Flexible direct current system consistency cooperative frequency supporting method and device based on state factors

Abstract

The invention discloses a flexible direct current system consistency cooperative frequency supporting method and device based on a state factor, and relates to the technical field of flexible direct current system cooperative frequency supporting, and the method comprises the steps: obtaining related data of a plurality of types of frequency modulation sources, carrying out the calculation of the state factor based on the related data of the plurality of types of frequency modulation sources, and obtaining the state factor of the plurality of types of frequency modulation sources, the related data of the multiple types of frequency modulation sources comprises parameter data of the multiple types of frequency modulation sources, safety upper and lower limit data of the multiple types of frequency modulation sources and parameter data of the multiple types of frequency modulation sources when a frequency event occurs; based on the state factors of multiple types of frequency modulation sources, consistency control is carried out, through consensus protocol regulation and control, each frequency modulation source controls the corresponding state factor to be consistent with the disturbed power grid, so that mutual binding is realized, and frequency support is provided for the disturbed power grid according to the frequency modulation capability of the frequency modulation source, the multi-class frequency modulation source comprises an offshore wind turbine generator, a flexible direct current system, a non-synchronous alternating current power grid and an energy storage system, frequency modulation energy of the whole system is reasonably called to participate in disturbed power grid frequency support, and safety and stability of the frequency modulation source are guaranteed.

Description

Technical Field

[0001] The present invention relates to the technical field of coordinated frequency support for flexible direct current systems, and in particular to a method and device for consistent coordinated frequency support for flexible direct current systems based on state factors. Background Art

[0002] In recent years, offshore wind power has developed rapidly. Due to the long distance from the shore, large-capacity and long-distance power transmission is required, so multi-terminal flexible direct current transmission grid connection has obvious advantages. However, the offshore wind farm connected to the grid via multi-terminal flexible direct current transmission is decoupled from the onshore power grid and cannot directly provide frequency support for it. Therefore, it is of great significance to study the frequency support technology of offshore wind power connected to the grid via multi-terminal flexible direct current transmission system.

[0003] Existing research usually calls on wind turbines, flexible direct current systems, non-disturbance power grids and energy storage to provide frequency support for the disturbed power grid, but this also brings certain risks, such as wind turbine stalling, flexible direct current system DC voltage and energy storage charge state are too low and exceed the safety range, non-disturbance power grids produce greater frequency fluctuations than disturbed power grids, etc. Once this happens, it will have a serious impact on the entire system. Therefore, the output of each frequency modulation source should be reasonably called to ensure its own safety and stability.

[0004] In this regard, the academic community has proposed a variety of allocation strategies to reasonably allocate frequency regulation power. However, current research focuses on the output allocation between similar frequency regulation sources, such as between wind turbines, between non-disturbance power grids, etc., ignoring the coordinated control between different types of frequency regulation sources, failing to take a comprehensive approach from the perspective of the entire system, and having certain limitations, which not only increases the control difficulty, but also increases the safety risks of each frequency regulation source, which is not conducive to the stable operation of the entire system. Summary of the invention

[0005] In order to solve the deficiencies mentioned in the above background technology, the purpose of the present invention is to provide a method and device for consistent collaborative frequency support of a flexible direct current system based on state factors, which ensures the safety and stability of the frequency modulation source itself by rationally calling the frequency modulation energy of the entire system to participate in the frequency support of the disturbed power grid.

[0006] In a first aspect, the purpose of the present invention can be achieved by the following technical solution: a method for coordinating frequency support of a flexible direct current system based on a state factor, the method comprising the following steps:

[0007] Acquire multiple types of frequency modulation source related data, calculate state factors based on the multiple types of frequency modulation source related data, and obtain state factors of the multiple types of frequency modulation sources, wherein the multiple types of frequency modulation source related data include multiple types of frequency modulation source parameter data, multiple types of frequency modulation source safety upper and lower limit data, and multiple types of frequency modulation source parameter data when frequency events occur;

[0008] Based on the state factors of multiple types of frequency modulation sources and consistency control, each frequency modulation source controls its corresponding state factor to be consistent with the disturbed power grid through consensus protocol regulation, so that they are bound to each other and jointly provide frequency support for the disturbed power grid according to their own frequency regulation capabilities. Among them, the multiple types of frequency modulation sources include offshore wind turbines, flexible direct current systems, asynchronous AC power grids and energy storage systems.

[0009] In combination with the first aspect, in some implementations of the first aspect, the method further includes: the multiple types of frequency modulation source parameter data include: offshore wind turbine speed ω ri , offshore AC grid frequency f OWF , flexible DC system DC voltage U dc , non-synchronous AC grid frequency f j Energy storage state of charge SOC es .

[0010] In combination with the first aspect, in certain implementations of the first aspect, the method further includes: the safety upper and lower limit data of the multiple types of frequency modulation sources include: offshore wind turbine generator set ω ri_max ,ω ri_min ; Frequency of offshore AC power grid f OWF_max 、f OWF_min ; Flexible DC system DC voltage U dc_max , U dc_min ; Asynchronous AC grid frequency f j_max 、f j_min ; Energy storage state of charge SOC es_max , SOC es_min , it is also necessary to determine the reference value of the offshore AC power grid frequency f OWF_ref .

[0011] In combination with the first aspect, in some implementations of the first aspect, the method further includes: the multiple types of frequency modulation source parameter data when the frequency event occurs include: the speed ω of the offshore wind turbine when the frequency event occurs ri0 , flexible DC system voltage U dc0 , non-synchronous AC grid frequency f j0 , Energy storage state of charge SOC es0 .

[0012] In combination with the first aspect, in some implementations of the first aspect, the method further includes: the process of calculating the state factor based on multiple types of frequency modulation source related data includes:

[0013] The calculation formula of wind turbine state factor is:

[0014]

[0015] In the formula, J i is the moment of inertia of the wind turbine;

[0016] The frequency modulation energy of the flexible DC system comes from the DC support capacitor on it, so the calculation formula of the state factor is:

[0017]

[0018] In the formula, C eq is the equivalent supporting capacitance of the flexible DC system;

[0019] For a non-synchronous AC power grid, it can be equivalent to a synchronous unit, and the calculation formula of the state factor is:

[0020]

[0021] In the formula, J jeq is the moment of inertia of the equivalent synchronous unit, ω jeq is the real-time rotor speed of the equivalent unit, ω jeq0 is the initial speed of the equivalent unit when the frequency event occurs, ω jeq_max ,ω jeq_min These are the safe upper and lower limits of the rotor speed of the equivalent unit;

[0022] The relationship between the synchronous generator rotor speed and frequency is:

[0023]

[0024] Where, ω and p are the rotor speed and pole number of the synchronous generator, f syn is the generator output AC frequency, and the corrected asynchronous AC grid state factor is:

[0025]

[0026] Finally, the calculation formula of the energy storage system state factor is as follows:

[0027]

[0028] In combination with the first aspect, in some implementations of the first aspect, the method further includes: the state factors based on multiple types of frequency modulation sources and consistency control, the consensus protocol regulated by the consensus protocol is as follows:

[0029] x i =y=z j =s es .

[0030] In combination with the first aspect, in some implementations of the first aspect, the method further includes: in the process of performing consistency control based on state factors of multiple types of frequency modulation sources,

[0031] The offshore wind farm is decoupled from the onshore asynchronous power grid due to the flexible DC system and cannot directly perceive the frequency changes of the disturbed power grid. Therefore, it is necessary to map the frequency of the disturbed power grid to the offshore AC power grid through the DC voltage changes of the flexible DC system, thereby eliminating the need for communication equipment and increasing the speed of frequency information transmission. The flexible DC system responds to the consistency consensus protocol, and the state factor is consistent with the disturbed power grid, so the frequency of the offshore AC power grid is controlled to meet the following formula:

[0032]

[0033] In a second aspect, in order to achieve the above-mentioned object, the present invention discloses a state factor-based flexible direct current system consistent coordinated frequency support device, comprising:

[0034] A state factor calculation module is used to obtain multiple types of frequency modulation source related data, calculate the state factor based on the multiple types of frequency modulation source related data, and obtain the state factors of the multiple types of frequency modulation sources, wherein the multiple types of frequency modulation source related data include multiple types of frequency modulation source parameter data, multiple types of frequency modulation source safety upper and lower limit data, and multiple types of frequency modulation source parameter data when a frequency event occurs;

[0035] The collaborative frequency support module is used to perform consistency control based on the state factors of multiple types of frequency modulation sources. Through consensus protocol regulation, each frequency modulation source controls its corresponding state factor to be consistent with the disturbed power grid, so that they are bound to each other and jointly provide frequency support for the disturbed power grid based on their own frequency regulation capabilities. Among them, the multiple types of frequency modulation sources include offshore wind turbines, flexible direct current systems, asynchronous AC power grids and energy storage systems.

[0036] In another aspect of the present invention, in order to achieve the above-mentioned purpose, a terminal device is disclosed, including a memory, a processor, and a computer program stored in the memory and capable of running on the processor, wherein the memory stores a computer program capable of running on the processor, and when the processor loads and executes the computer program, the state factor-based flexible direct current system consistent collaborative frequency support method as described above is adopted.

[0037] In another aspect of the present invention, in order to achieve the above-mentioned purpose, a computer-readable storage medium is disclosed, in which a computer program is stored. When the computer program is loaded and executed by a processor, the state factor-based flexible direct current system consistent collaborative frequency support method as described above is adopted.

[0038] Beneficial effects of the present invention:

[0039] The present invention quantitatively evaluates the frequency modulation capability of each frequency modulation source, so that the frequency modulation power can be reasonably allocated; the present invention does not require communication equipment, and each frequency modulation source only needs to collect local information to provide frequency support for the disturbed power grid, which not only improves the frequency modulation reliability, but also speeds up the system response speed; the present invention breaks through the traditional technology that mostly focuses on the research on output distribution between similar frequency modulation sources, but starts from the perspective of the entire system, coordinates all potential frequency modulation sources in the system to jointly participate in the frequency support of the disturbed power grid, improves the utilization rate of frequency modulation energy, and ensures the safety and stability of the frequency modulation source itself. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0041] Figure 1 It is a schematic flow chart of the method of the present invention;

[0042] Figure 2 It is a control block diagram of the method for coherent coordinated frequency support of a multi-terminal flexible direct current system based on state factors of the present invention;

[0043] Figure 3 This is a control flow chart of a method for coordinating frequency support of a multi-terminal flexible direct current system based on state factors according to the present invention;

[0044] Figure 4 This is the topological structure diagram of the simulation model of the offshore wind power multi-terminal flexible direct current grid-connected system;

[0045] Figure 5 It is the simulation result of the multi-terminal flexible direct current system consistent coordinated frequency support method based on state factor of the present invention on the simulation model;

[0046] Figure 6 It is a schematic diagram of the structure of the device of the present invention. DETAILED DESCRIPTION

[0047] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. 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.

[0048] Embodiment 1:

[0049] like Figure 1 As shown, a method for coherent coordinated frequency support of a flexible DC system based on a state factor comprises the following steps:

[0050] S101: Acquire multiple types of frequency modulation source related data, calculate state factors based on the multiple types of frequency modulation source related data, and obtain state factors of the multiple types of frequency modulation sources, wherein the multiple types of frequency modulation source related data include multiple types of frequency modulation source parameter data, multiple types of frequency modulation source safety upper and lower limit data, and multiple types of frequency modulation source parameter data when frequency events occur;

[0051] Specifically, determine the safety upper and lower limits of multiple frequency regulation sources, including the upper and lower limits of offshore wind turbine speeds. ri_max ,ω ri_min ; Upper and lower limits of the frequency of the offshore AC power grid f OWF_max 、f OWF_min ; Upper and lower limits of DC voltage of flexible DC system U dc_max , U dc_min ; Upper and lower limits of frequency of non-synchronous AC power grid f j_max 、f j_min ; Energy storage state of charge upper and lower limits SOC es_max , SOC es_min In addition, it is also necessary to determine the reference value of the offshore AC power grid frequency f OWF_ref ;

[0052] Real-time collection of offshore wind turbine speed ω ri , offshore AC grid frequency f OWF , flexible DC system DC voltage U dc , non-synchronous AC grid frequency f j Energy storage state of charge SOC es ;

[0053] Record the speed of offshore wind turbines when the frequency event occurs ri0 , flexible DC system voltage U dc0 , non-synchronous AC grid frequency f j0 , Energy storage state of charge SOC es0 ;

[0054] Calculate the state factors of offshore wind turbines, flexible direct current systems, asynchronous AC power grids, and energy storage systems, denoted as x i ,y,z j 、s es , used to evaluate the frequency modulation capability of each frequency modulation source under the same standard system;

[0055] The calculation formula of wind turbine state factor is:

[0056]

[0057] In the formula, J i is the moment of inertia of the wind turbine.

[0058] The frequency modulation energy of the flexible DC system comes from the DC support capacitor on it, so the calculation formula of its state factor is:

[0059]

[0060] In the formula, C eq is the equivalent supporting capacitance of the flexible DC system.

[0061] For a non-synchronous AC power grid, it can be equivalent to a synchronous unit, so the calculation formula of its state factor is:

[0062]

[0063] In the formula, J jeq is the moment of inertia of the equivalent synchronous unit, ω jeq is the real-time rotor speed of the equivalent unit, ω jeq0 is the initial speed of the equivalent unit when the frequency event occurs, ω jeq_max ,ω jeq_min These are the safe upper and lower limits of the rotor speed of the equivalent unit.

[0064] From the knowledge of electrical machinery, we know that the relationship between the rotor speed and frequency of a synchronous generator is:

[0065]

[0066] Where, ω and p are the rotor speed and pole number of the synchronous generator, f syn is the generator output AC frequency, so the corrected asynchronous AC grid state factor is:

[0067]

[0068] Finally, the calculation formula of the energy storage system state factor is as follows:

[0069]

[0070] S102: Based on the state factors of multiple types of frequency modulation sources and performing consistency control, each frequency modulation source controls its corresponding state factor to be consistent with the disturbed power grid through consensus protocol regulation, so that they are bound to each other and jointly provide frequency support for the disturbed power grid based on their own frequency regulation capabilities, wherein the multiple types of frequency modulation sources include offshore wind turbines, flexible direct current systems, asynchronous AC power grids and energy storage systems.

[0071] Specifically, consistency control is adopted and regulated through consensus protocol. Each frequency regulation source controls its state factor to be consistent with the disturbed power grid, so as to achieve mutual binding and jointly provide frequency support for the disturbed power grid according to its own frequency regulation capability.

[0072] The consensus protocol in the consistency control is as follows:

[0073] x i =y=z j =s es

[0074] Under consistency control, the offshore wind farm is decoupled from the onshore asynchronous power grid due to the flexible DC system, and cannot directly perceive the frequency changes of the disturbed power grid. Therefore, it is necessary to map the frequency of the disturbed power grid to the offshore AC power grid through the DC voltage changes of the flexible DC system, thereby eliminating the need for communication equipment and increasing the speed of frequency information transmission. The flexible DC system responds to the consistency consensus protocol, and its state factor is consistent with that of the disturbed power grid, so the frequency of the offshore AC power grid can be controlled to satisfy the following formula:

[0075]

[0076] Specifically, the present invention is further described below by way of embodiments:

[0077] The topological structure of the simulation model of offshore wind power multi-terminal flexible direct current grid-connected system is shown in Figure 4 , where the energy storage system uses power-type energy storage - supercapacitors to provide fast frequency support for the disturbed power grid.

[0078] The system mainly consists of an offshore wind farm, an offshore converter station, three onshore converter stations, three unconnected onshore AC power grids and 50 parallel supercapacitors. The wind farm contains three aggregated wind turbines with wind speeds of 8m / s, 8.5m / s and 9m / s (1-3) respectively. Each aggregated wind turbine is aggregated by 20 5MW permanent magnet direct-drive wind turbines. The parameters of the wind turbine models are shown in Table 1. The capacitance value of the supercapacitor is 100F and the rated voltage is 160V. For the non-synchronous AC power grid, because this paper mainly studies its frequency response, it is equivalent to a synchronous unit, and the inertia time constants of the equivalent units are set to be 4.5s, 4s and 3.5s (1-3), respectively, and the rated capacities are 500MVA, 333MVA and 166MVA respectively, and the equivalent load powers are 525MW, 350MW and 175MW respectively. Other parameters of the offshore wind power multi-terminal flexible direct current grid-connected system are as follows: the capacity of the sea-land converter station is 300MVA, the DC side voltage is ±300kV, the AC side voltage of the offshore converter station is 220kV, the AC side voltage of the onshore converter station is 150kV, the DC support capacitance of the flexible direct current system is 7.5mF, the distances from the offshore converter station to the three onshore converter stations are 100km, 150km, and 200km respectively, and the distance between the energy storage system and the asynchronous grid 3 is 20km.

[0079] Table 1 5MW wind turbine model parameters

[0080]

[0081] The following simulation verification is carried out, and a comparative analysis is made with the traditional frequency support method. The comparative simulation example is set up as follows:

[0082] Case 1 (method of the invention, MOI): using the state factor-based multi-terminal flexible direct current system consistent coordinated frequency support method of the present invention;

[0083] Case 2 (traditional method, TDM): The offshore wind farm adopts centralized control, while the multi-terminal flexible direct current system and the energy storage system both adopt droop control.

[0084] The safety lower limits of the offshore wind turbine speed, the DC voltage of the flexible DC system, the state of charge of the energy storage system, the frequency of the offshore AC power grid, and the asynchronous AC power grid are set to 0.7pu, 0.9pu, 0.2pu, 49.8Hz, and 49.8Hz, respectively. At 5s, the asynchronous AC power grid 1 experiences a sudden load increase of 120MW and a frequency drop. The simulation results of the comparative example are shown in Figure 5 As shown. It can be seen that under the traditional method, since the multi-terminal flexible DC system adopts droop control, the output power of the onshore converter station is affected by the droop coefficient, and the frequency regulation stability is poor. Once the droop coefficient is set improperly, the non-disturbance grid may even produce a larger frequency fluctuation than the disturbed grid, such as Figure 5 (Ba), the frequency fluctuation of the asynchronous power grid 3 even exceeds that of the disturbed power grid 1. In contrast, the method of the present invention coordinates all frequency modulation sources in the whole system to jointly participate in the frequency support of the disturbed power grid through consistency control. The ones with strong frequency modulation capability will produce more, and the ones with weak frequency modulation capability will produce less. While achieving a good frequency regulation effect, the safety and stability of the frequency modulation source itself are guaranteed. Figure 5 (Ab), the higher the speed of the aggregated fan, the more energy it releases, and the greater the speed drop. In addition, under the multi-terminal flexible direct current system consistency collaborative frequency support method based on the state factor of the present invention, the system does not need to install communication equipment, and each frequency modulation source only needs to collect local information to achieve global consistency control, which reduces communication delay and improves frequency modulation reliability.

[0085] It should be noted that this specific embodiment is based on a frequency drop event, which is only taken as an example and is not limited to applicable scenarios of the present invention. The same is applicable to a frequency sudden increase event.

[0086] Embodiment 2: In the second aspect, as Figure 6 As shown, in order to achieve the above-mentioned purpose, the present invention discloses a state factor-based flexible direct current system consistent coordinated frequency support device, comprising:

[0087] The state factor calculation module 11 is used to obtain multiple types of frequency modulation source related data, calculate the state factor based on the multiple types of frequency modulation source related data, and obtain the state factors of the multiple types of frequency modulation sources, wherein the multiple types of frequency modulation source related data include multiple types of frequency modulation source parameter data, multiple types of frequency modulation source safety upper and lower limit data, and multiple types of frequency modulation source parameter data when a frequency event occurs;

[0088] The collaborative frequency support module 12 is used to perform consistency control based on the state factors of multiple types of frequency modulation sources. Through consensus protocol regulation, each frequency modulation source controls its corresponding state factor to be consistent with the disturbed power grid, so that they are bound to each other and jointly provide frequency support for the disturbed power grid based on their own frequency regulation capabilities. The multiple types of frequency modulation sources include offshore wind turbines, flexible direct current systems, asynchronous AC power grids and energy storage systems.

[0089] Based on the same inventive concept, the present invention also provides a computer device, which includes: one or more processors, and a memory for storing one or more computer programs; the program includes program instructions, and the processor is used to execute the program instructions stored in the memory. The processor may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components, etc. It is the computing core and control core of the terminal, which is used to implement one or more instructions, specifically for loading and executing one or more instructions in a computer storage medium to implement the above method.

[0090] It needs to be further explained that, based on the same inventive concept, the present invention also provides a computer storage medium, on which a computer program is stored, and the computer program is executed by a processor to execute the above method. The storage medium can adopt any combination of one or more computer-readable media. The computer-readable medium can be a computer-readable signal medium or a computer-readable storage medium. The computer-readable storage medium can be, for example, but not limited to, an electrical, magnetic, optical, electrical, magnetic, infrared, or semiconductor system, device or device, or any combination of the above. More specific examples (non-exhaustive list) of computer-readable storage media include: an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above. In the present invention, a computer-readable storage medium can be any tangible medium containing or storing a program, which can be used by an instruction execution system, device or device or used in combination with it.

[0091] In the description of this specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present disclosure. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0092] The above shows and describes the basic principles, main features and advantages of the present disclosure. Those skilled in the art should understand that the present disclosure is not limited by the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present disclosure. Without departing from the spirit and scope of the present disclosure, the present disclosure may have various changes and improvements, and these changes and improvements fall within the scope of the present disclosure to be protected.

Claims

1. A method for coherent frequency support of flexible DC system based on state factor, characterized in that: The method comprises the following steps: Acquire multiple types of frequency modulation source related data, calculate state factors based on the multiple types of frequency modulation source related data, and obtain state factors of the multiple types of frequency modulation sources, wherein the multiple types of frequency modulation source related data include multiple types of frequency modulation source parameter data, multiple types of frequency modulation source safety upper and lower limit data, and multiple types of frequency modulation source parameter data when frequency events occur; Based on the state factors of multiple types of frequency modulation sources and consistency control, each frequency modulation source controls its corresponding state factor to be consistent with the disturbed power grid through consensus protocol regulation, so that they are bound to each other and jointly provide frequency support for the disturbed power grid according to their own frequency regulation capabilities. Among them, the multiple types of frequency modulation sources include offshore wind turbines, flexible direct current systems, asynchronous AC power grids and energy storage systems.

2. The method for coherent coordinated frequency support of flexible DC system based on state factor according to claim 1 is characterized in that: The multiple types of frequency modulation source parameter data include: offshore wind turbine speed ω ri , offshore AC grid frequency f OWF , flexible DC system DC voltage U dc , non-synchronous AC grid frequency f j Energy storage state of charge SOC es .

3. The method for coherent coordinated frequency support of flexible DC system based on state factor according to claim 1, characterized in that: The safety upper and lower limit data of the multiple types of frequency regulation sources include: offshore wind turbines ω ri_max ,ω ri_min ; Frequency of offshore AC power grid f OWF_max 、f OWF_min ; Flexible DC system DC voltage U dc_max , U dc_min ; Asynchronous AC grid frequency f j_max 、f j_min ; Energy storage state of charge SOC es_max , SOC es_min , it is also necessary to determine the reference value of the offshore AC power grid frequency f OWF_ref .

4. The method for coherent coordinated frequency support of flexible DC system based on state factor according to claim 1, characterized in that: The multiple types of frequency modulation source parameter data when the frequency event occurs include: the speed of the offshore wind turbine when the frequency event occurs ri0 , flexible DC system voltage U dc0 , non-synchronous AC grid frequency f j0 , Energy storage state of charge SOC es0 .

5. The method for coherent coordinated frequency support of flexible DC system based on state factor according to claim 1, characterized in that: The process of calculating the state factor based on multiple types of frequency modulation source related data includes: The calculation formula of wind turbine state factor is: In the formula, J i is the moment of inertia of the wind turbine; The frequency modulation energy of the flexible DC system comes from the DC support capacitor on it, so the calculation formula of the state factor is: In the formula, C eq is the equivalent supporting capacitance of the flexible DC system; For a non-synchronous AC power grid, it can be equivalent to a synchronous unit, and the calculation formula of the state factor is: In the formula, J jeq is the moment of inertia of the equivalent synchronous unit, ω jeq is the real-time rotor speed of the equivalent unit, ω jeq0 is the initial speed of the equivalent unit when the frequency event occurs, ω jeq_max ,ω jeq_min These are the safe upper and lower limits of the rotor speed of the equivalent unit; The relationship between the synchronous generator rotor speed and frequency is: Where, ω and p are the rotor speed and pole number of the synchronous generator, f syn is the generator output AC frequency, and the corrected asynchronous AC grid state factor is: Finally, the calculation formula of the energy storage system state factor is as follows:

6. The method for coherent coordinated frequency support of flexible DC system based on state factor according to claim 1, characterized in that: The consensus protocol based on the state factors of multiple frequency modulation sources and consistency control and regulated by the consensus protocol is as follows: x i =y=z j =s es 。 7. The method for coherent coordinated frequency support of flexible DC system based on state factor according to claim 6, characterized in that: In the process of consistency control based on the state factors of multiple types of frequency modulation sources, The offshore wind farm is decoupled from the onshore asynchronous power grid due to the flexible DC system and cannot directly perceive the frequency changes of the disturbed power grid. Therefore, it is necessary to map the frequency of the disturbed power grid to the offshore AC power grid through the DC voltage changes of the flexible DC system, thereby eliminating the need for communication equipment and increasing the speed of frequency information transmission. The flexible DC system responds to the consistency consensus protocol, and the state factor is consistent with the disturbed power grid, so the frequency of the offshore AC power grid is controlled to meet the following formula:

8. A flexible DC system consistency coordination frequency support device based on state factor, characterized in that: include: A state factor calculation module is used to obtain multiple types of frequency modulation source related data, calculate the state factor based on the multiple types of frequency modulation source related data, and obtain the state factors of the multiple types of frequency modulation sources, wherein the multiple types of frequency modulation source related data include multiple types of frequency modulation source parameter data, multiple types of frequency modulation source safety upper and lower limit data, and multiple types of frequency modulation source parameter data when a frequency event occurs; The collaborative frequency support module is used to perform consistency control based on the state factors of multiple types of frequency modulation sources. Through consensus protocol regulation, each frequency modulation source controls its corresponding state factor to be consistent with the disturbed power grid, so that they are bound to each other and jointly provide frequency support for the disturbed power grid based on their own frequency regulation capabilities. Among them, the multiple types of frequency modulation sources include offshore wind turbines, flexible direct current systems, asynchronous AC power grids and energy storage systems.

9. A terminal device, comprising a memory, a processor, and a computer program stored in the memory and capable of running on the processor, characterized in that: The memory stores a computer program that can be run on the processor. When the processor loads and executes the computer program, the state factor-based consistent collaborative frequency support method for a flexible direct current system according to any one of claims 1 to 7 is adopted.

10. A computer-readable storage medium having a computer program stored therein, characterized in that: When the computer program is loaded and executed by the processor, the state factor-based consistent coordinated frequency support method for a flexible direct current system according to any one of claims 1 to 7 is adopted.

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