and minimum operating DC voltage of the receiving-end converter; Indicates the maximum output power of the fan.

[0026] Furthermore, the step of generating a first primary frequency modulation control strategy according to the DC support inertia and the fan support damping includes:

[0027] By introducing the DC voltage of the receiving-end converter and the safety margin coefficient of the wind turbine operation, the DC support inertia and the wind turbine support damping are combined to generate the first primary frequency modulation control strategy; the first primary frequency modulation control strategy is expressed as:

[0028]

[0029] In the formula,

[0030]

[0031] in, Indicates the power change of the receiving-end converter; Indicates the instantaneous frequency change of the commutation bus; and denote virtual inertia and damping respectively; Indicates the fan power control droop coefficient; and They represent the rated DC voltage and the minimum operating DC voltage of the receiving-end converter respectively; It represents the lumped capacitance parameter of the receiving-end converter; and Respectively represent the rated frequency of the AC power grid and the minimum permissible frequency of the AC power grid; and They respectively represent the DC voltage of the receiving-end converter and the safety margin factor of the wind turbine operation.

[0032] Furthermore, the step of obtaining the energy storage support inertia and energy storage support damping based on the principle of maximizing the energy storage output power to cope with the system maximum frequency change rate and the system maximum frequency deviation includes:

[0033] Construct a system maximum frequency change rate model that takes into account both the DC system and the frequency support provided by the energy storage system;

[0034] Based on the principle of maximizing the energy storage output power to cope with the system's maximum frequency change rate and system's maximum frequency deviation, the corresponding change rate response energy storage output power model and deviation response energy storage output power model are established;

[0035] Obtaining the energy storage support inertia according to the system maximum frequency change rate model and the change rate response energy storage output power model;

[0036] The energy storage support damping is obtained according to the deviation response energy storage output power model.

[0037] Furthermore, the preset energy storage power control model is constructed based on the principle that the energy storage system charge percentage is higher than the minimum charge percentage to participate in secondary frequency modulation and the energy storage system charge percentage is lower than the minimum charge percentage to restore its own charge state;

[0038] The preset energy storage power control model is expressed as:

[0039]

[0040] in, Indicates the power change of the energy storage system in the secondary frequency regulation; and Indicates the real-time charge percentage of the energy storage system; and Respectively represent the proportional and integral coefficients of frequency control; and are the proportional and integral coefficients of the state of charge control respectively.

[0041] In a second aspect, an embodiment of the present invention provides a frequency active support and control system for a new energy collection station, the system comprising:

[0042] A first modeling module is used to establish a first coupling relationship model between a DC voltage reference value and an AC frequency of a receiving-end converter based on a principle of maximizing power support of the receiving-end converter;

[0043] A second modeling module is used to establish a second coupling relationship model between the wind turbine power and the DC voltage of the receiving-end converter according to a preset wind turbine control principle;

[0044] a first strategy generating module, configured to obtain a DC support inertia and a fan support damping according to the first coupling relationship model and the second coupling relationship model, and to generate a first primary frequency modulation control strategy according to the DC support inertia and the fan support damping;

[0045] A second strategy generation module is used to obtain energy storage support inertia and energy storage support damping based on the principle of maximizing energy storage output power to cope with the system maximum frequency change rate and the system maximum frequency deviation, and generate a second primary frequency modulation control strategy according to the energy storage support inertia and the energy storage support damping;

[0046] A primary frequency modulation module, used to perform primary frequency modulation control of a new energy collection station according to the first primary frequency modulation control strategy and the second primary frequency modulation control strategy;

[0047] The secondary frequency regulation module is used to respond to the completion of the primary frequency regulation control and execute the secondary frequency regulation control of the new energy collection station according to the preset energy storage power control model and the preset wind turbine power control model.

[0048] In a third aspect, an embodiment of the present invention further provides a computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the above method when executing the computer program.

[0049] In a fourth aspect, an embodiment of the present invention further provides a computer-readable storage medium having a computer program stored thereon, wherein the computer program implements the steps of the above method when executed by a processor.

[0050] The present application provides a method, system, device and medium for active frequency support control of a new energy collection station. The method realizes a first coupling relationship model between the DC voltage reference value of the receiving-end converter and the AC frequency based on the principle of maximizing the power support of the receiving-end converter, and a second coupling relationship model between the fan power and the DC voltage of the receiving-end converter is established according to the preset fan control principle, and the DC support inertia and the fan support damping are obtained according to the first coupling relationship model and the second coupling relationship model, and a first primary frequency modulation control strategy is generated according to the DC support inertia and the fan support damping, and the energy storage support inertia and the energy storage support damping are obtained based on the principle of maximizing the energy storage output power to cope with the system maximum frequency change rate and the system maximum frequency deviation. After the second primary frequency modulation control strategy is generated according to the energy storage support inertia and the energy storage support damping, the primary frequency modulation control of the new energy collection station is executed according to the first primary frequency modulation control strategy and the second primary frequency modulation control strategy, and in response to the completion of the primary frequency modulation control, the technical solution of executing the secondary frequency modulation control of the new energy collection station according to the preset energy storage power control model and the preset fan power control model. Compared with the existing technology, the frequency active support and control method of the new energy collection station generates a primary frequency regulation strategy for the new energy collection station by establishing a coupling relationship between the DC voltage of the receiving-end converter and the frequency of the commutation bus and the power of the offshore wind turbine, and combines the energy storage with the principle of maximum output power to cope with the maximum frequency change rate and the maximum frequency deviation of the system. In addition, the secondary frequency regulation strategy is generated based on the collaborative support of the energy storage system and the wind turbine while considering the recovery of the operating status. Without increasing the additional control cost, various resources in the collection station can be coordinated for grid frequency regulation, thereby achieving low-cost, efficient and reliable AC frequency stability control effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 Schematic diagram of an application scenario of the frequency active support control method of a new energy collection station in an embodiment of the present invention;

[0052] Figure 2 It is a flow chart of the method for actively supporting and controlling the frequency of a new energy collection station in an embodiment of the present invention;

[0053] Figure 3 Schematic diagram of frequency modulation response curve of a new energy collection station under different frequency modulation conditions in an embodiment of the present invention;

[0054] Figure 4 1 is a schematic diagram of the variation curves of AC frequency and MMC DC voltage under secondary frequency modulation in an embodiment of the present invention;

[0055] Figure 5 It is a structural diagram of the active frequency support and control system of the new energy collection station in the embodiment of the present invention;

[0056] Figure 6It is a diagram of the internal structure of a computer device in an embodiment of the present invention. DETAILED DESCRIPTION

[0057] In order to make the purpose, technical scheme and beneficial effects of the present application clearer, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. Obviously, the embodiments described below are part of the embodiments of the present invention and are only used to illustrate the present invention, but are not used to limit the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0058] The method for active frequency support and control of a new energy collection station provided by the present invention can be understood as an application defect based on the existing new power system that only relies on the configuration of energy storage for frequency support but does not reasonably utilize the existing resources in the new energy collection station for coordinated frequency regulation, resulting in insufficient power grid frequency regulation capability and high frequency regulation costs. Instead, a new energy collection station that participates in the frequency regulation of the receiving-end power grid by actively supporting and controlling the frequency of the power grid by coordinating the DC system, wind turbine and energy storage system in the collection station for stable control of the AC frequency of the power grid on the basis of considering the recovery of the operating status and not increasing the additional control cost is proposed. The control mechanism can be applied as follows: Figure 1 The IEEE 39-node system shown (the offshore wind power transmission system based on MMC-HVDC is connected to the power grid through a new energy collection station, and a battery energy storage system is configured in the new energy collection station). The following embodiments will explain in detail the frequency active support control method of the new energy collection station of the present invention.

[0059] In one embodiment, Figure 2 As shown, a method for actively supporting and controlling the frequency of a new energy collection station is provided, comprising the following steps:

[0060] S11. Based on the principle of maximizing the power support of the receiving-end converter, a first coupling relationship model between the DC voltage reference value of the receiving-end converter and the AC frequency is established; wherein, the principle of maximizing the power support of the receiving-end converter can be understood as that when the frequency of the receiving-end power grid is the lowest, the receiving-end modular multilevel converter MMC (Modular Multilevel Converter) should release as much energy as possible to provide power support; correspondingly, the first coupling relationship model can be understood as the coupling relationship between the DC voltage reference voltage of the receiving-end MMC and the AC frequency of the MMC commutation bus, which can reflect how the DC voltage reference value changes in real time according to the coupling relationship when the instantaneous frequency of the AC power grid changes, so as to achieve the effect that the MMC DC voltage reliably responds to the frequency changes of the AC power grid.

[0061] Specifically, the step of establishing a first coupling relationship model between the DC voltage reference value and the AC frequency of the receiving-end converter based on the receiving-end converter power support maximization principle includes:

[0062] According to the minimum operating value of the DC voltage and the rated DC voltage of the receiving-end converter, a model of the maximum energy allowed to be released by the converter is established; wherein, the minimum operating value of the DC voltage and the rated DC voltage of the receiving-end converter MMC may vary due to the actual MMC configuration; correspondingly, the maximum energy allowed to be released by the converter is actually affected by the minimum operating value of the DC voltage of the MMC, the rated DC voltage and the MMC lumped capacitance parameters, and should satisfy that the MMC DC voltage is the minimum when the frequency of the receiving-end power grid is the lowest. Based on this, the model of the maximum energy allowed to be released by the converter can be established, which is expressed as:

[0063] (1)

[0064] in, and Respectively represent the rated DC voltage and the minimum operating DC voltage of the receiving-end converter; C eq It represents the lumped capacitance parameter of the receiving-end converter; Indicates that the receiving-end converter is allowed to release the maximum energy.

[0065] According to the maximum energy model allowed to be released by the converter, the rated frequency of the AC grid, the minimum allowable frequency of the AC grid, the instantaneous frequency of the commutation bus and the rated DC voltage, based on the principle of maximizing the power support of the receiving-end converter, the first coupling relationship model is established; wherein, the principle of maximizing the power support of the receiving-end converter as described above should enable the maximum energy allowed to be released by the MMC to be maximized to provide power support. Based on this, it is required that at any time when the power system is running, the MMC DC voltage reference value corresponding to the lowest frequency of the grid must be the minimum, that is:

[0066] (2)

[0067] Based on formula (2), the mathematical expression of the DC voltage reference value of the receiving-end converter (the first coupling relationship model) can be easily obtained, which is expressed as:

[0068] (3)

[0069] in, and They represent the DC voltage reference value and rated DC voltage of the receiving-end converter respectively; It indicates the maximum energy allowed to be released by the receiving-end converter, which can be calculated by formula (1); It represents the lumped capacitance parameter of the receiving-end converter; and They represent the rated frequency of the AC power grid at the receiving end and the minimum permissible frequency of the AC power grid at the receiving end respectively; It represents the instantaneous frequency of the commutation bus, and represents the instantaneous frequency of the MMC commutation bus during the operation of the power system.

[0070] The first coupling relationship model established by the above method steps can well reflect the effect of the DC voltage of the receiving-end converter on the instantaneous frequency regulation of the AC power grid. In the actual operation process, when the instantaneous frequency of the AC power grid is f ac When the frequency of the AC power grid changes, the DC voltage reference value of the receiving-end converter can be changed in real time according to the coupling relationship shown in formula (3), thereby achieving the effect that the MMC DC voltage responds to the change of the AC power grid frequency.

[0071] S12. According to the preset wind turbine control principle, a second coupling relationship model between the wind turbine power and the DC voltage of the receiving-end converter is established; wherein the preset wind turbine control principle can be understood as a control method for offshore wind turbines specially designed to allow offshore wind turbines to participate in the frequency modulation of the AC system, taking into account the fact that the existing offshore wind turbines are connected to the AC power grid through flexible direct current and cannot directly feel the frequency change of the AC system. In this embodiment, the preset wind turbine control principle is preferably a droop control method in which the wind turbine adopts overspeed control and the wind turbine power adopts a droop control method coupled with the DC voltage of the receiving-end converter; correspondingly, the second coupling relationship model can be understood as the coupling control relationship between the wind turbine power and the MMC DC voltage when the DC line resistance loss is ignored; specifically, the second coupling relationship model is expressed as:

[0072] (4)

[0073] in, Indicates the reference power of the fan; Indicates the initial operating power of the fan; Indicates the fan power control droop coefficient; and They represent the operating DC voltage and rated DC voltage of the receiving-end converter respectively.

[0074] In practical applications, in order to ensure that the wind turbine power margin is compatible with the frequency modulation effect, this embodiment preferably changes the wind turbine power control droop coefficient in equation (4) to Set to:

[0075] (5)

[0076] in, Indicates the fan power control droop coefficient; Indicates the maximum output power of the fan; Indicates the initial operating power of the fan; and They respectively represent the rated DC voltage and the minimum operating DC voltage of the receiving-end converter.

[0077] The second coupling relationship model established above can well realize the coupling control of offshore wind turbine power and DC voltage of receiving-end converter, providing reliable support for offshore wind turbines to participate in AC system frequency regulation.

[0078] S13. According to the first coupling relationship model and the second coupling relationship model, the DC support inertia and the fan support damping are obtained, and the first primary frequency modulation control strategy is generated according to the DC support inertia and the fan support damping; wherein, the DC support inertia can be understood as the frequency modulation inertia support provided by the MMC DC side equivalent capacitor release power obtained based on the first coupling relationship model between the DC voltage reference value of the receiving end converter and the AC frequency; the fan support damping can be understood as the frequency modulation damping support provided by the offshore wind turbine release power obtained based on the second coupling relationship model between the wind turbine power and the DC voltage of the receiving end converter; based on the principle that the support power provided by the DC support inertia and the fan support damping needs to be transmitted to the AC power grid through the MMC, the frequency modulation control strategy in which the DC system and the offshore wind turbine jointly participate in the primary frequency modulation can be directly obtained according to the DC support inertia and the fan support damping; the specific process of generating the first primary frequency modulation control strategy according to the DC support inertia and the fan support damping is as follows:

[0079] According to the coupling relationship between the MMC DC voltage reference value and the commutation bus frequency shown in equation (3), it can be further obtained that:

[0080] (6)

[0081] in, Represents the energy change of the MMC lumped capacitance.

[0082] By taking the derivative of both sides of equation (6) with respect to t, we can obtain:

[0083] (7)

[0084] in, Indicates the change in power released by the MMC lumped capacitor.

[0085] In practice, the instantaneous frequency of the commutation bus Rated frequency of the receiving AC grid (1.0 pu) has little deviation, so equation (7) is approximated as:

[0086] (8)

[0087] in, Indicates the change in instantaneous frequency of the commutation bus.

[0088] Based on formula (3), when the AC grid frequency at the receiving end changes, the DC voltage will change accordingly; and based on formula (4), when the AC grid frequency at the receiving end changes, the output power of the offshore wind turbine will change accordingly, and the droop coefficient It reflects the magnitude of the change in the output power of the offshore wind turbine with the frequency of the receiving AC power grid, and the damping relationship of the offshore wind turbine in response to the frequency deviation of the receiving AC power grid can be expressed as:

[0089] (9)

[0090] In the formula, represents damping; Indicates the change in power released by offshore wind turbines.

[0091] Based on equations (8) and (9), the change in the output power of the MMC at the receiving end with the frequency deviation of the commutation bus can be expressed as:

[0092] (10)

[0093] In the formula,

[0094] (11)

[0095] in, Indicates the change in MMC output power; Indicates the frequency change of the MMC commutation bus; and represent virtual inertia and damping respectively.

[0096] In principle, the DC voltage and offshore wind turbine can be directly implemented to coordinate and participate in the primary frequency regulation based on equations (10) and (11). However, considering that after the primary frequency regulation is completed, the DC voltage and wind turbine speed will decrease accordingly, and long-term operation in this state will cause safety and economic problems. In order to ensure that the operating state of the DC and wind turbine is restored as soon as possible during the secondary frequency regulation, this embodiment preferably introduces the DC voltage and wind turbine safety margin coefficient to appropriately reduce the DC capacitor and the supporting power of the wind turbine participating in the primary frequency regulation. The degree to which the DC voltage and the fan speed deviate from the rated operating state after the primary frequency modulation is completed is reduced in a manner. Specifically, the step of generating the first primary frequency modulation control strategy according to the DC support inertia and the fan support damping includes:

[0097] By introducing the DC voltage of the receiving-end converter and the safety margin coefficient of the wind turbine operation, the DC support inertia and the wind turbine support damping are combined to generate the first primary frequency modulation control strategy; the first primary frequency modulation control strategy is expressed as:

[0098] (12)

[0099] in, Indicates the power change of the receiving-end converter; Indicates the instantaneous frequency change of the commutation bus; and denote virtual inertia and damping respectively; and They respectively represent the DC voltage of the receiving-end converter and the safety margin factor of the wind turbine operation, and both can be set according to actual application requirements.

[0100] In addition, considering that it is difficult to meet the demand for providing frequency support to the AC power grid by relying solely on offshore wind turbines and DC systems, and that in a frequency modulation process, the quantities that need to be paid attention to at all times include the frequency change speed and the frequency deviation, to ensure that the frequency change speed is not too fast and the frequency deviation compared to the rated value is not too large, this embodiment preferably further utilizes the energy storage system to cooperate with the offshore wind turbines and the DC system to provide frequency modulation support to the AC power grid through the following steps, so as to achieve more reliable frequency modulation support.

[0101] S14. Based on the principle of maximizing the energy storage output power to cope with the system's maximum frequency change rate and the system's maximum frequency deviation, the energy storage support inertia and energy storage support damping are obtained, and the second primary frequency modulation control strategy is generated based on the energy storage support inertia and the energy storage support damping; wherein, the principle of maximizing the energy storage output power to cope with the system's maximum frequency change rate and the system's maximum frequency deviation can be understood as during a primary frequency modulation, when the system has the maximum frequency change rate, the energy storage system needs to output the maximum power to provide the maximum inertia support to suppress the frequency change rate with the maximum force, and when the system frequency deviation reaches the maximum value, the energy storage system's output power needs to be fully utilized to play the role of maximum power support. Correspondingly, the energy storage support inertia can be understood as the inertia support provided by the energy storage system required to suppress the system frequency change rate, and the energy storage support damping can be understood as the damping support provided by the energy storage system required to suppress the system frequency deviation.

[0102] Specifically, the steps of obtaining the energy storage support inertia and energy storage support damping based on the principle of maximizing the energy storage output power to cope with the system maximum frequency change rate and the system maximum frequency deviation include:

[0103] A system maximum frequency change rate model is constructed after considering the frequency support provided by the DC system and the energy storage system. The system maximum frequency change rate model can be understood as a mathematical expression of the maximum frequency change rate that may occur in the system after considering the frequency support of the DC system and the energy storage system, which is expressed as:

[0104] (13)

[0105] In the formula, and Respectively represent the system inertia and the inertia provided by the energy storage system; H v Represents the inertia provided by the DC system; Indicates the maximum power shortage that may occur in the system; Indicates the maximum frequency change rate that may occur in the system.

[0106] Based on the principle of maximizing the energy storage output power to cope with the maximum frequency change rate and the maximum frequency deviation of the system, the corresponding change rate response energy storage output power model and deviation response energy storage output power model are established; among which, the change rate response energy storage output power model can be understood as a mathematical expression that satisfies the maximum power output requirement of the energy storage system when the system has the maximum frequency change rate, which is expressed as:

[0107] (14)

[0108] In the formula, Indicates the maximum output power of the energy storage system.

[0109] The deviation response energy storage output power model can be understood as a mathematical expression of the maximum power demand of the energy storage system when the AC power grid has the maximum frequency deviation and does not trigger the three defense lines during the transient process, which is expressed as:

[0110] (15)

[0111] In the formula, Indicates the maximum output power of the energy storage system; Indicates the damping coefficient of the energy storage system participating in primary frequency modulation; It indicates the maximum frequency deviation of the system when the AC power grid does not trigger the three lines of defense during transient process.

[0112] According to the system maximum frequency change rate model and the change rate response energy storage output power model, the energy storage support inertia is obtained; wherein the energy storage support inertia can be directly derived based on equations (13) and (14), expressed as:

[0113] (16)

[0114] in, Represents the energy storage support inertia, that is, the inertia provided by the energy storage system.

[0115] According to the deviation response energy storage output power model, the energy storage support damping is obtained; wherein the energy storage support damping can be directly derived based on formula (15), expressed as:

[0116] (17)

[0117] Based on the energy storage support inertia and energy storage support damping shown in equations (16) and (17), the output power change of the energy storage system can be set, that is, the second primary frequency modulation control strategy is obtained; specifically, it is expressed as:

[0118] (18)

[0119] In the formula, Indicates the change in output power of the energy storage system.

[0120] S15. Execute the primary frequency regulation control of the new energy collection station according to the first primary frequency regulation control strategy and the second primary frequency regulation control strategy; wherein, the primary frequency regulation control of the new energy collection station can be understood as simultaneously coordinating the change in the output power of the receiving-end MMC and the change in the output power of the energy storage system as the power support for the new energy collection station to participate in the primary frequency regulation, that is, merging the first primary frequency regulation control strategy and the second primary frequency regulation control strategy obtained above to generate the primary frequency regulation control strategy of the new energy collection station, which is used to actively support and regulate the frequency of the AC power grid.

[0121] S16. In response to the completion of the primary frequency regulation control, the secondary frequency regulation control of the new energy collection station is executed according to the preset energy storage power control model and the preset wind turbine power control model; wherein, the secondary frequency regulation control of the new energy collection station can be understood as a system secondary frequency regulation that is executed to restore the frequency to the rated value based on the fact that there will be a certain frequency variation in the receiving-end power grid after the primary frequency regulation control (differential regulation).

[0122] Taking into account that the resource entities participating in the secondary frequency regulation need to have the ability to provide power support for a relatively long period of time, offshore wind turbines can participate in the secondary frequency regulation by releasing their own power margin and increasing the captured wind energy. However, the energy magnitude of the DC side capacitor of the flexible DC converter station is relatively small, and it is difficult to provide power support in the minute-level secondary frequency regulation. In order to ensure the safe and economical operation of the power grid, this embodiment preferably retains the offshore wind turbines to participate in the secondary frequency regulation after the primary frequency regulation is executed, and after the flexible DC converter station participates in the primary frequency regulation, allows it to restore its own DC voltage as soon as possible and no longer participate in the secondary frequency regulation.

[0123] At the same time, in order to ensure the normal operation of the energy storage system, this embodiment preferably selectively participates in the secondary frequency regulation of the system according to the energy storage system's own charge state during the secondary frequency regulation: if the energy storage system charge percentage is low, the secondary frequency regulation process should aim to restore the AC system frequency and the energy storage charge state, and no frequency regulation is provided; if the energy storage system charge percentage is high, the wind turbine power margin and energy storage energy are simultaneously called to restore the AC system frequency during the secondary frequency regulation process; that is, the energy storage system charge percentage is higher than When the energy storage system participates in the secondary frequency modulation of the AC system, it helps the AC system to restore the frequency, and the energy storage system charge percentage is lower than When the energy storage system is in a state of charge, it should aim to restore its own state of charge.

[0124] In order to facilitate the effective tracking of the reference quantity by the control quantity during the frequency modulation process, in this embodiment, preferably, the preset energy storage power control model and the preset wind turbine power control model are both set to PI control models (i.e., proportional-integral control). Specifically, the preset energy storage power control model is constructed based on the principle that the energy storage system charge percentage is higher than the minimum charge percentage to participate in the secondary frequency modulation and the energy storage system charge percentage is lower than the minimum charge percentage to restore its own charge state. The power change of the energy storage system during the secondary frequency modulation process can be set to:

[0125] (19)

[0126] in, Indicates the power change of the energy storage system in the secondary frequency regulation; and Indicates the real-time charge percentage and minimum charge percentage of the energy storage system; and They represent the proportional and integral coefficients of frequency control respectively, which can be obtained based on actual application requirements and experience debugging; and They are the proportional and integral coefficients of the state of charge control, which can be obtained based on actual application requirements and experience debugging.

[0127] The preset wind turbine power control model in this embodiment can be expressed as:

[0128] (20)

[0129] In the formula, Indicates the reference power of the fan in the secondary frequency regulation; and They represent the proportional and integral coefficients of the secondary frequency control of offshore wind turbines respectively; Indicates the initial operating power of the fan.

[0130] Based on equations (19) and (20), it can be seen that under the joint action of offshore wind turbines and energy storage systems, combined with the existing secondary frequency regulation configuration scheme in the AC system, the AC system frequency can be gradually restored to the rated value, and the energy storage system selectively participates in the system secondary frequency regulation according to its own charge state. Based on the coupling control of DC voltage and AC system frequency, when the AC system frequency is restored to the rated value, the DC voltage on the flexible DC inverter side will also be restored to the rated value, ultimately stabilizing the AC grid frequency.

[0131] In the embodiment of the present application, a first coupling relationship model between the DC voltage reference value and the AC frequency of the receiving-end converter is established based on the principle of maximizing the power support of the receiving-end converter, a second coupling relationship model between the fan power and the DC voltage of the receiving-end converter is established according to the preset fan control principle, and the DC support inertia and the fan support damping are obtained according to the first coupling relationship model and the second coupling relationship model, a first primary frequency modulation control strategy is generated according to the DC support inertia and the fan support damping, and energy storage support inertia and energy storage support damping are obtained based on the principle of maximizing the energy storage output power to cope with the system maximum frequency change rate and the system maximum frequency deviation, after the second primary frequency modulation control strategy is generated according to the energy storage support inertia and the energy storage support damping, the primary frequency modulation control of the new energy collection station is executed according to the first primary frequency modulation control strategy and the second primary frequency modulation control strategy, and in response to the completion of the primary frequency modulation control, the second primary frequency modulation control strategy of the new energy collection station is executed according to the preset energy storage power control model and the preset fan power control model. The secondary frequency control scheme effectively solves the application defects of the existing new power system that only relies on the configuration of energy storage for frequency support but fails to reasonably utilize the existing resources in the new energy collection station for coordinated frequency regulation, resulting in insufficient grid frequency regulation ability and high frequency regulation cost. By establishing the coupling relationship between the DC voltage of the receiving-end converter and the frequency of the commutation bus and the power of the offshore wind turbine, the primary frequency regulation strategy of the new energy collection station is generated by combining the energy storage with the principle of maximum output power to cope with the maximum frequency change rate and the maximum frequency deviation of the system. In addition, when considering the recovery of the operating status, the secondary frequency regulation strategy is generated based on the coordinated support of the energy storage system and the wind turbine. On the basis of not increasing the additional regulation cost, various resources in the collection station can be coordinated for grid frequency regulation, achieving low-cost, efficient and reliable AC frequency stability control effect, providing reliable technical support for offshore wind power to participate in AC grid frequency regulation through new energy collection stations with flexible direct current collection, and having very important guiding significance for building a new power system with a high proportion of new energy power sources.

[0132] In addition, in order to verify the application value of the frequency active support control method for the new energy collection station provided in this application, this embodiment also uses PSS / E (Power System Simulator / Engineering) simulation analysis software, based on Figure 1 The frequency modulation simulation is performed in a modified IEEE 39-bus system as shown in FIG. Figure 1 As shown in Figure 1, the offshore wind power transmission system based on MMC-HVDC is connected to the grid through the renewable energy collection station at node 17, and a battery energy storage system is configured in the renewable energy collection station. The main parameters of the offshore wind power transmission system are shown in Table 1. The total installed capacity of the original calculation example of the IEEE 39-node system is about 8050 MVA, and the load is 6124 MW. After the offshore wind power is connected, the unit capacity and output remain unchanged, and all loads increase proportionally to maintain the balance between supply and demand.

[0133] Table 1 Main parameters of offshore wind power transmission system

[0134]

[0135] Assume that the offshore wind turbine reserves 20% of its capacity to participate in the frequency regulation of the receiving grid, with a per-unit value of 0.2 pu. The minimum frequency deviation allowed by the receiving grid is -0.01 pu, and the minimum DC voltage allowed by the flexible DC converter station is 0.9 pu. It can be calculated that the virtual inertia presented by the flexible DC converter station is 0.0085. The droop coefficient between the wind turbine power and the DC voltage is 2 pu, which is converted into a virtual damping coefficient of 6.67 pu for the receiving grid. It can be seen that it is very difficult to provide energy support to the receiving grid by relying on the energy storage of the submodule capacitor of the flexible DC converter station, and it is difficult to improve the receiving grid. The flexible DC converter station participates in the frequency regulation of the receiving grid through its own DC voltage, which plays a more important role in transmitting information. The maximum output power of the energy storage system is set to 100 MW, and the maximum power shortage that may occur in the AC system is 0.1 pu. It can be calculated that the virtual inertia that the energy storage system can provide is 0.25 pu, and the virtual damping coefficient that can be provided is 1.67 pu. Under the above parameter settings, a load step of 0.1 pu is set in the system, and the system frequency dynamic response curve before and after the flexible direct current system and energy storage system participate in frequency modulation is obtained as follows: Figure 3 As shown, the AC frequency and MMC DC voltage change curves under secondary frequency modulation are as follows Figure 4 shown.

[0136] Depend on Figure 3 It can be seen that based on the original state of MMC, when MMC participates in frequency modulation, the lowest frequency point of the system is significantly improved, from -0.4 Hz to -0.28 Hz. After the flexible direct current system participates in frequency modulation, the frequency modulation effect of the energy storage system is further considered. Figure 3 It can be seen that after the frequency modulation of the energy storage system is superimposed, the system frequency stability is further improved. Under a load step of 10% of the total system capacity, the lowest point of the system frequency is only -0.25 Hz. When the primary frequency modulation is completed, the AC frequency will have a certain deviation from the rated value, and the secondary frequency modulation will be activated. Figure 4 It can be seen that after the wind turbine and energy storage participate in the secondary frequency regulation, the AC system frequency and the MMC DC voltage are restored to the rated value. Therefore, the simulation results verify that the frequency active support control method of the new energy collection station considering the operation state recovery proposed in the present invention can efficiently and reliably realize the frequency active support control.

[0137] It should be noted that although the steps in the above flowchart are shown in sequence according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified in this document, there is no strict order restriction for the execution of these steps, and these steps can be executed in other orders.

[0138] In one embodiment, Figure 5 As shown, a frequency active support and control system for a new energy collection station is provided, and the system includes:

[0139] The first modeling module 1 is used to establish a first coupling relationship model between a DC voltage reference value and an AC frequency of a receiving-end converter based on a principle of maximizing power support of the receiving-end converter;

[0140] The second modeling module 2 is used to establish a second coupling relationship model between the wind turbine power and the DC voltage of the receiving-end converter according to a preset wind turbine control principle;

[0141] A first strategy generating module 3, configured to obtain a DC support inertia and a fan support damping according to the first coupling relationship model and the second coupling relationship model, and generate a first primary frequency modulation control strategy according to the DC support inertia and the fan support damping;

[0142] The second strategy generation module 4 is used to obtain the energy storage support inertia and the energy storage support damping based on the principle of maximizing the energy storage output power to cope with the system maximum frequency change rate and the system maximum frequency deviation, and generate a second primary frequency modulation control strategy according to the energy storage support inertia and the energy storage support damping;

[0143] A primary frequency modulation module 5, configured to perform primary frequency modulation control of a new energy collection station according to the first primary frequency modulation control strategy and the second primary frequency modulation control strategy;

[0144] The secondary frequency regulation module 6 is used to execute the secondary frequency regulation control of the new energy collection station according to the preset energy storage power control model and the preset wind turbine power control model in response to the completion of the primary frequency regulation control.

[0145] For the specific definition of the frequency active support and control system of the new energy collection station, please refer to the definition of the frequency active support and control method of the new energy collection station mentioned above, and the corresponding technical effects can also be obtained equivalently, which will not be repeated here. Each module in the above-mentioned frequency active support and control system of the new energy collection station can be implemented in whole or in part through software, hardware and a combination thereof. The above-mentioned modules can be embedded in or independent of the processor in the computer device in the form of hardware, or can be stored in the memory of the computer device in the form of software, so that the processor can call and execute the operations corresponding to the above modules.

[0146] Figure 6FIG. 1 shows an internal structure diagram of a computer device in an embodiment, and the computer device may specifically be a terminal or a server. Figure 6 As shown, the computer device includes a processor, a memory, a network interface, a display, a camera and an input device connected through a system bus. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The network interface of the computer device is used to communicate with an external terminal through a network connection. When the computer program is executed by the processor, a method for actively supporting and controlling the frequency of a new energy collection station is implemented. The display screen of the computer device can be a liquid crystal display screen or an electronic ink display screen, and the input device of the computer device can be a touch layer covered on the display screen, or a button, trackball or touchpad set on the computer device housing, or an external keyboard, touchpad or mouse, etc.

[0147] It can be understood by those skilled in the art that Figure 6 The structure shown in the figure is only a block diagram of a part of the structure related to the present application scheme, and does not constitute a limitation on the computer device to which the present application scheme is applied. The specific computing device may include more or fewer components than shown in the figure, or combine certain components, or have the same component arrangement.

[0148] In one embodiment, a computer device is provided, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the steps of the above method are implemented when the processor executes the computer program.

[0149] In one embodiment, 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.

[0150] In summary, an embodiment of the present invention provides a method, system, device and medium for active frequency support and control of a new energy collection station. The method for active frequency support and control of a new energy collection station realizes the establishment of a first coupling relationship model between the DC voltage reference value of the receiving-end converter and the AC frequency based on the principle of maximizing the power support of the receiving-end converter, and establishes a second coupling relationship model between the fan power and the DC voltage of the receiving-end converter according to the preset fan control principle, and obtains the DC support inertia and the fan support damping according to the first coupling relationship model and the second coupling relationship model, generates a first primary frequency modulation control strategy according to the DC support inertia and the fan support damping, and obtains the energy storage support inertia and the energy storage support damping based on the principle of maximizing the energy storage output power to cope with the system maximum frequency change rate and the system maximum frequency deviation, generates the second primary frequency modulation control strategy according to the energy storage support inertia and the energy storage support damping, and executes the new energy collection station according to the first primary frequency modulation control strategy and the second primary frequency modulation control strategy. A technical solution for primary frequency regulation control of a source collection station, and in response to the completion of the primary frequency regulation control, executing secondary frequency regulation control of a new energy collection station according to a preset energy storage power control model and a preset wind turbine power control model. The method generates a primary frequency regulation strategy for a new energy collection station by establishing a coupling relationship between the DC voltage of a receiving-end converter and the frequency of a commutation bus and the power of an offshore wind turbine, and combines the energy storage with the principle of responding to the maximum frequency change rate and the maximum frequency deviation of the system with the maximum output power. In addition, a secondary frequency regulation strategy is generated based on the collaborative support of the energy storage system and the wind turbine, while considering the recovery of the operating state. On the basis of not increasing the additional regulation cost, multiple resources in the collection station can be collaboratively used for grid frequency regulation, achieving a low-cost, efficient and reliable AC frequency stabilization control effect, thereby providing reliable technical support for offshore wind power to participate in AC grid frequency regulation through a new energy collection station where flexible direct current is collected, and has very important guiding significance for building a new power system with a high proportion of new energy power sources.

[0151] Each embodiment in this specification is described in a progressive manner, and the same or similar parts of each embodiment can be directly referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment. It should be noted that the technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, all possible combinations of the technical features in the above-mentioned embodiments are not described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0152] The above-mentioned embodiments only express several preferred implementation modes of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in the technical field, several improvements and substitutions can be made without departing from the technical principles of the present invention, and these improvements and substitutions should also be regarded as the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be based on the protection scope of the claims.

Claims

1. A frequency active support control method for a new energy collection station, characterized in that: The method comprises the following steps: Based on the principle of maximizing the power support of the receiving-end converter, a first coupling relationship model between the DC voltage reference value and the AC frequency of the receiving-end converter is established; According to the preset wind turbine control principle, a second coupling relationship model between the wind turbine power and the DC voltage of the receiving-end converter is established; According to the first coupling relationship model and the second coupling relationship model, a DC support inertia and a fan support damping are obtained, and according to the DC support inertia and the fan support damping, a first primary frequency modulation control strategy is generated; Based on the principle of maximizing the energy storage output power to cope with the maximum frequency change rate of the system and the maximum frequency deviation of the system, the energy storage support inertia and the energy storage support damping are obtained, and according to the energy storage support inertia and the energy storage support damping, a second primary frequency modulation control strategy is generated; According to the first primary frequency regulation control strategy and the second primary frequency regulation control strategy, performing primary frequency regulation control of the new energy collection station; In response to the completion of the primary frequency regulation control, the secondary frequency regulation control of the new energy collection station is performed according to the preset energy storage power control model and the preset wind turbine power control model; Wherein, the first primary frequency modulation control strategy represents: In the formula, in, Indicates the power change of the receiving-end converter; Indicates the instantaneous frequency change of the commutation bus; and denote virtual inertia and damping respectively; Indicates the fan power control droop coefficient; and They represent the rated DC voltage and the minimum operating DC voltage of the receiving-end converter respectively; It represents the lumped capacitance parameter of the receiving-end converter; and Respectively represent the rated frequency of the AC power grid and the minimum permissible frequency of the AC power grid; and They represent the DC voltage of the receiving-end converter and the safety margin factor of the wind turbine operation respectively; The second primary frequency modulation control strategy is expressed as: In the formula, in, Indicates the change in output power of the energy storage system; represents the energy storage support inertia; represents the energy storage support damping; Indicates the maximum output power of the energy storage system; It indicates the maximum frequency deviation of the system when the AC power grid does not trigger the three lines of defense during transient process; Indicates the system inertia; H v Represents the inertia provided by the DC system; Indicates the maximum power deficit that may occur in the system.

2. The frequency active support control method of the new energy collection station according to claim 1 is characterized in that: The step of establishing a first coupling relationship model between the DC voltage reference value and the AC frequency of the receiving-end converter based on the receiving-end converter power support maximization principle includes: Establishing a maximum energy release model of the converter according to the minimum operating value of the DC voltage and the rated DC voltage of the receiving-end converter; The first coupling relationship model is established according to the maximum energy release model allowed by the converter, the rated frequency of the AC power grid, the minimum allowable frequency of the AC power grid, the instantaneous frequency of the commutation bus and the rated DC voltage, based on the principle of maximizing the power support of the receiving-end converter.

3. The frequency active support control method of the new energy collection station as claimed in claim 2 is characterized in that: The first coupling relationship model is expressed as: In the formula, in, , and They respectively represent the DC voltage reference value, rated DC voltage and minimum operating DC voltage of the receiving-end converter; Indicates the maximum energy that the receiving-end converter is allowed to release; It represents the lumped capacitance parameter of the receiving-end converter; and Respectively represent the rated frequency of the AC power grid and the minimum permissible frequency of the AC power grid; Indicates the instantaneous frequency of the commutation bus.

4. The frequency active support control method of the new energy collection station according to claim 1 is characterized in that: The preset fan control principle is that the fan adopts overspeed control and the fan power adopts a droop control mode coupled with the DC voltage of the receiving-end converter; the second coupling relationship model is expressed as: In the formula, in, Indicates the reference power of the fan. Indicates the initial operating power of the fan; Indicates the fan power control droop coefficient; , and They respectively represent the operating DC voltage, rated DC voltage and minimum operating DC voltage of the receiving-end converter; Indicates the maximum output power of the fan.

5. The frequency active support control method of the new energy collection station according to claim 1 is characterized in that: The step of generating a first primary frequency modulation control strategy according to the DC support inertia and the fan support damping comprises: By introducing the DC voltage of the receiving-end converter and the safety margin coefficient of the wind turbine operation, the DC support inertia and the wind turbine support damping are combined to generate the first primary frequency modulation control strategy.

6. The frequency active support control method of the new energy collection station according to claim 1 is characterized in that: The steps of obtaining the energy storage support inertia and energy storage support damping based on the principle of maximizing the energy storage output power to cope with the system maximum frequency change rate and the system maximum frequency deviation include: Construct a system maximum frequency change rate model that takes into account both the DC system and the frequency support provided by the energy storage system; Based on the principle of maximizing the energy storage output power to cope with the system's maximum frequency change rate and system's maximum frequency deviation, the corresponding change rate response energy storage output power model and deviation response energy storage output power model are established; Obtaining the energy storage support inertia according to the system maximum frequency change rate model and the change rate response energy storage output power model; The energy storage support damping is obtained according to the deviation response energy storage output power model.

7. The frequency active support control method of a new energy collection station as claimed in claim 1, characterized in that: The preset energy storage power control model is constructed based on the principle that the energy storage system charge percentage is higher than the minimum charge percentage to participate in secondary frequency modulation and the energy storage system charge percentage is lower than the minimum charge percentage to restore its own charge state; The preset energy storage power control model is expressed as: in, Indicates the power change of the energy storage system in the secondary frequency regulation; and Indicates the real-time charge percentage of the energy storage system; and Respectively represent the proportional and integral coefficients of frequency control; and are the proportional and integral coefficients of the state of charge control respectively.

8. A frequency active support and control system for a new energy collection station, characterized in that: The system comprises: A first modeling module is used to establish a first coupling relationship model between a DC voltage reference value and an AC frequency of a receiving-end converter based on a principle of maximizing power support of the receiving-end converter; A second modeling module is used to establish a second coupling relationship model between the wind turbine power and the DC voltage of the receiving-end converter according to a preset wind turbine control principle; a first strategy generating module, configured to obtain a DC support inertia and a fan support damping according to the first coupling relationship model and the second coupling relationship model, and to generate a first primary frequency modulation control strategy according to the DC support inertia and the fan support damping; A second strategy generation module is used to obtain energy storage support inertia and energy storage support damping based on the principle of maximizing energy storage output power to cope with the system maximum frequency change rate and the system maximum frequency deviation, and generate a second primary frequency modulation control strategy according to the energy storage support inertia and the energy storage support damping; A primary frequency regulation module, used to perform primary frequency regulation control of a new energy collection station according to the first primary frequency regulation control strategy and the second primary frequency regulation control strategy; A secondary frequency regulation module, for executing secondary frequency regulation control of a new energy collection station according to a preset energy storage power control model and a preset wind turbine power control model in response to completion of the primary frequency regulation control; Wherein, the first primary frequency modulation control strategy represents: In the formula, in, Indicates the power change of the receiving-end converter; Indicates the instantaneous frequency change of the commutation bus; and denote virtual inertia and damping respectively; Indicates the fan power control droop coefficient; and They represent the rated DC voltage and the minimum operating DC voltage of the receiving-end converter respectively; It represents the lumped capacitance parameter of the receiving-end converter; and Respectively represent the rated frequency of the AC power grid and the minimum permissible frequency of the AC power grid; and They represent the DC voltage of the receiving-end converter and the safety margin factor of the wind turbine operation respectively; The second primary frequency modulation control strategy is expressed as: In the formula, in, Indicates the change in output power of the energy storage system; represents the energy storage support inertia; represents the energy storage support damping; Indicates the maximum output power of the energy storage system; It indicates the maximum frequency deviation of the system when the AC power grid does not trigger the three lines of defense during transient process; Indicates the system inertia; H v Represents the inertia provided by the DC system; Indicates the maximum power deficit that may occur in the system.

9. A computer device comprising a memory, a processor and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 7 are implemented.

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