Offshore wind power plant grid-connected side active resonance suppression method, system, equipment and medium

Abstract

The invention belongs to the technical field of power grid harmonic suppression, and discloses an offshore wind plant grid-connected side active resonance suppression method, system and device and a medium so as to overcome the limitation of a traditional control strategy. The method comprises the following steps: enabling a high-voltage active resonance suppression device and an offshore wind plant-submarine cable system to be equivalent to a composite system; acquiring a grid-connected point voltage vector and an offshore wind plant current vector for sampling processing to obtain a grid-connected point voltage and an offshore wind plant current respectively corresponding to each resonance so as to construct a composite vector of the composite system; and determining a suppression mode for each resonance based on the composite vector, calculating a current harmonic component control value and a total output current control value of each output of the high-voltage active resonance suppression device, and generating a driving signal to realize active resonance suppression of the grid-connected side of the offshore wind plant. According to the method, decoupling of two control targets of the grid-connected line harmonic current and the power grid background harmonic voltage is realized, so that the electric energy quality of the offshore wind power plant is improved, and the grid-connected performance is optimized.

Description

Technical Field

[0001] The present invention belongs to the technical field of power grid harmonic suppression, and specifically relates to a method, system, equipment and medium for suppressing active resonance on the grid-connected side of an offshore wind farm. Background Art

[0002] With the transformation of the global energy structure and the growing demand for clean energy, offshore wind farms have become an important direction for the development of renewable energy in my country's coastal areas due to their clean and environmentally friendly operation mode and efficient energy utilization efficiency. On 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 power 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 will not only amplify the harmonics generated by themselves during the grid connection process, but also amplify the background harmonics of the power grid. This phenomenon causes significant harmonic voltage distortion at the public access point of the power grid, which in turn poses a potential threat to the safe and stable operation of the power transmission and transformation equipment of the power grid.

[0003] Given 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, the existing solution to this problem is to add a high-voltage active resonance suppression device to the wind farm, which can automatically track harmonic signals and actively filter harmonics. At present, the control strategies of high-voltage active resonance suppression devices used in offshore wind farm harmonic management mainly include wind farm harmonic current suppression strategy and power grid background harmonic voltage suppression strategy. The harmonic current suppression strategy outputs harmonic current in reverse to offset the harmonic components in the grid-connected line. However, this strategy is limited to controlling the harmonics injected by the wind farm into the grid, and has no positive effect on the suppression of the background harmonics of the grid itself, and usually cannot fully utilize the full capacity of the filter; the harmonic voltage suppression strategy tracks the voltage changes to form a virtual "low impedance" channel, so that the harmonics of 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 at the same time, which limits the promotion and application scope of high-voltage active resonance suppression devices.

[0004] In summary, the traditional control strategy has limitations and cannot take into account both the wind farm harmonic current and the grid background harmonic control objectives, which restricts the fast and flexible adjustment capability of the high-voltage active resonance suppression device. Summary of the invention

[0005] Based on the above-mentioned shortcomings and deficiencies in the prior art, one of the objects of the present invention is to solve at least one or more of the above-mentioned problems in the prior art. In other words, one of the objects of the present invention is to provide an active resonance suppression method, system, equipment and medium on the grid-connected side of an offshore wind farm that meets one or more of the above-mentioned needs, aiming to achieve the decoupling of the two control targets of the harmonic current of the grid-connected line and the background harmonic voltage of the power grid, thereby ensuring the efficient and flexible control of the high-voltage active resonance suppression device in the harmonic management of the offshore wind farm, thereby improving the power quality of the offshore wind farm and optimizing the grid-connected performance.

[0006] In order to achieve the above-mentioned object of the invention, the present invention adopts the following technical solutions: In a first aspect, the present invention provides a method for suppressing active resonance on the grid-connected side of an offshore wind farm, comprising the steps of: S1. The high voltage active resonance suppression device and the offshore wind farm-submarine cable system are equivalent to a composite system; S2. Obtaining the voltage vector of the grid connection point and offshore wind farm current vector Sampling is performed to obtain the grid connection point voltage corresponding to each resonance. and offshore wind farm current Thus, a composite vector of the composite system is constructed; S3, performing a step of determining a suppression mode for each resonance based on the composite vector, the step of determining the suppression mode comprising: S31, performing a - Transformation value, and based on this, calculate the voltage amplitude corresponding to this resonance and current amplitude ; S32, obtaining a preset voltage threshold and current threshold ; S33, the voltage amplitude and the voltage threshold , the current amplitude and the current threshold Compare them respectively, and select a corresponding inhibition mode based on the comparison results; S4, based on the suppression mode obtained in step S3, calculate the current harmonic component control value of each output of the high-voltage active resonance suppression device , thus calculating the total output current control value of the high-voltage active resonance suppression device A corresponding PWM drive signal is generated, and active resonance suppression on the grid-connected side of the offshore wind farm is achieved based on the PWM drive signal.

[0007] 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 also included: Obtaining preset resonance control conditions; The expression of the resonance control condition is: , Assume the total number of resonances is , is the number of resonances, then, , and They are the grid connection point voltage, offshore wind farm current and the harmonic output current of the high-voltage active resonance suppression device. Subharmonic components, is the limit value of the sum of the harmonic voltage at the grid connection point, is the limit value of the sum of harmonic currents in offshore wind farms, It is the limit value of the sum of harmonic currents of the high-voltage active resonance suppression device.

[0008] As a preferred solution, the voltage amplitude and current amplitude The calculation formula is: , Assume the total number of resonances is , is the number of resonances, then, , , and They are the grid connection point voltage Subharmonic components Value, grid voltage Subharmonic components Value, current of offshore wind farm Subharmonic components Value and current of offshore wind farm Subharmonic components value.

[0009] As a preferred solution, the step S33 of selecting a corresponding suppression mode based on the comparison result is specifically: When the voltage amplitude is less than the voltage threshold , and the current amplitude Greater than the current threshold When the harmonic current shunt control mode is used for resonance control; Otherwise, the conventional control mode is selected for resonant control.

[0010] As a preferred solution, step S4 calculates the current harmonic component control value of each output of the high-voltage active resonance suppression device based on the suppression mode obtained in step S3. , including the steps of: For the current amplitude conduct - Transform to obtain the harmonic component of the offshore wind farm current The measured values ​​are and ; Based on the control formula of the harmonic current shunt control mode or the control formula of the conventional control mode, the harmonic current quantity output by the composite system is calculated. The command values ​​are and ; Based on the harmonic current quantity output by the composite system The command value and the harmonic component of the offshore wind farm current The measured values ​​are used to calculate the harmonic components of the current output of the high-voltage active resonance suppression device. Command value; The current harmonic components of each output of the high-voltage active resonance suppression device The command value is inversely transformed to obtain the current harmonic component control value of each output of the high-voltage active resonance suppression device .

[0011] As a preferred solution, the control formula of the harmonic current shunt control mode is: , Assume the total number of resonances is , is the number of resonances, then, is the harmonic component of the offshore wind farm current Measured value, The current of the offshore wind farm Subharmonic components, is the limit value of the sum of harmonic currents in offshore wind farms; The conventional control mode control formula is: .

[0012] As a preferred solution, the current harmonic components of each output of the high-voltage active resonance suppression device are The formula for calculating the command value is: , In the formula, and The harmonic current output of the composite system Command value, and is the harmonic component of the offshore wind farm current Measurement value; 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.

[0013] In a second aspect, the present invention provides an offshore wind farm grid-connected side active resonance suppression system, characterized in that it is used to implement the offshore wind farm grid-connected side active resonance suppression method as described in the first aspect.

[0014] In a third aspect, the present invention provides an electronic device, wherein the computer device includes a memory, a processor, and a computer program, and when the computer program is executed by the processor, the active resonance suppression method on the grid-connected side of an offshore wind farm as described in the first aspect is implemented.

[0015] In a fourth aspect, the present invention provides a computer-readable storage medium having a computer program stored thereon, wherein when the computer program is executed by a processor, the method for suppressing active resonance on the grid-connected side of an offshore wind farm as described in the first aspect is implemented.

[0016] Compared with the prior art, the present invention has the following beneficial effects: The present invention firstly equates the high-voltage active resonance suppression device and the offshore wind farm-submarine cable system to a composite system, and then uses the composite vector of the composite system to calculate the output current of the high-voltage active resonance suppression device, thereby achieving the purpose of suppressing the harmonics at the grid connection point. The present invention does not need to add a high-voltage shunt reactor, does not increase the floor space, has a low cost, can more effectively utilize the harmonic regulation ability of the submarine cable itself, and takes into account the amplification of the wind farm harmonic current and the suppression of the background harmonic voltage of the power grid. It has strong adaptability to the power grid and is easier to implement; the control method is simple and easy to implement; the parameter calculation formula is concise and clear, which can significantly improve the calculation efficiency and meet the actual work needs.

[0017] Further or more detailed beneficial effects will be described in detail in conjunction with specific examples in the specific implementation manner. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 It is a schematic diagram of an application scenario of the active resonance suppression method on the grid-connected side of an offshore wind farm described in an embodiment of the present invention.

[0020] Figure 2 is Figure 1 A schematic diagram of the principle of achieving resonance suppression based on the composite vector in an application scenario.

[0021] Figure 3 is Figure 1 Circuit diagram for application scenarios.

[0022] Figure 4 It is an equivalent circuit diagram of an embodiment of the present invention for achieving resonance suppression based on the composite vector.

[0023] Figure 5 It is a flow chart of realizing resonance suppression based on the composite vector according to an embodiment of the present invention.

[0024] Figure 6 The embodiment of the present invention is based on - Schematic diagram of the transformation principle.

[0025] Figure 7 It is a schematic diagram of determining the suppression mode according to an embodiment of the present invention.

[0026] Figure 8 It is a schematic diagram of the principle of applying the suppression mode described in the embodiment of the present invention to suppress resonance.

[0027] Fig. 9 It is a simulation effect diagram of resonance control before applying the active resonance suppression method on the grid-connected side of an offshore wind farm described in an embodiment of the present invention.

[0028] Fig.10 It is a diagram of the simulation effect of resonance control after applying the active resonance suppression method on the grid-connected side of an offshore wind farm described in an embodiment of the present invention.

[0029] Fig.11 is a structural diagram of the electronic device provided in an embodiment of the present invention.

[0030] Figure Number: 1100. Electronic equipment; 1101, processor; 1102, communication bus; 1103, user interface; 1104, network interface; 1105, memory. DETAILED DESCRIPTION

[0031] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0032] In the following description, multiple embodiments of the present invention are provided, and different embodiments may be replaced or combined, so the present invention may also be considered to include all possible combinations of the same and / or different embodiments described. Therefore, 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 containing one or more of A, B, C, and D, all other possible combinations, even though the embodiment may not be clearly described in the following text.

[0033] The following description provides examples and does not limit the scope, applicability or examples set forth in the claims. Changes may be made to the functions and arrangements of the elements described without departing from the scope of the present invention. Various processes or components may be appropriately omitted, substituted or added to each example. For example, the described method may be performed in an order different from the described order, and various steps may be added, omitted or combined. In addition, the features described in some examples may be combined in other examples.

[0034] In order to facilitate a better understanding of the embodiments of the present invention, before explaining the specific implementation modes of the present invention in detail, its application scenarios are first described.

[0035] See also Figure 1-Figure 3 , Figure 1 A schematic diagram of an application scenario of the active resonance suppression method on the grid-connected side of an offshore wind farm is shown.

[0036] The active resonance suppression method on the grid-connected side of an offshore wind farm described in the embodiments of this specification is applied in the process. In these scenarios, the application of the active resonance suppression method on the grid-connected side of an offshore wind farm is intended to make up for the defects of the existing suppression strategy, realize the decoupling of the two control targets of the harmonic current of the grid-connected line and the background harmonic voltage of the power grid, and ensure the efficient and flexible control of the high-voltage active resonance suppression device in the harmonic management of the offshore wind farm, thereby improving the power quality of the offshore wind farm and optimizing the grid-connected performance.

[0037] The offshore wind farm-submarine cable system, the high-voltage active resonance suppression device, the composite vector and the like involved in multiple embodiments of this specification are described below. - A brief explanation of the transformation: Offshore wind farm-submarine cable system covers wind turbines and submarine cables. Wind turbines installed in waters far from the coast are usually located in areas with stronger and more stable winds to maximize the use of wind energy resources. In order to transmit the electricity produced by these generators to the land power grid, a submarine cable system is required. The system consists of multiple cables laid on the seabed and has the ability to withstand high voltage and harsh marine environments. The design and maintenance of the submarine cable system is crucial to ensure the efficient and reliable operation of offshore wind farms.

[0038] The high-voltage active resonance suppression device is an advanced power electronic device designed to detect and eliminate resonance problems in power systems. In power systems, resonance phenomena may cause voltage and current instability and even damage equipment. The device can effectively suppress resonance and ensure stable operation of the power system by monitoring grid parameters in real time and dynamically adjusting its internal electrical characteristics. This device is particularly important in high-voltage application scenarios such as offshore wind farms, as these systems are more susceptible to resonance problems.

[0039] Composite vectors are a mathematical tool used to describe and analyze vectors in multidimensional space. In power system analysis, composite vectors 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 composite vector, complex calculation and analysis processes can be simplified, allowing engineers to more intuitively understand and control the dynamic behavior of the power system. Composite vectors have important application value in the design and optimization of control strategies.

[0040] - Transformation is a mathematical transformation method used in power system analysis and control. This method converts the time-varying parameters in the three-phase AC system into DC parameters, thereby simplifying the analysis of the system's dynamic characteristics. Based on the synchronous rotating coordinate system, - The transformation decomposes the three-phase AC parameters into two orthogonal components: Quantity and This method is widely used in motor control, power electronic equipment and power management systems of offshore wind farms. By simplifying the complex AC parameters, - The transformation enables engineers to more efficiently design and implement precise control strategies.

[0041] Embodiment 1: like Figure 4-Figure 7As shown, this embodiment provides an active resonance suppression method for the grid-connected side of an offshore wind farm, comprising the steps of: S1, equating a high-voltage active resonance suppression device and an offshore wind farm-submarine cable system into a composite system; S2, obtaining a grid-connected point voltage vector and offshore wind farm current vector Sampling is performed to obtain the grid connection point voltage corresponding to each resonance. and offshore wind farm current Thus, a composite vector of the composite system is constructed; S3, based on the composite vector, a step of determining a suppression mode is performed for each resonance, the step of determining the suppression mode includes: S31, performing a suppression mode determination on the component corresponding to the resonance in the composite vector - Transformation value, and based on this, calculate the voltage amplitude corresponding to this resonance and current amplitude ; S32, obtain the preset voltage threshold and current threshold ; S33, the voltage amplitude and the voltage threshold , the current amplitude and the current threshold Compare them respectively, and select the corresponding suppression mode based on the comparison results; S4, calculate the current harmonic component control value of each output of the high-voltage active resonance suppression device based on the suppression mode obtained in step S3 , thus calculating the total output current control value of the high-voltage active resonance suppression device A corresponding PWM drive signal is generated, and active resonance suppression on the grid-connected side of the offshore wind farm is achieved based on the PWM drive signal.

[0042] It can be understood that since the capacitive harmonic current vector of the wind farm and the harmonic voltage vector of the public access point of the power grid are basically 90 degrees, ignoring the harmonic source of the offshore wind farm itself, the directions of the harmonic current vector from the wind farm and the harmonic current vector from the background of the power grid are basically coincident, but according to the harmonic impedance characteristics of the background of the power grid, there may be two situations of superposition or cancellation. This embodiment makes the high-voltage active resonance suppression device and the offshore wind farm-submarine cable system equivalent to a composite system, and by controlling the harmonic current vector output by the composite system, it takes into account the amplification and suppression of wind farm harmonics and the control of the background harmonic voltage of the power grid.

[0043] Specifically, this embodiment provides a preferred implementation of step S3, wherein before the step of determining the suppression mode for each resonance based on the composite vector, the step further includes: obtaining a preset resonance control condition; the expression of the resonance control condition is: , let the total number of resonances be , is the number of resonances, then, , and They are the grid connection point voltage, offshore wind farm current and the harmonic output current of the high-voltage active resonance suppression device. Subharmonic components, is the limit value of the sum of the harmonic voltage at the grid connection point, is the limit value of the sum of harmonic currents in offshore wind farms, It is the limit value of the sum of harmonic currents of the high-voltage active resonance suppression device.

[0044] It can be understood that, in this embodiment, various parameters are set according to the characteristics of the offshore wind farm-submarine cable system, and the resonance control conditions obtained can effectively improve the implementation efficiency and meet the actual engineering needs.

[0045] Specifically, this embodiment provides a preferred implementation method, the voltage amplitude and current amplitude The calculation formula is: , let the total number of resonances be , is the number of resonances, then, , , and They are the grid connection point voltage Subharmonic components Value, grid voltage Subharmonic components Value, current of offshore wind farm Subharmonic components Value and current of offshore wind farm Subharmonic components value.

[0046] Specifically, this embodiment provides a preferred implementation, in which the step S33 of selecting a corresponding suppression mode based on the comparison result is as follows: when the voltage amplitude is less than the voltage threshold , and the current amplitude Greater than the current threshold When the harmonic current shunt control mode is used for resonance control, otherwise, the conventional control mode is used for resonance control.

[0047] More specifically, in the harmonic current shunting 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 public access point is as small as possible.

[0048] Specifically, this embodiment provides a preferred implementation of step S4, wherein the suppression mode obtained in step S3 is used to calculate the current harmonic component control value of each output of the high-voltage active resonance suppression device. , comprising the steps of: adjusting the current amplitude conduct - Transform to obtain the harmonic component of the offshore wind farm current The measured values ​​are and Based on the control formula of the harmonic shunt control mode or the control formula of the conventional control mode, the harmonic current quantity output by the composite system is calculated. The command values ​​are and Based on the harmonic current output of the composite system The command value and the harmonic component of the offshore wind farm current The measured values ​​are used to calculate the harmonic components of the current output of the high-voltage active resonance suppression device. Command value; The current harmonic components of each output of the high-voltage active resonance suppression device The command value is inversely transformed to obtain the current harmonic component control value of each output of the high-voltage active resonance suppression device .

[0049] Specifically, this embodiment provides a preferred implementation mode, the control formula of the harmonic current shunt control mode is: , let the total number of resonances be , is the number of resonances, then, is the harmonic component of the offshore wind farm current Measured value, The current of the offshore wind farm Subharmonic components, is the limit value of the sum of harmonic currents in offshore wind farms; the control formula of the conventional control mode is: .

[0050] Specifically, this embodiment provides a preferred implementation mode, wherein the current harmonic components of each output of the high-voltage active resonance suppression device are The formula for calculating the command value is: , where and The harmonic current output of the composite system Command value, and is the harmonic component of the offshore wind farm current Measured value; The total output current control value of the high voltage active resonance suppression device The calculation formula is , where is the total number of resonances, is the number of resonances.

[0051] Embodiment 2: This embodiment provides an offshore wind farm grid-connected side active resonance suppression system, which is used to implement the offshore wind farm grid-connected side active resonance suppression method as described in the first embodiment.

[0052] Embodiment three: like Fig.11 As 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.

[0053] The communication bus can be used to realize the connection and communication among the above-mentioned components.

[0054] The user interface may include buttons, and the optional user interface may also include a standard wired interface or a wireless interface.

[0055] The network interface may include but is not limited to a Bluetooth module, an NFC module, a Wi-Fi module, etc.

[0056] Among them, the processor may include one or more processing cores. The processor uses various interfaces and lines to connect the various parts of the entire electronic device, and executes various functions of the electronic device and processes data by running or executing instructions, programs, code sets or instruction sets stored in the memory, and calling data stored in the memory. Optionally, the processor can be implemented in at least one hardware form of DSP, FPGA, and PLA. The processor can integrate one or a combination of CPU, GPU, modem, etc. Among them, the CPU mainly processes the operating system, user interface, and application programs; the GPU is responsible for rendering and drawing the content to be displayed on the display; the modem is used to handle wireless communications. It can be understood that the above-mentioned modem may not be integrated into the processor, but may be implemented separately through a chip.

[0057] Among them, the memory may include RAM or ROM. Optionally, the memory includes a non-transitory computer-readable medium. The memory can be used to store instructions, programs, codes, code sets or instruction sets. The memory may include a program storage area and a data storage area, wherein the program storage area may store instructions for implementing an operating system, instructions for at least one function (such as a touch function, a sound playback function, an image playback function, etc.), instructions for implementing the above-mentioned various method embodiments, etc.; the data storage area may store data involved in the above-mentioned various method embodiments, etc. The memory may also be at least one storage device located away from the aforementioned processor. The memory as a computer storage medium may include an operating system, a network communication module, a user interface module and a resonance suppression application. The processor may be used to call the resonance suppression application stored in the memory and execute the steps of active resonance suppression on the grid-connected side of the offshore wind farm mentioned in the above-mentioned embodiment.

[0058] Embodiment 4: This embodiment provides a computer-readable storage medium, which stores instructions. When the computer-readable storage medium is executed on a computer or a processor, the computer or the processor executes the above-mentioned Figure 1-Figure 7 One or more steps in the illustrated embodiment. If the components of the electronic device described above 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.

[0059] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented by 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 process or function described in the embodiment of this specification is generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. 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 a website site, computer, server or data center to another website site, computer, server or data center by wired (e.g., coaxial cable, optical fiber, digital subscriber line (Digital Subscriber Line, DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) mode. 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 available media integrated. The available medium may be a magnetic medium (eg, a floppy disk, a hard disk, a magnetic tape), an optical medium (eg, a digital versatile disc (DVD)), or a semiconductor medium (eg, a solid state drive (SSD)).

[0060] A person skilled in the art can understand that all or part of the processes in the method of the first embodiment can be implemented by instructing the relevant hardware through a computer program, and the program can be stored in a computer-readable storage medium. When the program is executed, it can include the processes of the embodiments of the above methods. The aforementioned storage medium includes: ROM, RAM, magnetic disk or optical disk and other media that can store program codes. In the absence of conflict, the technical features in this embodiment and the implementation scheme can be combined arbitrarily.

[0061] Embodiment five: In order to verify the effectiveness of the active resonance suppression method for the offshore wind farm grid-connected side described in this specification, this embodiment is based on the actual application scenario of the method and Figure 8 The principle shown in the figure leads to the following conclusion: Figures 9 and 10 The simulation effect diagram before and after the resonance control is shown. Based on this, this embodiment fully proves the effectiveness of the active resonance suppression method on the grid-connected side of the offshore wind farm described in this specification.

[0062] It should be noted that, for the above-mentioned method embodiments, for the sake of simplicity, they are all described as a series of action combinations, but 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 required by the present invention.

[0063] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0064] The above is only an exemplary embodiment of the present invention and cannot be used to limit the scope of the present invention. That is, any equivalent changes and modifications made according to the teachings of the present invention are still within the scope of the present invention. After considering the specification and practicing the disclosure here, it will be easy for those skilled in the art to think of the implementation scheme of the present invention. The present invention is intended to cover any modification, use or adaptation of the present invention, which follows the general principles of the present invention and includes common knowledge or customary technical means in the art that are not recorded in the present invention. The description and examples 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-connected side of an offshore wind farm, characterized in that: Includes steps: S1. The high voltage active resonance suppression device and the offshore wind farm-submarine cable system are equivalent to a composite system; S2. Obtaining the voltage vector of the grid connection point and offshore wind farm current vector Sampling is performed to obtain the grid connection point voltage corresponding to each resonance. and offshore wind farm current Thus, a composite vector of the composite system is constructed; S3, performing a step of determining a suppression mode for each resonance based on the composite vector, the step of determining the suppression mode comprising: S31, performing a - Transformation value, and based on this, calculate the voltage amplitude corresponding to this resonance and current amplitude ; S32, obtaining a preset voltage threshold and current threshold ; S33, the voltage amplitude and the voltage threshold , the current amplitude and the current threshold Compare them respectively, and select a corresponding inhibition mode based on the comparison results; S4, based on the suppression mode obtained in step S3, calculate the current harmonic component control value of each output of the high-voltage active resonance suppression device , thus calculating the total output current control value of the high-voltage active resonance suppression device A corresponding PWM drive signal is generated, and active resonance suppression on the grid-connected side of the offshore wind farm is achieved based on the PWM drive signal.

2. The method for suppressing active resonance on the grid-connected side of an offshore wind farm according to claim 1, characterized in that: Before the step of determining the suppression mode for each resonance based on the composite vector in step S3, the step further includes: Obtaining preset resonance control conditions; The expression of the resonance control condition is: ， Assume the total number of resonances is , is the number of resonances, then, , and They are the grid connection point voltage, offshore wind farm current and the harmonic output current of the high-voltage active resonance suppression device. Subharmonic components, is the limit value of the sum of the harmonic voltage at the grid connection point, is the limit value of the sum of harmonic currents in offshore wind farms, It is the limit value of the sum of harmonic currents of the high-voltage active resonance suppression device.

3. The method for suppressing active resonance on the grid-connected side of an offshore wind farm according to claim 2, characterized in that: The voltage amplitude and current amplitude The calculation formula is: ， Assume the total number of resonances is , is the number of resonances, then, , , and They are the grid connection point voltage Subharmonic components Value, grid voltage Subharmonic components Value, current of offshore wind farm Subharmonic components Value and current of offshore wind farm Subharmonic components value.

4. The method for suppressing active resonance on the grid-connected side of an offshore wind farm according to claim 3, characterized in that: The step S33 of selecting a corresponding suppression mode based on the comparison result is specifically: When the voltage amplitude is less than the voltage threshold , and the current amplitude Greater than the current threshold When the harmonic current shunt control mode is used for resonance control; Otherwise, the conventional control mode is selected for resonant control.

5. The method for suppressing active resonance on the grid-connected side of an offshore wind farm according to claim 4, characterized in that: Step S4 calculates the current harmonic component control value of each output of the high-voltage active resonance suppression device based on the suppression mode obtained in step S3. , including the steps of: For the current amplitude conduct - Transform to obtain the harmonic component of the offshore wind farm current The measured values ​​are and ; Based on the control formula of the harmonic current shunt control mode or the control formula of the conventional control mode, the harmonic current quantity output by the composite system is calculated. The command values ​​are and ; Based on the harmonic current quantity output by the composite system The command value and the harmonic component of the offshore wind farm current The measured values ​​are used to calculate the harmonic components of the current output of the high-voltage active resonance suppression device. Command value; The current harmonic components of each output of the high-voltage active resonance suppression device The command value is inversely transformed to obtain the current harmonic component control value of each output of the high-voltage active resonance suppression device .

6. The method for suppressing active resonance on the grid-connected side of an offshore wind farm according to claim 5, characterized in that: The control formula of the harmonic current shunt control mode is: ， Assume the total number of resonances is , is the number of resonances, then, is the harmonic component of the offshore wind farm current Measured value, The current of the offshore wind farm Subharmonic components, is the limit value of the sum of harmonic currents in offshore wind farms; The conventional control mode control formula is: .

7. The method for suppressing active resonance on the grid-connected side of an offshore wind farm according to claim 6, characterized in that: The current harmonic components of each output of the high-voltage active resonance suppression device The formula for calculating the command value is: ， In the formula, and The harmonic current output of the composite system Command value, and is the harmonic component of the offshore wind farm current Measurement value; 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 offshore wind farm grid-connected side active resonance suppression system, characterized in that: Used to implement the active resonance suppression method on the grid-connected side of an offshore wind farm as described in any one of claims 1 to 7.

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

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