Oscillation suppression method and device for new energy station, storage medium and computer

Abstract

The application discloses a new energy field station oscillation suppression method and device, a storage medium and a computer. The method comprises the following steps: obtaining a preset working condition group containing multiple preset power working conditions and a preset frequency group containing multiple preset frequencies. The new energy field station including a wind turbine and a static synchronous compensator is tested as follows: the wind turbine is controlled to operate in the preset power working condition, a disturbance voltage with the preset frequency is injected at the voltage output end of the wind turbine, and the output voltage and the output current at the time are collected. The impedance parameters of the new energy field station are calculated based on the collected data, and whether the field station is in a negative damping state is determined. If the field station is in the negative damping state, the damping coefficient of the static synchronous compensator is adjusted until the field station is in a positive damping state under the disturbance of the wind turbine in each preset power working condition and preset frequency. Finally, the adjusted damping coefficient is determined as the damping coefficient of the static synchronous compensator. The above scheme can improve the stability of the power grid where the new energy field station is located.

Description

Technical Field

[0001] This invention relates to the field of new energy technology, and in particular to a method, apparatus, storage medium, and computer for oscillation suppression in new energy power plants. Background Technology

[0002] With the continuous increase in the proportion of renewable energy generation, the stability issues of renewable energy power plants with wind turbines during grid connection are becoming increasingly prominent. Especially in weak grid environments or grid environments with series compensation capacitors, complex dynamic interactions easily arise between the power electronic converters of renewable energy power plants and the grid impedance. This interaction may cause renewable energy power plants to exhibit equivalent negative damping characteristics at specific frequencies. Once negative damping occurs, the power system is prone to subsynchronous oscillations, seriously threatening the safe and stable operation of renewable energy power plants and the AC grid.

[0003] Currently, existing technical solutions generally adopt a passive response strategy. This involves filtering out the oscillating component from the current at the grid connection point of renewable energy power plants after detecting grid oscillations, and introducing virtual impedance to enhance damping at specific frequencies. However, the effectiveness of this emergency response method highly depends on precise matching of the oscillation frequency, often proving effective only at specific frequency points and failing to address the risk of random oscillations across a wide frequency range. This results in the grid still facing stability risks under complex operating conditions, making it difficult to effectively guarantee the stability of renewable energy power plants during grid-connected operation. Summary of the Invention

[0004] In view of this, this application provides a method, device, storage medium and computer for oscillation suppression of new energy power stations, the main purpose of which is to solve the technical problem of low stability of the power grid where the new energy power station is located.

[0005] According to a first aspect of the present invention, a method for suppressing oscillations in a renewable energy power station is provided. The renewable energy power station includes a wind turbine and a static synchronizing compensator (SRC) for suppressing power oscillations in the wind turbine. The connection terminal between the voltage output terminal of the wind turbine and the output terminal of the SRC serves as the grid connection terminal of the renewable energy power station, for connection to the AC power grid. The method includes: Obtain a preset operating condition group and a preset frequency group, wherein the preset operating condition group includes multiple preset power operating conditions and the preset frequency group includes multiple preset frequencies; Based on each preset power condition in the preset operating condition group and each preset frequency in the preset frequency group, the following tests are performed on the new energy power station: The wind turbine is controlled to operate at a preset power condition. A disturbance voltage with a preset frequency is injected into the voltage output terminal of the wind turbine, and the output voltage and output current of the wind turbine under the action of the disturbance voltage are collected. Based on the output voltage and the output current, calculate the impedance parameters of the new energy power station; Based on the impedance parameters, it is determined whether the new energy power station is in a negative damping state. When the new energy power station is in a negative damping state, the damping coefficient of the stationary synchronous condenser is changed until the new energy power station is in a positive damping state when the wind turbine is injected with a disturbance voltage of a preset frequency under each preset power condition. The modified damping coefficient is determined as the target damping coefficient of the static synchronous condenser, so as to suppress the subsynchronous oscillation phenomenon of the AC power grid when the new energy power station is connected to the AC power grid.

[0006] In an optional embodiment, determining whether the new energy power station is in a negative damping state based on the impedance parameter includes: determining the impedance phase of the new energy power station based on the impedance parameter, and determining whether the absolute value of the impedance phase exceeds 90 degrees; when the absolute value of the impedance phase exceeds 90 degrees, determining that the new energy power station is in a negative damping state.

[0007] In an optional embodiment, changing the damping coefficient of the stationary synchronous condenser includes: obtaining the current damping coefficient of the stationary synchronous condenser, inputting the impedance phase and the damping coefficient into a pre-trained damping coefficient optimization model to obtain a modified damping coefficient value output by the damping coefficient optimization model, and adjusting the damping coefficient of the stationary synchronous condenser to the modified damping coefficient value.

[0008] In an optional embodiment, calculating the impedance parameters of the new energy power station based on the output voltage and the output current includes: determining the positive sequence voltage value output by the wind turbine based on the output voltage, and determining the positive sequence current value output by the wind turbine based on the output current; and determining the impedance parameters of the new energy power station based on the positive sequence voltage value and the positive sequence current value.

[0009] In an optional embodiment, the output voltage is a three-phase voltage, and the output current is a three-phase current. Determining the positive-sequence voltage value output by the wind turbine based on the output voltage, and determining the positive-sequence current value output by the wind turbine based on the output current, includes: determining the A-phase voltage, B-phase voltage, and C-phase voltage of the output voltage, and calculating the positive-sequence voltage value based on the A-phase voltage, the B-phase voltage, the C-phase voltage, and a preset rotation factor; determining the A-phase current, the B-phase current, and the C-phase current of the output current, and calculating the positive-sequence current value based on the A-phase current, the B-phase current, the C-phase current, and the preset rotation factor. In an optional embodiment, the preset power conditions include active power conditions characterizing the wind turbine in different output states, and reactive power conditions characterizing the wind turbine in different reactive power support states.

[0010] In an optional embodiment, the active power condition in the preset power condition includes one of the no-load power condition, the intermediate power condition, and the full-load power condition; the reactive power condition in the preset power condition includes one of the capacitive reactive power compensation condition, the inductive reactive power compensation condition, and the no reactive power condition.

[0011] According to a second aspect of the present invention, an oscillation suppression device for a new energy power station is provided, the device comprising: The data acquisition module is used to acquire a preset operating condition group and a preset frequency group, wherein the preset operating condition group includes a variety of preset power operating conditions and the preset frequency group includes a variety of preset frequencies. The test execution module is used to perform tests on the new energy power station based on each preset power condition in the preset operating condition group and each preset frequency in the preset frequency group. The test execution module includes: The power calculation module is used to control the wind turbine to operate under a preset power condition, inject a disturbance voltage with a preset frequency into the voltage output terminal of the wind turbine, and collect the output voltage and output current of the wind turbine under the action of the disturbance voltage. An impedance calculation module is used to calculate the impedance parameters of the new energy power station based on the output voltage and the output current. The cyclic testing module is used to determine whether the new energy power station is in a negative damping state based on the impedance parameters, and when the new energy power station is in a negative damping state, to change the damping coefficient of the static synchronous condenser until the new energy power station is in a positive damping state when the wind turbine is injected with a disturbance voltage of a preset frequency under each preset power condition. The result output module is used to determine the changed damping coefficient as the target damping coefficient of the static synchronous condenser, so as to suppress the subsynchronous oscillation phenomenon of the AC power grid when the new energy power station is connected to the AC power grid.

[0012] According to a third aspect of the present invention, a storage medium is provided having a computer program stored thereon, which, when executed by a processor, implements the above-described oscillation suppression method for new energy power stations.

[0013] According to a fourth aspect of the present invention, a computer is provided, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the above-described oscillation suppression method for new energy power stations.

[0014] This invention provides a method, device, storage medium, and computer for oscillation suppression in renewable energy power plants. A static synchronous condenser is installed at the grid connection end of the wind turbine in the renewable energy power plant. By actively traversing the impedance state of the renewable energy power plant under preset operating conditions and frequency combinations, a damping coefficient is set for the static synchronous condenser to ensure that the renewable energy power plant remains in a positive damped state under all operating conditions. This proactively enhances the grid connection stability of the renewable energy power plant, effectively overcoming the limitations of existing passive response strategies that only target specific frequency points and are unable to cope with broadband oscillations. It ensures that the renewable energy power plant maintains a positive damped state under various complex operating conditions, fundamentally suppressing subsynchronous oscillations in the power grid. This significantly enhances the adaptability of the renewable energy power plant to different power grid environments, thereby greatly improving the operational stability and security of the renewable energy power plant and the power grid system.

[0015] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0016] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and, together with their description, serve to explain the invention and do not constitute an undue limitation thereof. In the drawings: Figure 1 This diagram illustrates the structure of a new energy power station according to an embodiment of the present invention. Figure 2 A flowchart illustrating an oscillation suppression method for a new energy power station provided by an embodiment of the present invention is shown. Figure 3 This diagram illustrates one of the impedance frequency scanning results provided by an embodiment of the present invention; Figure 4This is a second schematic diagram of an impedance frequency scanning result provided by an embodiment of the present invention; Figure 5 This diagram illustrates a connection configuration between a wind turbine and a voltage and current acquisition device according to an embodiment of the present invention. Figure 6 The third schematic diagram illustrates an impedance frequency scanning result provided by an embodiment of the present invention; Figure 7 The fourth schematic diagram illustrates an impedance frequency scanning result provided by an embodiment of the present invention; Figure 8 A logic diagram of a virtual synchronization control provided by an embodiment of the present invention is shown; Figure 9 The fifth illustration shows an impedance frequency scanning result provided by an embodiment of the present invention; Figure 10 This is shown as a sixth schematic diagram of an impedance frequency scanning result provided by an embodiment of the present invention; Figure 11 A schematic diagram of the time-domain response waveform of active power in a power network provided by an embodiment of the present invention is shown. Figure 12 A schematic diagram of a spectrum analysis result provided by an embodiment of the present invention is shown; Figure 13 The diagram shows a structural schematic of an oscillation suppression device for a new energy power station provided in an embodiment of the present invention. Detailed Implementation

[0017] The present invention will be described in detail below with reference to the accompanying drawings and embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in the present application can be combined with each other.

[0018] With the continuous increase in the proportion of renewable energy generation, the stability issues of renewable energy power plants with wind turbines during grid connection are becoming increasingly prominent. Especially in weak grid environments or grid environments with series compensation capacitors, complex dynamic interactions easily arise between the power electronic converters of renewable energy power plants and the grid impedance. This interaction may cause the renewable energy power plant to exhibit equivalent negative damping characteristics at specific frequencies. Once negative damping occurs, the power system is prone to subsynchronous oscillations, seriously threatening the safe and stable operation of renewable energy power plants and the AC grid. Currently, existing technical solutions generally adopt a passive response strategy, that is, after detecting grid oscillations, filtering out the oscillating component in the current at the renewable energy power plant's grid connection point and introducing virtual impedance to enhance damping at specific frequencies. However, the effectiveness of this emergency handling method is highly dependent on precise matching of the oscillation frequency, often only effective at specific frequency points, and difficult to cope with the risk of random oscillations over a wide frequency range. This results in the grid still facing stability risks under complex operating conditions, making it difficult to effectively guarantee the stability of renewable energy power plants during grid connection.

[0019] To address the aforementioned problems, in one embodiment, a method for suppressing oscillations in a new energy power station is provided. This is illustrated by taking the application of this method to a computer for suppressing oscillations in a new energy power station as an example; here, as... Figure 1 As shown, the new energy power station 100 is connected to an AC power grid with a capacitor compensation device 400 connected in series. Specifically, the new energy power station 100 includes a wind turbine 200 and a static synchronous compensator 300 for suppressing power oscillations on the grid-connected side of the wind turbine 200. The connection point where the voltage output terminal of the wind turbine 200 is connected to the output terminal of the static synchronous compensator 300 serves as the grid-connected terminal of the new energy power station 100, used to connect to the AC power grid through the grid connection point 500. Specifically, the voltage output terminal of the wind turbine 200 is connected to the low-voltage side coil of the first transformer 130, the high-voltage side coil of the first transformer 130 is connected to the output terminal of the static synchronous compensator 300 and the low-voltage side coil of the second transformer 140, respectively, and the high-voltage side coil of the second transformer 140 is connected to the grid connection point 500 via the capacitor compensation device 400. Further, the wind turbine 200 can be a doubly-fed wind turbine; further, as... Figure 2 As shown, this method includes the following steps: 101. Obtain the preset operating condition group and preset frequency group; The preset operating condition group includes multiple preset power operating conditions, and the preset frequency group includes multiple preset frequencies. Furthermore, Figure 3 and Figure 4 The impedance frequency sweep results on the grid side are shown after a capacitor compensation device is connected in series. For example... Figure 3As shown, the introduction of series compensation capacitors significantly alters the impedance characteristics of the power grid system. In the low-frequency range of 1Hz-20Hz, the impedance amplitude exhibits a noticeable dip and rise, such as... Figure 4 As shown, the voltage phase exhibits strong capacitive characteristics near 20Hz, indicating that the power grid is prone to forming a resonant circuit with the wind turbine in this frequency band.

[0020] Based on this, the frequency range that is prone to causing negative resistance and LC resonance can be determined as the selection range of frequencies in the preset frequency group based on the impedance characteristics of the wind turbine system in the sub-synchronous frequency band. By analyzing the capacitive impedance characteristics of the power network containing series compensation capacitors in the sub-synchronous frequency band, combined with the frequency range in which the doubly-fed induction generator (DFIG) exhibits inductive impedance, the selection range of frequencies in the preset frequency group can be determined to be 1Hz to 20Hz. Specifically, multiple characteristic frequency points can be selected as preset frequencies within the 1Hz to 20Hz range for subsequent damping coefficient determination to ensure that the DFIG does not have negative damping in this frequency band. Furthermore, the selection range of frequencies in the preset frequency group can be determined according to actual conditions and is also applicable to this embodiment.

[0021] Furthermore, the preset power conditions include active power conditions characterizing wind turbines in different output states, and reactive power conditions characterizing wind turbines in different reactive power support states. Here, the preset power conditions consist of both active and reactive power conditions, with each preset power condition including one active power condition and one reactive power condition. By combining these two conditions, the complex operating characteristics of wind turbines in the actual power grid—both transmitting active power and regulating reactive power—can be comprehensively reflected. This ensures that subsequent damping coefficient tests and optimizations based on this set of conditions are more representative and adaptable, effectively covering the operating modes of wind turbines under different power factors and grid dispatch requirements.

[0022] Furthermore, the active power conditions in the preset power conditions include one of the following: no-load power conditions, intermediate power conditions, and full-load power conditions; the reactive power conditions in the preset power conditions include one of the following: capacitive reactive power compensation conditions, inductive reactive power compensation conditions, and no reactive power conditions.

[0023] Specifically, the active power test range can start from 0 p.u. (zero rated power) and gradually increase to 1.0 p.u. (rated power) in increments of 0.1 p.u. 0 p.u. can be used as the no-load power condition, 1.0 p.u. can be used as the full-load power condition, and 0.1 p.u. to 0.9 p.u. can be used as different intermediate power conditions. This ensures that the active power conditions cover the entire operating range of the wind turbine from the shutdown state to the rated power output, thus ensuring the continuity and integrity of the test data.

[0024] Furthermore, the reactive power conditions in the preset power conditions include one of the following: capacitive reactive power compensation condition, inductive reactive power compensation condition, and no reactive power generation condition. For each set active power point, the computer running this method needs to examine its electrical characteristics under three typical states: generating capacitive reactive power, generating inductive reactive power, and generating no reactive power, in order to simulate the actual operating mode of the wind turbine under different grid voltage regulation requirements.

[0025] Furthermore, by combining the aforementioned active power and reactive power operating conditions, a multi-dimensional test matrix is ​​constructed. In this matrix, 11 key points of active power (from 0p.u. to 1.0pu.) are coupled with three states of reactive power, forming approximately 33 key test conditions. This comprehensive measurement method, covering all operating conditions, can accurately acquire the impedance characteristics of the doubly-fed induction generator (DFIG) at different operating points, providing a data foundation for subsequent damping coefficient adjustments and ensuring the wind turbine's ability to support the power grid under various complex operating conditions.

[0026] Furthermore, in actual operation, different active power reference values ​​and reactive power reference values ​​can be set by adjusting the control strategy of the rotor-side frequency converter of the wind turbine generator, so that the wind turbine generator is in different active power and reactive power operating conditions.

[0027] Furthermore, such as Figure 5 As shown, the wind turbine 200 can be a doubly-fed induction generator (DFIG) that outputs three-phase electricity. Its voltage output terminal can be connected to a voltage and current acquisition device 210, which may include voltage and current sensors to acquire the A-phase voltage, B-phase voltage, C-phase voltage, A-phase current, B-phase current, and C-phase current output by the wind turbine 200, and send the acquisition results to a computer running this method. Furthermore, a disturbance voltage generator 220 can be installed at the voltage output terminal of the wind turbine 200. Multiple voltage output devices 221 of the disturbance voltage generator 220 can be connected to each phase power transmission line of the wind turbine 200 to output disturbance voltages to the voltage output terminal of the wind turbine 200.

[0028] 102. Based on each preset power condition in the preset operating condition group and each preset frequency in the preset frequency group, perform the following tests on the new energy power station: 103. Control the wind turbine to operate at a preset power condition, inject a disturbance voltage with a preset frequency into the voltage output terminal of the wind turbine, and collect the output voltage and output current of the wind turbine under the action of the disturbance voltage.

[0029] Specifically, to ensure the wind turbine operates stably at a predetermined power level, a disturbance voltage with a predetermined frequency is injected at the turbine outlet using a disturbance voltage generator. Simultaneously, a voltage and current acquisition device collects the turbine's output voltage and current in real time under this disturbance.

[0030] 104. Based on the output voltage and the output current, calculate the impedance parameters of the new energy power station.

[0031] Specifically, the positive sequence voltage value output by the wind turbine in the new energy power station can be determined based on the output voltage, and the positive sequence current value output by the wind turbine can be determined based on the output current. Here, the A-phase voltage, B-phase voltage, and C-phase voltage of the output voltage can be determined, and the positive sequence voltage value is calculated based on the A-phase voltage, B-phase voltage, C-phase voltage, and a preset rotation factor. Specifically, the positive sequence voltage value can be calculated using Formula 1: (1) in, This is the positive sequence voltage value. The preset rotation factor can have the following values: , This is the voltage of phase A. This is the voltage of phase B. This is the voltage of phase C.

[0032] Furthermore, the A-phase current, B-phase current, and C-phase current of the output current can be determined, and the positive sequence current value can be calculated based on the A-phase current, B-phase current, C-phase current, and a preset rotation factor.

[0033] Specifically, the positive sequence current value can be calculated using formula 2: (2) in, This is the positive sequence current value. The preset rotation factor has a value of , This is the current in phase A. This is the B-phase current. This represents the C-phase current.

[0034] Furthermore, based on the positive sequence voltage value and the positive sequence current value, the impedance parameters of the new energy power station under the influence of the disturbance voltage at the preset frequency are determined; specifically, the impedance parameters can be calculated based on Formula 3: (3) in, For impedance parameters, This is the positive sequence current value. This is the positive sequence voltage value. Let Z be the frequency of the wind turbine's output voltage at the current moment. Here, the calculated impedance parameter can be in the form Z = R + jX, where R is the real part of the impedance and X is the imaginary part. Furthermore, the impedance phase corresponding to the impedance parameter can be determined based on Equation 4. θ=tan 1(X / R)(4) Where θ is the impedance phase, R is the real part of the impedance, and X is the imaginary part of the impedance.

[0035] 105. Based on the impedance parameters, determine whether the new energy power station is in a negative damping state, and when the new energy power station is in a negative damping state, change the damping coefficient of the static synchronous condenser until the new energy power station is in a positive damping state when the wind turbine is injected with a disturbance voltage of a preset frequency under each preset power condition. Specifically, the stability state of a renewable energy power station can be determined based on impedance parameters. Specifically, the impedance phase of the impedance parameters can be analyzed to determine whether the renewable energy power station is in a negative damping state. When the absolute value of the calculated impedance phase exceeds 90 degrees, it indicates that the renewable energy power station exhibits negative damping characteristics, meaning that the renewable energy power station continuously absorbs energy from the grid, causing subsynchronous oscillations to diverge. Therefore, the renewable energy power station is determined to be in a negative damping state. Conversely, when the absolute value of the impedance phase does not exceed 90 degrees, it indicates that the renewable energy power station exhibits a positive damping state.

[0036] Here, Figure 6 and Figure 7 This demonstrates the impedance frequency sweep results of a new energy power station without effective damping control. Figure 7 It can be seen that within the subsynchronous frequency band, the impedance phase of the power system fluctuates drastically around 20Hz and crosses the 0° line, with the phase value between 92.27° and 110°, exhibiting obvious negative damping characteristics. This means that the system is very likely to resonate with the grid impedance at this frequency, inducing subsynchronous oscillation.

[0037] Furthermore, after determining that the new energy power station is in a negative damping state, the damping coefficient of the stationary synchronous condenser can be optimized and adjusted. Specifically, such as... Figure 8 As shown, based on virtual synchro technology, the damping coefficient in the virtual synchronization control process of a stationary synchronous synchro can be adjusted. The equivalent output impedance characteristics of the static synchronous condenser are adjusted so that the adjusted static synchronous condenser can provide sufficient positive damping support for the new energy power station, so that the new energy power station is in a positive damping state.

[0038] Here, the adjustment process employs an iterative mechanism. Specifically, when the wind turbine operates at a preset power condition, a disturbance voltage of a specific frequency is injected into its voltage output terminal. If, after adjusting the damping coefficient of the static synchronous condenser, the renewable energy power station remains in a negative damping state, the damping coefficient is further optimized. If the renewable energy power station has recovered to a positive damping state, the frequency of the disturbance voltage is switched, and the above testing and adjustment steps are repeated. This cycle continues until, under the influence of disturbance voltages of all preset frequencies at the preset power condition, the renewable energy power station can stably maintain a positive damping state, thus confirming that it possesses good full-frequency damping characteristics under this power condition.

[0039] Subsequently, the preset power conditions of the wind turbines are adjusted, and the positive damping stability of the renewable energy power station under these new conditions is verified. If the renewable energy power station exhibits a negative damping state after injecting a disturbance voltage at a preset frequency, the damping coefficient of the static synchronous condenser needs to be readjusted, and a full-band disturbance test must be conducted again. This process will be iterated repeatedly until all combinations of preset power conditions and preset frequencies have been traversed, ensuring that the renewable energy power station can stably maintain a positive damping state under every test condition, i.e., the absolute value of the impedance phase is less than 90°, thereby completely eliminating the risk of subsynchronous resonance and ensuring the safe and stable grid-connected operation of the unit across the entire operating range.

[0040] Furthermore, Figure 9 and Figure 10 The impedance frequency scan results of the AC power grid after damping coefficient optimization are presented. Figure 9 It can be seen that in the subsynchronous frequency band around 20Hz, the system's impedance phase remains consistently between -90° and 90°, specifically between -40.56° and 38.81° at 20Hz, without any phase crossing phenomenon. Figure 10 The amplitude curve shown is smooth without severe resonance spikes. This indicates that the new energy power station adjusted by the method in this embodiment exhibits positive damping characteristics, and the system is in a stable operating state under this condition with sufficient stability margin.

[0041] 106. The modified damping coefficient is determined as the target damping coefficient of the static synchronous condenser, so as to suppress the subsynchronous oscillation phenomenon of the AC power grid when the new energy power station is connected to the AC power grid.

[0042] Specifically, the modified damping coefficient can be determined as the target damping coefficient of the static synchronous condenser, aiming to provide optimal dynamic control parameters for the static synchronous condenser during grid connection to effectively suppress subsynchronous oscillations in the grid. In specific engineering applications, when renewable energy power plants are connected to the grid, changes in AC grid impedance or weak grid environments can easily trigger subsynchronous oscillations, threatening the safety and stability of the generating units and the grid. By setting the aforementioned damping coefficient, which has been iteratively verified and ensures that the renewable energy power plant is in a positive damping state under all operating conditions and frequency band disturbances, as the target damping coefficient and loading it into the converter control loop of the static synchronous condenser, the renewable energy power plant can possess sufficient positive damping characteristics during operation. When the grid experiences subsynchronous frequency disturbances, this target damping coefficient can respond quickly and generate a reverse suppression effect, consuming oscillation energy and disrupting the resonance conditions of subsynchronous oscillations, thereby maintaining the equivalent impedance of the system within a stable range and fundamentally ensuring the safe and stable grid connection and operation of the renewable energy power plant.

[0043] The oscillation suppression method for renewable energy power plants provided in this embodiment can actively enhance the grid connection stability of renewable energy power plants by setting a static synchronous condenser at the grid connection end of the wind turbine of the renewable energy power plant and actively traversing the impedance state of the renewable energy power plant under preset operating conditions and frequency combinations to set a damping coefficient for the static synchronous condenser that enables the renewable energy power plant to be in a positive damping state under all operating conditions. This effectively overcomes the limitations of existing passive response strategies that only target specific frequency points and are difficult to cope with broadband oscillations, ensuring that the renewable energy power plant maintains a positive damping state under various complex operating conditions. This fundamentally suppresses the phenomenon of subsynchronous oscillation in the power grid, significantly enhances the adaptability of renewable energy power plants to different power grid environments, and thus greatly improves the operational stability and security of renewable energy power plants and the power grid system.

[0044] In an optional embodiment, the method of changing the damping coefficient of the stationary synchronous condenser includes: obtaining the current damping coefficient of the stationary synchronous condenser, inputting the impedance phase and the damping coefficient into a pre-trained damping coefficient optimization model to obtain a modified damping coefficient value output by the damping coefficient optimization model, and adjusting the damping coefficient of the stationary synchronous condenser to the modified damping coefficient value.

[0045] Specifically, the damping coefficient of the static synchronous condenser under its current operating state, and the impedance phase calculated from the output voltage and current of the wind turbine, can be obtained. These two key characteristic parameters are used as input variables and fed into a pre-trained damping coefficient optimization model. Here, based on its internally learned nonlinear mapping relationship, the model outputs an optional damping coefficient modification value and adjusts the actual damping coefficient of the static synchronous condenser to this modification value.

[0046] Here, during the model training phase, historical data on the adjustment of the damping coefficient of a stationary synchronous condenser can be obtained. This includes the impedance phase before each adjustment, the damping coefficient before adjustment, and the final target damping coefficient after adjustment. During training, the impedance phase and damping coefficient before adjustment are used as input training samples, and the corresponding target damping coefficient is used as a label, thereby supervising the training of the damping coefficient optimization model. Through this process, the model can autonomously learn and master the inherent mapping law between the impedance phase and the damping coefficient. Therefore, when the real-time impedance phase and damping coefficient are obtained, the model can quickly calculate the optimal damping coefficient modification value, significantly improving the automation and efficiency of damping coefficient adjustment. The embodiment provided in this application, by introducing a pre-trained damping coefficient optimization model, transforms the traditional trial-and-error method into a data-driven intelligent decision-making algorithm, enabling the scheme to quickly calculate the optimal modification value based on the real-time impedance phase and damping coefficient, significantly improving the efficiency and accuracy of parameter adjustment.

[0047] Furthermore, Figure 11 The time-domain response waveform of the active power in the power network is given. Figure 12 The corresponding spectral analysis results are given. Among them, Figure 12 The first curve in the diagram represents the power spectrum characteristics during the oscillation divergence phase, and the second curve represents the power spectrum characteristics during the oscillation suppression phase. Furthermore, as... Figure 11 As shown, after the new energy power station is connected to the series compensation system, the system begins to oscillate at 11s when the series compensation is put into operation, and the power amplitude gradually diverges. However, at 12.5s, when the parallel static synchronous condenser is put into operation, the amplitude of the oscillation waveform rapidly decays, indicating that the device effectively suppresses system oscillation. Combined with... Figure 12 It can be seen that during the oscillation divergence stage, the system has a significant amplitude peak at about 9Hz, indicating that the system has strong subsynchronous oscillations; while in the stable stage after the static synchronous condenser is put into operation, the amplitude at the original oscillation frequency has been greatly reduced, further verifying the effective suppression capability of the static synchronous condenser of this method for specific subsynchronous oscillation frequencies.

[0048] The oscillation suppression method for new energy power plants provided in this embodiment can accurately match the changes in the operating conditions of the power system by dynamically adjusting the damping coefficient in the virtual synchronization control according to the actual operating characteristics of the electric field. This ensures that the wind farm exhibits positive damping characteristics under risky frequency bands and all operating conditions, effectively solving the problem of subsynchronous oscillation that easily occurs when a doubly fed wind farm is connected to the grid via series compensation, and significantly improving the stability and security of the power grid system.

[0049] Furthermore, as Figure 2The specific implementation of the method shown in this embodiment provides an oscillation suppression device for a new energy power station, such as... Figure 13 As shown, the device includes: a data acquisition module 31 and a test execution module 32, wherein the test execution module 32 includes an energy calculation module 321, an impedance calculation module 322, a cyclic test module 323, and a result output module 324.

[0050] The data acquisition module 31 can be used to acquire a preset operating condition group and a preset frequency group, wherein the preset operating condition group includes a variety of preset power operating conditions and the preset frequency group includes a variety of preset frequencies. The test execution module 32 can be used to perform tests on new energy power plants based on each preset power condition in the preset operating condition group and each preset frequency in the preset frequency group. The power calculation module 321 can be used to control the wind turbine to operate under a preset power condition, inject a disturbance voltage with a preset frequency into the voltage output terminal of the wind turbine, and collect the output voltage and output current of the wind turbine under the action of the disturbance voltage. Impedance calculation module 322 can be used to calculate the impedance parameters of the new energy power station based on the output voltage and the output current; The cyclic test module 323 can be used to determine whether the new energy power station is in a negative damping state based on the impedance parameters, and when the new energy power station is in a negative damping state, change the damping coefficient of the static synchronous condenser until the new energy power station is in a positive damping state when the wind turbine is injected with a disturbance voltage of a preset frequency under each preset power condition. The result output module 324 can be used to determine the changed damping coefficient as the target damping coefficient of the static synchronous condenser, so as to suppress the subsynchronous oscillation phenomenon of the AC power grid when the new energy power station is connected to the AC power grid.

[0051] In specific application scenarios, the cyclic test module 323 can be used to determine the impedance phase of the new energy power station based on the impedance parameters, and determine whether the absolute value of the impedance phase exceeds 90 degrees; when the absolute value of the impedance phase exceeds 90 degrees, it is determined that the new energy power station is in a negative damping state.

[0052] In a specific application scenario, the cyclic testing module 323 can be used to obtain the current damping coefficient of the stationary synchronous condenser, input the impedance phase and the damping coefficient into a pre-trained damping coefficient optimization model, obtain the damping coefficient modification value output by the damping coefficient optimization model, and adjust the damping coefficient of the stationary synchronous condenser to the damping coefficient modification value.

[0053] In specific application scenarios, the impedance calculation module 322 can be used to determine the positive sequence voltage value output by the wind turbine based on the output voltage, and to determine the positive sequence current value output by the wind turbine based on the output current; and to determine the impedance parameters of the new energy power station based on the positive sequence voltage value and the positive sequence current value.

[0054] In specific application scenarios, the output voltage is a three-phase voltage, and the output current is a three-phase current. The impedance calculation module 322 can be used to determine the A-phase voltage, B-phase voltage, and C-phase voltage of the output voltage, and calculate the positive sequence voltage value based on the A-phase voltage, the B-phase voltage, the C-phase voltage, and a preset rotation factor; determine the A-phase current, the B-phase current, and the C-phase current of the output current, and calculate the positive sequence current value based on the A-phase current, the B-phase current, the C-phase current, and a preset rotation factor.

[0055] It should be noted that other corresponding descriptions of the functional units involved in the oscillation suppression device for a new energy power station provided in this embodiment can be found in [reference needed]. Figure 2 The corresponding description in [the document] will not be repeated here.

[0056] Based on the above, Figure 2 Accordingly, this embodiment also provides a storage medium storing a computer program that, when executed by a processor, implements the above-described method. Figure 2 The method for suppressing oscillations in new energy power stations is shown.

[0057] Based on this understanding, the technical solution of this application can be embodied in the form of a software product. The software product to be identified can be stored in a non-volatile storage medium (such as a CD-ROM, USB flash drive, mobile hard drive, etc.) and includes several instructions to cause a computer (such as a personal computer, server, or network device, etc.) to execute the methods described in the various implementation scenarios of this application.

[0058] Based on the above, Figure 2 The method shown, and Figure 13 The embodiment of the oscillation suppression device for the new energy power station shown herein, in order to achieve the above objective, also provides a computer for executing the oscillation suppression method for the new energy power station. Specifically, this computer can be a personal computer, server, smartphone, tablet computer, smartwatch, or other network device, etc. The computer includes a storage medium and a processor; the storage medium is used to store computer programs and an operating system; the processor is used to execute the computer program to implement the above-described... Figure 2 The method shown.

[0059] Optionally, the computer may also include internal memory, a communication interface, a network interface, a camera, radio frequency (RF) circuitry, sensors, audio circuitry, a Wi-Fi module, a display screen, and input devices such as a keyboard. The communication interface may also include a USB interface, a card reader interface, etc. The network interface may optionally include a standard wired interface or a wireless interface (such as a Wi-Fi interface).

[0060] Those skilled in the art will understand that the computer structure for recognizing operational actions provided in this embodiment does not constitute a limitation on the computer, and may include more or fewer components, or combine certain components, or have different component arrangements.

[0061] The storage medium may also include an operating system and a network communication module. The operating system is a program that manages the aforementioned computer hardware and software resources to be identified, supporting the operation of information processing programs and other software and / or programs to be identified. The network communication module is used to enable communication between the various components within the storage medium, as well as communication with other hardware and software in the information processing computer.

[0062] Through the above description of the embodiments, those skilled in the art can clearly understand that this application can be implemented by means of software plus necessary general-purpose hardware platform, or it can be implemented by hardware. By applying the technical solution of this application, firstly, a preset operating condition group and a preset frequency group are obtained, wherein the preset operating condition group includes multiple preset power operating conditions, and the preset frequency group includes multiple preset frequencies; then, based on each preset power operating condition in the preset operating condition group and each preset frequency in the preset frequency group, the following tests are performed on the new energy power station: controlling the wind turbine to operate in a preset power operating condition, injecting a disturbance voltage with a preset frequency into the voltage output terminal of the wind turbine, and collecting the output voltage and output current of the wind turbine under the action of the disturbance voltage; further, based on the output voltage and the preset frequency, the following tests are performed on the new energy power station: controlling the wind turbine to operate in a preset power operating condition, injecting a disturbance voltage with a preset frequency into the voltage output terminal of the wind turbine, and collecting the output voltage and output current of the wind turbine under the action of the disturbance voltage; further, based on the output voltage and the preset frequency, the following tests are performed on the new energy power station. The output current is described, and the impedance parameters of the renewable energy power station are calculated. Further, based on the impedance parameters, it is determined whether the renewable energy power station is in a negative damping state. If the renewable energy power station is in a negative damping state, the damping coefficient of the static synchronous condenser is changed until the renewable energy power station is in a positive damping state when the wind turbine injects disturbance voltages of different preset frequencies under each preset power condition. Further, the changed damping coefficient is determined as the target damping coefficient of the static synchronous condenser to suppress subsynchronous oscillations in the AC power grid when the renewable energy power station is connected to the AC power grid. Compared with existing technologies, this improves the stability of the power grid where the renewable energy power station is located.

[0063] Those skilled in the art will understand that the accompanying drawings are merely schematic diagrams of a preferred embodiment, and the modules or processes shown in the drawings are not necessarily essential for implementing this application. Those skilled in the art will understand that the modules in the apparatus of the embodiment can be distributed within the apparatus of the embodiment as described, or can be modified to be located in one or more apparatuses different from this embodiment. The modules of the above-described embodiment can be combined into one module, or further divided into multiple sub-modules.

[0064] The serial numbers in this application are for descriptive purposes only and do not represent the superiority or inferiority of any particular implementation scenario. The above disclosures are merely a few specific implementation scenarios of this application; however, this application is not limited thereto, and any variations conceived by those skilled in the art should fall within the protection scope of this application.

Claims

1. A method for suppressing oscillations in renewable energy power plants, characterized in that, The new energy power station includes a wind turbine and a static synchronous compensator (SRC) for suppressing power oscillations in the wind turbine. The connection point between the voltage output terminal of the wind turbine and the output terminal of the SRC serves as the grid connection terminal of the new energy power station, allowing it to connect to the AC power grid. The method includes: Obtain a preset operating condition group and a preset frequency group, wherein the preset operating condition group includes multiple preset power operating conditions and the preset frequency group includes multiple preset frequencies; Based on each preset power condition in the preset operating condition group and each preset frequency in the preset frequency group, the following tests are performed on the new energy power station: The wind turbine is controlled to operate at a preset power condition. A disturbance voltage with a preset frequency is injected into the voltage output terminal of the wind turbine, and the output voltage and output current of the wind turbine under the action of the disturbance voltage are collected. Based on the output voltage and the output current, calculate the impedance parameters of the new energy power station; Based on the impedance parameters, it is determined whether the new energy power station is in a negative damping state. When the new energy power station is in a negative damping state, the damping coefficient of the stationary synchronous condenser is changed until the new energy power station is in a positive damping state when the wind turbine is injected with a disturbance voltage of a preset frequency under each preset power condition. The modified damping coefficient is determined as the target damping coefficient of the static synchronous condenser, so as to suppress the subsynchronous oscillation phenomenon of the AC power grid when the new energy power station is connected to the AC power grid.

2. The method according to claim 1, characterized in that, The step of determining whether the renewable energy power station is in a negative damping state based on the impedance parameter includes: Based on the impedance parameters, the impedance phase of the new energy power station is determined, and it is determined whether the absolute value of the impedance phase exceeds 90 degrees. When the absolute value of the impedance phase exceeds 90 degrees, the new energy power station is determined to be in a negative damping state.

3. The method according to claim 2, characterized in that, The change of the damping coefficient of the stationary synchronous camera includes: Obtain the current damping coefficient of the stationary synchronous condenser, and input the impedance phase and the damping coefficient into a pre-trained damping coefficient optimization model to obtain the damping coefficient modification value output by the damping coefficient optimization model, and adjust the damping coefficient of the stationary synchronous condenser to the modified damping coefficient value.

4. The method according to claim 1, characterized in that, The calculation of the impedance parameters of the new energy power station based on the output voltage and the output current includes: Based on the output voltage, the positive sequence voltage value output by the wind turbine is determined, and based on the output current, the positive sequence current value output by the wind turbine is determined. Based on the positive sequence voltage value and the positive sequence current value, the impedance parameters of the new energy power station are determined.

5. The method according to claim 4, characterized in that, The output voltage is a three-phase voltage, and the output current is a three-phase current; The step of determining the positive-sequence voltage value output by the wind turbine based on the output voltage, and determining the positive-sequence current value output by the wind turbine based on the output current, includes: Determine the A-phase voltage, B-phase voltage, and C-phase voltage of the output voltage, and calculate the positive sequence voltage value based on the A-phase voltage, the B-phase voltage, the C-phase voltage, and a preset rotation factor; The A-phase current, B-phase current, and C-phase current of the output current are determined, and the positive sequence current value is calculated based on the A-phase current, the B-phase current, the C-phase current, and a preset rotation factor.

6. The method according to any one of claims 1 to 5, characterized in that, The preset power conditions include active power conditions that characterize wind turbines in different output states, and reactive power conditions that characterize wind turbines in different reactive power support states.

7. The method according to claim 6, characterized in that, The active power condition in the preset power condition includes one of the following: no-load power condition, intermediate power condition, and full-load power condition. The reactive power conditions in the preset power conditions include one of the following: capacitive reactive power compensation condition, inductive reactive power compensation condition, and no reactive power generation condition.

8. An oscillation suppression device for a new energy power station, installed in the new energy power station as described in any one of claims 1 to 7, characterized in that, The device includes: The data acquisition module is used to acquire a preset operating condition group and a preset frequency group, wherein the preset operating condition group includes a variety of preset power operating conditions and the preset frequency group includes a variety of preset frequencies. The test execution module is used to perform tests on the new energy power station based on each preset power condition in the preset operating condition group and each preset frequency in the preset frequency group. The test execution module includes: The power calculation module is used to control the wind turbine to operate under a preset power condition, inject a disturbance voltage with a preset frequency into the voltage output terminal of the wind turbine, and collect the output voltage and output current of the wind turbine under the action of the disturbance voltage. An impedance calculation module is used to calculate the impedance parameters of the new energy power station based on the output voltage and the output current. The cyclic testing module is used to determine whether the new energy power station is in a negative damping state based on the impedance parameters, and when the new energy power station is in a negative damping state, to change the damping coefficient of the static synchronous condenser until the new energy power station is in a positive damping state when the wind turbine is injected with a disturbance voltage of a preset frequency under each preset power condition. The result output module is used to determine the changed damping coefficient as the target damping coefficient of the static synchronous condenser, so as to suppress the subsynchronous oscillation phenomenon of the AC power grid when the new energy power station is connected to the AC power grid.

9. A storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 1 to 7.

10. A computer, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 1 to 7.

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