Subsynchronous oscillation suppression method and device for new energy delivery system

Abstract

The invention discloses a subsynchronous oscillation suppression method and device for a new energy delivery system, relates to the technical field of new energy system optimization, and mainly aims to ensure the completeness of system impedance under various operation conditions and improve the effectiveness and reliability of oscillation suppression measures. According to the main technical scheme, the method comprises the following steps: testing first impedance curves of a system side and a new energy side of the new energy delivery system under typical operation conditions; judging whether the new energy side has an oscillation risk or not according to the first impedance curve of the system side and the first impedance curve of the new energy side by using a Nyquist stability criterion; and if the new energy side has the oscillation risk under the typical operation condition, optimizing the negative damping frequency band of the new energy side based on the phase-locked loop parameter or the current loop proportional-integral parameter, so that the new energy side does not have the oscillation risk under the typical operation condition. The subsynchronous oscillation suppression method is used for carrying out subsynchronous oscillation suppression on the new energy delivery system.

Description

Technical Field

[0001] The present application relates to the technical field of new energy system optimization, and in particular to a method and device for suppressing subsynchronous oscillations of a new energy transmission system. Background Art

[0002] During the integration of renewable energy, complex system structures and variable operating conditions have led to frequent subsynchronous oscillations, seriously impacting the safe and stable operation of the power system. For example, 8Hz oscillations caused by the interaction between doubly-fed wind turbines and series compensation in the Guyuan region, and multi-band oscillations in the Zhangbei flexible DC converter station and its sending-end system, have been reported. These issues are often influenced by operating conditions. For example, oscillations in the Guyuan region primarily occur at low power output levels at night, while oscillations in the flexible DC converter station are more likely to occur at high power output levels.

[0003] Currently, existing technologies for suppressing subsynchronous oscillations in renewable energy transmission systems primarily focus on optimizing control parameters or adding damping control schemes under a single operating condition on the renewable energy side. While these can mitigate oscillations under specific operating conditions to a certain extent, they fail to fully consider the impact of different operating conditions on system stability and struggle to ensure the completeness of system impedance under various operating conditions, thus impacting the effectiveness and reliability of oscillation suppression measures. Summary of the Invention

[0004] In view of the above problems, the present application provides a method and device for suppressing subsynchronous oscillations in a new energy transmission system. The main purpose is to ensure the integrity of the system impedance under various operating conditions and improve the effectiveness and reliability of oscillation suppression measures.

[0005] To solve the above technical problems, this application proposes the following solutions:

[0006] In a first aspect, the present application provides a method for suppressing subsynchronous oscillations in a new energy transmission system, the method comprising:

[0007] Testing the first impedance curves of the system side and the new energy side of the renewable energy transmission system under typical operating conditions. The typical operating conditions are used to characterize the operating points selected after the active power range of the renewable energy transmission system is coarsely divided into multiple power intervals. The impedance curves include the impedance amplitude and impedance phase at each frequency point.

[0008] Using the Nyquist stability criterion, judging whether there is an oscillation risk on the new energy side based on the first impedance curves of the system side and the new energy side, the oscillation risk being used to indicate that a phase difference between the impedance phases of the system side and the new energy side exceeds 180 degrees when the impedance amplitudes are equal, and that a stability margin between the system side and the new energy side does not meet a preset requirement when the phase difference does not exceed 180 degrees;

[0009] If the new energy side has the oscillation risk under the typical operating conditions, the negative damping frequency band of the new energy side is optimized based on the phase-locked loop parameters or the current loop proportional integral parameters so that the new energy side does not have the oscillation risk under the typical operating conditions.

[0010] In a second aspect, the present application provides a device for suppressing subsynchronous oscillations of a new energy transmission system, the device comprising:

[0011] A first test unit is configured to test first impedance curves of the system side and the new energy side of the new energy transmission system under typical operating conditions. The typical operating conditions are used to characterize the operating points selected after the active power range of the new energy transmission system is coarsely divided into multiple power intervals. The impedance curve includes the impedance amplitude and impedance phase at each frequency point.

[0012] a judgment unit, configured to judge, using a Nyquist stability criterion, whether there is an oscillation risk on the new energy side based on the first impedance curves of the system side and the new energy side, respectively, obtained by the first testing unit, wherein the oscillation risk is used to indicate that a phase difference between the impedance phases of the system side and the new energy side exceeds 180 degrees when the impedance amplitudes are equal, and that a stability margin between the system side and the new energy side does not meet a preset requirement when the phase difference does not exceed 180 degrees;

[0013] An optimization unit is used to optimize the negative damping frequency band of the new energy side based on the phase-locked loop parameters or the current loop proportional integral parameters if the judgment unit determines that the new energy side has the oscillation risk under the typical operating conditions, so that the new energy side does not have the oscillation risk under the typical operating conditions.

[0014] In order to achieve the above-mentioned purpose, according to the third aspect of the present application, a storage medium is provided, which includes a stored program, wherein when the program is running, the device where the storage medium is located is controlled to execute the subsynchronous oscillation suppression method of the new energy transmission system of the first aspect mentioned above.

[0015] In order to achieve the above-mentioned purpose, according to the fourth aspect of the present application, a processor is provided, which is used to run a program, wherein the program, when running, executes the subsynchronous oscillation suppression method of the new energy transmission system of the first aspect.

[0016] By means of the above technical solution, the present application provides a method and apparatus for suppressing subsynchronous oscillations in a new energy transmission system. When subsynchronous oscillation suppression is required for the new energy transmission system, the first impedance curves of the system side and the new energy side of the new energy transmission system are first tested under typical operating conditions. The typical operating conditions are used to characterize the operating points selected after the active power range of the new energy transmission system is coarsely divided into multiple power intervals. The impedance curve includes the impedance amplitude and impedance phase at each frequency point. Then, using the Nyquist stability criterion, it is determined whether there is an oscillation risk on the new energy side based on the first impedance curves of the system side and the new energy side. The oscillation risk is used to characterize whether the phase difference between the impedance phases of the system side and the new energy side exceeds 180 degrees when the impedance amplitudes are equal, and whether the stability margin between the system side and the new energy side does not meet preset requirements when the phase difference does not exceed 180 degrees. Finally, if there is an oscillation risk on the new energy side under typical operating conditions, the negative damping frequency band of the new energy side is optimized based on the phase-locked loop parameters or the current loop proportional-integral parameters to ensure that there is no oscillation risk on the new energy side under typical operating conditions. The technical solution provided in this application can divide the active power range into multiple power intervals in a coarse-grained manner, and select representative operating points for testing, ensuring a comprehensive evaluation of the system behavior under different operating conditions. Whether the phase difference between the impedance phases of the system side and the new energy side exceeds 180 degrees when the impedance amplitudes are equal, and whether the stability margin between the system side and the new energy side does not meet the preset requirements when the phase difference does not exceed 180 degrees, is used to judge whether there is an oscillation risk on the new energy side. Not only the phase difference when the impedance amplitudes are equal is paid attention to, but also whether the stability margin meets the preset requirements is considered, making the risk assessment more detailed and comprehensive, and improving the effectiveness of the suppression measures. For specific operating conditions identified as having an oscillation risk, the negative damping frequency band can be optimized by adjusting the phase-locked loop parameters or the current loop proportional integral parameters, which can effectively reduce or eliminate the risk of subsynchronous oscillation, thereby significantly improving the stability and reliability of the new energy transmission system under various operating conditions. That is, by analyzing in detail the impact of different operating conditions on system stability and providing targeted oscillation suppression measures, the problem of existing technologies that only focus on a single operating condition and ignore the changing operating environment is solved, the completeness of system impedance under various operating conditions is ensured, and the effectiveness and reliability of oscillation suppression measures are improved.

[0017] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiment below. The accompanying drawings are for illustration purposes only and are not to be considered as limiting the present application. The same reference symbols are used throughout the drawings to represent the same components. In the drawings:

[0019] Figure 1 A flow chart of a method for suppressing subsynchronous oscillations in a new energy transmission system provided by an embodiment of the present application is shown;

[0020] Figure 2 A flow chart of another method for suppressing subsynchronous oscillations in a new energy transmission system provided by an embodiment of the present application is shown;

[0021] Figure 3 The following is a block diagram showing the composition of a subsynchronous oscillation suppression device for a new energy transmission system provided by an embodiment of the present application;

[0022] Figure 4 A block diagram of the composition of another subsynchronous oscillation suppression device for a new energy transmission system provided in an embodiment of the present application is shown. DETAILED DESCRIPTION

[0023] Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0024] Currently, existing technologies for suppressing subsynchronous oscillations in renewable energy transmission systems primarily focus on optimizing control parameters or adding damping control schemes under a single operating condition on the renewable energy side. While these can mitigate oscillations under specific operating conditions to a certain extent, they fail to fully consider the impact of different operating conditions on system stability and struggle to ensure the completeness of system impedance under various operating conditions, thus impacting the effectiveness and reliability of oscillation suppression measures.

[0025] After research, the inventors discovered that they could coarsely divide the active power range and select representative operating points as typical operating conditions. This allowed them to obtain the impedance amplitude and phase information at each frequency point on both the system and renewable energy sides. The Nyquist stability criterion was then used to identify oscillation risks. After identifying specific operating conditions with oscillation risks, the negative damping frequency band was optimized by adjusting the phase-locked loop parameters or the current loop proportional integral parameters. This approach, by analyzing in detail the impact of different operating conditions on system stability and providing targeted oscillation suppression measures, addresses the existing problem of focusing on a single operating condition while ignoring the changing operating environment. This ensures the integrity of the system impedance under various operating conditions and improves the effectiveness and reliability of oscillation suppression measures.

[0026] Based on the above considerations, the embodiment of the present application provides a method for suppressing subsynchronous oscillations in a new energy transmission system. This method can ensure the integrity of system impedance under various operating conditions and improve the effectiveness and reliability of oscillation suppression measures. The specific execution steps are as follows: Figure 1 Shown, including:

[0027] 101. Test the first impedance curves of the system side and the new energy side of the new energy transmission system under typical operating conditions.

[0028] Among them, the typical operating conditions are used to characterize the active power range of the new energy transmission system. The operating points are selected after coarse-grained division of multiple power intervals. The impedance curve includes the impedance amplitude and impedance phase at each frequency point.

[0029] In this step, the active power range of the renewable energy transmission system is divided into several major power ranges. For example, the low power range (0-0.35 pu), the medium power range (0.35-0.7 pu), and the high power range (0.7-1.0 pu). A representative operating point is selected within each power range to obtain the typical operating conditions. For example, the low power typical operating point P = 0.1 pu, the medium power typical operating point P = 0.6 pu, and the high power typical operating point P = 0.9 pu.

[0030] Experimental testing was conducted at selected typical operating points, recording the impedance amplitude and phase of the renewable energy generator at each frequency point within the 1Hz to 2500Hz frequency range. The test simultaneously measured the impedance characteristics of both the system side (grid side) and the renewable energy side (generator side), and recorded these data to form separate impedance curves, which served as the primary impedance curve.

[0031] 102. Using the Nyquist stability criterion, determine whether there is an oscillation risk on the renewable energy side based on the respective first impedance curves of the system side and the renewable energy side.

[0032] Among them, oscillation risk is used to characterize that the phase difference between the impedance phases of the system side and the new energy side exceeds 180 degrees when the impedance amplitudes are equal, and the stability margin between the system side and the new energy side does not meet the preset requirements when the phase difference does not exceed 180 degrees.

[0033] In this step, the Nyquist stability criterion is used to analyze the first impedance curves of the system side and the new energy side. This criterion evaluates whether there is an oscillation risk on the new energy side by comparing the two first impedance curves. That is, when the impedance amplitudes of the system side and the new energy side are equal, if the phase difference between the two exceeds 180 degrees, it is considered that there is an oscillation risk. If the phase difference does not exceed 180 degrees, the stability margin of the new energy side is further calculated. The stability margin refers to the ability of a control system to remain stable when the gain or phase of its open-loop transfer function changes. In this embodiment, it is used to reflect the robustness of the new energy side, that is, how large a parameter change the new energy side can tolerate without losing stability.

[0034] Stability margin includes two aspects: amplitude margin and phase margin. The amplitude margin refers to how many times the open-loop gain of the renewable energy side can be increased without causing instability when the phase difference between the system and renewable energy sides reaches -180° (i.e., the feedback signal and the input signal are completely opposite in phase). In other words, it indicates how much the gain of the renewable energy side needs to be reduced to achieve critical stability when the phase lag on the renewable energy side results in a phase difference of 180 degrees. The larger the amplitude margin, the less likely the renewable energy side will become unstable due to gain changes. The phase margin, on the other hand, indicates how many degrees the phase lag is from -180° when the gain is 1 (or 0dB). In other words, it indicates how many degrees the phase lag on the renewable energy side needs to be before it becomes unstable when the gain on the renewable energy side reaches unity (i.e., the closed-loop gain is 1). The larger the phase margin, the less likely the system will become unstable due to changes in phase lag.

[0035] Correspondingly, the preset requirements are set according to the amplitude margin and / or phase margin. Specifically, the amplitude margin is defined as when the phase difference between the two is 180 degrees, the amplitude is required to be equal or less than a specific margin threshold (for example, the amplitude margin is less than or equal to 0.5-0.8); the phase margin is defined as when the amplitudes of the two are equal, the phase difference is required not to exceed another specific margin threshold (such as the phase margin is greater than or equal to 150-170 degrees). If the calculated stability margin does not meet the preset requirements, it is also considered that there is an oscillation risk. If there is an oscillation risk on the new energy side under typical operating conditions, execute step 103. If there is no oscillation risk on the new energy side under typical operating conditions, it can be preliminarily considered that the new energy side is stable.

[0036] 103. Optimize the negative damping frequency band of the new energy side based on the phase-locked loop parameters or the current loop proportional integral parameters so that there is no oscillation risk on the new energy side under typical operating conditions.

[0037] In this step, the frequency band with oscillation risk identified in step 102 is determined as a negative damping frequency band. Optimizing the phase-locked loop parameters for the negative damping frequency band can adjust the negative damping frequency band on the new energy side. In other words, increasing the phase-locked loop bandwidth can expand the negative damping frequency band on the new energy side, thereby improving the dynamic response performance of the system. The phase-locked loop transfer function G PLL This can be optimized by adjusting relevant parameters. Optimizing the proportional integral (PI) parameters of the current loop can adjust the negative damping of the new energy unit.

[0038] It should be noted that for the optimization of the phase-locked loop parameters or the current loop proportional-integral parameters, corresponding optimization logics can be used, such as synchronous optimization logic, alternating optimization logic, etc. During the optimization process, corresponding control gradients can be set for the phase-locked loop parameters or the current loop proportional-integral parameters, and iterative optimization can be achieved according to the control gradients and the above-mentioned optimization logic. After the optimization of step 103, the first impedance curves of the system side and the new energy side of the new energy transmission system under typical operating conditions are tested again, that is, the impedance characteristics under all typical operating conditions are measured to confirm whether the requirements of step 102 are met under typical operating conditions. If there are still conditions that do not meet the requirements, return to step 103 to continue optimization until there is no oscillation risk on the new energy side under typical operating conditions.

[0039] Based on the above Figure 1It can be seen from the implementation method that the present application provides a method for suppressing subsynchronous oscillations of a new energy transmission system, which can divide the active power range into multiple power intervals in a coarse-grained manner, and select representative operating points for testing, ensuring a comprehensive evaluation of the system behavior under different operating conditions. Whether the phase difference between the impedance phase of the system side and the new energy side exceeds 180 degrees when the impedance amplitudes are equal, and whether the stability margin between the system side and the new energy side does not meet the preset requirements when the phase difference does not exceed 180 degrees, is used to judge whether the new energy side has an oscillation risk. Not only the phase difference when the impedance amplitudes are equal is paid attention to, but also whether the stability margin meets the preset requirements is considered, making the risk assessment more detailed and comprehensive, and improving the effectiveness of the suppression measures. For specific operating conditions where oscillation risks are identified, the negative damping frequency band can be optimized by adjusting the phase-locked loop parameters or the current loop proportional integral parameters, which can effectively reduce or eliminate the risk of subsynchronous oscillations, thereby significantly improving the stability and reliability of the new energy transmission system under various operating conditions. That is, by analyzing in detail the impact of different operating conditions on system stability and providing targeted oscillation suppression measures, the problem of existing technologies that only focus on a single operating condition and ignore the changing operating environment is solved, the completeness of system impedance under various operating conditions is ensured, and the effectiveness and reliability of oscillation suppression measures are improved.

[0040] Furthermore, the preferred embodiment of the present application is in the above Figure 1 Based on this, a detailed description of the process of suppressing subsynchronous oscillations in the renewable energy transmission system is given. The specific steps are as follows: Figure 2 Shown, including:

[0041] 201. Divide the active power range of the new energy transmission system into multiple operating condition intervals in a coarse-grained manner in advance, and obtain a high-power operating interval, a medium-power operating interval, and a low-power operating interval.

[0042] In this step, the maximum and minimum active power output capabilities of the renewable energy transmission system are pre-determined. For example, assume that the designed maximum output of the renewable energy transmission system is 1.0 pu (per unit), while the minimum output may be close to 0 p.u.

[0043] Based on actual application needs and technical requirements, the entire active power range is divided into three main operating ranges at a coarse granularity: low power operating range (0-0.35 pu), medium power operating range (0.35-0.7 pu), and high power operating range (0.7-1.0 pu). This division ensures coverage of all possible operating conditions, from low to high loads, and each range represents a specific power level characteristic.

[0044] 202. A target active power value is selected as an operating point in each of the high-power operating range, the medium-power operating range, and the low-power operating range to obtain a typical operating condition.

[0045] In this step, a representative target active power value is selected in each power interval as an operating point. The selection principle can be based on historical data, system performance characteristics or engineering experience, for example, based on historical data analysis or the use of clustering algorithms. For example, for the low-power operating interval (0-0.35pu), P=0.1pu can be selected as the operating point, because this point usually represents the operation of the system at night or during low-load periods. For the medium-power operating interval (0.35-0.7pu), P=0.6pu can be selected as the operating point, which represents the working state of the system when it is under medium load. For the high-power operating interval (0.7-1.0pu), P=0.9pu can be selected as the typical operating point to reflect the operation of the system close to full load or during peak hours.

[0046] There are two implementation methods for determining the target active power value:

[0047] Method 1:

[0048] A target active power value is selected as an operating point in the high-power operating range, the medium-power operating range and the low-power operating range respectively. The specific execution process of obtaining the typical operating condition is as follows: the active power value corresponding to the occurrence of system stability-related events is extracted from the historical operating data on the new energy side. The system stability-related events include at least voltage fluctuations and frequency deviations; the occurrence frequency of each active power value in the high-power operating range, the medium-power operating range and the low-power operating range is calculated respectively; the active power value with the highest occurrence frequency in the high-power operating range, the medium-power operating range and the low-power operating range is selected as the respective target active power value.

[0049] For this approach, historical operating data, including but not limited to active power (P), reactive power (Q), voltage (V), and frequency (f), is pre-extracted from the database or log files of the renewable energy transmission system. Specific events related to system stability, such as voltage fluctuations and frequency deviations, are identified within this historical operating data. For example, the voltage fluctuation threshold is set to ±5% of the rated voltage, and the frequency deviation threshold is set to ±0.2 Hz. For each identified event, the corresponding active power value P is recorded. Based on the previously defined high-power operating range (0.7-1.0 pu), medium-power operating range (0.35-0.7 pu), and low-power operating range (0-0.35 pu), all extracted active power values are assigned to corresponding ranges. For each active power value within each power range, the number of occurrences is calculated. Specifically, a counter can be created to record the number of occurrences of different active power values within each power range. All identified events and their corresponding active power values are iterated over, and the counter is updated. After the statistics are collected, the frequency of occurrence of each active power value within each power range is obtained. In each power interval, find the active power value with the highest frequency and select it as the target active power value. It represents the operating state that occurs most frequently in this interval, possibly because it approaches the boundary conditions of system stability more frequently. Perform preliminary verification on the selected target active power value to ensure that it can indeed reflect the main characteristics of the interval. If some values are found to be unsatisfactory (for example, too much concentration on a specific value and ignoring other important situations), appropriate adjustments can be made based on engineering experience and actual conditions. In addition, it is also possible to consider introducing additional criteria or weights to balance the selection process, such as combining the changing trends of other system parameters such as voltage and current for comprehensive evaluation.

[0050] For example, the voltage fluctuation and frequency deviation events and their corresponding active power values that occurred in the new energy transmission system in the past year are collected. All events with voltage fluctuations exceeding ±5% and frequency deviations exceeding ±0.2Hz are extracted, and the active power values when these events occurred are recorded. All extracted active power values are divided into three power intervals: large, medium, and small. The frequency of occurrence of different active power values in each interval is counted. For example, in the low power interval (0-0.35pu), it was found that the power value of 0.1pu appeared 15 times, while the power value of 0.2pu appeared 10 times. In the low power interval, the 0.1pu with the highest frequency of occurrence is selected as the operating point. Similarly, 0.6pu is selected in the medium power interval and 0.9pu is selected in the high power interval.

[0051] Method 2:

[0052] A target active power value is selected as the operating point in the high-power operating range, the medium-power operating range and the low-power operating range respectively. The specific execution process of obtaining the typical operating condition is as follows: the active power value and related system parameters in the historical operating data of the new energy side are used as feature vectors, and the feature vectors are clustered using a clustering algorithm to obtain clustering results. The related system parameters include at least voltage, current and power factor; according to the clustering results, the cluster centers corresponding to the high-power operating range, the medium-power operating range and the low-power operating range are determined, and the representative power value of each cluster center is selected as the respective target active power value.

[0053] For this approach, historical operating data, including but not limited to active power (P), reactive power (Q), voltage (V), current (I), and power factor (PF), is extracted from the database or log files of the renewable energy transmission system in advance. It should be noted that this historical operating data must cover different time periods and various operating conditions.

[0054] Clean the collected data to remove outliers or missing values. Standardize the data to eliminate the influence of different dimensions. For example, use the Z-score standardization method to transform all parameters into a distribution with a mean of 0 and a standard deviation of 1. Combine the active power value (P) at each time point with relevant system parameters (such as voltage V, current I, and power factor PF) to form a feature vector. Cluster the feature vector using a clustering algorithm. Common clustering algorithms include K-means, DBSCAN, and hierarchical clustering. Predetermine the number of clusters based on actual needs and experience. Since the active power range is divided into three intervals, K = 3 can be set as a preliminary value. Perform cluster analysis on all feature vectors using the selected clustering algorithm. Using K-means as an example, the specific steps are as follows: Randomly initialize K cluster centers. Calculate the distance of each sample to each cluster center and assign it to the nearest cluster center. Update the position of each cluster center to the average value of all samples within that cluster. Repeat this process until the cluster center stops changing or the maximum number of iterations is reached. Based on the clustering results, each cluster is assigned to a corresponding high, medium, or low power interval. The distribution of active power values P within each cluster is examined to determine its interval. For each cluster, the mean or median of the active power values P of all samples within it is calculated as the representative power value for that cluster. For example, in a cluster with a low power interval, if the active power values of all samples are 0.1 pu, 0.12 pu, and 0.15 pu, respectively, their mean value of 0.123 pu can be selected as the operating point for that interval.

[0055] For example, a historical data set of the past year of the renewable energy transmission system is collected, including active power P, voltage V, current I, and power factor PF. The data is cleaned and standardized to construct a feature vector X = [P, V, I, PF]. The feature vector is clustered using the K-means algorithm, with K set to 3. After multiple iterations, three cluster centers C1, C2, and C3 are obtained. The distribution of active power values within each cluster is analyzed, and C1 is assigned to the low power range (0-0.35 pu), C2 to the medium power range (0.35-0.7 pu), and C3 to the high power range (0.7-1.0 pu). For C1 (low power range), the average active power value P of all samples within it is calculated to be 0.12 pu, which is used as the operating point of this range. Similarly, for C2 (medium power range) and C3 (high power range), their respective representative power values are calculated, such as 0.6 pu and 0.9 pu.

[0056] Through the above two methods, the typical operating conditions of each power range can be scientifically determined, so as to more accurately evaluate the stability and oscillation risk of the renewable energy transmission system, which not only improves the accuracy of the selection, but also enhances the effectiveness and reliability of the suppression strategy.

[0057] 203. Test the first impedance curves of the system side and the new energy side of the new energy transmission system under typical operating conditions.

[0058] This step is combined with the description of step 101 in the above method, and the same content will not be repeated here.

[0059] 204. Using the Nyquist stability criterion, determine whether there is an oscillation risk on the renewable energy side based on the respective first impedance curves of the system side and the renewable energy side.

[0060] This step is combined with the description of step 102 in the above method, and the same content is not repeated here. It should be noted that the stability margin includes the amplitude margin and the phase margin; the specific expression of the preset requirement is: when the phase difference between the impedance phases is equal to 180 degrees, the amplitude margin between the system side and the renewable energy side is less than or equal to the first margin threshold, and the first margin threshold corresponds to a range of 0.5-0.8; when the impedance amplitudes are equal, the phase margin between the system side and the renewable energy side is greater than or equal to the second margin threshold, and the second margin threshold corresponds to a range of 150-170 degrees.

[0061] Among them, the first margin threshold can be set from the perspective of safety and practical operability. According to previous empirical data and industry standards, the common amplitude margin range is 6dB to 20dB (that is, a gain of about 2 to 10 times), which is converted to a per-unit value of about 0.5 to 0.1. For new energy transmission systems, considering their dynamic characteristics and the complexity of the operating environment, it is generally recommended to set it between 0.5 and 0.8. Through system simulation and experimental verification, the actual performance of the system under different amplitude margins is determined. For example, different operating conditions can be simulated in a laboratory environment, and the response under different amplitude margins can be observed to find the optimal threshold range.

[0062] The second margin threshold can be set from the perspective of stability and robustness. For most control systems, the recommended phase margin range is 45 to 60 degrees (corresponding to a negative phase angle of 135 to 120 degrees). However, for applications with higher dynamic response requirements such as new energy transmission systems, it is generally recommended to set it between 150 and 170 degrees to provide sufficient stability margin. Similarly, the performance of the system under different phase margins can be verified through simulation and experiments. For example, by changing the control parameters and observing the response characteristics of the system under different phase margins, such as changes in overshoot, adjustment time, and stability, the optimal phase margin threshold can be determined.

[0063] It should be noted that different application scenarios may require different threshold settings. For example, for some applications with extremely high requirements for response speed, a lower amplitude margin and a higher phase margin may be preferred, while for situations that focus more on stability, the opposite is true. If the new energy side itself has strong nonlinearity or there are large uncertainty factors, a more conservative margin threshold may need to be set to ensure the overall stability of the new energy transmission system. Using the Nyquist stability criterion, if there is an oscillation risk on the new energy side under typical operating conditions, step 205 is executed. If there is no oscillation risk on the new energy side under typical operating conditions, step 206 is executed.

[0064] 205. Optimize the negative damping frequency band of the new energy side based on the phase-locked loop parameters or the current loop proportional integral parameters so that there is no oscillation risk on the new energy side under typical operating conditions.

[0065] It should be noted that the specific execution process of optimizing the negative damping frequency band on the new energy side based on the phase-locked loop parameters or the current loop proportional-integral parameters is: taking the frequency band with oscillation risk as the negative damping frequency band; obtaining the alternating logic and control gradient between the phase-locked loop parameters and the current loop proportional-integral parameters; for the negative damping frequency band, iteratively optimize the phase-locked loop parameters or the current loop proportional-integral parameters according to the alternating logic and control gradient, so that there is no oscillation risk on the new energy side.

[0066] In this step, based on the Nyquist stability criterion analysis results, identify which frequency bands have oscillation risks. The identified frequency bands with oscillation risks are marked as "negative damping bands." These frequency bands are the key areas for subsequent parameter optimization. Phase-locked loop parameters typically include bandwidth, damping ratio, etc. The current loop proportional-integral parameters include the proportional coefficient and integral coefficient. The phase-locked loop transfer function G PLL This can be optimized by adjusting relevant parameters. Optimizing the proportional integral (PI) parameters of the current loop can adjust the negative damping of the new energy unit. The specific formula is as follows:

[0067]

[0068] Among them, Z new is the impedance of the new energy unit (new energy side), L wind and R wind is the filter branch parameter of the new energy unit, U dc is the DC bus voltage, k pi and k ii is the current loop proportional and integral coefficient, I d and I q are the d-axis and q-axis currents at the grid connection point of the new energy unit, U d and U q is the d-axis and q-axis voltage of the grid-connected point of the new energy unit, G PLL The PLL transfer function is used. Through theoretical analysis or simulation tools (such as MATLAB / Simulink), study the impact of different parameter combinations on system performance and determine the trade-off between the PLL parameters and the current loop scaling parameters. For example, when adjusting the PLL bandwidth, how should the current loop proportional-integral coefficients be adjusted accordingly to maintain system stability?

[0069] It should be noted that, in this embodiment, the phase-locked loop parameters are adjusted first.

[0070] The control gradient is the specific step size for each parameter adjustment. The optimal adjustment step size can be determined through experiments or simulations to ensure rapid convergence while avoiding system instability caused by over-adjustment. Initially set the proportional-integral parameters of the phase-locked loop and current loop. Based on the alternating logic and the control gradient, gradually adjust the proportional-integral parameters of the phase-locked loop or current loop. For example, first try increasing the bandwidth of the phase-locked loop to expand the negative damping frequency band, while appropriately increasing the proportional coefficient of the current loop to enhance the system's dynamic response capability. After each adjustment, reassess the system stability to check whether the oscillation risk in the negative damping frequency band has been eliminated. If the risk of oscillation still exists, continue adjustments until the desired effect is achieved. Throughout the optimization process, record the parameters after each adjustment and their corresponding system performance, and ultimately save the optimal parameter combination that completely eliminates the oscillation risk on the new energy side.

[0071] Through the above detailed implementation method, the proportional-integral parameters of the phase-locked loop and the current loop can be effectively optimized, thereby eliminating the oscillation risk in the new energy transmission system and improving the overall stability and reliability of the system. This not only improves the safety of the system, but also enhances its ability to adapt to complex operating environments.

[0072] 206. Test the second impedance curves of the system side and the new energy side of the new energy transmission system under all operating conditions.

[0073] This step is combined with the description of step 101 in the above method for testing the first impedance curve under typical operating conditions. It is only necessary to switch the typical operating conditions to all operating conditions and test the second set of impedance curves in the same way. The same content will not be repeated here.

[0074] Among them, all operating conditions are used to characterize the operating points selected after the active power range of the renewable energy transmission system is divided into multiple power intervals with fine granularity. Specifically, the active power range is further subdivided to cover the entire power range in a more refined manner, and operating points are selected within each subdivided interval. That is, the active power range is divided into smaller steps (such as 0.1pu). For example, from 0p.u. to 1.0pu, every 0.1pu is an interval. One operating point is selected for each subdivided interval. For example, 0.0pu, 0.1pu, 0.2pu, ..., 1.0pu are selected as operating points.

[0075] 207. Using the Nyquist stability criterion, determine whether there is an oscillation risk on the renewable energy side based on the respective second impedance curves of the system side and the renewable energy side.

[0076] This step is combined with the description of the process of judging whether there is an oscillation risk on the new energy side based on the first impedance curve in step 102 of the above method. It is only necessary to judge whether there is an oscillation risk on the new energy side based on the second impedance curve in the same way. The same content will not be repeated here.

[0077] If the new energy side has oscillation risk under all operating conditions, step 208 is executed. If the new energy side does not have oscillation risk under all operating conditions, the new energy side in the new energy transmission system is considered stable and there is no subsynchronous oscillation.

[0078] 208. If there is an oscillation risk on the new energy side under all operating conditions, the negative damping frequency band on the new energy side shall be optimized based on the phase-locked loop parameters or the current loop proportional integral parameters so that there is no oscillation risk on the new energy side under all operating conditions.

[0079] This step is combined with the description of step 205 in the above method for optimizing the negative damping frequency band, and the same contents are not repeated here.

[0080] Furthermore, as a response to the above Figure 1-2 The implementation of the method embodiment shown in the figure, the embodiment of the present application provides a subsynchronous oscillation suppression device for a new energy transmission system, which is used to ensure the integrity of the system impedance under various operating conditions and improve the effectiveness and reliability of oscillation suppression measures. The embodiment of the device corresponds to the aforementioned method embodiment. For ease of reading, this embodiment will no longer repeat the details of the aforementioned method embodiment one by one, but it should be clear that the device in this embodiment can correspond to all the contents of the aforementioned method embodiment. Specifically, Figure 3 As shown, the device includes:

[0081] A first testing unit 31 is configured to test first impedance curves of the system side and the new energy side of the new energy transmission system under typical operating conditions. The typical operating conditions are used to characterize the operating points selected after the active power range of the new energy transmission system is coarsely divided into multiple power intervals. The impedance curve includes the impedance amplitude and impedance phase at each frequency point.

[0082] a judgment unit 32, configured to use a Nyquist stability criterion to judge whether there is an oscillation risk on the new energy side based on the first impedance curves of the system side and the new energy side obtained by the first testing unit 31, wherein the oscillation risk is used to indicate that a phase difference between the impedance phases of the system side and the new energy side exceeds 180 degrees when the impedance amplitudes are equal, and that a stability margin between the system side and the new energy side does not meet a preset requirement when the phase difference does not exceed 180 degrees;

[0083] The optimization unit 33 is used to optimize the negative damping frequency band of the new energy side based on the phase-locked loop parameters or the current loop proportional integral parameters if the judgment unit 32 determines that the new energy side has the oscillation risk under the typical operating conditions, so that the new energy side does not have the oscillation risk under the typical operating conditions.

[0084] Further, such as Figure 4 As shown, the device also includes:

[0085] A second testing unit 34 is configured to test the second impedance curves of the system side and the new energy side of the new energy transmission system under all operating conditions if the judgment unit 32 determines that the new energy side does not have the oscillation risk under the typical operating condition, wherein all operating conditions are used to represent the operating points selected after the active power range of the new energy transmission system is finely divided into multiple power intervals;

[0086] The judging unit 32 is further configured to judge whether the new energy side has the oscillation risk according to the second impedance curves of the system side and the new energy side obtained by the second testing unit 34 by using the Nyquist stability criterion;

[0087] The optimization unit 33 is also used to optimize the negative damping frequency band of the new energy side based on the phase-locked loop parameters or the current loop proportional integral parameters if the judgment unit 32 determines that the new energy side has the oscillation risk under all the operating conditions, so that the new energy side does not have the oscillation risk under all the operating conditions.

[0088] Further, such as Figure 4 As shown, the device also includes:

[0089] a division unit 35 configured to divide the active power range of the new energy transmission system into a plurality of operating condition intervals in a coarse-grained manner before the first testing unit 31 to obtain a high-power operating interval, a medium-power operating interval, and a low-power operating interval;

[0090] The determination unit 36 is configured to select a target active power value as an operating point in each of the high-power operating interval, the medium-power operating interval, and the low-power operating interval obtained by the division unit 35 to obtain the typical operating condition.

[0091] Further, such as Figure 4 As shown,

[0092] The low-power operating range is 0-0.35pu, and the typical operating condition is 0.1pu;

[0093] The medium power operating range is 0.35-0.7 pu, and the typical operating condition is 0.6 pu;

[0094] The high-power operating range is 0.7-1.0 pu, and the typical operating condition is 0.9 pu.

[0095] Further, such as Figure 4 As shown, the determining unit 36 includes:

[0096] An extraction module 361 is configured to extract, from the historical operating data of the new energy side, an active power value corresponding to a system stability-related event, wherein the system stability-related event includes at least voltage fluctuation and frequency deviation;

[0097] a calculation module 362, configured to calculate the occurrence frequency of each of the active power values obtained by the extraction module 361 in the high-power operation interval, the medium-power operation interval, and the low-power operation interval, respectively;

[0098] The first determination module 363 is configured to select the active power value with the highest occurrence frequency in the high-power operation interval, the medium-power operation interval, and the low-power operation interval obtained by the calculation module 362 as the respective target active power values.

[0099] Further, such as Figure 4 As shown, the determining unit 36 includes:

[0100] a processing module 364 configured to use the active power value and related system parameters in the historical operating data of the new energy side as feature vectors, and cluster the feature vectors using a clustering algorithm to obtain clustering results, wherein the related system parameters include at least voltage, current, and power factor;

[0101] The second determination module 365 is used to determine the cluster centers corresponding to the high-power operating interval, the medium-power operating interval and the low-power operating interval according to the clustering results obtained by the processing module 364, and select the representative power value of each cluster center as the respective target active power value.

[0102] Further, such as Figure 4 As shown, the optimization unit 33 includes:

[0103] A confirmation module 331 is configured to use a frequency band with an oscillation risk as the negative damping frequency band;

[0104] An acquisition module 332 is configured to acquire an alternating logic and a control gradient between the phase-locked loop parameters and the current loop proportional-integral parameters;

[0105] The optimization module 333 is used to iteratively optimize the phase-locked loop parameters or the current loop proportional integral parameters according to the alternating logic and the control gradient obtained by the acquisition module 332 for the negative damping frequency band obtained by the confirmation module 331, so that the oscillation risk does not exist on the new energy side.

[0106] Further, such as Figure 4 As shown,

[0107] The stability margin includes amplitude margin and phase margin;

[0108] The specific expression of the preset requirement is:

[0109] When the phase difference between the impedance phases is equal to 180 degrees, the amplitude margin between the system side and the new energy side is less than or equal to a first margin threshold;

[0110] When the impedance amplitudes are equal, the phase angle margin between the system side and the new energy side is greater than or equal to a second margin threshold.

[0111] Further, such as Figure 4 As shown,

[0112] The range corresponding to the first margin threshold is 0.5-0.8;

[0113] The second margin threshold corresponds to a range of 150-170 degrees.

[0114] Furthermore, the embodiment of the present application also provides a storage medium, which is used to store a computer program, wherein when the computer program is running, the device where the storage medium is located is controlled to execute the above Figure 1-2 The method for suppressing subsynchronous oscillation of the renewable energy transmission system described in .

[0115] Furthermore, the embodiment of the present application also provides a processor, which is used to run a program, wherein the program executes the above Figure 1-2 The method for suppressing subsynchronous oscillation of the renewable energy transmission system described in .

[0116] In the above embodiments, the description of each embodiment has its own focus. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0117] It is understood that the relevant features of the above methods and devices can be referenced to each other. In addition, the terms "first" and "second" in the above embodiments are used to distinguish between the embodiments, and do not represent the advantages and disadvantages of the embodiments.

[0118] Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0119] The algorithms and displays provided herein are not inherently related to any particular computer, virtual system, or other device. Various general-purpose systems may also be used together with the teachings herein. Based on the above description, it is apparent that the structure required for constructing such systems is suitable. In addition, the present application is not directed to any specific programming language. It should be understood that various programming languages may be utilized to implement the present application described herein, and the description of the specific languages above is provided for the purpose of disclosing the preferred embodiment of the present application.

[0120] In addition, the memory may include non-permanent memory in a computer-readable medium, random access memory (RAM) and / or non-volatile memory in the form of read-only memory (ROM) or flash RAM, and the memory includes at least one memory chip.

[0121] Those skilled in the art will appreciate that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the present application can adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application can adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code.

[0122] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the steps in the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0123] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0124] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0125] In a typical configuration, a computing device includes one or more processors (CPUs), input / output interfaces, network interfaces, and memory.

[0126] The memory may include non-permanent memory in a computer-readable medium, random access memory (RAM) and / or non-volatile memory in the form of read-only memory (ROM) or flash RAM. The memory is an example of a computer-readable medium.

[0127] Computer-readable media includes permanent and non-permanent, removable and non-removable media that can be implemented by any method or technology to store information. The information can be computer-readable instructions, data structures, program modules or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technology, compact disc read-only memory (CD-ROM), digital versatile disc (DVD) or other optical storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices or any other non-transmission media that can be used to store information that can be accessed by a computing device. As defined herein, computer-readable media does not include transitory computer-readable media (transitory media), such as modulated data signals and carrier waves.

[0128] It should also be noted that the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, commodity, or apparatus that includes a series of elements includes not only those elements but also other elements not explicitly listed, or includes elements inherent to such process, method, commodity, or apparatus. In the absence of further limitations, an element defined by the phrase "comprises a ..." does not exclude the presence of other identical elements in the process, method, commodity, or apparatus that includes the element.

[0129] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Furthermore, the present application may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0130] The above are merely embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application should all be included within the scope of the claims of the present application.

Claims

1. A method for suppressing subsynchronous oscillations in a new energy transmission system, characterized in that: The method comprises: Testing the first impedance curves of the system side and the new energy side of the renewable energy transmission system under typical operating conditions. The typical operating conditions are used to characterize the operating points selected after the active power range of the renewable energy transmission system is coarsely divided into multiple power intervals. The impedance curves include the impedance amplitude and impedance phase at each frequency point. Using the Nyquist stability criterion, judging whether there is an oscillation risk on the new energy side based on the first impedance curves of the system side and the new energy side, the oscillation risk being used to indicate that a phase difference between the impedance phases of the system side and the new energy side exceeds 180 degrees when the impedance amplitudes are equal, and that a stability margin between the system side and the new energy side does not meet a preset requirement when the phase difference does not exceed 180 degrees; If the new energy side has the oscillation risk under the typical operating conditions, the negative damping frequency band of the new energy side is optimized based on the phase-locked loop parameters or the current loop proportional integral parameters so that the new energy side does not have the oscillation risk under the typical operating conditions.

2. The method according to claim 1, characterized in that If the new energy side does not have the oscillation risk under the typical operating condition, the method further includes: Testing the second impedance curves of the system side and the new energy side of the new energy transmission system under all operating conditions, wherein all operating conditions are used to characterize the operating points selected after finely dividing the active power range of the new energy transmission system into multiple power intervals; Using the Nyquist stability criterion, judging whether the new energy side has the oscillation risk according to the second impedance curves of the system side and the new energy side; If the new energy side has the oscillation risk under all the operating conditions, the negative damping frequency band of the new energy side is optimized based on the phase-locked loop parameters or the current loop proportional integral parameters so that the new energy side does not have the oscillation risk under all the operating conditions.

3. The method according to claim 1, characterized in that Before testing the first impedance curves of the system side and the new energy side of the new energy transmission system under typical operating conditions, the method further includes: The active power range of the renewable energy transmission system is pre-divided into multiple operating condition intervals with coarse granularity to obtain high-power operating interval, medium-power operating interval and low-power operating interval; A target active power value is respectively selected as an operating point in the high-power operating range, the medium-power operating range, and the low-power operating range to obtain the typical operating condition.

4. The method according to claim 3, characterized in that The low-power operating range is 0-0.35pu, and the typical operating condition is 0.1pu; The medium power operating range is 0.35-0.7 pu, and the typical operating condition is 0.6 pu; The high-power operating range is 0.7-1.0 pu, and the typical operating condition is 0.9 pu.

5. The method according to claim 3, characterized in that Selecting a target active power value as an operating point in each of the high-power operating range, the medium-power operating range, and the low-power operating range to obtain the typical operating condition includes: Extracting an active power value corresponding to a system stability-related event from the historical operating data of the new energy side, wherein the system stability-related event includes at least voltage fluctuation and frequency deviation; Calculating the occurrence frequency of each active power value in the high-power operation interval, the medium-power operation interval, and the low-power operation interval respectively; The active power value with the highest occurrence frequency in the high-power operation interval, the medium-power operation interval, and the low-power operation interval is selected as the respective target active power values.

6. The method according to claim 3, characterized in that Selecting a target active power value as an operating point in each of the high-power operating range, the medium-power operating range, and the low-power operating range to obtain the typical operating condition includes: Taking the active power value and related system parameters in the historical operation data of the new energy side as feature vectors, and clustering the feature vectors using a clustering algorithm to obtain a clustering result, wherein the related system parameters include at least voltage, current and power factor; The cluster centers corresponding to the high-power operating interval, the medium-power operating interval, and the low-power operating interval are determined according to the clustering results, and the representative power value of each cluster center is selected as the respective target active power value.

7. The method according to claim 1 or 2, characterized in that The negative damping frequency band of the new energy side is optimized based on the phase-locked loop parameters or the current loop proportional integral parameters, including: Using a frequency band with oscillation risk as the negative damping frequency band; Obtaining an alternating logic and a control gradient between the phase-locked loop parameters and the current loop proportional-integral parameters; For the negative damping frequency band, the phase-locked loop parameters or the current loop proportional-integral parameters are iteratively optimized according to the alternating logic and the control gradient, so that the oscillation risk does not exist on the new energy side.

8. The method according to claim 1 or 2, characterized in that The stability margin includes amplitude margin and phase margin; The specific expression of the preset requirement is: When the phase difference between the impedance phases is equal to 180 degrees, the amplitude margin between the system side and the new energy side is less than or equal to a first margin threshold; When the impedance amplitudes are equal, the phase angle margin between the system side and the new energy side is greater than or equal to a second margin threshold.

9. The method according to claim 8, characterized in that The range corresponding to the first margin threshold is 0.5-0.8; The second margin threshold corresponds to a range of 150-170 degrees.

10. A device for suppressing subsynchronous oscillations in a new energy transmission system, characterized in that: The device comprises: A first test unit is configured to test first impedance curves of the system side and the new energy side of the new energy transmission system under typical operating conditions. The typical operating conditions are used to characterize the operating points selected after the active power range of the new energy transmission system is coarsely divided into multiple power intervals. The impedance curve includes the impedance amplitude and impedance phase at each frequency point. a judgment unit, configured to judge, using a Nyquist stability criterion, whether there is an oscillation risk on the new energy side based on the first impedance curves of the system side and the new energy side, respectively, obtained by the first testing unit, wherein the oscillation risk is used to indicate that a phase difference between the impedance phases of the system side and the new energy side exceeds 180 degrees when the impedance amplitudes are equal, and that a stability margin between the system side and the new energy side does not meet a preset requirement when the phase difference does not exceed 180 degrees; An optimization unit is used to optimize the negative damping frequency band of the new energy side based on the phase-locked loop parameters or the current loop proportional integral parameters if the judgment unit determines that the new energy side has the oscillation risk under the typical operating conditions, so that the new energy side does not have the oscillation risk under the typical operating conditions.

11. A storage medium, characterized in that: The storage medium includes a stored program, wherein when the program is executed, the device where the storage medium is located is controlled to execute the subsynchronous oscillation suppression method for a new energy transmission system according to any one of claims 1 to 9.

12. A processor, characterized in that: The processor is configured to run a program, wherein the program, when running, executes the method for suppressing subsynchronous oscillation of a new energy transmission system according to any one of claims 1 to 9.

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