Broadband oscillation and broad spectrum identification method and device with multi-band variable window length

Abstract

The present application relates to a method and device for identifying broadband oscillations with a multi-band variable window length, wherein the method comprises: forming a frequency test set of a target frequency band based on multiple frequency test points in the target frequency band; calculating a window length corresponding to a single oscillation mode that satisfies a preset minimum condition; calculating a window length corresponding to a single oscillation mode that satisfies a preset maximum condition; integrating the window lengths in the frequency test set that satisfy the preset shortest condition to obtain a window length set that satisfies the preset shortest condition; integrating the window lengths in the frequency test set that satisfy the preset maximum condition to obtain a window length set that satisfies the preset maximum condition; integrating the frequency test set, the window length set that satisfies the preset shortest condition, and the window length set that satisfies the preset maximum condition to perform frequency band division and window length selection on the target frequency band. Thus, the problem that the related technology is difficult to balance the detection response speed and calculation accuracy requirements in a multi-modal oscillation scenario is solved.

Description

Technical Field

[0001] The present application relates to the technical field of broadband oscillation monitoring and identification in power systems, and in particular to a method and device for broadband oscillation broad spectrum identification with multiple frequency bands and variable window lengths. Background Art

[0002] In new power systems with a high proportion of renewable energy and power electronic equipment, broadband oscillations are becoming increasingly prominent. These oscillations are characterized by wide bandwidth, time-varying frequency and amplitude, and multiple oscillation modes, seriously endangering the safe and stable operation of equipment and systems. Therefore, it is necessary to develop a method for rapid and accurate identification of broadband oscillations in power systems, enable online measurement of broadband oscillation parameters, and provide data support for real-time analysis and adaptive suppression of broadband oscillations.

[0003] In related technologies, power spectrum analysis can be used to analyze the frequency band of oscillation energy distribution to determine whether low-frequency oscillation or sub / supersynchronous oscillation occurs. The time window length is adaptively selected based on the power spectrum, and an order determination method is designed based on singular value decomposition that does not require threshold selection to achieve adaptive and accurate order determination, thereby achieving accurate identification of the dominant oscillation modal parameters.

[0004] However, the relevant technology mainly targets the sub-supersynchronous frequency band and is difficult to apply to the wide-band detection requirements of new power systems. The computing speed is difficult to meet the needs of online measurement, and it is difficult to meet the detection accuracy requirements in multi-modal oscillation scenarios, and it is in urgent need of improvement. Summary of the Invention

[0005] The present application provides a method and device for identifying broadband oscillations with a multi-band variable window length, in order to solve the problem that related technologies are difficult to balance the requirements of detection response speed and calculation accuracy in multi-modal oscillation scenarios.

[0006] The first embodiment of the present application provides a method for identifying a wide-band oscillation with a multi-band variable window length, comprising the following steps: forming a frequency test set of the target frequency band based on multiple frequency test points in the target frequency band; calculating a window length that satisfies a preset minimum condition corresponding to a single oscillation mode based on user demand information on the amplitude of the wide-band oscillation mode and the frequency identification accuracy; calculating a window length that satisfies a preset maximum condition corresponding to the single oscillation mode based on user demand information on the identification speed of the wide-band oscillation; detecting whether the window length that satisfies the preset shortest condition traverses the frequency test set, and integrating the window lengths in the frequency test set when the window length that satisfies the preset shortest condition traverses the frequency test set. The window length that meets the preset minimum condition is obtained to obtain the window length set that meets the preset shortest condition; detect whether the window length that meets the preset maximum condition traverses the frequency test set, and when the window length that meets the preset maximum condition traverses the frequency test set, integrate the window length that meets the preset maximum condition in the frequency test set to obtain the window length set that meets the preset maximum condition; when the window length set that meets the preset shortest condition and the window length set that meets the preset maximum condition meet the preset validity condition, integrate the frequency test set, the window length set that meets the preset shortest condition and the window length set that meets the preset maximum condition to perform frequency band division and window length selection on the target frequency band.

[0007] Optionally, in one embodiment of the present application, the window length corresponding to a single oscillation mode that meets a preset minimum condition is calculated based on the user's requirement information on the broadband oscillation mode amplitude and the frequency identification accuracy, including: based on the user's requirement information on the broadband oscillation mode amplitude and the frequency identification accuracy, the industrial frequency signal and the single oscillation mode signal in the power system are superimposed to obtain a first test sampling signal in the target frequency band; based on the first test sampling signal, the identification error of the broadband oscillation mode amplitude and the frequency is calculated using an identification algorithm, and whether the window length meets a preset error condition based on the identification error; if the window length meets the preset error condition, the window length is determined to be the window length that meets the preset minimum condition, otherwise the window length is increased until the window length meets the preset minimum condition.

[0008] Optionally, in one embodiment of the present application, the calculation formula of the first test sampling signal is:

[0009] s1[n]=acos(2πfn / f s +φ)+a1cos(2πf1n / f s +φ1)n∈[1,N w ],

[0010] Among them, f sis the sampling frequency, a, f, φ are the amplitude, frequency and phase of the power frequency phasor respectively, a1, f1, φ1 are the phasor amplitude, frequency and phase of the oscillation mode respectively, N w is the number of sampling points in the time window, that is, the window length.

[0011] Optionally, in one embodiment of the present application, the window length corresponding to the single oscillation mode that meets the preset maximum condition is calculated based on the user's demand information on the broadband oscillation identification speed, including: based on the user's demand information on the broadband oscillation identification speed, when an oscillation step occurs, superimposing the power frequency signal and the single oscillation mode signal to obtain a second test sampling signal in the target frequency band; based on the second test sampling signal, using the identification algorithm to calculate the frequency detection time of the single oscillation mode when the time window slides at a preset step size, and judging whether the window length meets the preset detection time condition based on the frequency detection time; if the window length meets the preset detection time condition, determining the window length to be the window length that meets the preset maximum condition, otherwise reducing the window length until the window length meets the preset maximum condition.

[0012] Optionally, in one embodiment of the present application, the calculation formula of the second test sampling signal is:

[0013]

[0014] Among them, N s is the number of points corresponding to the time point when the oscillation step occurs, f s is the sampling frequency, a, f, φ are the amplitude, frequency and phase of the power frequency phasor respectively, a1, f1, φ1 are the phasor amplitude, frequency and phase of the oscillation mode respectively.

[0015] The second aspect of the present application provides a broadband oscillation wide spectrum identification device with a multi-band variable window length, comprising: a composition module for forming a frequency test set of the target frequency band based on multiple frequency test points in the target frequency band; a first calculation module for calculating the window length that meets the preset shortest condition corresponding to a single oscillation mode based on the user's demand information on the broadband oscillation mode amplitude and frequency identification accuracy; a second calculation module for calculating the window length that meets the preset longest condition corresponding to the single oscillation mode based on the user's demand information on the broadband oscillation identification speed; a first integration module for detecting whether the window length that meets the preset shortest condition traverses the frequency test set, and integrating the window length that meets the preset shortest condition if the window length that meets the preset shortest condition traverses the frequency test set. The window length that meets the preset shortest condition in the frequency test set is used to obtain the window length set that meets the preset shortest condition; a second integration module is used to detect whether the window length that meets the preset longest condition traverses the frequency test set, and when the window length that meets the preset longest condition traverses the frequency test set, integrate the window length that meets the preset longest condition in the frequency test set to obtain the window length set that meets the preset longest condition; an identification module is used to integrate the frequency test set, the window length set that meets the preset shortest condition and the window length set that meets the preset longest condition when the window length set that meets the preset shortest condition and the window length set that meets the preset longest condition meet the preset validity condition, so as to perform frequency band division and window length selection on the target frequency band.

[0016] Optionally, in one embodiment of the present application, the first calculation module includes: a first superposition unit, used to superimpose the power frequency signal and the single oscillation mode signal in the power system based on the user's requirement information on the broadband oscillation mode amplitude and the frequency identification accuracy, to obtain a first test sampling signal in the target frequency band; a first calculation unit, used to calculate the broadband oscillation mode amplitude and the identification error of the frequency based on the first test sampling signal using an identification algorithm, and judge whether the window length meets the preset error condition based on the identification error; a first determination unit, used to determine that the window length is the window length that meets the preset minimum condition when the window length meets the preset error condition, otherwise increase the window length until the window length meets the preset minimum condition.

[0017] Optionally, in one embodiment of the present application, the calculation formula of the first test sampling signal is:

[0018] s1[n]=acos(2πfn / f s +φ)+a1cos(2πf1n / f s +φ1) n∈[1,N w ],

[0019] Among them, fs is the sampling frequency, a, f, φ are the amplitude, frequency and phase of the power frequency phasor respectively, a1, f1, φ1 are the phasor amplitude, frequency and phase of the oscillation mode respectively, N w is the number of sampling points in the time window, that is, the window length.

[0020] Optionally, in one embodiment of the present application, the second calculation module includes: a second superposition unit, used to superimpose the power frequency signal and the single oscillation mode signal based on the user's demand information on the wide-band oscillation identification speed, when an oscillation step occurs, to obtain a second test sampling signal in the target frequency band; a second calculation unit, used to calculate the frequency detection time of the single oscillation mode when the time window slides at a preset step size based on the second test sampling signal using the identification algorithm, and judge whether the window length meets the preset detection time condition based on the frequency detection time; a second determination unit, used to determine that the window length is the window length that meets the preset maximum condition when the window length meets the preset detection time condition, otherwise reduce the window length until the window length meets the preset maximum condition.

[0021] Optionally, in one embodiment of the present application, the calculation formula of the second test sampling signal is:

[0022]

[0023] Among them, N s is the number of points corresponding to the time point when the oscillation step occurs, f s is the sampling frequency, a, f, φ are the amplitude, frequency and phase of the power frequency phasor respectively, a1, f1, φ1 are the phasor amplitude, frequency and phase of the oscillation mode respectively.

[0024] The third aspect of the present application provides an electronic device, comprising: a memory, a processor, and a computer program stored on the memory and executable on the processor, wherein the processor executes the program to implement the multi-band variable window length broadband oscillation and wide spectrum identification method as described in the above embodiment.

[0025] A fourth aspect of the present application provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the above-mentioned multi-band variable window length broadband oscillation and wide-spectrum identification method.

[0026] The fifth aspect of the present application provides a computer program product, which stores a computer program. When the program is executed by a processor, it implements the above-mentioned multi-band variable window length broadband oscillation and wide spectrum identification method.

[0027] To reduce the impact of medium- and high-frequency oscillations on the safe and stable operation of a large number of power electronic devices in power systems, the embodiments of the present application typically require suppression of broadband oscillations within several oscillation cycles. This places higher demands on oscillation detection speed. By utilizing a broadband oscillation online detection method that balances detection accuracy and speed, rapid and accurate detection of oscillations in different frequency bands can be achieved in multimodal oscillation scenarios. This resolves the difficulty of prioritizing both detection response speed and computational accuracy in multimodal oscillation scenarios, as encountered in related technologies.

[0028] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0030] Figure 1 This is a flow chart of a method for identifying broadband oscillations and broad spectrum using multiple frequency bands and variable window lengths according to an embodiment of the present application;

[0031] Figure 2 This is a schematic diagram of the shortest window length and the longest window length of each frequency band obtained by simulation calculation according to one embodiment of the present application;

[0032] Figure 3 This is a flow chart of a method for identifying broadband oscillations and broad spectrum using multiple frequency bands and variable window lengths according to one embodiment of the present application;

[0033] Figure 4 Schematic diagram of the structure of a multi-band variable window length broadband oscillation and broad spectrum identification device provided according to an embodiment of the present application;

[0034] Figure 5 A schematic diagram of the structure of an electronic device provided according to an embodiment of the present application. DETAILED DESCRIPTION

[0035] The following describes in detail embodiments of the present application, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present application, and should not be construed as limiting the present application.

[0036] The following describes the method and device for identifying broadband oscillations with a multi-band variable window length according to an embodiment of the present application with reference to the accompanying drawings. In response to the problem that the related technologies mentioned in the above background technology are difficult to balance the detection response speed and calculation accuracy requirements in a multi-modal oscillation scenario, the present application provides a method for identifying broadband oscillations with a multi-band variable window length. In this method, based on the existing broadband oscillation identification algorithm and in combination with the user's requirements for oscillation detection speed and detection accuracy, the key parameters affecting the algorithm performance, such as the frequency band division scheme of the target frequency band and the data window length of each frequency band, can be obtained through simulation calculation and optimization, thereby realizing fast and accurate online identification of broadband oscillation modes. Thus, the problem that the related technologies are difficult to balance the detection response speed and calculation accuracy requirements in a multi-modal oscillation scenario is solved.

[0037] Specifically, Figure 1 A flowchart of a method for identifying broadband oscillations and broad spectrum with a multi-band variable window length is provided in an embodiment of the present application.

[0038] like Figure 1 As shown, the multi-band variable window length broadband oscillation broad spectrum identification method includes the following steps:

[0039] In step S101 , a frequency test set of the target frequency band is composed based on a plurality of frequency test points in the target frequency band.

[0040] During the actual implementation process, before determining the shortest window length and the longest window length, the embodiments of the present application can set several frequency test points (which must include the start frequency and end frequency of the target frequency band) in the target frequency band to form a frequency test set F. For example, if the target frequency band is 3 to 2500 Hz, the frequencies of 3, 500, 1000, 1500, 2000, and 2500 Hz can be set as test points, and the test set F is composed of these frequencies.

[0041] In step S102 , based on the user's requirements for the amplitude of the broadband oscillation mode and the frequency identification accuracy, a window length corresponding to a single oscillation mode that meets a preset minimum condition is calculated.

[0042] It can be understood that the amplitude detection error A used in the embodiment of the present application to measure the broadband oscillation detection is error and frequency detection error f error Usually defined as:

[0043]

[0044]

[0045] in, and are the modal amplitude and frequency calculation results of the broadband oscillation identification algorithm, a and f1 are the theoretical values ​​of the broadband modal amplitude and frequency in the input voltage and current signals, respectively.

[0046] Existing online oscillation identification algorithms all require capturing measured voltage and current data within a time window, and then calculating the broadband modal phasors contained in the sampled data within this window length. Generally, the longer the data window, the higher the amplitude and frequency accuracy of the modal phasors. Therefore, when a user requires the identification accuracy of an oscillation mode amplitude and frequency, there must be a feasible minimum window length. The purpose of this part is to calculate the shortest window length corresponding to different frequency modes. In the embodiment of the present application, the window length that meets the preset minimum condition can be the shortest window length.

[0047] Specifically, the user in the embodiment of the present application can input the modal amplitude and frequency identification accuracy requirements for the broadband oscillation identification algorithm, for example, the modal and frequency identification accuracy can be required to be no higher than 5% and 0.2% respectively, and the shortest window length corresponding to a single oscillation mode can be calculated.

[0048] It should be noted that the preset minimum condition can be set by those skilled in the art according to actual conditions and is not specifically limited here.

[0049] Optionally, in one embodiment of the present application, based on the user's requirement information on the amplitude and frequency identification accuracy of the broadband oscillation mode, the window length corresponding to the single oscillation mode that meets the preset minimum condition is calculated, including: based on the user's requirement information on the amplitude and frequency identification accuracy of the broadband oscillation mode, the industrial frequency signal and the single oscillation mode signal in the power system are superimposed to obtain a first test sampling signal in the target frequency band; based on the first test sampling signal, the identification error of the broadband oscillation mode amplitude and frequency is calculated using an identification algorithm, and whether the window length meets the preset error condition is judged according to the identification error; if the window length meets the preset error condition, the window length is determined to be the window length that meets the preset minimum condition, otherwise the window length is increased until the window length meets the preset minimum condition.

[0050] It can be understood that, in the embodiment of the present application, satisfying the preset error condition may be that the error satisfies the accuracy requirement input by the user; and in the embodiment of the present application, the window length satisfying the preset minimum condition may be the shortest window length.

[0051] As a possible implementation method, the embodiment of the present application can, based on the user's demand information on the amplitude and frequency identification accuracy of the broadband oscillation mode, superimpose the power frequency signal and the single oscillation mode signal in the power system to obtain the first test sampling signal in the target frequency band, and based on the first test sampling signal, simulate and calculate the oscillation mode phasor contained in the test sampling signal based on the identification algorithm, calculate the identification error of the amplitude and frequency, and judge whether the error of the window length meets the accuracy requirement input by the user. The embodiment of the present application can reduce the number of sampling points in the time window, that is, the window length N, when the error meets the accuracy requirement input by the user. w Repeat this step to determine the shortest window length; if the error does not meet the accuracy requirement entered by the user, increase N w Repeat this step until the shortest window length N that meets the error requirement is found. 1f1 .

[0052] It should be noted that the preset error condition and the preset minimum condition can be set by those skilled in the art according to actual conditions and are not specifically limited here.

[0053] In one embodiment of the present application, the calculation formula of the first test sampling signal is:

[0054] s1[n]=acos(2πfn / f s +φ)+a1cos(2πf1n / f s +φ1)n∈[1,N w ],

[0055] Among them, f s is the sampling frequency, a, f, φ are the amplitude, frequency and phase of the power frequency phasor respectively, a1, f1, φ1 are the amplitude, frequency and phase of the oscillation mode respectively, N w is the number of sampling points in the time window, that is, the window length.

[0056] In step S103 , based on the user's requirement information on broadband oscillation identification speed, a window length corresponding to a single oscillation mode that meets a preset maximum condition is calculated.

[0057] It can be understood that in the embodiment of the present application, the window length that meets the preset maximum condition can be the longest window length.

[0058] The embodiment of the present application proposes to use the detection time of the oscillation mode frequency as a reference to measure the identification speed of the broadband oscillation identification algorithm, and defines the broadband oscillation frequency detection time ΔT as:

[0059] ΔT=t1-t0,

[0060] Among them, t0 is the moment when the oscillation mode is judged to appear. In most existing studies, the method commonly used to determine whether an oscillation mode appears is based on the amplitude of the oscillation mode. That is, when the ratio of the amplitude of a certain mode to the amplitude of the fundamental wave is greater than a certain threshold (for example, 1%), the oscillation mode is considered to appear. In common oscillation identification algorithm tests, most of them are tested in the form of oscillation steps, so t0 is the step time. t1 is the starting time when the frequency identification error of the oscillation mode always meets the requirements. For example, if the user requires the frequency identification error to be no more than 0.2%, then t1 is the starting time when the oscillation mode frequency measurement error does not exceed 0.2% and the measurement accuracy can be maintained.

[0061] Typically, the longer the time window used in an oscillation identification algorithm, the longer the frequency detection time. Therefore, when a user specifies a specific oscillation detection time for a particular mode, there must be a maximum feasible window length. The purpose of this section is to calculate the maximum window length corresponding to different frequency modes. In the embodiments of this application, the window length that meets the preset maximum condition can be the maximum window length.

[0062] During actual execution, the user in the embodiment of the present application can input identification speed requirements for the broadband oscillation identification algorithm, for example, requiring the frequency detection time to be no more than 15 oscillation cycles and calculating the longest window length corresponding to a single oscillation mode.

[0063] It should be noted that the preset maximum condition can be set by those skilled in the art according to actual conditions and is not specifically limited here.

[0064] Optionally, in one embodiment of the present application, based on the user's demand information on the broadband oscillation identification speed, the window length corresponding to the single oscillation mode that meets the preset maximum condition is calculated, including: based on the user's demand information on the broadband oscillation identification speed, when an oscillation step occurs, superimposing the power frequency signal and the single oscillation mode signal to obtain a second test sampling signal in the target frequency band; based on the second test sampling signal, using an identification algorithm to calculate the frequency detection time of the single oscillation mode when the time window slides at a preset step size, and judging whether the window length meets the preset detection time condition based on the frequency detection time; if the window length meets the preset detection time condition, determining the window length as the window length that meets the preset maximum condition, otherwise reducing the window length until the window length meets the preset maximum condition.

[0065] It is understandable that the preset detection time condition in the embodiment of the present application can be that the detection time meets the requirements input by the user.

[0066] In the actual implementation process, the embodiment of the present application can be based on the user's demand information on the broadband oscillation identification speed. When an oscillation step occurs, the power frequency signal and the single oscillation mode signal are superimposed to obtain a second test sampling signal in the target frequency band. Based on the second test sampling signal, the time window N is simulated and calculated using the identification algorithm. w The frequency detection time of the oscillation mode when sliding at a certain step length. When the detection time meets the requirements of the user input, increase the window length N w Repeat this step, and when the error does not meet the user input requirements, reduce N w Repeat this step until the longest window length N that meets the detection time requirement is found. 2f1 .

[0067] It should be noted that the preset detection time condition and the preset maximum condition can be set by those skilled in the art according to actual conditions and are not specifically limited here.

[0068] In one embodiment of the present application, the calculation formula of the second test sampling signal is:

[0069]

[0070] Among them, N s is the point number corresponding to the time point when the oscillation step occurs, f s is the sampling frequency, a, f, φ are the amplitude, frequency and phase of the power frequency phasor respectively, a1, f1, φ1 are the phasor amplitude, frequency and phase of the oscillation mode respectively.

[0071] In step S104, it is detected whether the window length that meets the preset shortest condition traverses the frequency test set, and if the window length that meets the preset shortest condition traverses the frequency test set, the window lengths that meet the preset shortest condition in the frequency test set are integrated to obtain a window length set that meets the preset shortest condition.

[0072] During the actual execution process, the embodiment of the present application can modify the oscillation mode frequency in the test sampling signal to f2, repeatedly set the test sampling signal s1[n] until the test set F is traversed, and integrate to obtain the shortest window length set N1 corresponding to the test set F under the error requirement. The embodiment of the present application can detect whether the shortest window length traverses the frequency test set, and when the shortest window length traverses the frequency test set, integrate the shortest window length in the frequency test set to obtain the shortest window length set.

[0073] It should be noted that the preset minimum condition can be set by those skilled in the art according to actual conditions and is not specifically limited here.

[0074] In step S105, it is detected whether the window length that meets the preset maximum condition traverses the frequency test set, and if the window length that meets the preset maximum condition traverses the frequency test set, the window lengths that meet the preset maximum condition in the frequency test set are integrated to obtain a window length set that meets the preset maximum condition.

[0075] During actual implementation, the embodiment of the present application can modify the oscillation mode frequency in the test sampling signal to f2, repeatedly set the test sampling signal s2[n] until the test set F is traversed, and integrate to obtain the longest window length set N2 corresponding to the test set F under the identification speed requirement. The embodiment of the present application can detect whether the longest window length traverses the frequency test set, and if the longest window length traverses the frequency test set, integrate the longest window lengths in the frequency test set to obtain the longest window length set.

[0076] It should be noted that the preset maximum condition can be set by those skilled in the art according to actual conditions and is not specifically limited here.

[0077] In step S106, when the window length set that meets the preset shortest condition and the window length set that meets the preset longest condition meet the preset validity condition, the frequency test set, the window length set that meets the preset shortest condition and the window length set that meets the preset longest condition are integrated to perform frequency band division and window length selection on the target frequency band.

[0078] It can be understood that the embodiment of the present application can obtain a frequency band division method and feasible window length selection for each frequency band that takes into account the user's requirements for oscillation identification accuracy and identification speed based on the test set F, shortest window length set N1 and longest window length set N2 obtained above.

[0079] As a possible implementation method, the embodiment of the present application can integrate the frequency test set, the shortest window length set and the longest window length set when the shortest window length set and the longest window length set are valid, so as to perform frequency band division and window length selection for the target frequency band. The embodiment of the present application can check the validity of the analysis result, that is, compare the shortest window length and the longest window length corresponding to each frequency in the test set F. If the shortest window length N of a certain frequency is 1fx Greater than the longest window length N 2fx , it is considered that the requirements of oscillation identification accuracy and identification speed entered by the user cannot be met at the same time, and the user is advised to update the requirements.

[0080] Divide the frequency bands according to N1 and N2, and adjust the feasible window length of each frequency band. It is required that for a frequency band [f1, f2] (both belong to the test set F), if the shortest window length of f1 is N 1f1 , the longest window length of f2 is N 2f2 , then the oscillation identification time window of this frequency band should satisfy:

[0081] N 1f1 ≤N w≤N 2f2 ,

[0082] If the window length does not exist, reselect the start frequency and end frequency of the frequency band.

[0083] The embodiment of the present application realizes the detection requirements of the entire target frequency band by splicing multiple frequency bands, and integrates the starting frequency, ending frequency and time window length of each frequency band.

[0084] It should be noted that the preset maximum condition can be set by those skilled in the art according to actual conditions and is not specifically limited here.

[0085] Specifically, it can be combined Figure 2 and Figure 3 As shown, the working principle of the multi-band variable window length broadband oscillation and broad spectrum identification method in the embodiment of the present application is described in detail with a specific embodiment.

[0086] The embodiment of the present application adopts the Hanning windowed DFT and trimodal interpolation algorithm, and obtains the frequency band division and window length selection for oscillation identification in the 3 to 2500 Hz frequency band through the method proposed in the present application.

[0087] First, the recognition accuracy of the oscillation amplitude and frequency is set to no more than 5% and 0.2% respectively, the frequency detection time is set to no more than 15 oscillation cycles, and the test set F = [3, 100, 200, 300, ..., 2400, 2500].

[0088] Then, according to the above steps, the shortest and longest window lengths of each frequency band are obtained by simulation calculation as follows: Figure 2 shown.

[0089] Afterwards, according to the process and requirements of the third part, the 3-2500 Hz frequency band division plan table is obtained, as shown in Table 1:

[0090] Table 1

[0091] Frequency band number Starting frequency Stop frequency feasible window length 1 3 100 2^14 2 100 200 2^10 3 200 500 2^9 4 500 1300 2^8 5 1300 1700 2^7 6 1700 2500 2^6

[0092] Finally, based on the frequency band division and parameter design scheme, the oscillation mode of any frequency in the 3-2500 Hz frequency band was tested. Some test results are shown in Table 2 below. It can be seen that the test accuracy and speed meet the input requirements, verifying the effectiveness of this method.

[0093] Table 2

[0094]

[0095]

[0096] like Figure 3As shown, the embodiment of the present application may include the following steps:

[0097] Step S301: setting a number of frequency test points in a target frequency band to form a frequency test set F.

[0098] Step S302: Input requirements for broadband oscillation mode amplitude and frequency identification accuracy.

[0099] Step S303: simulating and calculating the shortest window length corresponding to a single oscillation mode.

[0100] Step S304: Determine whether to traverse the test set F. If yes, execute step S305; if no, execute step S306.

[0101] Step S305: Integrate the shortest window length set N1 corresponding to the test set F under the error requirement.

[0102] Step S306: Update the oscillation frequency.

[0103] Step S307: Inputting the requirement for broadband oscillation identification speed.

[0104] Step S308: Simulate and calculate the longest window length corresponding to a single oscillation mode.

[0105] Step S309: Determine whether to traverse the test set F. If yes, execute step S310; if no, execute step S311.

[0106] Step S310: Integrate the longest window length set N2 corresponding to the test set F under the error requirement.

[0107] Step S311: Update the oscillation frequency.

[0108] Step S312: Determine whether the analysis result is valid. If so, execute step S313; if not, execute step S314.

[0109] Step S313: Perform frequency band division and window length selection based on F, N1, and N2.

[0110] Step S314: Update the oscillation identification accuracy or speed requirement.

[0111] Step S315: Integrate and obtain the frequency band division scheme and the window length of each frequency band.

[0112] According to the multi-band variable window length broadband oscillation broad spectrum identification method proposed in the embodiment of the present application, the shortest window length calculation method for oscillation identification considering amplitude and frequency detection accuracy, the longest window length calculation method for oscillation identification considering detection speed, and the broadband frequency band division and window length optimization setting method taking into account detection accuracy and speed are proposed. Based on the existing broadband oscillation identification algorithm and combined with the user's requirements for oscillation detection speed and detection accuracy, through simulation calculation and optimization, the frequency band division scheme of the target frequency band and the data window length of each frequency band, which are key parameters affecting the algorithm performance, are obtained, thereby achieving fast and accurate online identification of broadband oscillation modes. This solves the problem that related technologies are difficult to balance the detection response speed and calculation accuracy requirements in multi-modal oscillation scenarios.

[0113] Next, a multi-band variable window length broadband oscillation and broad spectrum identification device proposed according to an embodiment of the present application will be described with reference to the accompanying drawings.

[0114] Figure 4 It is a structural diagram of a multi-band variable window length broadband oscillation and broad spectrum identification device according to an embodiment of the present application.

[0115] like Figure 4 As shown, the multi-band variable window length broadband oscillation broad spectrum identification device 10 includes: a composition module 100 , a first calculation module 200 , a second calculation module 300 , a first integration module 400 , a second integration module 500 and an identification module 600 .

[0116] Specifically, the composition module 100 is configured to compose a frequency test set of the target frequency band based on a plurality of frequency test points in the target frequency band.

[0117] The first calculation module 200 is configured to calculate a window length corresponding to a single oscillation mode that satisfies a preset minimum condition based on user requirements for broadband oscillation mode amplitude and frequency identification accuracy.

[0118] The second calculation module 300 is configured to calculate a window length corresponding to a single oscillation mode that satisfies a preset maximum condition based on user demand information on broadband oscillation identification speed.

[0119] The first integration module 400 is used to detect whether the window length that meets the preset shortest condition traverses the frequency test set, and when the window length that meets the preset shortest condition traverses the frequency test set, integrate the window length that meets the preset shortest condition in the frequency test set to obtain a window length set that meets the preset shortest condition.

[0120] The second integration module 500 is used to detect whether the window length that meets the preset maximum condition traverses the frequency test set, and when the window length that meets the preset maximum condition traverses the frequency test set, integrate the window length that meets the preset maximum condition in the frequency test set to obtain a window length set that meets the preset maximum condition.

[0121] The identification module 600 is used to integrate the frequency test set, the window length set that meets the preset shortest condition, and the window length set that meets the preset longest condition when the window length set that meets the preset shortest condition and the window length set that meets the preset longest condition meet the preset validity condition, so as to perform frequency band division and window length selection on the target frequency band.

[0122] Optionally, in one embodiment of the present application, the first calculation module 200 includes: a first superposition unit, a first calculation unit and a first determination unit.

[0123] Among them, the first superposition unit is used to superimpose the power frequency signal and the single oscillation mode signal in the power system based on the user's demand information on the broadband oscillation mode amplitude and frequency identification accuracy to obtain the first test sampling signal in the target frequency band.

[0124] The first calculation unit is used to calculate the identification error of the broadband oscillation mode amplitude and frequency using an identification algorithm based on the first test sampling signal, and determine whether the window length meets a preset error condition according to the identification error.

[0125] The first determining unit is configured to determine the window length as a window length that satisfies a preset minimum condition when the window length satisfies a preset error condition; otherwise, the window length is increased until the window length satisfies the preset minimum condition.

[0126] Optionally, in one embodiment of the present application, the calculation formula of the first test sampling signal is:

[0127] s1[n]=acos(2πfn / f s +φ)+a1cos(2πf1n / f s +φ1)n∈[1,N w ],

[0128] Among them, f s is the sampling frequency, a, f, φ are the amplitude, frequency and phase of the power frequency phasor respectively, a1, f1, φ1 are the amplitude, frequency and phase of the oscillation mode respectively, N w is the number of sampling points in the time window, that is, the window length.

[0129] Optionally, in one embodiment of the present application, the second calculation module 300 includes: a second superposition unit, a second calculation unit and a second determination unit.

[0130] The second superposition unit is used to superimpose the power frequency signal and the single oscillation mode signal based on the user's requirement information on the broadband oscillation identification speed to obtain a second test sampling signal in the target frequency band when an oscillation step occurs.

[0131] The second calculation unit is used to calculate the frequency detection time of the single oscillation mode when the time window slides at a preset step size based on the second test sampling signal using an identification algorithm, and determine whether the window length meets the preset detection time condition according to the frequency detection time.

[0132] The second determining unit is configured to determine the window length as a window length that meets a preset maximum condition when the window length meets a preset detection time condition; otherwise, reduce the window length until the window length meets the preset maximum condition.

[0133] Optionally, in one embodiment of the present application, the calculation formula of the second test sampling signal is:

[0134]

[0135] Among them, N s is the point number corresponding to the time point when the oscillation step occurs, f s is the sampling frequency, a, f, φ are the amplitude, frequency and phase of the power frequency phasor respectively, a1, f1, φ1 are the phasor amplitude, frequency and phase of the oscillation mode respectively.

[0136] It should be noted that the above explanation of the embodiment of the multi-band variable window length broadband oscillation broad spectrum identification method is also applicable to the multi-band variable window length broadband oscillation broad spectrum identification device of this embodiment, and will not be repeated here.

[0137] The multi-band, variable-window-length, broadband oscillation, broad-spectrum identification device proposed in this application embodiment optimizes oscillation detection parameters for oscillations in different frequency bands, while balancing detection accuracy and speed, meeting the requirements for online broadband oscillation detection in new power systems. This addresses the difficulty of prior art in balancing detection response speed and computational accuracy in multimodal oscillation scenarios.

[0138] Figure 5 This is a schematic diagram of the structure of an electronic device provided in an embodiment of the present application. The electronic device may include:

[0139] Memory 501 , processor 502 , and computer programs stored in the memory 501 and executable on the processor 502 .

[0140] When the processor 502 executes the program, the broadband oscillation and broad spectrum identification method with multiple frequency bands and variable window lengths provided in the above embodiments is implemented.

[0141] Furthermore, the electronic device further includes:

[0142] The communication interface 503 is used for communication between the memory 501 and the processor 502 .

[0143] The memory 501 is used to store computer programs that can be run on the processor 502 .

[0144] The memory 501 may include a high-speed RAM memory, and may also include a non-volatile memory (non-volatile memory), such as at least one disk memory.

[0145] If the memory 501, processor 502, and communication interface 503 are implemented independently, the communication interface 503, memory 501, and processor 502 can be connected to each other via a bus and communicate with each other. The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus. The bus can be divided into an address bus, a data bus, a control bus, etc. For ease of representation, Figure 5 Only one thick line is used in the diagram, but this does not mean that there is only one bus or one type of bus.

[0146] Optionally, in a specific implementation, if the memory 501, the processor 502 and the communication interface 503 are integrated on a chip, the memory 501, the processor 502 and the communication interface 503 can communicate with each other through an internal interface.

[0147] The processor 502 may be a central processing unit (CPU), an application specific integrated circuit (ASIC), or one or more integrated circuits configured to implement the embodiments of the present application.

[0148] This embodiment further provides a computer-readable storage medium having a computer program stored thereon. When the program is executed by a processor, the above-mentioned method for identifying broadband oscillations and broad spectrums with multiple frequency bands and variable window lengths is implemented.

[0149] An embodiment of the present application further provides a computer program product storing a computer program, which, when executed by a processor, implements the above-mentioned method for identifying broadband oscillations and broad spectrums with multi-band variable window lengths.

[0150] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or N embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and features of different embodiments or examples without contradiction.

[0151] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of technical features indicated. Thus, a feature specified as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of this application, "N" means at least two, for example, two, three, etc., unless otherwise specifically defined.

[0152] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, fragment or portion of code comprising one or N executable instructions for implementing a custom logical function or process step, and the scope of the preferred embodiments of the present application includes alternative implementations in which functions may be performed in a different order than shown or discussed, including performing functions in a substantially simultaneous manner or in a reverse order depending on the functions involved, which should be understood by those skilled in the art to which the embodiments of the present application pertain.

[0153] The logic and / or steps represented in the flowcharts or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing the logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (e.g., a computer-based system, a system including a processor, or other system that can fetch and execute instructions from an instruction execution system, apparatus, or device). For purposes of this specification, a "computer-readable medium" can be any device that can contain, store, communicate, propagate, or transport a program for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable media include the following: an electrical connection with one or N wires (electronic devices), a portable computer disk cartridge (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and programmable read-only memory (EPROM or flash memory), fiber optic devices, and a portable compact disc read-only memory (CDROM). In addition, the computer-readable medium may even be paper or other suitable medium on which the program is printed, since the program can be obtained electronically by optically scanning the paper or other medium and then editing, interpreting or processing it in other suitable ways as necessary, and then storing it in a computer memory.

[0154] It should be understood that various parts of the present application can be implemented using hardware, software, firmware, or a combination thereof. In the above embodiment, the N steps or methods can be implemented using software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented using hardware, as in another embodiment, any one of the following technologies known in the art or a combination thereof can be used to implement: a discrete logic circuit having a logic gate circuit for implementing a logic function on a data signal, an application-specific integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0155] Those skilled in the art will understand that all or part of the steps in the method of the above embodiment can be completed by instructing related hardware through a program, and the program can be stored in a computer-readable storage medium. When the program is executed, it includes one or a combination of the steps of the method embodiment.

[0156] In addition, the functional units in the various embodiments of the present application may be integrated into a processing module, or each unit may exist physically separately, or two or more units may be integrated into a module. The above-mentioned integrated module may be implemented in the form of hardware or in the form of a software functional module. If the integrated module is implemented in the form of a software functional module and sold or used as an independent product, it may also be stored in a computer-readable storage medium.

[0157] The storage medium mentioned above may be a read-only memory, a magnetic disk, or an optical disk, etc. Although the embodiments of the present application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present application. Persons skilled in the art may make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present application.

Claims

1. A method for identifying broadband oscillations and broad spectrum with a multi-band variable window length, characterized in that: The following steps are involved: forming a frequency test set of the target frequency band based on a plurality of frequency test points in the target frequency band; Based on the user's requirements for broadband oscillation mode amplitude and frequency identification accuracy, calculate the window length corresponding to a single oscillation mode that meets the preset minimum conditions; Based on the user's requirement information on broadband oscillation identification speed, calculating a window length corresponding to the single oscillation mode that meets a preset maximum condition; detecting whether the window length that meets the preset shortest condition traverses the frequency test set, and if the window length that meets the preset shortest condition traverses the frequency test set, integrating the window lengths that meet the preset shortest condition in the frequency test set to obtain the window length set that meets the preset shortest condition; detecting whether the window length that meets the preset maximum condition traverses the frequency test set, and if the window length that meets the preset maximum condition traverses the frequency test set, integrating the window lengths that meet the preset maximum condition in the frequency test set to obtain the window length set that meets the preset maximum condition; When the window length set that meets the preset shortest condition and the window length set that meets the preset longest condition meet the preset validity condition, the frequency test set, the window length set that meets the preset shortest condition and the window length set that meets the preset longest condition are integrated to perform frequency band division and window length selection on the target frequency band.

2. The method according to claim 1, characterized in that The calculation of the window length corresponding to a single oscillation mode that meets a preset minimum condition based on the user's requirement information on the amplitude of the broadband oscillation mode and the frequency identification accuracy includes: Based on the user's requirement information on the broadband oscillation modal amplitude and the frequency identification accuracy, superimposing the power frequency signal and the single oscillation modal signal in the power system to obtain a first test sampling signal in the target frequency band; Based on the first test sampling signal, using an identification algorithm to calculate the broadband oscillation modal amplitude and the identification error of the frequency, and judging whether the window length meets a preset error condition according to the identification error; If the window length satisfies the preset error condition, the window length is determined to be the window length that satisfies the preset shortest condition; otherwise, the window length is increased until the window length satisfies the preset shortest condition.

3. The method according to claim 2, characterized in that The calculation formula of the first test sampling signal is: s1[n]=acos(2πfn / f s +φ)+a1cos(2πf1n / f s +φ1)n∈[1,N w ], Among them, f s is the sampling frequency, a, f, φ are the amplitude, frequency and phase of the power frequency phasor respectively, a1, f1, φ1 are the phasor amplitude, frequency and phase of the oscillation mode respectively, N w is the number of sampling points in the time window, that is, the window length.

4. The method according to claim 3, characterized in that The calculating, based on the user's requirement information on the broadband oscillation identification speed, a window length corresponding to the single oscillation mode that satisfies a preset maximum condition, includes: Based on the user's requirement information on the broadband oscillation identification speed, when an oscillation step occurs, superimposing the power frequency signal and the single oscillation mode signal to obtain a second test sampling signal in the target frequency band; Based on the second test sampling signal, using the identification algorithm to calculate the frequency detection time of a single oscillation mode when the time window slides at a preset step length, and judging whether the window length meets a preset detection time condition according to the frequency detection time; If the window length satisfies the preset detection time condition, the window length is determined to be the window length that satisfies the preset maximum condition; otherwise, the window length is reduced until the window length satisfies the preset maximum condition.

5. The method according to claim 4, characterized in that The calculation formula of the second test sampling signal is: Among them, N s is the number of points corresponding to the time point when the oscillation step occurs, f s is the sampling frequency, a, f, φ are the amplitude, frequency and phase of the power frequency phasor respectively, a1, f1, φ1 are the phasor amplitude, frequency and phase of the oscillation mode respectively.

6. A multi-band variable window length broadband oscillation and broad spectrum identification device, characterized in that: include: a composition module, configured to compose a frequency test set of the target frequency band based on a plurality of frequency test points in the target frequency band; The first calculation module is used to calculate the window length corresponding to the single oscillation mode that meets the preset minimum condition based on the user's requirement information on the amplitude of the broadband oscillation mode and the frequency identification accuracy; A second calculation module is used to calculate the window length corresponding to the single oscillation mode that meets the preset maximum condition according to the demand information; a first integration module, configured to detect whether the window length satisfying the preset shortest condition traverses the frequency test set, and, if the window length satisfying the preset shortest condition traverses the frequency test set, integrate the window lengths satisfying the preset shortest condition in the frequency test set to obtain the window length set satisfying the preset shortest condition; a second integration module, configured to detect whether the window length satisfying the preset maximum condition traverses the frequency test set, and, if the window length satisfying the preset maximum condition traverses the frequency test set, integrate the window lengths satisfying the preset maximum condition in the frequency test set to obtain the window length set satisfying the preset maximum condition; An identification module is used to integrate the frequency test set, the window length set that meets the preset shortest condition and the window length set that meets the preset longest condition when the window length set that meets the preset shortest condition and the window length set that meets the preset longest condition meet the preset validity condition, so as to perform frequency band division and window length selection on the target frequency band.

7. The device according to claim 6, characterized in that The first calculation module includes: a superposition unit, configured to superimpose the power frequency signal and the single oscillation mode signal in the power system based on the user's requirement information on the broadband oscillation mode amplitude and the frequency identification accuracy, to obtain a first test sampling signal in the target frequency band; a calculation unit, configured to calculate, based on the first test sampling signal, an identification error of the broadband oscillation modal amplitude and the frequency using an identification algorithm, and determine whether the window length meets a preset error condition according to the identification error; A determination unit is configured to determine, when the window length satisfies the preset error condition, that the window length is the window length that satisfies the preset minimum condition; otherwise, increase the window length until the window length satisfies the preset minimum condition.

8. An electronic device, characterized in that: include: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the multi-band variable window length broadband oscillation and broad spectrum identification method according to any one of claims 1 to 5.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: The program is executed by a processor to implement the multi-band variable window length broadband oscillation and broad spectrum identification method as described in any one of claims 1 to 5.

10. A computer program product comprising a computer program, characterized in that The computer program is executed to implement the multi-band variable window length broadband oscillation and broad spectrum identification method according to any one of claims 1 to 5.

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