Method, system, device and medium for suppressing grid-connected side active resonance of offshore wind farm

Abstract

The present invention belongs to the technical field of power grid harmonic suppression, and discloses an active resonance suppression method, system, device and medium for the grid connection side of an offshore wind farm to overcome the limitations of traditional control strategies. The method of the present invention includes equivalenting a high-voltage active resonance suppression device and an offshore wind farm-submarine cable system into a composite system; sampling the grid connection point voltage vector and the offshore wind farm current vector to obtain the grid connection point voltage and the offshore wind farm current corresponding to each resonance respectively, so as to construct a composite vector of the composite system; determining a suppression mode for each resonance based on the composite vector, calculating the control values of the current harmonic components output by the high-voltage active resonance suppression device for each time and the total output current control value, and generating a driving signal to realize active resonance suppression on the grid connection side of the offshore wind farm. The present invention realizes the decoupling of two control objectives of harmonic current in the grid connection line and grid background harmonic voltage, thereby improving the power quality of the offshore wind farm and optimizing the grid connection performance.

Description

Technical Field

[0001] The present invention belongs to the technical field of power grid harmonic suppression, and particularly relates to an active resonance suppression method, system, device and medium for the grid connection side of an offshore wind farm. Background Art

[0002] With the transformation of the global energy structure and the increasing demand for clean energy, offshore wind farms have become an important direction for renewable energy development in China's coastal areas due to their clean and environmentally friendly operation mode and high energy utilization efficiency. At the technical level, the power transmission of offshore wind farms is similar to the overhead lines of onshore AC power grids, and both need to be transmitted to the land grid over long distances through submarine AC power cables. However, due to the inherent high positive sequence capacitance and low series impedance characteristics of submarine AC power cables, offshore wind farms not only amplify the harmonics generated by themselves during the grid connection process, but also amplify the grid background harmonics. This phenomenon causes a significant harmonic voltage distortion rate at the common connection point of the power grid, which poses a potential threat to the safe and stable operation of power grid transmission and transformation equipment.

[0003] In view of the fact that passive filters inevitably generate capacitive reactive power under power frequency conditions, which in turn causes the problem of reactive power imbalance in wind farms. To address this problem, the existing solution is to add a high-voltage active resonance suppression device in the wind farm, which can automatically track harmonic signals and actively filter harmonics. Currently, the control strategies of the high-voltage active resonance suppression devices used for harmonic governance in offshore wind farms mainly include two types: the harmonic current suppression strategy of the wind farm and the grid background harmonic voltage suppression strategy. The harmonic current suppression strategy cancels the harmonic components in the grid connection line by inversely outputting harmonic current. However, this strategy is only limited to controlling the harmonics injected from the wind farm into the grid and has no positive effect on suppressing the grid's own background harmonics, and usually cannot fully utilize the full capacity of the filter; the harmonic voltage suppression strategy forms a virtual "low impedance" channel by tracking voltage changes, so that the harmonics of both the wind farm and the power system flow into the active filter, but this strategy may cause the line harmonic current to exceed the limit. Both of these control strategies have certain limitations in practical applications and cannot be used simultaneously, thus restricting the popularization and application scope of high-voltage active resonance suppression devices.

[0004] In summary, the traditional control strategies have limitations and cannot take into account the two control objectives of wind farm harmonic current and grid background harmonics, restricting the fast and flexible adjustment ability of high-voltage active resonance suppression devices. Summary of the Invention

[0005] Based on the above-mentioned disadvantages and deficiencies in the prior art, one of the objectives of the present invention is to at least solve one or more of the above problems existing in the prior art. In other words, one of the objectives of the present invention is to provide a method, system, device and medium for suppressing active resonance on the grid side of an offshore wind farm that meet one or more of the aforementioned requirements, aiming to decouple the two control objectives of harmonic current in the grid connection line and grid background harmonic voltage, ensuring the efficient and flexible control of the high-voltage active resonance suppression device in the harmonic governance of the offshore wind farm, thereby improving the power quality of the offshore wind farm and optimizing the grid connection performance.

[0006] To achieve the above-mentioned invention objectives, the present invention adopts the following technical solutions:

[0007] In the first aspect, the present invention provides a method for suppressing active resonance on the grid side of an offshore wind farm, including the steps of:

[0008] S1. Equivalent the high-voltage active resonance suppression device and the offshore wind farm - submarine cable system into a composite system;

[0009] S2. Obtain the grid connection point voltage vector and the offshore wind farm current vector and perform sampling processing to obtain the grid connection point voltage and the offshore wind farm current corresponding to each resonance respectively, thereby constructing the composite vector of the composite system;

[0010] S3. Based on the composite vector, execute the step of determining the suppression mode for each resonance. The step of determining the suppression mode includes:

[0011] S31. Perform - transformation on the component corresponding to this resonance in the composite vector to obtain value, and calculate the voltage amplitude and the current amplitude corresponding to this resonance based on this;

[0012] S32. Obtain the preset voltage threshold and the current threshold ;

[0013] S33. Compare the voltage amplitude with the voltage threshold , the current amplitude with the current threshold respectively, and select the corresponding suppression mode based on the comparison results;

[0014] S4. Calculate the control values of the current harmonic components output by each time of the high-voltage active resonance suppression device based on the suppression mode obtained in step S3 , so as to calculate the total output current control value of the high-voltage active resonance suppression device And generate the corresponding PWM drive signal, and realize the active resonance suppression on the grid-connected side of the offshore wind farm based on the PWM drive signal

[0015] As a preferred solution, before the step of determining the suppression mode for each resonance based on the composite vector in step S3, the following steps are further included

[0016] Obtain the preset resonance control conditions

[0017] The expression of the resonance control condition is

[0018] ,

[0019] Let the total number of resonances be , be the number of this resonance, then in the formula , and are the th harmonic components of the grid-connected point voltage, the offshore wind farm current and the harmonic output current of the high-voltage active resonance suppression device respectively is the limit value of the total harmonic voltage at the grid-connected point is the limit value of the total harmonic current of the offshore wind farm is the limit value of the total harmonic current of the high-voltage active resonance suppression device

[0020] As a preferred solution, the calculation formulas for the voltage amplitude and the current amplitude are

[0021] ,

[0022] Let the total number of resonances be , be the number of this resonance, then in the formula , , and are the th harmonic component value of the grid-connected point voltage, the th harmonic component value of the grid-connected point voltage, the th harmonic component value of the offshore wind farm current and the th harmonic component value

[0023] As a preferred solution, the selecting of the corresponding suppression mode based on the comparison result in step S33 is specifically as follows:

[0024] When the voltage amplitude is less than the voltage threshold , and the current amplitude is greater than the current threshold , the harmonic shunt control mode is selected for resonance control;

[0025] Otherwise, the conventional control mode is selected for resonance control.

[0026] As a preferred solution, the calculating of the control values of the current harmonic components output by the high-voltage active resonance suppression device based on the suppression mode obtained in step S4 includes the steps of:

[0027] Perform a transformation on the current amplitude - to obtain the measurement values of the current harmonic components of the offshore wind farm, which are and respectively;

[0028] Based on the harmonic shunt control mode control formula or the conventional control mode control formula, calculate the command values of the harmonic current amounts output by the composite system, which are and respectively;

[0029] Based on the command values of the harmonic current amounts output by the composite system and the measurement values of the current harmonic components of the offshore wind farm, calculate the command values of the current harmonic components output by the high-voltage active resonance suppression device;

[0030] Perform an inverse transformation on the command values of the current harmonic components output by the high-voltage active resonance suppression device to obtain the control values of the current harmonic components output by the high-voltage active resonance suppression device .

[0031] As a preferred solution, the harmonic shunt control mode control formula is

[0032] ,

[0033] Let the total number of resonance times be , is the number of times of this resonance. In the formula, is the measurement value of the harmonic component of the current of the offshore wind farm for this time, is the th harmonic component of the current of the offshore wind farm, is the limit value of the total harmonic current of the offshore wind farm;

[0034] The control formula of the conventional control mode is .

[0035] As a preferred solution, the calculation formula of the command value of the current harmonic component output by each time of the high-voltage active resonance suppression device is

[0036] ,

[0037] In the formula, and are the command values of the harmonic current quantity output by the composite system, and are the measurement values of the harmonic component of the current of the offshore wind farm for this time;

[0038] The calculation formula of the total output current control value of the high-voltage active resonance suppression device is

[0039] ,

[0040] In the formula, is the total number of resonances, is the number of resonances.

[0041] In a second aspect, the present invention provides an active resonance suppression system for the grid connection side of an offshore wind farm, which is characterized in that it is used to implement the active resonance suppression method for the grid connection side of an offshore wind farm as described in the first aspect.

[0042] In a third aspect, the present invention provides an electronic device. The computer device includes a memory, a processor, and a computer program. When the computer program is executed by the processor, it implements the active resonance suppression method for the grid connection side of an offshore wind farm as described in the first aspect.

[0043] In a fourth aspect, the present invention provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by the processor, it implements the active resonance suppression method for the grid connection side of an offshore wind farm as described in the first aspect.

[0044] Compared with the prior art, the present invention has the following beneficial effects:

[0045] The present invention first equivalent the high-voltage active resonance suppression device and the offshore wind farm - submarine cable system into a composite system, and then calculates the output current of the high-voltage active resonance suppression device by means of the composite vector of the composite system, so as to achieve the purpose of suppressing the harmonic at the grid connection point. The present invention does not need to add a high-voltage shunt reactor, does not increase the floor area, and has a low cost. It can make more effective use of the harmonic regulation ability of the submarine cable itself, while taking into account the amplification of the harmonic current of the wind farm and the suppression of the grid background harmonic voltage. It has strong adaptability to the grid and is easier to implement; and the control method is simple and easy to realize; the parameter calculation formula is concise and clear, which can significantly improve the calculation efficiency and meet the actual work needs.

[0046] Further or more detailed beneficial effects will be described in combination with specific embodiments in the specific implementation manner. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0048] Figure 1 is a schematic diagram of the application scenario of the active resonance suppression method on the grid connection side of the offshore wind farm described in the embodiment of the present invention.

[0049] Figure 2 is in Figure 1 the schematic diagram of the principle of realizing resonance suppression based on the composite vector under the application scenario.

[0050] Figure 3 is in Figure 1 the circuit schematic diagram under the application scenario.

[0051] Figure 4 is the equivalent circuit diagram of realizing resonance suppression based on the composite vector in the embodiment of the present invention.

[0052] Figure 5 is the flowchart of realizing resonance suppression based on the composite vector in the embodiment of the present invention.

[0053] Figure 6 is based on - the schematic diagram of the principle of transformation in the embodiment of the present invention.

[0054] Figure 7 is the schematic diagram of determining the suppression mode described in the embodiment of the present invention.

[0055] Figure 8 It is a schematic diagram of the principle of suppressing resonance by applying the suppression mode described in the embodiments of the present invention.

[0056] Figure 9 It is a simulation effect diagram of pre-resonance control for the grid-connected side active resonance suppression method described in the embodiments of the present invention for an offshore wind farm.

[0057] Figure 10 It is a simulation effect diagram of post-resonance control for the grid-connected side active resonance suppression method described in the embodiments of the present invention for an offshore wind farm.

[0058] Figure 11 It is a structural diagram of the electronic device provided in the embodiments of the present invention.

[0059] Reference numerals in the drawings:

[0060] 1100, electronic device;

[0061] 1101, processor; 1102, communication bus; 1103, user interface; 1104, network interface; 1105, memory. Detailed implementation manners

[0062] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention.

[0063] In the following description, multiple embodiments of the present invention are provided, and different embodiments can be replaced or combined. Therefore, the present invention can also be considered to include all possible combinations of the same and / or different embodiments described. Thus, if one embodiment includes features A, B, and C, and another embodiment includes features B and D, then the present invention should also be considered to include embodiments including all other possible combinations of A, B, C, and D, even though such embodiments may not be explicitly described in the following content.

[0064] The following description provides examples and does not limit the scope, applicability, or examples set forth in the claims. Changes can be made to the functions and arrangements of the described elements without departing from the scope of the content of the present invention. Each example can appropriately omit, substitute, or add various processes or components. For example, the described method can be executed in a different order from the described order, and various steps can be added, omitted, or combined. In addition, the features described in some examples can be combined into other examples.

[0065] To facilitate a better understanding of the embodiments of the present invention, before explaining the detailed implementation manners of the present invention in detail, its application scenarios will be described first.

[0066] Please refer to Figures 1 - 3, Figure 1 It shows a schematic diagram of the application scenario of the active resonance suppression method on the grid side of the offshore wind farm.

[0067] In the process of applying the active resonance suppression method on the grid side of the offshore wind farm described in the embodiments of this specification, in these scenarios, the application of the active resonance suppression method on the grid side of the offshore wind farm aims to make up for the defects of the existing suppression strategies, achieve the decoupling of the two control objectives of harmonic current in the grid-connected line and grid background harmonic voltage, ensure the efficient and flexible control of the high-voltage active resonance suppression device in the harmonic governance of the offshore wind farm, thereby improving the power quality of the offshore wind farm and optimizing the grid connection performance.

[0068] The following gives a simple explanation of the offshore wind farm - submarine cable system, high-voltage active resonance suppression device, complex vector, and - transformation involved in multiple embodiments of this specification:

[0069] The offshore wind farm - submarine cable system includes wind turbines and submarine cables. Wind turbines installed in the waters far from the coast are usually located in areas with stronger and more stable winds to maximize the utilization of wind energy resources. To transmit the electricity generated by these generators to the onshore grid, a submarine cable system is required. This system consists of multiple cables laid on the seabed and is capable of withstanding high voltages and harsh marine environments. The design and maintenance of the submarine cable system are crucial for ensuring the efficient and reliable operation of the offshore wind farm.

[0070] The high-voltage active resonance suppression device is an advanced power electronic device designed to detect and eliminate resonance problems in the power system. In the power system, resonance phenomena may cause voltage and current instability and even damage to equipment. By continuously monitoring the grid parameters and dynamically adjusting its internal electrical characteristics, this device can effectively suppress resonance and ensure the stable operation of the power system. In high-voltage application scenarios such as offshore wind farms, this device is particularly important because these systems are more vulnerable to resonance problems.

[0071] As a mathematical tool, the complex vector is used to describe and analyze vectors in multi-dimensional space. In power system analysis, the complex vector can be used to represent the combination of multiple different vectors such as voltage, current, or other electrical parameters. By integrating these parameters into a complex vector, the complex calculation and analysis process can be simplified, enabling engineers to more intuitively understand and control the dynamic behavior of the power system. The complex vector has important application value in the design and optimization of control strategies.

[0072] - The transformation is a mathematical transformation method applied to power system analysis and control. This method converts the time-varying parameters in a three-phase alternating current system into direct current parameters, thereby simplifying the analysis of the system's dynamic characteristics. Based on the synchronous rotating coordinate system, - the transformation decomposes the three-phase alternating current parameters into two orthogonal components: component and component. This method is widely used in motor control, power electronic devices, and the power management system of offshore wind farms. By simplifying the complex alternating current parameters, - the transformation enables engineers to more effectively design and implement precise control strategies.

[0073] Example 1:

[0074] As Figures 4 - 7 shown, this example provides an active resonance suppression method for the grid connection side of an offshore wind farm, including the steps: S1. Equivalent the high-voltage active resonance suppression device and the offshore wind farm - submarine cable system into a composite system; S2. Obtain the grid connection point voltage vector and the offshore wind farm current vector for sampling processing to obtain the grid connection point voltage and the offshore wind farm current corresponding to each resonance respectively, thereby constructing the composite vector of the composite system; S3. Based on the composite vector, execute the steps of determining the suppression mode for each resonance. The steps of determining the suppression mode include: S31. Perform - transformation on the component corresponding to this resonance in the composite vector to obtain value, and calculate the voltage amplitude and the current amplitude corresponding to this resonance based on this; S32. Obtain the preset voltage threshold and the current threshold ; S33. Compare the voltage amplitude with the voltage threshold , and compare the current amplitude with the current threshold respectively, and select the corresponding suppression mode based on the comparison results; S4. Calculate the control value of each output current harmonic component of the high-voltage active resonance suppression device based on the suppression mode obtained in step S3, thereby calculating the total output current control value And generate corresponding PWM drive signals, and realize active resonance suppression on the grid-connected side of the offshore wind farm based on the PWM drive signals.

[0075] It can be understood that since the capacitive harmonic current vector of the wind farm and the harmonic voltage vector at the common connection point of the power grid are basically at 90 degrees, ignoring the harmonic sources of the offshore wind farm itself, the directions of the two vectors of the harmonic current vector from the wind farm and the harmonic current vector from the power grid background are basically coincident. However, according to the harmonic impedance characteristics of the power grid background, there may be two situations of superposition or cancellation. In this embodiment, the high-voltage active resonance suppression device and the offshore wind farm-submarine cable system are equivalently regarded as a composite system, and by controlling the harmonic current vector output by the composite system, both the amplification and suppression of the wind farm harmonics and the governance of the harmonic voltage of the power grid background are taken into account.

[0076] Specifically, this embodiment provides a preferred implementation manner of step S3. Before the step of determining the suppression mode for each resonance based on the composite vector, the steps further include: obtaining a preset resonance control condition; the expression of the resonance control condition is , assuming the total number of resonances is , is the number of this resonance, then in the formula, , and are the th harmonic components of the grid connection point voltage, the offshore wind farm current, and the harmonic output current of the high-voltage active resonance suppression device respectively, is the limit value of the total harmonic voltage at the grid connection point, is the limit value of the total harmonic current of the offshore wind farm, is the limit value of the total harmonic current of the high-voltage active resonance suppression device.

[0077] It can be understood that in this embodiment, each parameter is set according to the characteristics of the offshore wind farm-submarine cable system, and the obtained resonance control condition can effectively improve the implementation efficiency and meet the needs of actual engineering.

[0078] Specifically, this embodiment provides a preferred implementation manner. The calculation formulas for the voltage amplitude and the current amplitude are: , assuming the total number of resonances is , is the number of this resonance, then in the formula, , , and are the th harmonic component value of the grid connection point voltage, the of the subharmonic component value, the subharmonic component of the current of the offshore wind farm value, and the subharmonic component of the current of the offshore wind farm value.

[0079] Specifically, this embodiment provides a preferred implementation manner. The selecting the corresponding suppression mode based on the comparison result in step S33 is specifically as follows: When the voltage amplitude is less than the voltage threshold , and the current amplitude is greater than the current threshold , the harmonic shunt control mode is selected for resonance control; otherwise, the conventional control mode is selected for resonance control.

[0080] More specifically, in the harmonic shunt control mode, it should be ensured that the harmonic current of the offshore wind farm does not exceed the limit value, and in the conventional control mode, it should be ensured that the voltage at the common connection point is as small as possible.

[0081] Specifically, this embodiment provides a preferred implementation manner of step S4. Calculating the control values of the current harmonic components output by each stage of the high-voltage active resonance suppression device based on the suppression mode obtained in step S3 , includes the steps of: performing a - transformation on the current amplitude to obtain the and measured values of the subharmonic component of the current of the offshore wind farm; calculating the command values of the harmonic current quantity output by the composite system based on the harmonic shunt control mode control formula or the conventional control mode control formula, which are respectively and ; calculating the command values of the harmonic current quantity output by the composite system and the measured values of the subharmonic component of the current of the offshore wind farm, and calculating the command values of the current harmonic components output by each stage of the high-voltage active resonance suppression device;

[0082] Performing an inverse transformation on the command values of the current harmonic components output by each stage of the high-voltage active resonance suppression device to obtain the control values of the current harmonic components output by each stage of the high-voltage active resonance suppression device .

[0083] Specifically, this embodiment provides a preferred implementation manner. The harmonic shunt control mode control formula is , let the total number of resonances be , be the number of this resonance, then in the formula, is the measured value of the harmonic component of the current of the offshore wind farm, is the th harmonic component of the current of the offshore wind farm, is the limit value of the total harmonic current of the offshore wind farm; the control formula of the conventional control mode is .

[0084] Specifically, this embodiment provides a preferred implementation manner, and the calculation formula of the command value of the current harmonic component output by each time of the high-voltage active resonance suppression device is , in the formula, and are the command values of the harmonic current quantity output by the composite system, and are the measured values of the harmonic component of the current of the offshore wind farm; the total output current control value of the high-voltage active resonance suppression device has a calculation formula of , in the formula, is the total number of resonances, is the number of resonances.

[0085] Embodiment 2:

[0086] This embodiment provides an active resonance suppression system on the grid connection side of an offshore wind farm for implementing the active resonance suppression method on the grid connection side of an offshore wind farm as described in Embodiment 1.

[0087] Embodiment 3:

[0088] As Figure 11 shown, this embodiment provides an electronic device, which may include: at least one processor, at least one network interface, a user interface, a memory, and at least one communication bus.

[0089] Among them, the communication bus can be used to realize the connection and communication of the above-mentioned various components.

[0090] Among them, the user interface may include buttons, and the optional user interface may further include a standard wired interface and a wireless interface.

[0091] Among them, the network interface may but is not limited to include a Bluetooth module, an NFC module, a Wi-Fi module, etc.

[0092] Among them, the processor may include one or more processing cores. The processor uses various interfaces and circuits to connect various parts within the entire electronic device. By running or executing instructions, programs, code sets, or instruction sets stored in the memory, and by calling the data stored in the memory, it executes various functions of the electronic device and processes data. Optionally, the processor may be implemented in at least one hardware form of DSP, FPGA, or PLA. The processor may integrate one or a combination of several of CPU, GPU, and modem, etc. Among them, the CPU mainly processes the operating system, user interface, application programs, etc.; the GPU is responsible for rendering and drawing the content to be displayed on the display screen; the modem is used to process wireless communication. It can be understood that the above-mentioned modem may not be integrated into the processor and may be implemented separately by a single chip.

[0093] Among them, the memory may include RAM and may also include ROM. Optionally, the memory includes a non-transitory computer-readable medium. The memory can be used to store instructions, programs, code, code sets, or instruction sets. The memory may include a program storage area and a data storage area. Among them, the program storage area may store instructions for implementing the operating system, instructions for at least one function (such as touch function, sound playback function, image playback function, etc.), instructions for implementing the above-mentioned various method embodiments, etc.; the data storage area may store the data involved in the above-mentioned various method embodiments. Optionally, the memory may also be at least one storage device located far from the aforementioned processor. As a computer storage medium, the memory may include an operating system, a network communication module, a user interface module, and a resonance suppression application program. The processor may be used to call the resonance suppression application program stored in the memory and execute the steps of active resonance suppression on the grid connection side of the offshore wind farm mentioned in the foregoing embodiments.

[0094] Embodiment 4:

[0095] This embodiment provides a computer-readable storage medium. Instructions are stored in the computer-readable storage medium. When they run on a computer or a processor, they cause the computer or the processor to execute one or more of the steps in the above-mentioned Figures 1 - 7 illustrated embodiments. If the various component modules of the above-mentioned electronic device are implemented in the form of software functional units and sold or used as independent products, they can be stored in the computer-readable storage medium.

[0096] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the processes or functions described in the embodiments of this specification are generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices. The computer instructions can be stored in a computer-readable storage medium or transmitted through the computer-readable storage medium. The computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center in a wired manner (such as coaxial cable, optical fiber, Digital Subscriber Line (DSL)) or wirelessly (such as infrared, wireless, microwave, etc.). The computer-readable storage medium can be any available medium that can be accessed by a computer or a data storage device such as a server or data center that includes one or more integrated available media. The available medium can be a magnetic medium (for example, floppy disk, hard disk, magnetic tape), an optical medium (for example, Digital Versatile Disc (DVD)), or a semiconductor medium (for example, Solid State Disk (SSD)), etc.

[0097] Those of ordinary skill in the art can understand that all or part of the processes in the method of the above-mentioned Embodiment 1 can be completed by instructing relevant hardware through a computer program. This program can be stored in a computer-readable storage medium. When this program is executed, it can include the processes of the embodiments of the above-mentioned various methods. The foregoing storage medium includes: various media such as ROM, RAM, magnetic disk, or optical disc that can store program codes. Without conflict, the technical features in this embodiment and the implementation solutions can be combined arbitrarily.

[0098] Embodiment 5:

[0099] To verify the effectiveness of the method for suppressing active resonance on the grid side of the offshore wind farm described in this specification, this embodiment is based on the actual application scenario of this method and Figure 8 the principle shown, and obtains the comparative simulation effect diagrams before and after resonance governance as shown in Figures 9 to 10 Accordingly, this embodiment fully proves the effectiveness of the method for suppressing active resonance on the grid side of the offshore wind farm described in this specification.

[0100] It should be noted that, for the foregoing method embodiments, for the sake of simple description, they are all expressed as a series of action combinations. However, those skilled in the art should know that the present invention is not limited by the described action sequence, because according to the present invention, certain steps can be performed in other sequences or simultaneously. Secondly, those skilled in the art should also know that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily essential to the present invention.

[0101] In the above embodiments, the descriptions of the respective embodiments have their own emphases. For the parts not detailed in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0102] The foregoing are only exemplary embodiments of the present invention and should not be used to limit the scope of the present invention. That is, all equivalent changes and modifications made in accordance with the teachings of the present invention still fall within the scope covered by the present invention. After considering the specification and practicing the disclosure herein, those skilled in the art will readily conceive of other embodiments of the present invention. The present invention is intended to cover any variations, uses, or adaptations of the present invention that follow the general principles of the present invention and include common general knowledge or conventional technical means in the technical field not recorded in the present invention. The specification and embodiments are only regarded as exemplary, and the scope and spirit of the present invention are defined by the claims.

Claims

1. A method for suppressing active resonance on the grid connection side of an offshore wind farm, characterized in that, Including the steps: S1. Equivalent the high-voltage active resonance suppression device and the offshore wind farm - submarine cable system into a composite system; S2. Obtain the grid connection point voltage vector and the offshore wind farm current vector Perform sampling processing to obtain the grid connection point voltage corresponding to each resonance and the offshore wind farm current Thereby constructing the composite vector of the composite system; S3. Based on the composite vector, perform the step of determining the suppression mode for each resonance, and the step of determining the suppression mode includes: S31. Transform the component corresponding to this resonance in the composite vector to obtain a - value, and calculate the voltage amplitude and current amplitude corresponding to this resonance based on this; ; S32. Obtain a preset voltage threshold and a current threshold ; S33. Compare the voltage amplitude with the voltage threshold , compare the current amplitude with the current threshold respectively, and select a corresponding suppression mode based on the comparison results. The selection of the corresponding suppression mode based on the comparison results includes that when the voltage amplitude is less than the voltage threshold , and the current amplitude is greater than the current threshold , select the harmonic shunt control mode for resonance control; S4. Calculate the control values of the current harmonic components of each output of the high-voltage active resonance suppression device based on the suppression mode obtained in step S3 , so as to calculate the total output current control value of the high-voltage active resonance suppression device And generate the corresponding PWM drive signal, and realize the active resonance suppression on the grid-connected side of the offshore wind farm based on the PWM drive signal.

2. The active resonance suppression method for the grid connection side of an offshore wind farm according to claim 1, wherein Before the step of determining the suppression mode for each resonance based on the composite vector in step S3, there is also a step: Obtain the preset resonance control conditions; The expression of the resonance control conditions is ， Let the total number of resonances be , be the number of this resonance. Then, in the formula, , and are the -th harmonic components of the grid connection point voltage, the offshore wind farm current, and the harmonic output current of the high-voltage active resonance suppression device respectively. is the limit value of the total harmonic voltage at the grid connection point, is the limit value of the total harmonic current of the offshore wind farm, is the limit value of the total harmonic current of the high-voltage active resonance suppression device.

3. A method for suppressing active resonance on the grid connection side of an offshore wind farm according to claim 2, characterized in that, The voltage amplitude and the current amplitude are calculated by the following formula: ， Let the total number of resonances be , be the number of this resonance. Then in the formula, , , and are respectively the value of the th harmonic component of the grid connection point voltage, the th harmonic component of the grid connection point voltage, the value of the th harmonic component of the offshore wind farm current, and the value of the th harmonic component of the offshore wind farm current. value.

4. A grid-connected side active resonance suppression method for an offshore wind farm according to claim 3, characterized in that Specifically, the corresponding suppression mode is selected based on the comparison result in step S33: When the voltage amplitude is less than the voltage threshold , and the current amplitude is greater than the current threshold , the harmonic shunt control mode is selected for resonance control; Otherwise, select the conventional control mode for resonance control.

5. A method for suppressing active resonance on the grid side of an offshore wind farm according to claim 4, characterized in that, Calculating the control values of the current harmonic components output by each time of the high-voltage active resonance suppression device based on the suppression mode obtained in step S3 as described in step S4 , including the steps of: For the current amplitude perform - transformation to obtain the measured values of the current sub-harmonic components of the offshore wind farm, which are respectively and and ; Based on the harmonic shunt control mode control formula or the conventional control mode control formula, the harmonic current values output by the composite system are calculated to be command values, which are respectively and ; Based on the harmonic current quantity output by the composite system command value and the harmonic component of the current of the offshore wind farm at this time measurement value, calculate the command value of the current harmonic component output by the high-voltage active resonance suppression device at each order command value; Inverse-transform the current harmonic component of each output of the high-voltage active resonance suppression device to obtain the control value of the current harmonic component of each output of the high-voltage active resonance suppression device .

6. According to the method for suppressing active resonance on the grid side of an offshore wind farm as claimed in claim 5, wherein: The control formula of the harmonic shunt control mode is ， Let the total number of resonances be , be the number of this resonance. Then in the formula, is the measured value of the harmonic component of the current of the offshore wind farm, is the th harmonic component of the current of the offshore wind farm, is the limit value of the total harmonic current of the offshore wind farm; The control formula of the conventional control mode is .

7. According to the method for suppressing active resonance on the grid side of an offshore wind farm as claimed in claim 6, wherein: The calculation formula for the command value of the current harmonic components output by each time of the high-voltage active resonance suppression device is as follows ， Wherein, and are the command values of the harmonic current output by the composite system, and are the measured values of the harmonic component of the current of the offshore wind farm; The total output current control value of the high-voltage active resonance suppression device The calculation formula is ， In the formula, is the total number of resonances, is the number of resonances.

8. An active resonance suppression system on the grid connection side of an offshore wind farm, characterized in that, It is used to implement the method for suppressing active resonance on the grid side of an offshore wind farm as claimed in any one of claims 1 to 7.

9. A computer device, the computer device comprising a memory, a processor, and a computer program, characterized in that, When the computer program is executed by a processor, it implements the method for suppressing active resonance on the grid side of an offshore wind farm as claimed in any one of claims 1 to 7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the method for suppressing active resonance on the grid side of an offshore wind farm as claimed in any one of claims 1 to 7.

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