Station impedance remodeling method and system for broadband oscillation suppression of wind power plant

Abstract

The invention discloses a station impedance remodeling method and system for broadband oscillation suppression of a wind power plant, and the method comprises the steps: carrying out the impedance characteristic measurement and modeling of a grid-connected point of the wind power plant, and determining an optimization target of impedance remodeling; based on the optimization target of impedance remodeling, cooperative control is carried out on a wind turbine generator set and a super-capacitor static phase modifier in the wind power plant through a multi-frequency-band coordination control strategy, so that the impedance of the wind power plant is remodeled; performing online evaluation on the impedance characteristic of the wind power plant subjected to impedance remodeling, and calculating a system impedance margin formed by the wind power plant and an external power grid; and according to the impedance margin, dynamically adjusting the cooperative control parameter, so that the impedance characteristic of the grid-connected point of the wind power plant after impedance remodeling is matched with the optimization target of the impedance remodeling. According to the scheme of the invention, the method achieves the optimal configuration of resources and the most efficient inhibition effect through the cooperative control of the wind turbine generator and the super-capacitor static phase modifier.

Description

Technical Field

[0001] This application generally relates to the field of power system stability control technology. More specifically, this application relates to a method and system for suppressing broadband oscillations in wind farms and for reshaping the impedance of wind farms. Background Technology

[0002] In recent years, with the transformation of the global energy structure, new energy sources, represented by wind power, have developed rapidly, and the installed capacity of wind power has continued to grow rapidly. However, large-scale wind power grid connection has also brought new challenges to the stable operation of the power grid.

[0003] As a power generation device connected to the grid via power electronic converters, wind turbines exhibit fundamentally different dynamic characteristics from traditional synchronous generators. Under specific grid conditions, complex interactions can easily occur between wind farms and the grid system, leading to broadband oscillations. These oscillations cover a wide frequency range, typically including subsynchronous oscillations (SSOs) from 0.1 Hz to 10 Hz, SSOs from 10 Hz to 50 Hz, and high-frequency oscillations above 50 Hz. If these oscillations occur and are not effectively suppressed, they will seriously threaten the safe and stable operation of the power system, and may even lead to cascading failures and large-scale grid disconnection accidents.

[0004] To address the broadband oscillation risks brought about by wind power grid connection, some explorations have been undertaken in existing technologies. However, these technologies typically rely on single devices (such as SVG) or single-level control (such as adjusting only the wind turbine controller), making it difficult to effectively address complex broadband oscillation problems involving coupled multiple frequency components. Furthermore, in existing technologies, wind turbines, reactive power compensation devices, and other equipment within wind farms usually operate independently, lacking a unified and coordinated control strategy. This not only makes it difficult to form a combined suppression force but may even lead to control conflicts. In addition, existing technologies struggle to perform impedance optimization and reshaping across the entire frequency band, exhibiting poor adaptability, especially under varying grid operating conditions or topologies. Secondly, to achieve a certain suppression effect, existing technologies often require the configuration of redundant compensation equipment, resulting in high overall construction and maintenance costs and unsatisfactory economic efficiency.

[0005] In view of this, there is an urgent need to provide a wind farm impedance reshaping scheme for broadband oscillation suppression, which can overcome the above-mentioned defects and build a broadband oscillation suppression system that can coordinate multiple types of equipment in the wind farm, achieve full-band impedance optimization, has adaptive capabilities, and takes into account economic efficiency. Summary of the Invention

[0006] In order to at least solve one or more of the technical problems mentioned above, this application proposes a site impedance reshaping scheme for wind farm broadband oscillation suppression in several aspects.

[0007] In a first aspect, this application provides a method for impedance reshaping of a wind farm to suppress broadband oscillations, comprising: measuring and modeling the impedance characteristics of the wind farm's grid connection point to identify potential oscillation risk frequency bands and determine the optimization target for impedance reshaping; based on the optimization target, coordinating the control of wind turbine generators and supercapacitor static condensers within the wind farm through a frequency-band coordinated control strategy to reshape the impedance of the wind farm; deploying a broadband impedance monitoring device to perform online evaluation of the impedance characteristics of the wind farm after impedance reshaping and calculating the system impedance margin of the wind farm and the external power grid; and dynamically adjusting the coordinated control parameters according to the impedance margin through the communication interface between the wind farm's control system and the supercapacitor static condenser, so that the impedance characteristics of the wind farm's grid connection point after impedance reshaping match the optimization target for impedance reshaping.

[0008] In some embodiments, during the process of measuring and modeling the impedance characteristics of the grid connection point of a wind farm, the following steps are performed: using an impedance measuring device to perform a broadband impedance scan at the grid connection point of the wind farm to obtain impedance data; establishing an equivalent impedance model of the wind farm based on the impedance data; and determining a target impedance curve to guide impedance reshaping based on the equivalent impedance model of the wind farm.

[0009] In some embodiments, the frequency band coordinated control strategy includes: in the low-frequency and subsynchronous frequency bands, impedance reshaping is performed by the combined action of the wind turbine's impedance reshaping strategy and the supercapacitor static condenser's network control strategy; in the high-frequency band, impedance reshaping is performed by the supercapacitor static condenser's power regulation strategy and adaptive damping network control strategy.

[0010] In some embodiments, the impedance reshaping strategy of the wind turbine includes: optimizing the controller parameters of the wind turbine; and adjusting its external impedance characteristics by introducing a virtual impedance controller into the control logic of the wind turbine.

[0011] In some embodiments, during the optimization of the controller parameters of the wind turbine, the parameters of the inner current loop controller, the outer current loop controller, and the phase-locked loop of the wind turbine are optimized.

[0012] In some embodiments, introducing a virtual impedance controller into the control logic of the wind turbine includes: generating a virtual impedance component in the controller of the wind turbine according to a frequency-dependent virtual admittance function, and superimposing the virtual impedance component onto the output reference signal of the controller.

[0013] In some embodiments, the network control strategy of the supercapacitor static condenser includes: making the supercapacitor static condenser exhibit positive impedance characteristics to the outside world.

[0014] In some embodiments, the power regulation strategy of the supercapacitor static phase converter includes: dynamically adjusting the ratio of active power damping to reactive power support to suppress oscillations in the high-frequency band.

[0015] In some embodiments, the adaptive damping network control strategy includes: dynamically adjusting the parameters of the adaptive damping network according to the impedance characteristics of the wind farm grid connection point, so that the fluctuation of the wind farm impedance characteristics is kept within a preset range of its full impedance value; wherein, the adaptive damping network includes adjustable inductors, capacitors and resistors integrated inside the supercapacitor static condenser.

[0016] In a second aspect, this application provides a wind farm impedance reshaping system for broadband oscillation suppression. The system employs the wind farm impedance reshaping method for broadband oscillation suppression as described in any embodiment of the first aspect. The system includes: an impedance characteristic measurement and modeling module for measuring and modeling the impedance characteristics of the wind farm's grid connection point to identify potential oscillation risk frequency bands and determine the optimization target for impedance reshaping; an impedance reshaping module for coordinating the control of wind turbine generators and supercapacitor static condensers within the wind farm based on the impedance reshaping optimization target using a frequency-band coordinated control strategy to reshape the wind farm's impedance; a system impedance margin calculation module for deploying a broadband impedance monitoring device to perform online evaluation of the impedance characteristics of the reshaped wind farm and calculate the system impedance margin of the wind farm and the external power grid; and a coordinated control adjustment module for dynamically adjusting coordinated control parameters based on the impedance margin through the communication interface between the wind farm's control system and the supercapacitor static condenser, so that the impedance characteristics of the wind farm's grid connection point after impedance reshaping match the impedance reshaping optimization target.

[0017] Through the wind farm impedance reshaping scheme for broadband oscillation suppression provided above, the embodiments of this application, through measurement and modeling, transform oscillation suppression from a blind response to a goal-oriented approach, ensuring that all measures are targeted and effective. By employing coordinated control of wind turbine generators and supercapacitor static condensers, optimal resource allocation and the most efficient suppression effect are achieved. Through online monitoring and dynamic adjustment based on impedance margin, the entire system is endowed with the ability to self-assess and self-optimize, enabling it to proactively adapt to changes in the external power grid and always maintain the wind farm in the most stable operating state.

[0018] Furthermore, in some embodiments, a frequency-band coordinated control strategy decomposes the complex broadband oscillation problem into sub-problems of different frequency bands, and assigns a corresponding strategy to each sub-problem. This fully leverages the strengths of various devices and control strategies, achieving optimal resource utilization and maximizing control efficiency. Simultaneously, it avoids mutual interference between different control objectives, ensuring the entire suppression system is logically clear, stable, and reliable. Moreover, through this collaborative approach where each component performs its specific function, the strategy can comprehensively cover and precisely eliminate various oscillation threats from low to high frequencies with extremely high efficiency and targeting, ensuring the stable operation of wind farms under various operating conditions.

[0019] Furthermore, in some embodiments, an impedance reshaping strategy for wind turbines is employed to collaboratively optimize multi-dimensional parameters of the phase-locked loop (PLL) and inner / outer loop controllers, resulting in comprehensive fine-tuning of the wind turbine and fundamentally strengthening its stability. Simultaneously, a frequency-dependent virtual impedance is introduced, which precisely generates a reverse virtual impedance component only at the specific frequency where the problem occurs, achieving precise suppression without affecting the operation of other normal frequency bands. This strategy, combining fundamental optimization with precise targeting, makes the impedance reshaping of wind turbines comprehensive, fundamentally sound, flexible, and efficient, greatly enhancing its ability to independently suppress oscillations.

[0020] Furthermore, in some embodiments, an adaptive damping network control strategy can monitor the impedance characteristics of the grid connection point in real time and react immediately upon detecting harmful fluctuations. By dynamically adjusting the adjustable inductors, capacitors, and resistors integrated within the adaptive damping network, precise damping can be achieved. Moreover, this adaptive capability ensures that the wind farm can actively and continuously stabilize its impedance characteristics within a safe range, greatly enhancing the system's robustness and self-healing ability in the face of grid disturbances. Attached Figure Description

[0021] The above and other objects, features, and advantages of exemplary embodiments of this application will become readily understood by reading the following detailed description with reference to the accompanying drawings. In the drawings, several embodiments of this application are illustrated by way of example and not limitation, and the same or corresponding reference numerals denote the same or corresponding parts, wherein:

[0022] Figure 1 An exemplary flowchart of a wind farm impedance reshaping method for suppressing broadband oscillations according to an embodiment of this application is shown;

[0023] Figure 2 An exemplary flowchart illustrating the impedance characteristic measurement and modeling of the grid connection point of a wind farm according to an embodiment of this application is shown;

[0024] Figure 3An exemplary structural block diagram of a wind farm broadband oscillation suppression station impedance reshaping system according to an embodiment of this application is shown. Detailed Implementation

[0025] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0026] It should be understood that the terms "comprising" and "including" used in the specification and claims of this application indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0027] It should also be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application. As used in this specification and claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used in this specification and claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes such combinations.

[0028] Figure 1 An exemplary flowchart of a wind farm broadband oscillation suppression method 100 according to an embodiment of this application is shown.

[0029] like Figure 1 As shown, in step S110, the impedance characteristics of the grid connection point of the wind farm are measured and modeled to identify potential oscillation risk frequency bands and determine the optimization target of impedance reshaping.

[0030] In the embodiments of this application, the specific process involved in step S110 can be found in [reference needed]. Figure 2 .

[0031] Figure 2 An exemplary flowchart illustrating the impedance characteristic measurement and modeling of the grid connection point of a wind farm according to an embodiment of this application is shown.

[0032] like Figure 2As shown, in step S210, an impedance measurement device is used to perform a wideband impedance scan at the wind farm's grid connection point to obtain impedance data. In step S220, an equivalent impedance model of the wind farm is established based on the impedance data. In step S230, a target impedance curve for guiding impedance reshaping is determined according to the equivalent impedance model of the wind farm.

[0033] In the embodiments of this application, during step S210, an impedance measuring device injects a series of weak voltage or current disturbance signals with different frequencies into the grid connection point, testing each frequency point from a very low frequency (e.g., 0.1 Hz, corresponding to subsynchronous oscillation) to a higher frequency (e.g., 1000 Hz, corresponding to high-frequency harmonic oscillation). While injecting the disturbance signal at each frequency, the device accurately measures the impedance data of the wind farm at this grid connection point, including voltage and current responses. Specifically, the impedance data includes the impedance amplitude of the wind farm (i.e., the magnitude of the obstruction to current flow at the corresponding frequency) and the impedance phase angle (the time difference or phase difference between voltage and current).

[0034] In the embodiments of this application, during the execution of step S220, the impedance data is transformed into a continuous and intuitive wind farm impedance equivalent model through data fitting and system identification algorithms.

[0035] In the embodiments of this application, during the execution of step S230, potential oscillation risk frequency bands are identified based on the wind farm impedance equivalent model, and a target impedance curve guiding impedance reshaping is formed through the identified potential oscillation risk frequency bands, which is used as the optimization target for impedance reshaping.

[0036] Specifically, in the process of generating a target impedance curve to guide impedance reshaping by identifying potential oscillation risk frequency bands, in negatively damped frequency bands (e.g., 25Hz), the real part of the impedance in that band is designed to be significantly positive, i.e., injecting strong positive damping to eliminate oscillations at their source. In frequency bands where the model shows sharp resonance peaks (e.g., 450Hz), these peaks are flattened in the target impedance curve, becoming a gentle, well-damped curve to avoid high-frequency resonance. In other inherently stable frequency bands, the target impedance curve can remain unchanged.

[0037] Step S110 transforms wind farm oscillation suppression from a past experience-based, passive response model into a forward-looking and scientifically sound systems engineering approach based on precise data. It achieves a comprehensive assessment of the wind farm's electrical characteristics across the entire frequency band through broadband scanning, accurately diagnoses potential oscillation risks through modeling and analysis, and finally provides a clear, quantifiable, and actionable optimization blueprint by setting a target impedance curve. This method not only accurately locates and eliminates oscillation problems in specific frequency bands (such as negative damping and sharp resonance) at their root, but more importantly, it provides a unified and coordinated optimization objective for all subsequent complex control strategies, ensuring targeted and efficient coordination of suppression measures, thereby significantly improving the stability and reliability of the entire wind farm's grid-connected operation.

[0038] After completing step S110, in step S120, based on the optimization objective of impedance reshaping, the wind turbine generators and supercapacitor static condensers in the wind farm are coordinated and controlled through a frequency band coordinated control strategy to reshape the impedance of the wind farm.

[0039] In the embodiments of this application, during the execution of the frequency band coordinated control strategy, impedance reshaping is achieved in the low-frequency and subsynchronous frequency bands through the coordinated action of the wind turbine impedance reshaping strategy and the supercapacitor static condenser network control strategy. In the high-frequency band, impedance reshaping is achieved through the power regulation strategy of the supercapacitor static condenser and the adaptive damping network control strategy.

[0040] In the embodiments of this application, the low frequency and subsynchronous frequency bands are frequency bands of 0.1Hz-50Hz, and the high frequency bands are frequency bands greater than 50Hz.

[0041] Specifically, the impedance reshaping strategy for wind turbines includes optimizing the controller parameters of the wind turbines and adjusting their external impedance characteristics by introducing a virtual impedance controller into the control logic of the wind turbines.

[0042] In the embodiments of this application, during the optimization of the controller parameters of the wind turbine, the parameters of the inner current loop controller, the outer current loop controller, and the phase-locked loop of the wind turbine are optimized.

[0043] Specifically, in the process of optimizing the parameters of the wind turbine's inner current loop controller, the proportional gain and integral gain of the inner current loop controller are adjusted. Under the premise of ensuring stability, an optimal combination of proportional gain and integral gain parameters is found through simulation and calculation, so that the current loop can respond quickly and execute accurately.

[0044] Specifically, by optimizing the parameters of the outer loop controller of the wind turbine, the active power response characteristics and reactive power response characteristics of the wind turbine are adjusted, so that the active and reactive power output of the wind turbine is stable and efficient, and has good dynamic support capabilities.

[0045] Specifically, by optimizing the parameters of the phase-locked loop (PLL), the negative damping effect introduced in specific frequency bands (especially the subsynchronous band) is minimized while ensuring synchronization accuracy. This negative damping effect is a key factor inducing oscillations. In optimizing the PLL parameters, the bandwidth and parameters are carefully designed to find an optimal ratio that allows the PLL to reliably track the power grid while effectively suppressing its own negative damping characteristics, thereby enhancing the wind turbine's contribution to grid stability.

[0046] In the embodiments of this application, during the process of introducing a virtual impedance controller into the control logic of the wind turbine, a virtual impedance component is generated in the controller of the wind turbine according to a frequency-dependent virtual admittance function, and the virtual impedance component is superimposed on the output reference signal of the controller.

[0047] Specifically, the calculation formula involved in superimposing the virtual impedance component into the controller's output reference signal is: I_ref_new=I_ref-(U_pcc×Y_virtual), where I_ref_new is the output reference signal with the superimposed virtual impedance component, I_ref is the output reference signal, U_pcc is the grid connection point voltage of the wind farm, and Y_virtual is the virtual impedance component.

[0048] Specifically, the virtual impedance component is expressed as: Y_virtual(s) = G(s) + jB(s), where s is the frequency variable, G(s) is the virtual conductance, B(s) is the virtual susceptance, j is the virtual unit, G(s) is the real part of the virtual impedance component Y_virtual, and B(s) is the imaginary part of the virtual impedance component Y_virtual. The virtual conductance primarily provides positive damping, specifically designed to absorb and dissipate oscillating energy at specific frequencies. The virtual susceptance primarily alters the system's resonant point, thereby avoiding dangerous resonant frequencies. G(s) and B(s) are designed to be functions of frequency, their values ​​becoming large at dangerous frequency points and almost zero at other normal operating frequencies. This ensures that the virtual impedance component can cancel out oscillations at dangerous frequency points where oscillations may occur.

[0049] By using a preset frequency function (Y_virtual), the system is activated only at specific frequency points where harmful oscillations occur, generating a virtual correction signal specifically designed to counteract these oscillations. During normal grid operation, it remains completely invisible, avoiding any unnecessary interference to the system. It not only directly absorbs and dissipates oscillation energy using virtual conductance but also actively alters the system's resonant point using virtual magnetic susceptibility, fundamentally avoiding dangerous resonant frequencies. This software-based virtual control method significantly enhances the wind turbine's ability to actively maintain grid stability without requiring expensive physical equipment, thereby strengthening the overall safety of the wind farm and its adaptability to complex grid environments.

[0050] Specifically, during the implementation of the grid control strategy for the supercapacitor static condenser, the supercapacitor static condenser is made to exhibit positive impedance characteristics to the outside world.

[0051] Specifically, in implementing the grid-connected control strategy for supercapacitor static condensers, the first step is to change the control process of the supercapacitor static condenser, transforming it from a traditional grid-following mode to an active grid-connected mode. By simulating the core operating mechanism of a traditional synchronous generator in the control algorithm, the supercapacitor static condenser no longer passively adapts to the grid voltage, but instead, like a virtual generator, actively generates a stable and controllable voltage and frequency reference set internally. This transformation shapes the supercapacitor static condenser from a current source into a voltage source with predictable behavior, laying a solid foundation for subsequently accurately shaping its external electrical characteristics.

[0052] Next, within this robust framework of grid control, a specialized impedance shaping controller is designed to operate precisely within the target low-frequency range (0.1Hz-50Hz). By adjusting control commands in real time, it ensures that the supercapacitor static condenser exhibits pure and benign positive impedance characteristics. This is equivalent to setting a clear electrical behavior criterion for the supercapacitor static condenser at the algorithmic level: regardless of external disturbances, its voltage and current response remains consistent, exhibiting a stable positive resistance or positive reactance, thereby providing strong damping for the power grid.

[0053] Wind turbine generators may exhibit unstable negative impedance at certain low-frequency points, while the strong positive impedance provided by the supercapacitor static condenser can precisely compensate for and cancel it out. Through this complementary cooperation, the two work together to reshape the low-frequency impedance of the entire wind farm, fundamentally eliminating potential oscillation risks, greatly enhancing the system's stability margin, and ensuring that the entire wind farm can safely supply power to the grid as a stable and reliable whole.

[0054] Specifically, during the implementation of the power regulation strategy of the supercapacitor static phase condenser, the ratio of active power damping to reactive power support is dynamically adjusted to suppress oscillations in the high-frequency band.

[0055] In the embodiments of this application, during the execution of the power regulation strategy of the supercapacitor static condenser (SSC), firstly, once a dangerous impedance fluctuation or negative damping characteristic is detected at a certain high-frequency point, the oscillation frequency is immediately locked, becoming the target that needs to be precisely suppressed, thus completing a crucial step from passive monitoring to proactive problem detection. Next, after accurately locking down the problem, the system enters the core stage of intelligent decision-making and parameter optimization. Based on the identified oscillation frequency and impedance characteristics, the controller activates a preset power allocation algorithm to dynamically calculate the optimal suppression strategy. This is not a simple power injection, but rather a precise adjustment of the ratio of active power damping to reactive power support, generating a new set of adaptive damping network parameters for the specific oscillation. Then, these new adaptive damping network parameters are applied to the control core of the SSC without delay, while the strategy activates its overload potential, injecting a powerful, precisely modulated instantaneous power into the grid within milliseconds of the oscillation occurring. This customized power pulse acts directly on the oscillation point, forcefully suppressing it. The entire process forms a high-speed closed loop, continuously performing the cycle of "diagnosis-decision-execution" until the impedance fluctuation at the grid connection point returns to a safe preset range, thereby ensuring the stable operation of the wind farm under high-frequency disturbances.

[0056] Through power regulation strategies, high-frequency real-time monitoring and high-speed closed-loop control are achieved, completing the entire process of "diagnosis-decision-execution" within milliseconds of oscillation occurrence. Furthermore, it does not blindly inject power but precisely targets the specific oscillation frequency causing the problem and intelligently calculates the optimal combination ratio of active power damping and reactive power support, avoiding unnecessary interference to other parts of the power grid. In addition, this strategy fully activates and utilizes the overload potential of supercapacitors' instantaneous power throughput, providing a powerful power surge at critical moments to forcefully quell oscillations. Thus, at minimal cost, it significantly enhances the wind farm's ability to cope with high-frequency disturbances, ensuring the safe and stable operation of the power grid.

[0057] Specifically, during the execution of the adaptive damping network control strategy, the parameters of the adaptive damping network are dynamically adjusted according to the impedance characteristics of the wind farm's grid connection point, so that the fluctuation of the wind farm's impedance characteristics remains within the preset range of its full impedance value.

[0058] In some embodiments of this application, the preset range of the full-scale impedance is less than 25%. In other embodiments, the preset range of the full-scale impedance can also be set according to actual needs and historical experience, and this application does not impose any restrictions on it.

[0059] In embodiments of this application, the adaptive damping network includes adjustable inductors, capacitors, and resistors integrated within the supercapacitor stationary phase-shifting camera.

[0060] In the embodiments of this application, based on the impedance characteristics of the wind farm's grid connection point and the optimization objective of impedance reshaping, the system identifies the problem frequency point and the degree of impedance deviation, and determines the parameters corresponding to the adaptive damping network. For example, the optimization objective might be at a frequency of 400Hz, and the parameter corresponding to the adaptive damping network would be the resistance value. Then, the controller activates a built-in optimization algorithm (possibly based on PI control, fuzzy logic, neural networks, or model predictive control, etc.) to adjust the parameters corresponding to the adaptive damping network. By adjusting these parameters, the fluctuation of the wind farm's impedance characteristics is kept within a preset range of its full impedance value.

[0061] By employing an adaptive damping network control strategy, specific and measurable performance indicators, such as fluctuations of less than 25%, are set, making the control objectives clear and the system performance readily apparent. Furthermore, instead of simply increasing or decreasing damping indiscriminately, the system can precisely identify specific problem frequency points and adjust the integrated virtual inductance, capacitance, and resistance parameters accordingly, achieving targeted solutions and avoiding unnecessary disturbances to other frequency bands of the power grid.

[0062] After completing step S120, in step S130, a broadband impedance monitoring device is deployed to evaluate the impedance characteristics of the wind farm after impedance reshaping online, and the system impedance margin of the wind farm and the external power grid is calculated.

[0063] In the embodiments of this application, after obtaining the impedance characteristics of the wind farm after impedance reshaping, the ratio of the wind farm-side impedance to the grid-side impedance is calculated to obtain the system impedance margin composed of the wind farm and the external grid.

[0064] By introducing an impedance margin, the safe distance of the system from the instability boundary is quantified. This is a forward-looking indicator that enables system managers to anticipate risks.

[0065] After step S130 is completed, in step S140, based on the impedance margin, the collaborative control parameters are dynamically adjusted through the communication interface between the wind farm's control system and the supercapacitor static condenser, so that the impedance characteristics of the wind farm's grid connection point after impedance reshaping match the optimization target of impedance reshaping.

[0066] In the embodiments of this application, the collaborative control parameters include the control parameters adopted by the impedance reshaping strategy of the wind turbine, the control parameters adopted by the network control strategy of the supercapacitor static condenser, the control parameters adopted by the power regulation strategy of the supercapacitor static condenser, and the control parameters adopted by the adaptive damping network control strategy.

[0067] In the embodiments of this application, if the system impedance margin is sufficient and meets expectations, the wind farm's control system will maintain the current cooperative control parameters. If the margin is insufficient or below a safety threshold, the wind farm's control system determines that the current cooperative control parameters are not optimal and require immediate adjustment. At this time, the wind farm's control system sends an adjustment command to the controller of the supercapacitor static condenser (SSC) through a high-speed, reliable communication interface (e.g., industrial Ethernet, fiber optic communication). The wind farm's control system calculates the necessary adjustment to the cooperative control parameters based on the specific circumstances of the insufficient margin (e.g., at which frequency the margin is lowest, whether it is a insufficient phase margin or an insufficient amplitude margin). Upon receiving the new parameters, the supercapacitor static condenser (SSC) immediately updates its control logic and fine-tunes its output characteristics. This ensures that the measured impedance characteristics at the grid connection point perfectly match the initially set impedance reshaping optimization target.

[0068] Step S140 matches the impedance characteristics of the wind farm's grid connection point after impedance reshaping with the optimization target of impedance reshaping. This eliminates the deviation between theory and reality caused by factors such as model errors, environmental changes, or equipment state drift, ensuring optimal control performance. Furthermore, this is a dynamic adjustment process. This means that whenever poor margin or deviation from the target is detected, this fine-tuning process will be triggered. This gives the entire system the ability to continuously learn and self-improve, enabling it to maintain the wind farm in an optimal and stable operating state autonomously over the long term.

[0069] In summary, through the wind farm impedance reshaping scheme for broadband oscillation suppression provided above, the embodiments of this application, through measurement and modeling, transform oscillation suppression from a blind response to a goal-oriented approach, ensuring that all measures are targeted and effective. By employing coordinated control of wind turbine generators and supercapacitor static condensers, optimal resource allocation and the most efficient suppression effect are achieved. Through online monitoring and dynamic adjustment based on impedance margin, the entire system is endowed with the ability to self-assess and self-optimize, enabling it to proactively adapt to changes in the external power grid and always maintain the wind farm in the most stable operating state.

[0070] Furthermore, in some embodiments, a frequency-band coordinated control strategy decomposes the complex broadband oscillation problem into sub-problems of different frequency bands, and assigns a corresponding strategy to each sub-problem. This fully leverages the strengths of various devices and control strategies, achieving optimal resource utilization and maximizing control efficiency. Simultaneously, it avoids mutual interference between different control objectives, ensuring the entire suppression system is logically clear, stable, and reliable. Moreover, through this collaborative approach where each component performs its specific function, the strategy can comprehensively cover and precisely eliminate various oscillation threats from low to high frequencies with extremely high efficiency and targeting, ensuring the stable operation of wind farms under various operating conditions.

[0071] Furthermore, in some embodiments, an impedance reshaping strategy for wind turbines is employed to collaboratively optimize multi-dimensional parameters of the phase-locked loop (PLL) and inner / outer loop controllers, resulting in comprehensive fine-tuning of the wind turbine and fundamentally strengthening its stability. Simultaneously, a frequency-dependent virtual impedance is introduced, which precisely generates a reverse virtual impedance component only at the specific frequency where the problem occurs, achieving precise suppression without affecting the operation of other normal frequency bands. This strategy, combining fundamental optimization with precise targeting, makes the impedance reshaping of wind turbines comprehensive, fundamentally sound, flexible, and efficient, greatly enhancing its ability to independently suppress oscillations.

[0072] Furthermore, in some embodiments, an adaptive damping network control strategy can monitor the impedance characteristics of the grid connection point in real time and react immediately upon detecting harmful fluctuations. By dynamically adjusting the adjustable inductors, capacitors, and resistors integrated within the adaptive damping network, precise damping can be achieved. Moreover, this adaptive capability ensures that the wind farm can actively and continuously stabilize its impedance characteristics within a safe range, greatly enhancing the system's robustness and self-healing ability in the face of grid disturbances.

[0073] This application also provides a station impedance reshaping system for suppressing broadband oscillations in wind farms. The system can use the aforementioned station impedance reshaping method 100 for suppressing broadband oscillations in wind farms, or other methods can be used for station impedance reshaping. This application does not impose any restrictions on this method.

[0074] Figure 3 An exemplary structural block diagram of a wind farm broadband oscillation suppression station impedance reshaping system according to an embodiment of this application is shown.

[0075] like Figure 3 As shown, the system 300 includes an impedance characteristic measurement and modeling module 310, an impedance reshaping module 320, a system impedance margin calculation module 330, and a collaborative control adjustment module 340. In the embodiments of this application, the impedance characteristic measurement and modeling module 310, the impedance reshaping module 320, the system impedance margin calculation module 330, and the collaborative control adjustment module 340 can be separate units or integrated into the same controller; this application does not impose any restrictions here.

[0076] Specifically, the impedance characteristic measurement and modeling module 310 is used to measure and model the impedance characteristics of the grid connection point of the wind farm in order to identify potential oscillation risk frequency bands and determine the optimization target of impedance reshaping.

[0077] Specifically, the impedance reshaping module 320 is used to reshape the impedance of the wind farm by coordinating the wind turbines and supercapacitor static condensers in the wind farm through a frequency band coordinated control strategy based on the optimization objective of impedance reshaping.

[0078] Specifically, the internal system impedance margin calculation module 330 is used to deploy a broadband impedance monitoring device to perform online evaluation of the impedance characteristics of the wind farm after impedance reshaping, and to calculate the system impedance margin of the wind farm and the external power grid.

[0079] Specifically, the collaborative control adjustment module 340 is used to dynamically adjust the collaborative control parameters according to the impedance margin through the communication interface between the wind farm's control system and the supercapacitor static condenser, so that the impedance characteristics of the wind farm's grid connection point after impedance reshaping match the optimization target of the impedance reshaping.

[0080] When system 300 performs station impedance reshaping using the aforementioned wind farm broadband oscillation suppression station impedance reshaping method 100, the aforementioned step S110 is executed through the impedance characteristic measurement and modeling module 310, the aforementioned step S120 is executed through the impedance reshaping module 320, the aforementioned step S130 is executed through the system impedance margin calculation module 330, and the aforementioned step S140 is executed through the coordinated control adjustment module 340. The specific execution process can be found above and will not be repeated here.

[0081] While numerous embodiments of this application have been shown and described herein, it will be apparent to those skilled in the art that such embodiments are provided by way of example only. Many modifications, alterations, and alternatives will arise for those skilled in the art without departing from the spirit and intent of this application. It should be understood that various alternatives to the embodiments of this application described herein may be employed in the practice of this application. The appended claims are intended to define the scope of protection of this application and therefore cover equivalents or alternatives within the scope of these claims.

Claims

1. A method for suppressing broadband oscillations in wind farms to reshape the impedance of wind farms, characterized in that, include: Impedance characteristics of the grid connection point of the wind farm are measured and modeled to identify potential oscillation risk frequency bands and determine the optimization target for impedance reshaping. Based on the optimization objective of impedance reshaping, a frequency-band coordinated control strategy is used to coordinate the control of wind turbines and supercapacitor static condensers in the wind farm in order to reshape the impedance of the wind farm. Deploy broadband impedance monitoring devices to conduct online assessments of the impedance characteristics of wind farms after impedance reshaping, and calculate the system impedance margin of the wind farm and the external power grid. Based on the impedance margin, the collaborative control parameters are dynamically adjusted through the communication interface between the wind farm's control system and the supercapacitor static condenser, so that the impedance characteristics of the wind farm's grid connection point after impedance reshaping match the optimization target of impedance reshaping.

2. The method for suppressing broadband oscillations in wind farms and reshaping the station impedance according to claim 1, characterized in that, The following steps are performed during the impedance characteristic measurement and modeling of the grid connection point of a wind farm: An impedance measurement device was used to perform a wideband impedance scan at the grid connection point of the wind farm to obtain impedance data. An equivalent impedance model of the wind farm is established based on the impedance data. The target impedance curve for guiding impedance reshaping is determined based on the equivalent impedance model of the wind farm.

3. The method for suppressing broadband oscillations in wind farms and reshaping the station impedance according to claim 1, characterized in that, The frequency band coordination control strategy includes: In the low-frequency and subsynchronous frequency bands, impedance reshaping is achieved through the combined effect of the impedance reshaping strategy of the wind turbine and the grid control strategy of the supercapacitor static condenser. In the high-frequency band, impedance reshaping is achieved through the power regulation strategy and adaptive damping network control strategy of the supercapacitor static phase converter.

4. The method for suppressing broadband oscillations in wind farms and reshaping the station impedance according to claim 3, characterized in that, The impedance reshaping strategy for wind turbines includes: optimizing the controller parameters of the wind turbines; and adjusting their external impedance characteristics by introducing a virtual impedance controller into the control logic of the wind turbines.

5. The method for suppressing broadband oscillations in wind farms and reshaping the station impedance according to claim 4, characterized in that, During the optimization of the controller parameters of the wind turbine, the parameters of the inner current loop controller, the outer current loop controller, and the phase-locked loop of the wind turbine are optimized.

6. The method for suppressing broadband oscillations in wind farms and reshaping the station impedance according to claim 4 or 5, characterized in that, Introducing a virtual impedance controller into the control logic of the wind turbine includes: generating a virtual impedance component in the controller of the wind turbine based on a frequency-dependent virtual admittance function, and superimposing the virtual impedance component onto the output reference signal of the controller.

7. The method for suppressing broadband oscillations in wind farms and reshaping the station impedance according to claim 3, characterized in that, The network control strategy for the supercapacitor static condenser includes making the supercapacitor static condenser exhibit positive impedance characteristics to the outside world.

8. The method for suppressing broadband oscillations in wind farms and reshaping the station impedance according to claim 3 or 7, characterized in that, The power regulation strategy of the supercapacitor static condenser includes: dynamically adjusting the ratio of active power damping to reactive power support to suppress oscillations in the high-frequency band.

9. The method for suppressing broadband oscillations in wind farms and reshaping the station impedance according to claim 3, characterized in that, The adaptive damping network control strategy includes: dynamically adjusting the parameters of the adaptive damping network according to the impedance characteristics of the wind farm grid connection point, so that the fluctuation of the wind farm impedance characteristics is kept within a preset range of its full impedance value. The adaptive damping network includes adjustable inductors, capacitors, and resistors integrated within the supercapacitor stationary camera.

10. A wind farm impedance reshaping system for broadband oscillation suppression, characterized in that, The system employs the wind farm broadband oscillation suppression method as described in any one of claims 1-9 to perform wind farm impedance reshaping, wherein the system comprises: The impedance characteristic measurement and modeling module is used to measure and model the impedance characteristics of the grid connection point of a wind farm to identify potential oscillation risk frequency bands and determine the optimization target for impedance reshaping. The impedance reshaping module is used to reshape the impedance of the wind farm by coordinating the control of wind turbines and supercapacitor static condensers in the wind farm based on the optimization objective of impedance reshaping through a frequency band coordinated control strategy. The system impedance margin calculation module is used to deploy broadband impedance monitoring devices to evaluate the impedance characteristics of the wind farm after impedance reshaping online, and to calculate the system impedance margin of the wind farm and the external power grid. The collaborative control adjustment module is used to dynamically adjust the collaborative control parameters based on the impedance margin through the communication interface between the wind farm's control system and the supercapacitor static condenser, so that the impedance characteristics of the wind farm's grid connection point after impedance reshaping match the optimization target of the impedance reshaping.

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