A new energy flexible direct transmission system wide frequency oscillation adaptive suppression method and device

Abstract

The application discloses a new energy flexible direct current transmission system wide-frequency oscillation adaptive suppression method and device, and the method comprises the following steps: adjusting a band-pass filter according to a detected oscillation frequency, so as to screen an oscillation component based on the adjusted band-pass filter; inputting the oscillation frequency and an operating condition into a pre-trained mapping relationship model to obtain mapping data of a phase margin and a damping coefficient, wherein the damping coefficient is within a preset adjustment range; selecting a target damping coefficient from the preset adjustment range according to the mapping data and a preset target phase margin, wherein the target damping coefficient makes the mapped phase margin reach the preset target phase margin; and suppressing the wide-frequency oscillation of the system according to the oscillation component and the target damping coefficient. The application can realize online adaptive suppression of the wide-frequency oscillation of the new energy flexible direct current transmission system, is suitable for different operating conditions, and can significantly improve the stability of the power system.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of power electronics, and particularly relates to a new energy flexible direct current transmission system wide frequency oscillation adaptive suppression method and device. BACKGROUND

[0002] The new energy flexible direct current transmission system (i.e. new energy station-flexible direct current transmission system) is a typical power electronic interconnection system. Due to the wideband control interaction between power electronic converters, the system faces serious wide frequency oscillation risks. The wide frequency oscillation caused by the interaction between the new energy station and the flexible direct current transmission system is a new stability problem of the power system.

[0003] At present, the existing wide frequency oscillation suppression technology of the new energy flexible direct current transmission system is mostly targeted at specific oscillation frequency bands and specific operating conditions. However, the actual system operating conditions are variable, and the stability influencing factors are complex, and often accompanied by time-varying oscillation frequencies or even multiple mode oscillations coexist. Such randomness and time-varying nature lead to poor adaptability of traditional oscillation suppression measures. That is, the existing wide frequency oscillation suppression technology of the new energy flexible direct current transmission system cannot achieve online adaptive suppression of wide frequency oscillation under complex and variable system operating conditions, resulting in the power system cannot be safely and stably operated.

[0004] At present, there is no effective solution to the above problems. SUMMARY

[0005] The embodiments of the present application provide a new energy flexible direct current transmission system wide frequency oscillation adaptive suppression method and device to solve the problem that the prior art cannot achieve online adaptive suppression of the new energy flexible direct current transmission system wide frequency oscillation under complex and variable system operating conditions, resulting in the power system cannot be safely and stably operated.

[0006] In a first aspect, the embodiments of the present application provide a new energy flexible direct current transmission system wide frequency oscillation adaptive suppression method, which comprises:

[0007] Adjusting the band-pass filter according to the detected oscillation frequency, so as to filter the oscillation component based on the adjusted band-pass filter;

[0008] Inputting the oscillation frequency and the operating condition into a pre-trained mapping relationship model to obtain mapping data of the phase margin and the damping coefficient, the damping coefficient being within a preset adjustment range;

[0009] Selecting a target damping coefficient from the preset adjustment range according to the mapping data and a preset target phase margin, the target damping coefficient making the mapped phase margin reach the preset target phase margin;

[0010] Suppressing the wide frequency oscillation of the system according to the oscillation component and the target damping coefficient.

[0011] In some embodiments, the method further comprises:

[0012] collecting three-phase current data of an AC side of the sending-end HVDC converter;

[0013] detecting an oscillation frequency of the system according to the three-phase current data;

[0014] Accordingly, the adjusting the band-pass filter according to the detected oscillation frequency comprises:

[0015] adjusting a center frequency of the band-pass filter according to the oscillation frequency.

[0016] In some embodiments, the detecting the oscillation frequency of the system according to the three-phase current data comprises:

[0017] performing data processing analysis on the three-phase current data to obtain different frequency component amplitudes, the different frequency component amplitudes comprising a fundamental frequency component amplitude and other frequency component amplitudes except the fundamental frequency component amplitude;

[0018] determining a ratio of each of the other frequency component amplitudes to the fundamental frequency component amplitude;

[0019] comparing the ratio with a preset threshold to determine whether the system is oscillating according to a comparison result;

[0020] when it is determined that the system is oscillating, determining a target frequency component corresponding to a target frequency component amplitude in the different frequency component amplitudes as the oscillation frequency, the target frequency component amplitude being greater than a preset amplitude threshold.

[0021] In some embodiments, the mapping relationship model is obtained by training in the following manner:

[0022] selecting damping coefficient sample data of the virtual impedance, center frequency sample data of the band-pass filter, operating condition sample data, and phase margin sample data corresponding to the operating condition;

[0023] training a neural network model by taking the damping coefficient sample data of the virtual impedance, the center frequency sample data of the band-pass filter, and the operating condition sample data as input data and taking the phase margin sample data as output data, to obtain the mapping relationship model.

[0024] In some embodiments, the selecting the target damping coefficient from the preset adjustment range according to the mapping data and the preset target phase margin comprises:

[0025] setting a change step of the damping coefficient, and selecting a first damping coefficient from the preset adjustment range according to the change step;

[0026] determine a first phase margin mapped by the first damping coefficient according to the mapping data and the first damping coefficient;

[0027] determine whether the first phase margin reaches a preset target phase margin, and if so, take the first damping coefficient as a target damping coefficient.

[0028] In some embodiments, the suppressing the broadband oscillation of the system according to the oscillation component and the target damping coefficient comprises:

[0029] multiplying the oscillation component and the target damping coefficient, and superimposing a multiplication result into a modulation voltage of the sending-end HVDC converter to obtain an updated modulation voltage;

[0030] suppressing the broadband oscillation of the system based on the updated modulation voltage.

[0031] In some embodiments, the system comprises a new energy HVDC sending system, and the new energy unit in the new energy HVDC sending system comprises at least one of a photovoltaic power generation unit, a doubly-fed wind turbine generator, and a direct-drive wind turbine generator.

[0032] In a second aspect, the embodiments of the present specification also provide a new energy HVDC sending system broadband oscillation adaptive suppression device, which comprises:

[0033] an oscillation component screening module configured to adjust a band-pass filter according to the detected oscillation frequency, and screen an oscillation component based on the adjusted band-pass filter;

[0034] a prediction module configured to input the oscillation frequency and an operating condition into a pre-trained mapping relationship model to obtain mapping data of a phase margin and a damping coefficient, the damping coefficient being in a preset adjustment range;

[0035] a target damping coefficient selection module configured to select a target damping coefficient from the preset adjustment range according to the mapping data and a preset target phase margin, the target damping coefficient making the mapped phase margin reach the preset target phase margin;

[0036] a suppression module configured to suppress a broadband oscillation of the system according to the oscillation component and the target damping coefficient.

[0037] In a third aspect, the embodiments of the present specification also provide a computer device comprising a memory, a processor, and a computer program / instruction stored in the memory, the processor executing the computer program / instruction to implement the steps of the above new energy HVDC sending system broadband oscillation adaptive suppression method.

[0038] In a fourth aspect, the embodiments of the present specification also provide a computer-readable storage medium, which stores computer programs / instructions, and the computer programs / instructions are executed by a processor to implement the steps of the new energy flexible direct transmission system wide-frequency oscillation adaptive suppression method.

[0039] The embodiments of the present specification provide a new energy flexible direct transmission system wide-frequency oscillation adaptive suppression method and device. First, a band-pass filter is adjusted according to a detected oscillation frequency, so as to filter an oscillation component based on the adjusted band-pass filter. Then, the oscillation frequency and an operating condition are input into a pre-trained mapping relationship model to obtain mapping data of a phase margin and a damping coefficient, the damping coefficient being within a preset adjustment range. Then, a target damping coefficient is selected from the preset adjustment range according to the mapping data and a preset target phase margin, the target damping coefficient making the mapped phase margin reach the preset target phase margin. Finally, the wide-frequency oscillation of the system is suppressed according to the oscillation component and the target damping coefficient. In the embodiments of the present specification, the center frequency of the band-pass filter can be adjusted in real time and accurately through the online detected oscillation frequency, so that the oscillation component can be filtered in real time and accurately based on the adjusted band-pass filter, so that the subsequent wide-frequency adaptive suppression can be effectively suppressed in combination with the selected target damping coefficient. By inputting the online detected oscillation frequency and the operating condition into the trained mapping relationship model, the mapping data of the phase margin and the damping coefficient can be accurately and quickly obtained. By taking the operating condition as the model input data, the subsequent wide-frequency adaptive suppression can be applied to the complex time-varying system condition. Through the mapping data of the phase margin and the damping coefficient and the target phase margin, the online selection of the target damping coefficient can be realized, so that the wide-frequency oscillation online adaptive suppression can be realized according to the target damping coefficient and the filtered oscillation component. The wide-frequency oscillation online adaptive suppression can be applied to different operating conditions, so that the stability of the power system can be significantly improved. BRIEF DESCRIPTION OF DRAWINGS

[0040] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, brief descriptions will be given to the drawings needed in the embodiments or prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative effort. In the drawings:

[0041] Figure 1 is a structural composition schematic diagram of the adaptive wide-frequency oscillation suppression system provided by the embodiments of the present specification;

[0042] Figure 2 is a flowchart of a new energy flexible direct transmission system wide-frequency oscillation adaptive suppression method provided by the embodiments of the present specification;

[0043] Figure 3 is a whole schematic diagram of voltage and current waveforms and an output waveform of an adaptive wideband oscillation suppression system provided by an embodiment of the present specification;

[0044] Figure 4 is a schematic diagram of voltage and current waveforms provided by an embodiment of the present specification;

[0045] Figure 5 is a structural composition schematic diagram of a new energy flexible direct current transmission system wideband oscillation adaptive suppression device provided by an embodiment of the present specification;

[0046] Figure 6 is a structural composition schematic diagram of an electronic device provided by an embodiment of the present specification. DETAILED DESCRIPTION

[0047] In order for those skilled in the art to better understand the technical solutions in the present specification, the technical solutions in the present specification will be described clearly and completely in the following with reference to the drawings in the embodiments of the present specification. Obviously, the described embodiments are only part of the embodiments of the present specification, not all the embodiments. Based on the embodiments in the present specification, all other embodiments obtained by those skilled in the art without creative labor should be within the scope of protection of the present specification.

[0048] Developing new energy is an important way to achieve the "double carbon" goal. The power system is developing towards a high proportion of renewable energy and a high proportion of power electronic equipment (i.e. "double high"). Flexible direct current transmission technology has gradually become the mainstream scheme of high voltage direct current transmission. However, the new energy flexible direct current transmission system is a typical 100% power electronic interconnection system. Due to the wideband control interaction between power electronic converters, this type of system faces serious wideband oscillation risks. The wideband oscillation caused by the interaction between new energy stations and flexible direct current transmission systems is a new stability problem of power systems and a key technical problem to be solved.

[0049] At present, the oscillation suppression methods of new energy flexible direct current transmission systems mainly include control parameter optimization, additional extra hardware devices, and additional damping control measures.

[0050] Among them, the control parameter optimization means that on the basis of the original parameter design method, further increase the stability constraint conditions of the interconnected system, optimize the system controller parameters, increase the damping level of the system at the oscillation frequency, and improve the stability of the system. However, such methods usually only optimize the parameters offline for specific operating conditions, and the parameters are generally not adjusted during actual operation, which is difficult to cope with the complex and variable operating conditions of the system and the time-varying characteristics of the oscillation.

[0051] The additional hardware device refers to using grid-side series-parallel flexible power transmission devices such as static synchronous compensator (STATCOM), static var generator (SVG) and the like, designing additional damping control, injecting reverse oscillation current to the system, and realizing the suppression of oscillation. Such method is simple to implement, and the oscillation can be suppressed by increasing a special damping device, but the flexibility and universality are poor, and the additional device will increase the investment cost.

[0052] The additional damping control refers to adding various filters or additional control signal channels in the original controller channel of the device based on the ideas of virtual impedance / admittance, disturbance signal blocking, disturbance signal compensation, and improved excitation, increasing the damping of the device near the oscillation frequency, and improving the stability of the system. The scheme is mainly based on the double closed-loop decoupling control structure in the dq coordinate system, realizes the additional damping control, and is widely applied in different new energy stations and flexible DC stations. Such method has certain suppression ability for specific oscillation mode in specific scene, but the control structure and parameters are usually fixed and unchanged, and the effect is poor in solving the wide frequency oscillation problem with time-varying frequency and amplitude.

[0053] In addition, some wide frequency oscillation suppression techniques are only applied in wind turbines, and applying the technique in each wind turbine in the wind farm and maintaining it will generate more cost. The existing wide frequency oscillation suppression techniques for new energy flexible DC transmission systems are mostly for specific oscillation frequency bands and specific operating conditions. However, the actual system operating conditions are variable, the stability influencing factors are complex, and often accompanied by time-varying oscillation frequency or even multi-mode oscillation coexistence. Such randomness and time-varying nature lead to poor adaptability of traditional oscillation suppression measures, and efficient suppression of wide frequency oscillation still has great challenges.

[0054] In view of the above problems existing in the existing method and the specific reasons for the above problems, the present application considers introducing a new energy flexible DC transmission system wide frequency oscillation adaptive suppression method and device, which can realize online adaptive suppression of wide frequency oscillation under complex and variable system operating conditions, ensure the safe and stable operation of the power system, and provide new technical support for solving the wide frequency oscillation problem of the new energy flexible DC transmission system.

[0055] Based on the above idea, the present specification provides a new energy flexible direct transmission system wide frequency oscillation adaptive suppression method. First, the center frequency of the band-pass filter in the virtual impedance is adjusted according to the detected oscillation frequency, and then the oscillation component in the current on the AC side of the sending end MMC is screened through the adjusted band-pass filter. Then, the oscillation frequency and the operating condition are input into the pre-trained mapping relationship model to obtain the mapping data of the phase margin and the damping coefficient, and the damping coefficient is within the preset adjustment range. Then, according to the mapping data and the preset target phase margin, the target damping coefficient is selected from the preset adjustment range, and the target damping coefficient makes the mapped phase margin reach the preset target phase margin. Finally, according to the oscillation component and the target damping coefficient, the wide frequency oscillation of the system is suppressed.

[0056] Referring to Figure 1 as shown, Figure 1 is a structural composition schematic diagram of the adaptive wide frequency oscillation suppression system provided by the present specification. The adaptive wide frequency oscillation suppression system (or adaptive wide frequency oscillation suppression link) can include an oscillation frequency online detection module, a virtual impedance module, and a damping parameter online update module. Among them, the oscillation frequency online detection module can collect the three-phase current data on the AC side of the sending end MMC and record it into the cache, and then detect the system oscillation frequency (f abc ) online and quickly according to the collected three-phase current data (i os ) on the AC side of the sending end MMC. The oscillation frequency online detection module can send the online detected oscillation frequency (f os ) to the virtual impedance module, and the virtual impedance module can adjust the center frequency of the band-pass filter in the virtual impedance according to the online detected oscillation frequency (f os ), and then screen out the oscillation component in the current on the AC side of the sending end MMC through the adjusted band-pass filter. The trained neural network model (i.e. the mapping relationship model in the present application) can be configured in the damping parameter online update module, the operating condition and the online detected oscillation frequency (f os ) can be input into the trained model to obtain the mapping data of the phase margin and the damping coefficient, and then the preset target phase margin is obtained, so that the damping coefficient (k b ) can be selected online according to the mapping data of the phase margin and the damping coefficient and the target phase margin, and the damping coefficient (i.e. the target damping coefficient in the present application) output by the damping parameter online update module can be sent to the virtual impedance module. Finally, the virtual impedance module can multiply the oscillation component screened by the band-pass filter by the target damping coefficient output by the damping parameter online update module, and then superimpose it into the modulation voltage of the basic controller of the sending end MMC, so as to realize the adaptive suppression of the wide frequency oscillation of the new energy flexible direct transmission system, which can be suitable for different operating conditions and can significantly improve the stable operation level of the system, wherein, uabc , u ref are measured three-phase AC voltages of the MMC, and u abc are used for feedback control of the MMC basic controller, ref are used for controlling switching actions of the MMC power electronic devices.

[0057] Figure 2 is a flowchart of a new energy flexible DC transmission system wide frequency oscillation adaptive suppression method provided by an embodiment of the present specification. Although the present specification provides the method operation steps or device structures as shown in the following embodiments or drawings, more or part of the operation steps or module units can be included in the method or device based on conventional or non-creative labor. In steps or structures that do not have necessary causal relationships in logic, the execution order of these steps or the module structure of the device is not limited to the execution order or module structure shown in the embodiments or drawings of the present specification. When the method or module structure is applied to actual device, server or terminal product, it can be sequentially executed or executed in parallel (for example, parallel processor or multi-thread processing environment, even including distributed processing, server cluster implementation environment) according to the method or module structure shown in the embodiments or drawings. For specific implementation, refer to Figure 2 As shown in the drawings, the method can be applied to the adaptive wide frequency oscillation suppression system described above, and the method can include the following contents.

[0058] S201: Adjusting the band-pass filter according to the detected oscillation frequency, to filter the oscillation component based on the adjusted band-pass filter.

[0059] In some embodiments, before adjusting the band-pass filter according to the detected oscillation frequency in S201, in specific implementation, it can further include:

[0060] Collecting three-phase current data of the AC side of the sending-end flexible DC converter;

[0061] Detecting the oscillation frequency of the system according to the three-phase current data;

[0062] Correspondingly, adjusting the band-pass filter according to the detected oscillation frequency in S201, in specific implementation, can include:

[0063] Adjusting the center frequency of the band-pass filter according to the oscillation frequency.

[0064] In some embodiments, the system in the present application can refer to a new energy flexible direct transmission system (i.e. a new energy station-flexible direct current transmission system, which is a power electronic interconnection system, and the interaction between them can cause wide frequency oscillation), and the frequency range of the wide frequency oscillation in the present application can be 1Hz-3000Hz. First, three-phase current data of the AC side of the sending end MMC (modular multilevel converter) can be collected, and then the oscillation frequency of the system can be detected online and quickly based on the collected three-phase current data (the oscillation frequency can be detected online and quickly based on the oscillation frequency online detection module in the adaptive wide frequency oscillation suppression system, and then the detected oscillation frequency can be sent to the virtual impedance module), so that the center frequency of the band-pass filter can be adjusted according to the oscillation frequency, and thus the oscillation component in the current of the AC side of the sending end MMC (modular multilevel converter) can be screened out based on the adjusted band-pass filter (the oscillation component can be screened out based on the virtual impedance module in the adaptive wide frequency oscillation suppression system), and the screened oscillation component can be used as one of the necessary parameters for the subsequent online suppression system to suppress the wide frequency oscillation. Through the online and quick detection of the oscillation frequency of the system, the center frequency of the band-pass filter can be adjusted in real time and accurately, and thus the oscillation component can be screened out in real time and accurately.

[0065] In some embodiments, the above-mentioned virtual impedance module can be composed of a second-order band-pass filter G b (s) and a damping coefficient k b in series, wherein the expression of the second-order band-pass filter G b (s) is:

[0066]

[0067] wherein s is a Laplace operator, ω n is the center angular frequency of the band-pass filter (i.e. the center frequency of the band-pass filter), ω n = 2πf os , and ζ is the damping ratio.

[0068] In some embodiments, the above-mentioned detection of the oscillation frequency of the system according to the three-phase current data can include, in specific implementation:

[0069] data processing and analysis of the three-phase current data to obtain different frequency component amplitudes, wherein the different frequency component amplitudes include a fundamental frequency component amplitude and other frequency component amplitudes except the fundamental frequency component amplitude;

[0070] determination of the ratio of each frequency component amplitude in the other frequency component amplitudes to the fundamental frequency component amplitude;

[0071] comparison of the ratio with a preset threshold value to determine whether the system has oscillated according to the comparison result;

[0072] When it is determined that the system is in oscillation, a target frequency component corresponding to a target frequency component amplitude in the different frequency component amplitudes is determined as the oscillation frequency, the target frequency component amplitude being greater than a preset amplitude threshold.

[0073] In some embodiments, the oscillation frequency online detection module in the adaptive wide-frequency oscillation suppression system can collect three-phase current data of the sending-end MMC AC side online and record the data into a cache, can perform data processing analysis on the collected three-phase current data (the data processing analysis can be, for example, FFT (Fast Fourier Transform) analysis after sliding window processing, wherein the window function adopts the Hanning window, each time a new data is collected, the new data is added to the tail, and the old data at the head is removed, and the FFT is Fourier decomposition of the periodic signal data in the window), can calculate the amplitudes of different frequency components, and the different frequency component amplitudes can include the fundamental frequency component amplitude and the amplitudes of other frequency components except the fundamental frequency component. Then, the ratios of each frequency component amplitude in the other frequency component amplitudes to the fundamental frequency component amplitude are determined, the ratios are compared with a preset threshold (the preset threshold can be set according to actual requirements, and the specification does not make specific limitations thereon), and whether the system is in oscillation is determined according to the comparison result. For example, if at least one ratio in the comparison result is greater than the preset threshold, it is considered that the system is in oscillation, and if there is no ratio greater than the preset threshold in the comparison result (i.e., all the ratios in the comparison result are less than the preset threshold), it is considered that the system is not in oscillation. When it is determined that the system is in oscillation, a target frequency component amplitude in the different frequency component amplitudes can be determined, and a target frequency component corresponding to the target frequency component amplitude is determined as the oscillation frequency when the system is in oscillation. The target frequency component amplitude is greater than a preset amplitude threshold, and the preset amplitude threshold can be set according to actual requirements, and the specification does not make specific limitations thereon. That is, whether the system is in oscillation can be determined according to whether the above ratio exceeds the preset threshold, and when it is determined that the system is in oscillation, the frequency corresponding to the maximum amplitude can be output as the oscillation frequency.

[0074] S202: input the oscillation frequency and the operating condition to a pre-trained mapping relationship model to obtain mapping data of the phase margin and the damping coefficient, the damping coefficient being in a preset adjustment range.

[0075] In some embodiments, the mapping relationship model in S202 can be trained in the following manner:

[0076] The damping coefficient sample data of the virtual impedance, the center frequency sample data of the band-pass filter, the operating condition sample data, and the phase margin sample data corresponding to the operating condition are selected.

[0077] The damping coefficient sample data of the virtual impedance, the center frequency sample data of the bandpass filter, and the operating condition sample data are used as input data, and the phase margin sample data is used as output data to train a neural network model to obtain the mapping relationship model.

[0078] In some embodiments, a broadband impedance model of a new energy flexible direct current transmission system can be established based on the damping parameter online update module in the adaptive broadband oscillation suppression system, and the damping coefficient sample data of the virtual impedance can be uniformly selected based on the broadband impedance model. Specifically, the new energy flexible direct current transmission system can include a main circuit part and a control part (e.g., Figure 1 The adaptive broadband oscillation suppression link within the dotted box is used as the control part, and the MMC basic controller outside the dotted box is used as the main circuit part. The circuit equation can be written for the main circuit, and the main circuit signal is input to the control through sampling; the control part can be written as the control equation, and the modulated voltage output can control the operation of the converter switching device, further acting on the main circuit. Therefore, the main circuit equation and the control equation can be combined to obtain the relationship between the three-phase voltage and current of the system, that is, the impedance. The above process is the process of establishing a broadband impedance model. According to the output signal u ref With the input signal i abc The ratio between them determines the order of magnitude of the damping coefficient, and the damping coefficient sample data are uniformly selected in the range of 0 to this order of magnitude according to an arithmetic progression (such as the tolerance is 1).

[0079] The impedance stability analysis method can be used to calculate sample data of different operating conditions and system phase margin sample data (or phase margin sample data) corresponding to different operating conditions. The damping coefficient sample data of the virtual impedance, the center frequency sample data of the bandpass filter, and the operating condition sample data can be used as input data, and the calculated system phase margin sample data corresponding to the operating condition can be used as output data. The neural network model is trained offline, and the trained neural network model can be used as a mapping relationship model. The mapping relationship model can be configured in the damping parameter online update module so that the damping coefficient can be selected online based on the mapping relationship model in the damping parameter online update module.

[0080] The basic principle of the impedance analysis method is to divide the renewable energy-sending flexible direct current interconnection system (i.e., the renewable energy flexible direct current transmission system) into two subsystems, "source" and "load," at the point of interaction. The renewable energy is represented by a Norton equivalent circuit, and the flexible direct current sending converter station is represented by a Thevenin equivalent circuit. The transfer function of the current at the grid connection point is calculated. If the impedance amplitudes of the renewable energy and the flexible direct current sending converter station are equal, and the phase angle difference between the flexible direct current converter station impedance and the renewable energy impedance is equal to or greater than 180°, the closed-loop system is critically stable or unstable. The distance between the phase angle difference and 180° is defined as the system's phase margin.

[0081] In some embodiments, the online detected oscillation frequency can be input into a pre-trained mapping relationship model as a band-pass filter center frequency in combination with an operating condition to obtain mapping data of the phase margin and the damping coefficient (i.e., mapping data between the damping coefficient in the virtual impedance and the system phase margin, which can be a mapping relationship or a specific mapping value, which is not specifically limited in the specification). The damping coefficient can be in a preset adjustment range, so that a target damping coefficient can be selected from the preset adjustment range subsequently, and the target damping coefficient can be used as another necessary parameter for subsequent online suppression of system wide-frequency oscillation. By inputting the online detected oscillation frequency and the operating condition into the trained mapping relationship model, the mapping data of the phase margin and the damping coefficient can be accurately and quickly obtained, thereby laying a foundation for subsequent online selection of the damping coefficient. By using the operating condition as the model input data, the subsequent wide-frequency adaptive suppression can be applied to complex time-varying system conditions.

[0082] S203: selecting a target damping coefficient from the preset adjustment range according to the mapping data and a preset target phase margin, the target damping coefficient making the mapped phase margin reach the preset target phase margin.

[0083] In some embodiments, the selecting of the target damping coefficient from the preset adjustment range according to the mapping data and the preset target phase margin in S203 can include, in specific implementation:

[0084] setting a change step of the damping coefficient, and selecting a first damping coefficient from the preset adjustment range according to the change step;

[0085] determining a first phase margin mapped by the first damping coefficient according to the mapping data and the first damping coefficient;

[0086] judging whether the first phase margin reaches a preset target phase margin, and if so, taking the first damping coefficient as the target damping coefficient.

[0087] In some embodiments, the change step of the damping coefficient can be set, for example, the change step can be set as 1Ω, the preset adjustment range can be set as 0Ω-60Ω, and the damping coefficient can be selected in the preset adjustment range in an increasing or decreasing manner according to the change step, for example, the damping coefficient of 1Ω, the damping coefficient of 2Ω, the damping coefficient of 3Ω, the damping coefficient of 4Ω, etc. are sequentially selected from the preset adjustment range of 0Ω-60Ω according to the change step of 1Ω. Specifically, the first damping coefficient can be selected from the preset adjustment range according to the change step, for example, the selected first damping coefficient can be the damping coefficient of 1Ω. Then, according to the mapping data (for example, the mapping relationship) of the phase margin and the damping coefficient and the first damping coefficient, the first phase margin mapped by the first damping coefficient is determined, and then it is judged whether the first phase margin reaches the preset target phase margin. If the preset target phase margin is reached, the first damping coefficient is taken as the target damping coefficient (the target damping coefficient is the damping coefficient that can make the mapped system phase margin reach the target phase margin, and can be taken as one of the necessary parameters for suppressing the wide frequency oscillation. The damping parameter online updating module in the adaptive wide frequency oscillation suppression system finally outputs the target damping coefficient). If the preset target phase margin is not reached, the second damping coefficient (for example, the selected second damping coefficient can be the damping coefficient of 2Ω) is continuously selected from the preset adjustment range according to the change step, the second damping coefficient is different from the first damping coefficient, and then the second phase margin mapped by the second damping coefficient is determined according to the mapping data (for example, the mapping relationship) of the phase margin and the damping coefficient and the second damping coefficient. Then it is judged whether the second phase margin reaches the preset target phase margin. If the preset target phase margin is reached, the second damping coefficient is taken as the target damping coefficient. Otherwise, the above process is repeatedly continued until the selected damping coefficient can make the mapped system phase margin reach the target phase margin, and then the damping coefficient can be taken as the target damping coefficient and output online. Through the mapping data of the phase margin and the damping coefficient and the target phase margin, the online selection of the target damping coefficient can be realized, so that the online adaptive suppression of the wide frequency oscillation can be realized according to the target damping coefficient and the screened oscillation component. The online adaptive suppression of the wide frequency oscillation can be applied to different operating conditions, so that the stability of the power system can be significantly improved.

[0088] It should be noted that, in order to make the system meet the stability target, the damping coefficient |k b | as small as possible, the damping coefficient k b is increased or decreased by a certain change step from 0. The above process can be performed in the damping parameter online updating module, that is, the damping coefficient k bthe damping parameter online updating module, and a mapping relationship between the phase margin and k b is obtained through a neural network model (mapping relationship model) in the module, the target phase margin of the system is set, and the damping coefficient k b is increased or decreased by a certain change step from the preset adjustment range, if a damping coefficient k b makes the mapped system phase margin reach the target phase margin, the damping coefficient k b is output as the target damping coefficient online.

[0089] S204: According to the oscillation component and the target damping coefficient, the wide-frequency oscillation of the system is suppressed.

[0090] In some embodiments, the wide-frequency oscillation of the system is suppressed according to the oscillation component and the target damping coefficient in S204, which can include the following steps in specific implementation:

[0091] The oscillation component and the target damping coefficient are multiplied, and the multiplication result is superimposed into the modulation voltage of the sending-end flexible HVDC converter to obtain an updated modulation voltage;

[0092] The wide-frequency oscillation of the system is suppressed based on the updated modulation voltage.

[0093] In some embodiments, the damping parameter online updating module can send the output target damping coefficient to the virtual impedance module. The virtual impedance module can multiply the oscillation component (or center frequency component) filtered by the band-pass filter by the target damping coefficient output by the damping parameter online updating module, and then superimpose it into the modulation voltage of the sending-end flexible HVDC converter (MMC) basic controller to obtain an updated modulation voltage, so as to realize online adaptive suppression of wide-frequency oscillation in the frequency range of 1Hz-3000Hz based on the updated modulation voltage.

[0094] In some embodiments, the system can include a new energy flexible HVDC sending-out system, and the new energy unit in the new energy flexible HVDC sending-out system can include at least one of the following: a photovoltaic power generation unit, a doubly-fed wind turbine generator, and a direct-drive wind turbine generator.

[0095] In some embodiments, the new energy unit can include but is not limited to a photovoltaic power generation unit, a doubly-fed wind turbine generator, or a direct-drive wind turbine generator, so that the wide-frequency oscillation adaptive suppression method of the new energy flexible HVDC sending-out system of the present application can be applied to various scenarios, i.e., it has the function of online detection of wide-frequency oscillation components of the new energy flexible HVDC sending-out system in the frequency range of 1Hz-3000Hz, and can adaptively suppress the wide-frequency oscillation problem that may occur in each operating condition of the new energy flexible HVDC sending-out system.

[0096] The various embodiments in the specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referred to each other, and each embodiment focuses on the difference from other embodiments. For specific description, refer to the description of the related processing related embodiments described above, which will not be repeated here.

[0097] The above describes the present application, however, it is worth noting that the specific embodiments are only for better illustration of the present application, and the specific embodiments of the description are described. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recited in the claims can be performed in an order different from that in the embodiments and still achieve the desired result. In addition, the processes depicted in the accompanying drawings do not necessarily require the specific order or sequential order shown to achieve the desired results. In some embodiments, multi-task processing and parallel processing are possible or can be advantageous.

[0098] The above method will be described in conjunction with a specific embodiment, however, it is worth noting that the specific embodiment is only for better illustration of the present application, and does not constitute an improper limitation on the present application.

[0099] Before the specific implementation, the wide-band impedance model of the new energy flexible transmission system can be established based on the damping parameter online updating module in the adaptive wide-band oscillation suppression system, the damping coefficient sample data of the virtual impedance can be uniformly selected based on the wide-band impedance model, the impedance stability analysis method is used to calculate the different operating condition sample data and the system phase margin sample data (or phase margin sample data) corresponding to the different operating conditions. The damping coefficient sample data of the virtual impedance, the center frequency sample data of the band-pass filter, and the operating condition sample data can be used as input data, and the calculated system phase margin sample data corresponding to the operating condition can be used as output data. The neural network model can be trained offline, and the trained neural network model can be used as a mapping relationship model. The mapping relationship model can be configured in the damping parameter online updating module, so that the damping coefficient can be selected online based on the mapping relationship model in the damping parameter online updating module.

[0100] In a specific implementation, the three-phase current data of the AC side of the sending-end MMC can be collected by the online detection module and recorded in the cache based on the oscillation frequency. The collected three-phase current data can be processed and analyzed (for example, FFT analysis after sliding window processing), and the amplitudes of different frequency components can be obtained. The amplitudes of different frequency components can include the amplitude of the fundamental frequency component and the amplitudes of other frequency components except the amplitude of the fundamental frequency component. The ratio of each frequency component amplitude in the amplitudes of other frequency components to the amplitude of the fundamental frequency component is determined, and the ratio is compared with the preset threshold value to determine whether the system has oscillation according to the comparison result. For example, if at least one ratio in the comparison result is greater than the preset threshold value, it is considered that the system has oscillation. If there is no ratio greater than the preset threshold value in the comparison result (i.e., all ratios in the comparison result are less than the preset threshold value), it is considered that the system has no oscillation. When it is determined that the system has oscillation, the target frequency component amplitude in the amplitudes of different frequency components can be determined, and the target frequency component corresponding to the target frequency component amplitude is taken as the oscillation frequency when the system has oscillation. The target frequency component amplitude is greater than the preset amplitude threshold value. The online detection module can send the detected oscillation frequency to the virtual impedance module.

[0101] The detected oscillation frequency can be taken as the center frequency of the band-pass filter and input into the pre-trained mapping relationship model in the damping parameter online updating module in combination with the operating condition, and the mapping data of the phase margin and the damping coefficient can be obtained. According to the mapping data and the preset target phase margin, the target damping coefficient is selected from the preset adjustment range, and the target damping coefficient can make the mapped phase margin reach the preset target phase margin. The target damping coefficient output by the damping parameter online updating module can be sent to the virtual impedance module.

[0102] The virtual impedance module can adjust the center frequency of the band-pass filter according to the detected oscillation frequency, so that the oscillation component in the current of the AC side of the sending-end MMC can be filtered based on the adjusted band-pass filter, and then multiplied by the target damping coefficient. The multiplication result is superimposed into the modulation voltage of the basic controller of the sending-end MMC to obtain an updated modulation voltage, so that the online adaptive suppression of the wide-frequency oscillation in the frequency range of 1 Hz-3000 Hz can be realized based on the updated modulation voltage.

[0103] The virtual impedance module can include a band-pass filter and a damping coefficient, the input signal is filtered by the band-pass filter to select the central frequency component and then multiplied by the damping coefficient to output; the oscillation frequency online detection module can include a buffer, a data sliding window program and an FFT calculation program, and the oscillation frequency in the input signal is detected; the damping parameter online updating module can include a neural network and a damping coefficient selection program, the trained neural network can obtain the mapping between the damping coefficient and the phase margin, and the damping coefficient selection program selects the damping coefficient online according to the target phase margin, and finally outputs the target damping coefficient.

[0104] In one specific implementation scenario, the oscillation of the direct-drive wind farm flexible direct current transmission system is taken as an example to introduce the specific implementation of the application. The direct-drive wind farm includes 200 direct-drive wind turbine generators, and each wind turbine generator has a rated active power of 4 MW. The flexible direct current converter adopts fixed alternating current voltage control and is equipped with the adaptive oscillation suppression system.

[0105] (1) The wideband impedance model of the direct-drive wind farm and the wideband impedance model of the flexible direct current converter station are respectively established, and frequency scanning is performed within 1Hz-3000Hz to verify the accuracy. The wideband impedance model of the additional active damping is established on the basis of the basic control of the flexible direct current converter station, and frequency scanning is performed within 1Hz-3000Hz to verify the accuracy.

[0106] (2) Based on the established impedance model, the damping coefficient of the virtual impedance is set to vary in the range of 0Ω-60Ω with a step of 1Ω; the center frequency of the band-pass filter varies in the range of 1Hz-100Hz with a step of 5Hz; the number of wind farms put into operation varies in the range of 10-200 with a step of 10; and the output of the wind farm varies in the range of 0.1p.u.-1.0p.u. with a step of 0.1p.u. The combination of the set parameters forms the input data. The phase margin of the system under each parameter and working condition is calculated, saved and output, forming the output data. The neural network model is trained offline with the input data and the output data.

[0107] (3) The three-phase current data of the sending end flexible direct current converter are collected online and recorded in the buffer. After the collected data are processed by the sliding window, FFT analysis is performed within 1Hz-3000Hz to obtain the amplitudes of different frequency components. Whether the system oscillates is determined according to whether the ratio of the amplitude of each frequency component to the amplitude of the fundamental frequency component exceeds 2%. If the system oscillates, the frequency corresponding to the maximum amplitude is output as the oscillation frequency.

[0108] (4) The adjustment range of the damping coefficient k b in the virtual impedance is set to 0Ω-60Ω. The operating condition and the online detected oscillation frequency are input into the damping parameter online updating module, and the neural network model in the module is used to obtain the phase margin and the adjustment range of k bthe mapping between k and the system phase margin, set the system target phase margin as 25°, so as to make |k| as small as possible and make the system meet the stability target b |k| as small as possible b |k| as small as possible b |k| as small as possible b |k| as small as possible

[0109] (5) The oscillation component output by the band-pass filter is multiplied by the damping coefficient, and then superimposed into the modulation voltage of the sending end HVDC basic controller, so as to realize adaptive suppression of wide-frequency oscillation. In the embodiment, in order to make the oscillation waveform easy to observe, a manually set signal is used to enable the adaptive oscillation suppression system.

[0110] The voltage and current waveforms of the PCC point and the output waveform of the adaptive wide-frequency oscillation suppression system after the system is running are shown in FIG. 3. Figure 3 Figure 3 From top to bottom, they are the waveform changes of voltage (KV) at different times (s), the waveform changes of current (KA) at different times (s), the waveform changes of oscillation frequency (Hz) at different times (s), and the waveform changes of damping coefficient (Ω) at different times (s). 200 wind turbine generators are put into the wind farm, and the initial wind farm output is set as 0.25 p.u. The system is stably running until 1.3 s, at which time the wind farm output is increased to 0.7. It can be seen that the system oscillates and gradually diverges, the oscillation frequency is detected as 56 Hz, at 2.6 s, the oscillation suppression measure is put into, the output damping coefficient k b is 38, and it can be seen that the oscillation is suppressed. At 4 s, the wind farm output is increased to 1.0, and it can be seen that the damping coefficient k b correspondingly increases to 60, and the system is stably running after a short oscillation.

[0111] In order to compare the effect of the adaptive wide-frequency oscillation suppression method, only the adaptive wide-frequency oscillation suppression method is replaced by a traditional virtual impedance with fixed parameters, the center frequency of the band-pass filter is set as 56 Hz, and the damping coefficient is set as 38. The voltage and current waveforms of the PCC point after the system is running are shown in FIG. 4. Figure 4 Figure 4 ​​The waveform changes of voltage (KV) at different times (s) and the waveform changes of current (KA) at different times (s) are sequentially shown from top to bottom. The wind farm is input with 200 wind turbine generators, and the initial output of the wind farm is set to 0.25 p.u. The system is stably operated until 1.3 s, and the output of the wind farm is increased to 0.7. It can be seen that the system oscillates and gradually diverges, and the virtual impedance is input at 2.6 s (that is, the oscillation suppression measure is input). The oscillation is suppressed. At 4 s, the output of the wind farm is increased to 1.0, and the system oscillates. Therefore, the traditional virtual impedance method cannot complete the oscillation suppression under the changing working condition, and the adaptive wide-frequency oscillation suppression method can adaptively suppress the wide-frequency oscillation of the system.

[0112] Although the present specification provides the method operation steps or device structures as shown in the following embodiments or drawings Figure 5 More or fewer operation steps or module units can be included in the method or device based on conventional or non-creative labor after the method or device is combined. In steps or structures that do not have necessary causality in logic, the execution order of the steps or the module structure of the device is not limited to the execution order or module structure shown in the embodiments or drawings of the present specification. When the method or module structure is applied in actual devices, servers or terminal products, it can be sequentially executed or executed in parallel (for example, in parallel processor or multi-thread processing environment, even including distributed processing, server cluster implementation environment) according to the method or module structure shown in the embodiments or drawings. Based on the above-mentioned new energy flexible direct current transmission system wide-frequency oscillation adaptive suppression method, the present specification also provides an embodiment of a new energy flexible direct current transmission system wide-frequency oscillation adaptive suppression device. As shown in the Figure 5 The device can specifically include the following modules:

[0113] The oscillation component screening module 501 can be configured to adjust a band-pass filter according to the detected oscillation frequency, and screen the oscillation component based on the adjusted band-pass filter.

[0114] The prediction module 502 can be configured to input the oscillation frequency and the operating condition into a pre-trained mapping relationship model to obtain mapping data of the phase margin and a damping coefficient, the damping coefficient being within a preset adjustment range.

[0115] The target damping coefficient selection module 503 can be configured to select a target damping coefficient from the preset adjustment range according to the mapping data and a preset target phase margin, the target damping coefficient making the mapped phase margin reach the preset target phase margin.

[0116] The suppression module 504 can be configured to suppress the wide-frequency oscillation of the system according to the oscillation component and the target damping coefficient.

[0117] In some embodiments, the oscillation component screening module 501 can further be specifically configured to collect three-phase current data of the AC side of the sending-end HVDC converter; detect an oscillation frequency of the system according to the three-phase current data; and the oscillation component screening module 501 can be specifically configured to adjust the center frequency of the band-pass filter according to the oscillation frequency.

[0118] In some embodiments, the oscillation component screening module 501 can further be specifically configured to perform data processing and analysis on the three-phase current data to obtain different frequency component amplitudes, the different frequency component amplitudes including a fundamental frequency component amplitude and other frequency component amplitudes except the fundamental frequency component amplitude; determine a ratio of each frequency component amplitude in the other frequency component amplitudes to the fundamental frequency component amplitude; compare the ratio with a preset threshold to determine whether the system has oscillation according to a comparison result; and when it is determined that the system has oscillation, determine a target frequency component corresponding to a target frequency component amplitude in the different frequency component amplitudes as the oscillation frequency, the target frequency component amplitude being greater than a preset amplitude threshold.

[0119] In some embodiments, the mapping relationship model in the prediction module 502 can be obtained by the following method: selecting damping coefficient sample data of a virtual impedance, center frequency sample data of a band-pass filter, operating condition sample data, and phase margin sample data corresponding to the operating condition; taking the damping coefficient sample data of the virtual impedance, the center frequency sample data of the band-pass filter, and the operating condition sample data as input data, and taking the phase margin sample data as output data, training a neural network model to obtain the mapping relationship model.

[0120] In some embodiments, the target damping coefficient selection module 503 can be specifically configured to set a change step of the damping coefficient, select a first damping coefficient from the preset adjustment range according to the change step; determine a first phase margin corresponding to the first damping coefficient according to the mapping data and the first damping coefficient; and determine whether the first phase margin reaches a preset target phase margin, and if so, take the first damping coefficient as the target damping coefficient.

[0121] In some embodiments, the suppression module 504 can be specifically configured to multiply the oscillation component and the target damping coefficient, superimpose a multiplication result to a modulation voltage of the sending-end HVDC converter to obtain an updated modulation voltage; and suppress the broadband oscillation of the system based on the updated modulation voltage.

[0122] In some embodiments, the system in the suppression module 504 can include a new energy HVDC sending system, and the new energy unit in the new energy HVDC sending system can include at least one of the following: a photovoltaic power generation unit, a doubly-fed wind turbine generator, and a direct-drive wind turbine generator.

[0123] As can be seen from the above, the new energy flexible direct transmission system wide frequency oscillation adaptive suppression device provided by the embodiments of the present specification can detect the oscillation mode online quickly, and on this basis, an artificial intelligence-based wide frequency oscillation adaptive suppression strategy is proposed, which can cope with complex time-varying system conditions, and provides new technical support for solving the wide frequency oscillation problem of the new energy flexible direct transmission system.

[0124] The embodiments of the present specification also provide an electronic device based on the above new energy flexible direct transmission system wide frequency oscillation adaptive suppression method, including a processor and a memory for storing program / instructions executable by the processor, and the processor can execute the following steps according to the program / instructions when implemented: adjusting a band-pass filter according to the detected oscillation frequency, to filter an oscillation component based on the adjusted band-pass filter; inputting the oscillation frequency and the operating condition into a pre-trained mapping relationship model to obtain mapping data of a phase margin and a damping coefficient, the damping coefficient being within a preset adjustment range; selecting a target damping coefficient from the preset adjustment range according to the mapping data and a preset target phase margin, the target damping coefficient making the mapped phase margin reach the preset target phase margin; and suppressing the wide frequency oscillation of the system according to the oscillation component and the target damping coefficient.

[0125] In order to be able to more accurately complete the above instructions, referring to Figure 6 The embodiments of the present specification also provide another specific electronic device, wherein the electronic device includes a network communication port 601, a processor 602 and a memory 603, and the above structures are connected by internal cables so that the respective structures can perform specific data interaction.

[0126] The network communication port 601 can be specifically used to adjust a band-pass filter according to the detected oscillation frequency, to filter an oscillation component based on the adjusted band-pass filter;

[0127] The processor 602 can be specifically used to input the oscillation frequency and the operating condition into a pre-trained mapping relationship model to obtain mapping data of a phase margin and a damping coefficient, the damping coefficient being within a preset adjustment range; select a target damping coefficient from the preset adjustment range according to the mapping data and a preset target phase margin, the target damping coefficient making the mapped phase margin reach the preset target phase margin; and suppress the wide frequency oscillation of the system according to the oscillation component and the target damping coefficient;

[0128] The memory 603 can be specifically used to store the corresponding instruction program.

[0129] In the embodiment, the network communication port 601 can be a virtual port bound with different communication protocols, so as to send or receive different data. For example, the network communication port can be a port responsible for web data communication, a port responsible for FTP data communication, or a port responsible for mail data communication. In addition, the network communication port can also be an entity communication interface or a communication chip. For example, it can be a wireless mobile network communication chip such as GSM, CDMA, etc.; it can also be a Wifi chip; it can also be a Bluetooth chip.

[0130] In the embodiment, the processor 602 can be implemented in any appropriate manner. For example, the processor can take the form of, for example, a microprocessor or processor and a computer readable medium storing computer readable program code (e.g., software or firmware) executable by the (micro)processor, logic gates, switches, an Application Specific Integrated Circuit (ASIC), a programmable logic controller, and an embedded microcontroller, etc. The present specification is not limited in this regard.

[0131] In the embodiment, the memory 603 can include multiple levels, and in a digital system, as long as it can save binary data, it can be a memory; in an integrated circuit, a circuit without a physical form and with a storage function is also called a memory, such as RAM, FIFO, etc.; in a system, a storage device with a physical form is also called a memory, such as a memory stick, a TF card, etc.

[0132] The embodiment of the present specification also provides a computer storage medium based on the above new energy flexible direct transmission system wide frequency oscillation adaptive suppression method, the computer storage medium stores computer programs / instructions, and when the computer programs / instructions are executed, the following are realized: adjusting a band-pass filter according to a detected oscillation frequency, so as to screen an oscillation component based on the adjusted band-pass filter; inputting the oscillation frequency and an operating condition into a pre-trained mapping relationship model to obtain mapping data of a phase margin and a damping coefficient, the damping coefficient being in a preset adjustment range; selecting a target damping coefficient from the preset adjustment range according to the mapping data and a preset target phase margin, the target damping coefficient making the mapped phase margin reach the preset target phase margin; and suppressing wide frequency oscillation of the system according to the oscillation component and the target damping coefficient.

[0133] In the embodiment, the storage medium includes, but is not limited to, a random access memory (RAM), a read-only memory (ROM), a cache, a hard disk drive (HDD), or a memory card. The storage medium can be used to store computer program instructions. The network communication unit can be an interface configured according to a standard of a communication protocol, and used for network connection communication.

[0134] In the embodiment, the functions and effects realized by the program instructions stored in the computer storage medium can be explained in comparison with other embodiments, and will not be described here.

[0135] The embodiment of the present disclosure further provides a computer program product based on the new energy flexible direct transmission system wide frequency oscillation adaptive suppression method, including a non-transitory computer readable storage medium storing computer programs / instructions, the computer programs / instructions being operable to cause a computer to perform the following steps: adjusting a band-pass filter according to a detected oscillation frequency, so as to filter an oscillation component based on the adjusted band-pass filter; inputting the oscillation frequency and an operating condition into a pre-trained mapping relationship model to obtain mapping data of a phase margin and a damping coefficient, the damping coefficient being within a preset adjustment range; selecting a target damping coefficient from the preset adjustment range according to the mapping data and a preset target phase margin, the target damping coefficient making the mapped phase margin reach the preset target phase margin; and suppressing a wide frequency oscillation of the system according to the oscillation component and the target damping coefficient.

[0136] Although the present disclosure provides method operation steps as described in the embodiments or flowcharts, more or fewer operation steps can be included based on conventional or non-inventive means. The order of steps listed in the embodiments is only one of many step execution orders, and does not represent the only execution order. When the device or client product is executed in practice, the method order shown in the embodiments or the drawings can be executed in sequence or in parallel (for example, in a parallel processor or multi-thread processing environment, or even in a distributed data processing environment). The terms "comprise", "include" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, product or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such a process, method, product or device. Without more limitations, it does not exclude the presence of other same or equivalent elements in the process, method, product or device including the elements. The terms "first", "second", etc. are used to represent names, and do not represent any particular order.

[0137] Those skilled in the art will also appreciate that, in addition to being implemented in purely computer readable program code, the controller can be implemented using logic gates, switches, application specific integrated circuits, programmable logic controllers, and embedded microcontrollers to perform the same functions as the method steps. Thus the controller can be considered a hardware component and the means for performing the various functions included therein can be considered structures within the hardware component. Alternatively, the means for performing the various functions can be considered both software modules and structures within the hardware component.

[0138] The specification can be described in the general context of computer-executable instructions, such as program modules, being executed by a computer. Generally, program modules include routines, programs, objects, components, data structures, classes, etc., that perform particular tasks or implement particular abstract data types. The specification can also be practiced in distributed computing environments where tasks are performed by remote processing devices that are linked through a communications network. In a distributed computing environment, program modules can be located in both local and remote computer storage media including memory storage devices.

[0139] As such, those skilled in the art will appreciate that the specification can be embodied in a software product, including a computer-readable medium containing computer software, program code, or instructions implementing the specification. The software product can be implemented in a software package, software, or on an apparatus such as a computer system.

[0140] The various embodiments described in the specification can be used alone or in combination with one another. Those skilled in the art will appreciate that the specification can be used in a variety of computer system environments or configurations. For example, the specification can be used in personal computers, server computers, hand-held or portable devices, tablet devices, multiprocessor systems, microprocessor-based systems, set top boxes, programmable consumer electronics, network PCs, minicomputers, mainframe computers, distributed computing environments that include any of the above systems or devices, and the like.

[0141] Although the specification has been described with reference to particular embodiments, those skilled in the art will appreciate that the specification can be practiced in many other ways without departing from the spirit of the specification. Accordingly, the appended claims are intended to encompass any and all embodiments within the spirit and scope of the specification.

Claims

1. A method for adaptive suppression of wideband oscillations in a new energy flexible direct transmission system, characterized in that, The method comprises: adjusting a band-pass filter according to the detected oscillation frequency to screen the oscillation component based on the adjusted band-pass filter; inputting the oscillation frequency and the operating condition into a pre-trained mapping relationship model to obtain mapping data of the phase margin and the damping coefficient, the damping coefficient being within a preset adjustment range; selecting a target damping coefficient from the preset adjustment range according to the mapping data and a preset target phase margin, the target damping coefficient making the mapped phase margin reach the preset target phase margin; suppressing the broadband oscillation of the system according to the oscillation component and the target damping coefficient; wherein the mapping relationship model is obtained by training in the following manner: selecting damping coefficient sample data of a virtual impedance, center frequency sample data of a band-pass filter, operating condition sample data, and phase margin sample data corresponding to the operating condition; taking the damping coefficient sample data of the virtual impedance, the center frequency sample data of the band-pass filter, and the operating condition sample data as input data, and taking the phase margin sample data as output data, training a neural network model to obtain the mapping relationship model; the selecting of the target damping coefficient from the preset adjustment range according to the mapping data and the preset target phase margin comprises: setting a change step of the damping coefficient, selecting a first damping coefficient from the preset adjustment range according to the change step; determining a first phase margin mapped by the first damping coefficient according to the mapping data and the first damping coefficient; determining whether the first phase margin reaches the preset target phase margin, and if so, taking the first damping coefficient as the target damping coefficient; the suppressing of the broadband oscillation of the system according to the oscillation component and the target damping coefficient comprises: multiplying the oscillation component and the target damping coefficient, and superimposing the multiplication result into a modulation voltage of the sending-end HVDC converter to obtain an updated modulation voltage; suppressing the broadband oscillation of the system based on the updated modulation voltage.

2. The method of claim 1, wherein, The method further comprises: collecting three-phase current data of the AC side of the sending-end HVDC converter; detecting the oscillation frequency of the system according to the three-phase current data; correspondingly, the adjusting of the band-pass filter according to the detected oscillation frequency comprises: adjusting the center frequency of the band-pass filter according to the oscillation frequency.

3. The method of claim 2, wherein, the detecting of the oscillation frequency of the system according to the three-phase current data comprises: performing data processing and analysis on the three-phase current data to obtain different frequency component amplitudes, the different frequency component amplitudes including a fundamental frequency component amplitude and other frequency component amplitudes except the fundamental frequency component amplitude; determining a ratio of each frequency component amplitude in the other frequency component amplitudes to the fundamental frequency component amplitude; comparing the ratio with a preset threshold to determine whether the system oscillates according to the comparison result; when it is determined that the system oscillates, determining a target frequency component corresponding to a target frequency component amplitude in the different frequency component amplitudes as the oscillation frequency, the target frequency component amplitude being greater than a preset amplitude threshold.

4. The method of claim 1, wherein, The system comprises a new energy flexible direct transmission system, and the new energy unit in the new energy flexible direct transmission system comprises at least one of a photovoltaic power generation unit, a doubly-fed wind turbine unit and a direct-drive wind turbine unit.

5. A new energy flexible direct transmission system wide frequency oscillation adaptive suppression device, characterized in that, Comprise: The oscillation component screening module is configured to adjust a band-pass filter according to the detected oscillation frequency, and screen the oscillation component based on the adjusted band-pass filter; The prediction module is configured to input the oscillation frequency and the operating condition into a pre-trained mapping relationship model to obtain mapping data of the phase margin and the damping coefficient, the damping coefficient being within a preset adjustment range; The target damping coefficient selection module is configured to select a target damping coefficient from the preset adjustment range according to the mapping data and a preset target phase margin, the target damping coefficient making the mapped phase margin reach the preset target phase margin; The suppression module is configured to suppress the broadband oscillation of the system according to the oscillation component and the target damping coefficient. The mapping relationship model is trained by the following method: Selecting damping coefficient sample data of a virtual impedance, center frequency sample data of a band-pass filter, operating condition sample data, and phase margin sample data corresponding to the operating condition; taking the damping coefficient sample data of the virtual impedance, the center frequency sample data of the band-pass filter, and the operating condition sample data as input data, and taking the phase margin sample data as output data, training a neural network model to obtain the mapping relationship model; The target damping coefficient is selected from the preset adjustment range according to the mapping data and a preset target phase margin, comprising: Setting a change step of the damping coefficient, selecting a first damping coefficient from the preset adjustment range according to the change step; determining a first phase margin mapped by the first damping coefficient according to the mapping data and the first damping coefficient; determining whether the first phase margin reaches a preset target phase margin, and if so, taking the first damping coefficient as the target damping coefficient; The target damping coefficient is selected from the preset adjustment range according to the mapping data and a preset target phase margin, comprising: Multiplying the oscillation component and the target damping coefficient, and adding the multiplication result to the modulation voltage of the sending-end flexible direct current converter to obtain an updated modulation voltage; suppressing the broadband oscillation of the system based on the updated modulation voltage.

6. A computer device comprising a memory, a processor, and a computer program / instructions stored on the memory, wherein, The processor executes the computer program / instructions to implement the steps of the method of any one of claims 1 to 4.

7. A computer readable storage medium having stored thereon computer programs / instructions, characterized in that, The computer program / instructions are executed by the processor to implement the steps of the method of any one of claims 1 to 4.

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