A method and system for evaluating the broadband oscillation suppression effect

Abstract

The application provides a method and system for evaluating the effect of wide frequency oscillation suppression, comprising: starting a wide frequency oscillation suppression device when a wide frequency oscillation occurs in a power system, collecting a system oscillation main frequency of the power system and an active power sequence of a grid connection point; dividing the system oscillation main frequency into multiple frequency bands according to a preset division mode; selecting evaluation parameters for each frequency band according to the oscillation characteristics of each frequency band; the evaluation parameters include a peak value detection criterion type, a sliding window length, a threshold value and a number of de-bouncing points; based on each frequency band, substituting the evaluation parameters of the frequency band into a wide frequency oscillation suppression evaluation algorithm, and combining the active power sequence to evaluate and obtain an evaluation result of the oscillation suppression effect under the frequency band; and the application can accurately evaluate the effect of wide frequency oscillation suppression.

Description

Technical Field

[0001] This invention relates to the field of online monitoring of power systems, and specifically to a method and system for evaluating the effectiveness of broadband oscillation suppression. Background Technology

[0002] With the development and construction of new power systems based on new energy sources, broadband oscillations caused by highly pervasive power electronic equipment are becoming increasingly prominent, and these oscillations occur frequently. Research shows that many power electronic devices have complex coupling mechanisms, easily triggering broadband oscillations, and the new broadband oscillation phenomenon covers an extremely wide frequency band.

[0003] Wideband oscillations are complex in mechanism, exhibiting strong nonlinearity, time-varying characteristics, and wide-area propagation. Current technologies generally employ strategies such as additional damping control and the deployment of mitigation devices. However, due to the complexity of wideband oscillation systems and the new dynamics introduced by mitigation devices, existing technologies have significant limitations and potential risks. Their adaptability across the entire frequency band and multiple operating modes is severely insufficient. If the suppression strategy is inappropriate, it may even trigger mode shifts or induce new instability modes, deteriorating the overall stability of the system. Even after the implementation of suppression devices, the effectiveness of wideband oscillation suppression in the power grid remains unclear, posing certain risks.

[0004] Therefore, how to evaluate the effect of broadband oscillation suppression, ensure the effectiveness of broadband oscillation control, avoid introducing secondary risks, and ensure the safe and stable operation of the power grid are important issues that urgently need to be addressed. Summary of the Invention

[0005] To address the lack of evaluation methods for broadband oscillation suppression in existing technologies, this invention proposes a method for evaluating broadband oscillation suppression effectiveness, comprising the following steps: When a broadband oscillation occurs in the power system, the broadband oscillation suppression device is activated to collect the system oscillation frequency and the active power sequence at the grid connection point of the power system. The system oscillation frequency is divided into multiple frequency bands according to a preset division method; evaluation parameters are selected for each frequency band based on its oscillation characteristics; the evaluation parameters include peak detection criterion type, sliding window length, threshold, and number of debouncing points; Based on each frequency band, the evaluation parameters of the frequency band are substituted into the broadband oscillation suppression evaluation algorithm, and the evaluation is performed in conjunction with the active power sequence to obtain the evaluation result of the frequency band.

[0006] Optionally, the step of substituting the evaluation parameters of the frequency band into the broadband oscillation suppression evaluation algorithm and combining it with the active power sequence to obtain the evaluation result of the frequency band includes: Substitute the peak detection criterion type, sliding window length, threshold, and number of debouncing points of the frequency band into the broadband oscillation suppression evaluation algorithm to obtain the broadband oscillation suppression evaluation algorithm corresponding to the frequency band. Based on the broadband oscillation suppression evaluation algorithm corresponding to the frequency band, using the peak detection criterion type of the frequency band, and according to the detection sliding window in the peak detection criterion type, the active power sequence is peak detected to obtain multiple peaks; Based on each peak value, the variance between the peak values ​​adjacent to the peak value is calculated as the variance of the peak value; based on the variance of the peak value, the variance of the multiple peak values ​​is truncated using the sliding window length of the frequency band to obtain the variance of the multiple peak values. Considering the divergence or convergence trend of the oscillation in the frequency band, the average of the variances of the multiple peaks is calculated to obtain the evaluation index of the peak. The evaluation result of the frequency band is obtained by comparing the results of multiple consecutive evaluation metrics with the threshold of the frequency band and combining the number of dejitter points of the frequency band.

[0007] Optionally, for each frequency band, the length of the sliding window selected for the frequency band is directly proportional to the frequency band, the threshold selected for the frequency band is inversely proportional to the frequency band, and the number of dejitter points selected for the frequency band is directly proportional to the frequency band.

[0008] Optionally, the broadband oscillation suppression evaluation algorithm based on the frequency band utilizes the peak detection criterion type of the frequency band and performs peak detection on the active power sequence according to the detection sliding window in the peak detection criterion type to obtain multiple peaks. The steps include: In the broadband oscillation suppression evaluation algorithm corresponding to the frequency band, the corresponding detection sliding window is selected according to the peak detection criterion type of the frequency band, and the active power sequence is sampled through the detection sliding window; During the sampling process, if the sampling value at the middle sampling point is the largest within each detection sliding window, then the sampling value at that sampling point is taken as the peak value. After sampling is completed, multiple peak values ​​are obtained.

[0009] Optionally, the calculation formula for the evaluation index is as follows:

[0010]

[0011] in, For the first Evaluation metrics corresponding to each peak; For the first The sum of the variances of the peak values; This indicates the divergence or convergence trend of the oscillations within the stated frequency band. =1 indicates that the oscillation has a divergent tendency. =-1 indicates that the oscillation has a tendency to converge; For the first The variance of each peak; Represent natural numbers; The sliding window length is the value of the frequency band.

[0012] Optionally, the evaluation result of the frequency band is obtained by comparing the results of multiple consecutive evaluation metrics with the threshold of the frequency band, combined with the number of dejitter points of the frequency band. Specific steps include: When multiple consecutive evaluation indicators are greater than the threshold, and the number of multiple consecutive evaluation indicators reaches the number of dejitter points of the frequency band, the evaluation result of the frequency band is determined to be wideband oscillation in a divergent state. When multiple consecutive evaluation indicators are all less than the negative value of the threshold, and the number of multiple consecutive evaluation indicators reaches the number of dejitter points of the frequency band, the evaluation result of the frequency band is determined to be a broadband oscillation with a convergence trend. When any of the evaluation indicators falls between the positive and negative values ​​of the threshold, the evaluation result of the frequency band is determined to be a broadband oscillation in a state of constant amplitude oscillation.

[0013] Optionally, after substituting the evaluation parameters of each frequency band into a broadband oscillation suppression evaluation algorithm and combining it with the active power sequence to obtain the evaluation result of the frequency band, the method further includes: When the evaluation result of the frequency band indicates that the broadband oscillation is in a divergent state, it is determined that the broadband oscillation suppression effect of the broadband oscillation suppression device is unqualified, and it is recommended to turn off the broadband oscillation suppression device. When the evaluation result of the frequency band shows that the broadband oscillation has a convergence trend, the broadband oscillation suppression effect of the broadband oscillation suppression device is deemed qualified. When the evaluation result of the frequency band indicates that the broadband oscillation is in a state of constant amplitude oscillation, it is determined that the broadband oscillation suppression effect of the broadband oscillation suppression device is not significant, and it is recommended to optimize the control and protection strategy of the broadband oscillation suppression device.

[0014] Furthermore, this application also provides an evaluation system for broadband oscillation suppression, comprising: The data acquisition module is used to activate the broadband oscillation suppression device when broadband oscillations occur in the power system, and to collect the system oscillation frequency and active power sequence of the grid connection point of the power system. The parameter selection module is used to divide the system oscillation frequency into multiple frequency bands according to a preset division method; and to select evaluation parameters for each frequency band based on the oscillation characteristics of each frequency band; the evaluation parameters include peak detection criterion type, sliding window length, threshold, and number of debouncing points; An evaluation module is used to substitute the evaluation parameters of each frequency band into a broadband oscillation suppression evaluation algorithm, and combine the evaluation with the active power sequence to obtain the evaluation result of the frequency band.

[0015] Optionally, the evaluation module is specifically used for: Based on each frequency band, the peak detection criterion type, sliding window length, threshold, and number of debouncing points of the frequency band are substituted into the broadband oscillation suppression evaluation algorithm to obtain the broadband oscillation suppression evaluation algorithm corresponding to the frequency band. Based on the broadband oscillation suppression evaluation algorithm corresponding to the frequency band, using the peak detection criterion type of the frequency band, and according to the detection sliding window in the peak detection criterion type, the active power sequence is peak detected to obtain multiple peaks; Based on each peak value, the variance between the peak values ​​adjacent to the peak value is calculated as the variance of the peak value; based on the variance of the peak value, the variance of the multiple peak values ​​is truncated using the sliding window length of the frequency band to obtain the variance of the multiple peak values. Considering the divergence or convergence trend of the oscillation in the frequency band, the average of the variances of the multiple peaks is calculated to obtain the evaluation index of the peak. The evaluation result of the frequency band is obtained by comparing the results of multiple consecutive evaluation metrics with the threshold of the frequency band and combining the number of dejitter points of the frequency band.

[0016] Optionally, the system further includes: an effect feedback module; The effect feedback module is used to determine that the broadband oscillation suppression effect of the broadband oscillation suppression device is unqualified and to suggest turning off the broadband oscillation suppression device when the evaluation result of the frequency band is that the broadband oscillation is in a divergent state; to determine that the broadband oscillation suppression effect of the broadband oscillation suppression device is qualified when the evaluation result of the frequency band is that the broadband oscillation is in a constant amplitude oscillation state; and to determine that the broadband oscillation suppression effect of the broadband oscillation suppression device is not significant when the evaluation result of the frequency band is that the broadband oscillation is in a constant amplitude oscillation state, and to suggest optimizing the control and protection strategy of the broadband oscillation suppression device.

[0017] Furthermore, this application also provides a computing device, comprising: one or more processors; A processor is used to execute one or more programs; When the one or more programs are executed by the one or more processors, an evaluation method for wideband oscillation suppression effect as described above is implemented.

[0018] In another aspect, this application also provides a computer-readable storage medium having a computer program stored thereon, which, when executed, implements the evaluation method for broadband oscillation suppression effect as described above.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention provides a method for evaluating the broadband oscillation suppression effect. When broadband oscillation occurs in the power system, a broadband oscillation suppression device is activated, and the system oscillation main frequency and the active power sequence at the grid connection point of the power system are collected. Based on the segmentation results of the system oscillation main frequency, evaluation parameters are selected for each frequency band and substituted into the broadband oscillation suppression evaluation algorithm. When using the broadband oscillation suppression evaluation algorithm for evaluation, the broadband oscillation suppression effect of the broadband oscillation suppression device can be accurately evaluated. Attached Figure Description

[0020] Figure 1 This is a flowchart of the broadband oscillation suppression effect evaluation method of the present invention; Figure 2 This is a schematic diagram of the algorithm flow for evaluating the broadband oscillation suppression effect of the present invention; Figure 3 This is a flowchart illustrating the start / stop determination process of the broadband oscillation suppression effect evaluation method of the present invention. Figure 4 This is a flowchart illustrating the parameter adaptation implementation of the broadband oscillation suppression effect evaluation method of the present invention. Figure 5 This is a schematic diagram of the structure of the evaluation system for the broadband oscillation suppression effect of the present invention; Figure 6 This is a block diagram of an electronic device according to the present invention. Detailed Implementation

[0021] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0022] Example 1: A method for evaluating the effectiveness of broadband oscillation suppression, such as Figure 1 As shown, it includes the following steps: Step 1: When broadband oscillation occurs in the power system, activate the broadband oscillation suppression device and collect the system oscillation frequency and the active power sequence at the grid connection point.

[0023] Furthermore, the specific content includes: S1. Power Acquisition and Calculation: This step is fundamental for rapidly evaluating the effectiveness of broadband oscillation suppression. It involves acquiring real-time dynamic data from the power grid to provide reliable data input for subsequent suppression effectiveness assessments. The specific implementation process is as follows: (1) Data source and measurement point layout: Based on the Wide Area Measurement System (WAMS), synchronous phasor measurement units (PMUs) are deployed at key electrical locations such as the beginning and end of major connecting lines and grid connection points of large new energy power plants.

[0024] The collected dynamic electrical quantities include, but are not limited to, three-phase voltage phasors, three-phase current phasors, and active power. Based on the actual data source access conditions on site, the active power at the grid connection point is collected or calculated in real time, using the following formula: P=U a I a +U b I b +U c I c in: P Active power at the grid connection point; U a , U b , U c These are three-phase voltage phasors; I a , I b , I c These are three-phase current phasors.

[0025] (2) Sampling and synchronization requirements: The PMU sampling frequency is no less than 50Hz to meet the requirements for capturing fast dynamic processes in the power system. All PMU devices are connected to a unified high-precision time synchronization system to ensure that the data from each measurement point are strictly aligned on the time axis, eliminating phase errors caused by time asynchrony.

[0026] S2. Algorithm start / stop determination: This step utilizes external data communication to determine the start and stop of the algorithm for rapidly evaluating the broadband oscillation suppression effect. The specific implementation process is as follows: (1) Signal acquisition: The system collects real-time data from monitoring platforms, including the system's oscillation frequency and amplitude, as well as the operating status of the broadband oscillation suppression device control system, to determine whether to activate the rapid evaluation module.

[0027] (2) Start-stop criteria: If the relevant monitoring platform detects broadband oscillations in the system, it sends signals such as the system oscillation frequency and amplitude. If the relevant broadband suppression device receives the system oscillation frequency, the control and protection system activates the broadband oscillation suppression function. When modifying the operating status, it immediately initiates a rapid evaluation algorithm for broadband oscillation suppression effectiveness to assess the suppression effect. Otherwise, the algorithm stops. Figure 3 As shown.

[0028] S3. Data Preprocessing: The raw PMU data contains high-frequency noise, and wideband oscillations are prone to multi-frequency oscillation coupling. This step is to preprocess the active power data sequence at the grid connection point to improve data quality. The specific implementation process is as follows: (1) Low-pass filtering: Real-time collected or calculated active power data at the grid connection point usually contains high-frequency noise. High-frequency noise and irrelevant harmonics are removed by low-pass filtering.

[0029] Using a first-order IIR low-pass filter, the original power data sequence for the grid connection point is denoted as follows: P grid (n) The filtered power data sequence is y(n) The specific filtering formula is as follows: y(n)=α×P grid (n)+(1-α)×y(n-1) in: α =2πf c / f s f c f is the cutoff frequency. s The sampling frequency; P grid (n) This is the original power data sequence; y(n- 1) This is the filtered power data sequence from the previous time step.

[0030] (2) Main frequency filtering: Considering the possibility of multi-frequency oscillation coupling in wideband oscillations, we perform main frequency filtering based on the received system oscillation main frequency, retaining the main frequency band signal and characteristic quantities for subsequent evaluation.

[0031] The main frequency is filtered using Fast Fourier Transform (FFT), and the processed... y(n) The signal is transformed into the frequency domain using FFT. Based on the system's dominant oscillation frequency, a single dominant frequency component is retained. Then, an inverse FFT is performed to transform it back into the time domain, yielding the active power data at that dominant frequency. p(n) .

[0032] (3) Power per unit: To eliminate the differences in the absolute value of active power under different operating conditions, a unified evaluation index for suppression effect is established. The denoised power signal is then normalized, and the normalized power data sequence is as follows: Y(n) .

[0033] Based on the current active power at the grid connection point, take the average value of the historical active power data from the previous 5 seconds. Considering the typical amplitude of wideband oscillations and data scaling in subsequent index calculations, actual nominal values ​​are selected. 1% is the active power baseline value, and the specific filtering formula is as follows:

[0034] in, p(n) This is the main frequency power data sequence; This represents the average power data.

[0035] Step 2: Divide the system oscillation frequency into multiple frequency bands according to the preset division method; select evaluation parameters for each frequency band based on the oscillation characteristics of each frequency band; the evaluation parameters include peak detection criterion type, sliding window length, threshold, and number of debouncing points.

[0036] Furthermore, for each frequency band, the length of the sliding window selected for the frequency band is directly proportional to the frequency band, the threshold selected for the frequency band is inversely proportional to the frequency band, and the number of dejitter points selected for the frequency band is directly proportional to the frequency band.

[0037] The specific content includes: S4. Parameter Adaptation: This step is crucial for rapidly evaluating the broadband oscillation suppression effect. To ensure the accuracy of the evaluation, this invention establishes an adaptive parameter mechanism for the rapid evaluation algorithm, adaptively selecting the key parameters. The specific implementation process is as follows: Based on the oscillation characteristics of each frequency band of the wideband oscillation, and according to the monitored system oscillation frequency range, the main parameters are adaptively selected using a frequency band division method. The system oscillation frequency f m Divided into low-frequency oscillations (f m <5Hz), subsynchronous / supersynchronous oscillation (5Hz≤f) m <100Hz), mid-to-high frequency oscillations (100Hz≤f) m <500Hz), high-frequency oscillation (500Hz≤f) m <1000Hz), such as Figure 4 As shown. Key algorithm parameters are automatically adjusted to ensure high accuracy and speed in evaluating oscillation suppression across the entire frequency band. The key algorithm parameters mainly include: (1) Real-time peak detection criterion type: This refers to the judgment logic used in the real-time peak detection step to determine whether an active power data point is an oscillation peak point.

[0038] This invention defines two main criterion types and switches the criteria according to the frequency band to which the system oscillation frequency belongs, so as to adapt to the active waveform characteristics under different frequency band oscillations.

[0039] (2) Length of the window for calculating the mean of peak variance : In the calculation of evaluation indicators, the sliding window length refers to the number of peak variances included when summing and averaging the peak variances. This determines the memory length and smoothing effect of the oscillation trend during the indicator calculation process, as well as the window length for the summation and averaging of peak variance. The smaller the value, the better it can maintain the original power fluctuation, and the more sensitive it is; The larger the value, the less random fluctuations and false alarms there will be.

[0040] Based on the oscillation characteristics of low-frequency oscillation power fluctuations being smooth and with large amplitude, and high-frequency oscillation power dynamic fluctuations being rapid and with small amplitude, and considering the physical time required for rapid evaluation, the window length of this invention is... The adaptive selection is directly proportional to the system's dominant oscillation frequency. The specific value is determined by dividing the frequency bands according to the actual evaluation scenario. In this embodiment, the window length... The value range is shown in Table 1: Table 1 Window Length Range of values

[0041] Among them, the window length selected for each frequency band is based on the oscillation characteristics of each frequency band. It is also directly proportional to each frequency band.

[0042] (3) Threshold ε for judging peak variance mean: The threshold value used to determine whether the mean of the peak variance of the evaluation index is significant is the quantitative boundary that distinguishes between "acceptable suppression effect", "insignificant effect" and "unacceptable effect".

[0043] Generally, low-frequency oscillations have larger amplitudes, while high-frequency oscillations have smaller amplitudes. The adaptive selection of the threshold ε in this invention is inversely proportional to the dominant frequency of the system oscillation, ensuring that the evaluation standard can adapt to the oscillation characteristics of wideband oscillations and reducing the risk of false alarms or missed alarms. Specific values ​​are divided into frequency bands according to the actual evaluation scenario. In this embodiment, the threshold values ​​are shown in Table 2. Table 2. Threshold ε value range

[0044] Among them, based on the oscillation characteristics of each frequency band, the threshold ε selected for each frequency band is also inversely proportional to each frequency band.

[0045] (4) Number of de-jitter points M: This refers to the number of consecutive evaluation indicators that meet the requirements before the final evaluation result is output. The debouncing points M are mainly used to eliminate misjudgments of evaluation results caused by accidental fluctuations or transient interference, thereby improving the robustness of the evaluation results.

[0046] The adaptive selection of the number of debouncing points M in this invention is directly proportional to the dominant frequency of system oscillation. For frequency bands or operating conditions requiring rapid response, M is taken as a smaller value; for frequency bands requiring stability judgment, M is taken as a larger value. The specific values ​​are divided into frequency bands according to the actual evaluation scenario. In this embodiment, the division of the number of debouncing points is shown in Table 3: Table 3 Range of De-jitter Points M

[0047] Among them, based on the oscillation characteristics of each frequency band, the number of dejitter points M selected for each frequency band is also proportional to the number of dejitter points for each frequency band.

[0048] Step 3: Based on each frequency band, substitute the evaluation parameters of the frequency band into the broadband oscillation suppression evaluation algorithm, and combine it with the active power sequence for evaluation to obtain the evaluation result of the oscillation suppression effect under that frequency band.

[0049] Further, the specific contents of step 3 include: (1) Substituting the peak detection criterion type, sliding window length, threshold and dejitter number of the frequency band into the broadband oscillation suppression evaluation algorithm to obtain the broadband oscillation suppression evaluation algorithm corresponding to the frequency band; (2) Based on the broadband oscillation suppression evaluation algorithm corresponding to the frequency band, using the peak detection criterion type of the frequency band, according to the detection sliding window in the peak detection criterion type, performing peak detection on the active power sequence to obtain multiple peaks; (3) Based on each peak, calculating the variance between the peaks adjacent to the peak among the multiple peaks as the variance of the peak; (4) Based on the variance of the peaks, using the sliding window length of the frequency band to truncate the variance of multiple peaks to obtain multiple peak variances; (5) Considering the divergence or convergence trend of oscillation under the frequency band, averaging the variances of multiple peaks to obtain the evaluation index of the peak; (6) Based on the comparison results between multiple consecutive evaluation indices and the threshold of the frequency band, combined with the number of dejitter points of the frequency band, obtaining the evaluation result of the frequency band.

[0050] Step (2) is explained in detail as follows: In the wideband oscillation suppression evaluation algorithm corresponding to the frequency band, the corresponding detection sliding window is selected according to the peak detection criterion type of the frequency band, and the active power sequence is sampled through the detection sliding window; during the sampling process, if the sampling value of the sampling point located in the middle position is the largest in each detection sliding window, the sampling value of that sampling point is taken as the peak value; after the sampling is completed, multiple peak values ​​are obtained.

[0051] Step (6) is explained in detail as follows: When multiple consecutive evaluation indicators are greater than the threshold and the number of multiple consecutive evaluation indicators reaches the number of dejitter points of the frequency band, the evaluation result of the frequency band is determined to be that the broadband oscillation is in a divergent state; when multiple consecutive evaluation indicators are less than the negative value of the threshold and the number of multiple consecutive evaluation indicators reaches the number of dejitter points of the frequency band, the evaluation result of the frequency band is determined to be that the broadband oscillation has a convergent trend; when any evaluation indicator is between the positive and negative values ​​of the threshold, the evaluation result of the frequency band is determined to be that the broadband oscillation is in a state of constant amplitude oscillation.

[0052] The specific content includes: S5. Real-time peak detection: This step is crucial for rapidly evaluating the broadband oscillation suppression effect, based on the per-unit active power data sequence obtained in the above steps. Y(n) Real-time detection of peak power A k This is for subsequent evaluation of the inhibitory effect.

[0053] To ensure the real-time and rapid evaluation of broadband oscillation suppression effectiveness, this invention combines the oscillation characteristics of different frequency bands and employs two different peak detection methods, specifically: (1) The oscillation frequency is 500Hz or below: Select a sliding window of 21 consecutive sampling points. i Indicate the sampling point and record the sampled value. Y(i-10)...Y(i-1), Y (i), Y(i+1)...Y(i+10) If the sampled values ​​satisfy: Y(i)>Y(i-1)&&Y(i)>Y(i-2)...&&Y(i)>Y(i-10)&& Y(i)>Y(i+1)&&Y(i)>Y(i+2)...&&Y(i)>Y(i+10) When the above conditions are met, record. Y(i) Peak value A k Otherwise, there will be no peak value.

[0054] (2) The oscillation frequency is above 500Hz: Select a sliding window with 5 consecutive sampling points and record the sampled values. Y(i-2), Y(i-1), Y(i), Y(i+1), Y(i +2) If the sampled values ​​satisfy: Y(i-1)>Y(i-2)&&Y(i)>Y(i-1)&&Y(i)>Y(i+1)&&Y(i+1)>Y(i+2) When the above conditions are met, record.Y(i) Peak value A k Otherwise, there will be no peak value.

[0055] S6. Calculation of Evaluation Indicators: This step is the core of achieving rapid evaluation of broadband oscillation suppression effectiveness. Based on the extracted peak value Ak, a mean peak variance index is established to characterize the real-time divergence, convergence, or equal amplitude of the oscillation, thereby quantifying the suppression effect. The specific calculation method is as follows: (1) Calculate the peak variance: Peak values ​​extracted from step S5 A k Each time a new peak is detected A k Calculate the peak value before the peak value variance r k :

[0056] (2) Sum of peak variances: Based on the system's dominant oscillation frequency, a length of [length value] is selected. Sliding window, The value of is determined by the adaptive selection in step S4, and the sign of the peak variance is defined based on the divergence or convergence trend of the oscillation. The peak variance is then summed, and the specific calculation method is as follows:

[0057] in: For the first The sum of the variances of the peak values; For the first The variance of each peak; Represent natural numbers; The sliding window length is the value of the frequency band.

[0058] A k >A k-1 At that time, the oscillations tend to diverge. =1; A k <A k-1 At that time, the oscillations showed a tendency to converge. =-1; Represents an integer.

[0059] (3) Calculate the mean of the peak variance: The peak variance and its arithmetic mean are used as an evaluation index for broadband oscillation suppression. The specific calculation method is as follows:

[0060] in, To adaptively select the window length, For the first Evaluation metrics corresponding to each peak.

[0061] S7. Evaluation Results Output: This step is the final output stage for rapidly evaluating the broadband oscillation suppression effect. Based on the obtained mean peak variance, the judgment threshold ε and the number of debouncing points M are set, with values ​​referring to the adaptive selection in step S4. The specific suppression effect evaluation criteria are as follows: when If the oscillation is greater than ε and persists for M points, then the oscillation is considered to be still diverging, and the oscillation suppression effect is unqualified; when If -ε < -ε and persists for M points, then the oscillation is considered to have a convergent trend, and the oscillation suppression effect is satisfactory; when -ε ≤ When ≤ε, it is considered that the oscillation is still in a state of constant amplitude oscillation, and the oscillation suppression effect is not obvious.

[0062] Step 4: When the evaluation result of the frequency band indicates that the broadband oscillation is in a divergent state, it is determined that the broadband oscillation suppression effect of the broadband oscillation suppression device is unqualified, and it is recommended to turn off the broadband oscillation suppression device; when the evaluation result of the frequency band indicates that the broadband oscillation has a convergent trend, it is determined that the broadband oscillation suppression effect of the broadband oscillation suppression device is qualified; when the evaluation result of the frequency band indicates that the broadband oscillation is in a constant amplitude oscillation state, it is determined that the broadband oscillation suppression effect of the broadband oscillation suppression device is not significant, and it is recommended to optimize the control and protection strategy of the broadband oscillation suppression device.

[0063] Furthermore, the evaluation results of the broadband oscillation suppression effect are fed back to the suppression device to provide auxiliary decision-making. If the suppression effect is unqualified, it is recommended to shut down the suppression device to avoid secondary risks; if the suppression effect is not obvious, it is recommended to optimize the control and protection strategy of the suppression device.

[0064] This invention achieves rapid online evaluation of broadband oscillation suppression effectiveness through real-time signal acquisition, adaptive parameter selection, peak detection, and evaluation index calculation. Figure 2 As shown, the rapid evaluation method for broadband oscillation suppression mainly includes the following: 1. Power Acquisition and Calculation: Real-time operating data of the grid connection point is collected by a synchronous phasor measurement unit (PMU), and the dynamic signal of active power is directly collected. Alternatively, based on the actual collection and measurement, the active power is calculated by the dynamic signals of the three-phase voltage and three-phase current at the grid connection point.

[0065] 2. Algorithm start / stop determination: Data from the monitoring platform, including the system oscillation frequency and amplitude, as well as the operating status of the broadband oscillation suppression device control system, are collected to determine whether to activate the rapid evaluation algorithm.

[0066] 3. Data preprocessing: The original signals from the grid connection point obtained by acquisition / calculation are preprocessed with noise reduction, normalization, etc., to eliminate dimensional differences and high-frequency noise interference. This includes, but is not limited to: (1) low-pass filtering. (2) main frequency filtering. (3) normalization processing.

[0067] 4. Parameter adaptation: Establish a rapid evaluation algorithm parameter system, and adaptively select the main parameters of the algorithm according to the system oscillation frequency range, including but not limited to: (1) real-time peak detection criterion type. (2) peak variance mean calculation window length. (3) peak variance mean judgment threshold. (4) number of debouncing points.

[0068] By combining the oscillation characteristics of each frequency band and adaptively selecting parameters, the accuracy of oscillation suppression effect assessment can be improved.

[0069] 5. Real-time peak detection: Based on the preprocessed active power data sequence and the adaptively selected real-time peak detection criterion type, active power real-time peak detection is performed to capture real-time active power peaks.

[0070] 6. Calculation of evaluation indicators: An evaluation index for broadband oscillation suppression effect was established, and the index was calculated based on the detection results of real-time peak values ​​and adaptive parameter selection.

[0071] 7. Evaluation Results Output: By comparing the calculated index results with the judgment threshold, a rapid evaluation of the broadband oscillation suppression effect is performed, yielding the evaluation results, including: (1) The inhibition effect is acceptable. (2) The inhibition effect is not obvious. (3) The inhibition effect is unacceptable.

[0072] The evaluation results are fed back to the broadband oscillation suppression device, and corresponding risk warnings and auxiliary decision-making are given based on the evaluation results.

[0073] Compared with existing technologies, the rapid evaluation method for broadband oscillation suppression effect of the present invention has the following significant advantages and positive effects: (1) Real-time performance: This method can collect the operation data of the grid connection point in real time and conduct online rapid evaluation of the suppression effect. At the same time, this method selects different peak detection methods according to the range of the oscillation frequency, which can effectively ensure the speed and real-time performance of the evaluation results. (2) Adaptability: This method establishes an algorithm parameter system and, based on the oscillation characteristics of each frequency band of wideband oscillation, adopts a frequency-segmented approach to adaptively select the main parameters for ultra-low frequency oscillation, low frequency oscillation, sub / supersynchronous oscillation, and mid-to-high frequency oscillation, according to the main frequency range of the system oscillation. This includes, but is not limited to, the window length for calculating the mean value of peak variance. The peak variance mean threshold ε, the number of dejitter points M, etc., can effectively ensure the accuracy of the evaluation of the suppression effect of broadband oscillation; (3) Engineering practicality: This method can feed back the real-time evaluation results to the broadband oscillation suppression device and display the real-time evaluation results to the control personnel in a visual form so that they can fully grasp the broadband oscillation suppression effect of the power system, provide auxiliary decision support, help to comprehensively improve the frequency stability of the power grid, and provide strong technical support for the safe, high-quality and economical operation of the power system.

[0074] Example 2: Based on the same inventive concept, this invention also provides an evaluation system for broadband oscillation suppression effect, such as... Figure 5 As shown, it includes: The data acquisition module is used to activate the broadband oscillation suppression device when broadband oscillations occur in the power system, and to collect the system oscillation frequency and the active power sequence at the grid connection point of the power system.

[0075] The parameter selection module is used to divide the system oscillation frequency into multiple frequency bands according to a preset division method; and to select evaluation parameters for each frequency band based on the oscillation characteristics of each frequency band. The evaluation parameters include peak detection criterion type, sliding window length, threshold, and number of debouncing points.

[0076] The evaluation module is used to input the evaluation parameters of each frequency band into the broadband oscillation suppression evaluation algorithm and combine them with the active power sequence to obtain the evaluation results of the frequency band.

[0077] The effect feedback module is used to determine that the broadband oscillation suppression device's effect is unqualified and recommend shutting down the broadband oscillation suppression device when the frequency band evaluation result shows that the broadband oscillation is in a divergent state; when the frequency band evaluation result shows that the broadband oscillation has a convergent trend, it determines that the broadband oscillation suppression device's effect is qualified; when the frequency band evaluation result shows that the broadband oscillation is in a constant amplitude oscillation state, it determines that the broadband oscillation suppression device's effect is not significant and recommends optimizing the control and protection strategy of the broadband oscillation suppression device.

[0078] Furthermore, the evaluation module is specifically used for: based on each frequency band, substituting the peak detection criterion type, sliding window length, threshold, and number of dejitter points of the frequency band into the broadband oscillation suppression evaluation algorithm to obtain the broadband oscillation suppression evaluation algorithm corresponding to the frequency band; based on the broadband oscillation suppression evaluation algorithm corresponding to the frequency band, using the peak detection criterion type of the frequency band, and according to the detection sliding window in the peak detection criterion type, performing peak detection on the active power sequence to obtain multiple peaks; based on each peak, calculating the variance between the peaks adjacent to the peak among the multiple peaks, as the variance of the peak; based on the variance of the peaks, using the sliding window length of the frequency band to truncate the variance of multiple peaks, obtaining multiple peak variances; considering the divergence or convergence trend of oscillations under the frequency band, averaging the variances of multiple peaks to obtain the evaluation index of the peaks; based on the comparison results between multiple consecutive evaluation indices and the threshold of the frequency band, combined with the number of dejitter points of the frequency band, obtaining the evaluation result of the frequency band.

[0079] Example 3: Based on the same inventive concept, the present invention also provides a computer device, such as... Figure 6 As shown, the computer device includes a processor and a memory. The memory stores a computer program, which includes program instructions. The processor executes the program instructions stored in the computer storage medium. The processor may be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. It is the computing and control core of the terminal, and is suitable for implementing one or more instructions. Specifically, it is suitable for loading and executing one or more instructions in the computer storage medium to implement the corresponding method flow or corresponding function, so as to realize the steps of the broadband oscillation suppression effect evaluation method in the above embodiment.

[0080] Example 4: Based on the same inventive concept, this invention also provides a storage medium, specifically a computer-readable storage medium (Memory), which is a memory device in a computer device used to store programs and data. It is understood that the computer-readable storage medium here can include both the built-in storage medium in the computer device and extended storage media supported by the computer device. The computer-readable storage medium provides storage space that stores the terminal's operating system. Furthermore, this storage space also stores one or more instructions suitable for loading and execution by a processor. These instructions can be one or more computer programs (including program code). It should be noted that the computer-readable storage medium here can be high-speed RAM or non-volatile memory, such as at least one disk storage device. The processor can load and execute one or more instructions stored in the computer-readable storage medium to implement the steps of the broadband oscillation suppression effect evaluation method in the above embodiments.

[0081] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0082] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0083] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxesFigure 1 The function specified in one or more boxes.

[0084] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0085] The above are merely embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention are included within the scope of the claims of the present invention pending approval.

Claims

1. A method for evaluating the effect of broadband oscillation suppression, characterized in that, Includes the following steps: When a broadband oscillation occurs in the power system, the broadband oscillation suppression device is activated to collect the system oscillation frequency and the active power sequence at the grid connection point of the power system. The system oscillation frequency is divided into multiple frequency bands according to a preset division method; evaluation parameters are selected for each frequency band based on its oscillation characteristics; the evaluation parameters include peak detection criterion type, sliding window length, threshold, and number of debouncing points; Based on each frequency band, the evaluation parameters of the frequency band are substituted into the broadband oscillation suppression evaluation algorithm, and the evaluation is performed in conjunction with the active power sequence to obtain the evaluation result of the frequency band.

2. The method as described in claim 1, characterized in that, The steps of substituting the evaluation parameters of the frequency band into the broadband oscillation suppression evaluation algorithm and combining them with the active power sequence to obtain the evaluation result of the frequency band include: Substitute the peak detection criterion type, sliding window length, threshold, and number of debouncing points of the frequency band into the broadband oscillation suppression evaluation algorithm to obtain the broadband oscillation suppression evaluation algorithm corresponding to the frequency band. Based on the broadband oscillation suppression evaluation algorithm corresponding to the frequency band, using the peak detection criterion type of the frequency band, and according to the detection sliding window in the peak detection criterion type, the active power sequence is subjected to peak detection to obtain multiple peaks; Based on each peak value, the variance between the peak values ​​adjacent to the peak value is calculated as the variance of the peak value; based on the variance of the peak value, the variance of the multiple peak values ​​is truncated using the sliding window length of the frequency band to obtain the variance of the multiple peak values. Considering the divergence or convergence trend of the oscillation in the frequency band, the average of the variances of the multiple peaks is calculated to obtain the evaluation index of the peak. The evaluation result of the frequency band is obtained by comparing the results of multiple consecutive evaluation metrics with the threshold of the frequency band and combining the number of dejitter points of the frequency band.

3. The method as described in claim 1, characterized in that, For each frequency band, the length of the sliding window selected for the frequency band is directly proportional to the frequency band, the threshold selected for the frequency band is inversely proportional to the frequency band, and the number of dejitter points selected for the frequency band is directly proportional to the frequency band.

4. The method as described in claim 2, characterized in that, The broadband oscillation suppression evaluation algorithm based on the frequency band utilizes the peak detection criterion type of the frequency band and performs peak detection on the active power sequence according to the detection sliding window in the peak detection criterion type to obtain multiple peaks. The steps include: In the broadband oscillation suppression evaluation algorithm corresponding to the frequency band, the corresponding detection sliding window is selected according to the peak detection criterion type of the frequency band, and the active power sequence is sampled through the detection sliding window; During the sampling process, if the sampling value at the middle sampling point is the largest within each detection sliding window, then the sampling value at that sampling point is taken as the peak value. After sampling is completed, multiple peak values ​​are obtained.

5. The method as described in claim 2, characterized in that, The calculation formula for the evaluation index is as follows: in, For the first Evaluation metrics corresponding to each peak; For the first The sum of the variances of the peak values; This indicates the divergence or convergence trend of oscillations within the stated frequency band. =1 indicates that the oscillation has a divergent tendency. =-1 indicates that the oscillation has a tendency to converge; For the first The variance of each peak; Represent natural numbers; The sliding window length is the value of the frequency band.

6. The method as described in claim 2, characterized in that, The evaluation result of the frequency band is obtained by comparing the results of multiple consecutive evaluation metrics with the threshold of the frequency band, combined with the number of dejitter points of the frequency band. The specific steps include: When multiple consecutive evaluation indicators are greater than the threshold, and the number of multiple consecutive evaluation indicators reaches the number of dejitter points of the frequency band, the evaluation result of the frequency band is determined to be wideband oscillation in a divergent state. When multiple consecutive evaluation indicators are all less than the negative value of the threshold, and the number of multiple consecutive evaluation indicators reaches the number of dejitter points of the frequency band, the evaluation result of the frequency band is determined to be a broadband oscillation with a convergence trend. When any of the evaluation indicators falls between the positive and negative values ​​of the threshold, the evaluation result of the frequency band is determined to be a broadband oscillation in a state of constant amplitude oscillation.

7. The method as described in claim 1 or 6, characterized in that, After substituting the evaluation parameters of each frequency band into a broadband oscillation suppression evaluation algorithm and combining it with the active power sequence to obtain the evaluation result of the frequency band, the method further includes: When the evaluation result of the frequency band indicates that the broadband oscillation is in a divergent state, it is determined that the broadband oscillation suppression effect of the broadband oscillation suppression device is unqualified, and it is recommended to turn off the broadband oscillation suppression device. When the evaluation result of the frequency band shows that the broadband oscillation has a convergence trend, the broadband oscillation suppression effect of the broadband oscillation suppression device is deemed qualified. When the evaluation result of the frequency band indicates that the broadband oscillation is in a state of constant amplitude oscillation, it is determined that the broadband oscillation suppression effect of the broadband oscillation suppression device is not significant, and it is recommended to optimize the control and protection strategy of the broadband oscillation suppression device.

8. A system for evaluating broadband oscillation suppression effectiveness, characterized in that, include: The data acquisition module is used to activate the broadband oscillation suppression device when broadband oscillations occur in the power system, and to collect the system oscillation frequency and active power sequence of the grid connection point of the power system. The parameter selection module is used to divide the system oscillation frequency into multiple frequency bands according to a preset division method; and to select evaluation parameters for each frequency band based on the oscillation characteristics of each frequency band; the evaluation parameters include peak detection criterion type, sliding window length, threshold, and number of debouncing points; An evaluation module is used to substitute the evaluation parameters of each frequency band into a broadband oscillation suppression evaluation algorithm, and combine the evaluation with the active power sequence to obtain the evaluation result of the frequency band.

9. The system as described in claim 8, characterized in that, The evaluation module is specifically used for: Based on each frequency band, the peak detection criterion type, sliding window length, threshold, and number of debouncing points of the frequency band are substituted into the broadband oscillation suppression evaluation algorithm to obtain the broadband oscillation suppression evaluation algorithm corresponding to the frequency band. Based on the broadband oscillation suppression evaluation algorithm corresponding to the frequency band, using the peak detection criterion type of the frequency band, and according to the detection sliding window in the peak detection criterion type, the active power sequence is subjected to peak detection to obtain multiple peaks; Based on each of the peak values, the variance between the peak values ​​adjacent to the peak value is calculated, and this variance is used as the variance of the peak value. Based on the variance of the peak value, the multi-peak variance is truncated using the sliding window length of the frequency band to obtain multiple peak variances; Considering the divergence or convergence trend of the oscillation in the frequency band, the average of the variances of the multiple peaks is calculated to obtain the evaluation index of the peak. The evaluation result of the frequency band is obtained by comparing the results of multiple consecutive evaluation metrics with the threshold of the frequency band and combining the number of dejitter points of the frequency band.

10. The system as described in claim 8, characterized in that, Also includes: Results feedback module; The effect feedback module is used to determine that the broadband oscillation suppression effect of the broadband oscillation suppression device is unqualified and to suggest turning off the broadband oscillation suppression device when the evaluation result of the frequency band is that the broadband oscillation is in a divergent state; to determine that the broadband oscillation suppression effect of the broadband oscillation suppression device is qualified when the evaluation result of the frequency band is that the broadband oscillation is in a constant amplitude oscillation state; and to determine that the broadband oscillation suppression effect of the broadband oscillation suppression device is not significant when the evaluation result of the frequency band is that the broadband oscillation is in a constant amplitude oscillation state, and to suggest optimizing the control and protection strategy of the broadband oscillation suppression device.

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