Method and device for detecting strand breakage fault of overhead ground wire, computer readable storage medium and electronic equipment

Abstract

The invention discloses a method and a device for detecting a strand breakage fault of an overhead ground wire, a computer readable storage medium and electronic equipment. The method comprises the following steps: collecting a vibration signal generated by an overhead ground wire at a fixed point; based on the vibration signal, at least establishing a historical response matrix and a future response matrix; based on the historical response matrix and the future response matrix, a covariance matrix of the vibration signals is determined, and the covariance matrix is used for representing statistical characteristics of the vibration signals; based on the covariance matrix, determining a current modal parameter of the vibration signal, the current modal parameter being used for representing an internal structure attribute of the overhead ground wire in a current operation state; and based on the current modal parameter and the standard modal parameter, determining a detection result of the strand breakage fault of the overhead ground wire, the detection result being used for indicating that the overhead ground wire has the strand breakage fault or does not have the strand breakage fault. The technical problem that it is difficult to detect the strand breakage fault of the overhead ground wire is solved.

Description

Technical Field

[0001] The present invention relates to the field of electric power technology, and in particular to a method, a device, a computer-readable storage medium and an electronic device for detecting a broken strand fault of an overhead ground wire. Background Art

[0002] At present, as an important component of the high-voltage transmission line system, the main function of overhead ground wires is to provide lightning protection for transmission lines and ensure the safety and stability of power transmission under severe weather conditions. However, overhead ground wires are exposed to the natural environment for a long time and are susceptible to external forces such as lightning strikes, wind and rain erosion, and mechanical wear, which can lead to broken or scattered strands on the outer layer of the ground wire. These faults not only reduce the electrical and mechanical performance of the ground wire, but may also induce line flashover discharge accidents, seriously threatening the overall operation safety of the power system.

[0003] In the related technologies, fault detection of overhead ground wires is usually achieved based on visual inspections by manual patrols, regular electrical performance tests, etc., which have problems such as slow response speed, low detection efficiency, and great influence of environmental factors. It is difficult to meet the needs of modern power systems for real-time monitoring and rapid fault location, and there is a technical problem that it is difficult to detect broken strand faults in overhead ground wires.

[0004] With respect to the above-mentioned technical problem of difficulty in detecting the broken strand fault of the overhead ground wire, no effective solution has been proposed so far. Summary of the invention

[0005] Embodiments of the present invention provide a method, device, computer-readable storage medium and processor for detecting a broken strand fault of an overhead ground wire, so as to at least solve the technical problem that it is difficult to detect a broken strand fault of an overhead ground wire.

[0006] According to one aspect of an embodiment of the present invention, a method for detecting a broken strand fault of an overhead ground wire is provided. The method comprises: collecting a vibration signal generated by the overhead ground wire at a fixed point, wherein the vibration signal is used to characterize the instantaneous response result of the overhead ground wire under external excitation; based on the vibration signal, at least a historical response matrix and a future response matrix are established, wherein the historical response matrix is ​​used to characterize the dynamic response characteristics of the overhead ground wire in the historical stage, and the future response matrix is ​​used to predict the dynamic response characteristics of the overhead ground wire in the future stage; based on the historical response matrix and the future response matrix, the covariance matrix of the vibration signal is determined, wherein the covariance matrix is ​​used to characterize the statistical characteristics of the vibration signal; based on the covariance matrix, the current modal parameters of the vibration signal are determined, wherein the current modal parameters are used to characterize the internal structural properties of the overhead ground wire in the current operating state; based on the current modal parameters and the standard modal parameters, the detection result of the broken strand fault of the overhead ground wire is determined, wherein the standard modal parameters are the modal parameters of the vibration signal generated when the overhead ground wire is in a normal operating state, and the detection result is used to indicate that there is a broken strand fault in the overhead ground wire, or the detection result is used to indicate that there is no broken strand fault in the overhead ground wire.

[0007] Optionally, based on the vibration signal, at least a historical response matrix and a future response matrix are established, including: arranging the vibration signals in order of collection time to obtain a time series; constructing a historical response matrix based on a first number of row data in the time series, and constructing a future response matrix based on a second number of column data in the time series, wherein the first number is greater than the second number.

[0008] Optionally, based on the covariance matrix, the current modal parameters of the vibration signal are determined, including: constructing a first Toeplitz matrix and a second Toeplitz matrix based on the covariance matrix, wherein the first Toeplitz matrix is ​​used to characterize the autocorrelation of the dynamic response of the overhead ground line in the historical stage, and the second Toeplitz matrix is ​​used to characterize the autocorrelation of the dynamic response of the overhead ground line in the future stage; based on the first Toeplitz matrix and the second Toeplitz matrix, the current modal parameters of the vibration signal are determined.

[0009] Optionally, based on the first Toeplitz matrix and the second Toeplitz matrix, the current modal parameters of the vibration signal are determined, including: performing singular value decomposition on the second Toeplitz matrix to obtain a singular value decomposition result; based on the singular value decomposition result and the first Toeplitz matrix, determining a discrete state matrix and an observation mapping matrix; based on the discrete state matrix and the observation mapping matrix, determining the current modal parameters.

[0010] Optionally, based on the discrete state matrix and the observation mapping matrix, the current modal parameters are determined, including: performing eigenvalue decomposition on the discrete state matrix to obtain an eigenvalue decomposition result, wherein the eigenvalue decomposition result includes at least eigenvalues ​​and eigenvectors; determining the vibration frequency and damping ratio of the overhead ground wire based on the eigenvalues, and determining the vibration form of the overhead ground wire in different modes based on the eigenvectors and the observation mapping matrix; and determining the vibration frequency of the overhead ground wire, the damping ratio of the overhead ground wire, and the vibration form of the overhead ground wire in different modes as the current modal parameters.

[0011] Optionally, based on current modal parameters and standard modal parameters, the detection result of the broken strand fault of the overhead ground wire is determined, including: constructing a stability diagram based on the current modal parameters, wherein the stability diagram is used to characterize the stability of the modal parameters; identifying abnormal modal parameters in the stability diagram, and removing the abnormal modal parameters from the current modal parameters to obtain the current true mode; based on the current true modal parameters and the standard modal parameters, the detection result of the broken strand fault of the overhead ground wire is determined.

[0012] Optionally, based on the current true modal parameters and the standard modal parameters, the detection result of the broken strand fault of the overhead ground wire is determined, including: comparing the current true modal parameters with the standard modal parameters to obtain a comparison result; in response to the comparison result indicating that the difference between the current true modal parameters and the standard modal parameters is greater than or equal to a preset threshold, determining that there is a broken strand fault in the overhead ground wire; in response to the comparison result indicating that the difference between the current true modal parameters and the standard modal parameters is less than the preset threshold, determining that there is no broken strand fault in the overhead ground wire.

[0013] According to another aspect of an embodiment of the present invention, a device for detecting a broken strand fault of an overhead ground wire is provided, comprising: a collection unit, for collecting a vibration signal generated by the overhead ground wire at a fixed point, wherein the vibration signal is used to characterize an immediate response result of the overhead ground wire under external excitation; an establishment unit, for establishing at least a historical response matrix and a future response matrix based on the vibration signal, wherein the historical response matrix is ​​used to characterize the dynamic response characteristics of the overhead ground wire in a historical stage, and the future response matrix is ​​used to predict the dynamic response characteristics of the overhead ground wire in a future stage; a first determination unit, for determining the vibration signal based on the historical response matrix and the future response matrix. A covariance matrix of the signal, wherein the covariance matrix is ​​used to characterize the statistical characteristics of the vibration signal; a second determination unit is used to determine the current modal parameters of the vibration signal based on the covariance matrix, wherein the current modal parameters are used to characterize the internal structural properties of the overhead ground wire under the current operating state; a third determination unit is used to determine the detection result of the broken strand fault of the overhead ground wire based on the current modal parameters and the standard modal parameters, wherein the standard modal parameters are the modal parameters of the vibration signal generated when the overhead ground wire is in normal operating state, and the detection result is used to indicate that there is a broken strand fault in the overhead ground wire, or the detection result is used to indicate that there is no broken strand fault in the overhead ground wire.

[0014] According to another aspect of an embodiment of the present invention, a computer-readable storage medium is also provided, the computer-readable storage medium including a stored program, wherein when the program is executed by a processor, the device where the storage medium is located is controlled to execute the method for detecting a broken strand fault of an overhead ground wire in an embodiment of the present invention.

[0015] According to another aspect of the embodiment of the present invention, a processor is provided, which is used to run a program, wherein when the program is run, the method for detecting a broken strand fault of an overhead ground wire in the embodiment of the present invention is executed.

[0016] According to another aspect of the embodiments of the present invention, a computer program product is provided, which includes computer instructions, and when the computer instructions are executed by a processor, the method for detecting a broken strand fault of an overhead ground wire in the embodiments of the present invention is implemented.

[0017] In an embodiment of the present invention, by collecting the vibration signal generated by the overhead ground wire at a fixed point, the dynamic response of the ground wire under external excitation can be reflected in real time. The historical response matrix and the future response matrix are constructed based on the vibration signal, which can not only understand the dynamic characteristics of the ground wire based on past behavior, but also predict its future response mode. This dual-matrix construction strategy combining history and prediction greatly enhances the foresight and responsiveness of fault identification. Based on the historical response matrix and the future response matrix, the covariance matrix of the vibration signal is determined. The covariance matrix not only captures the random fluctuation characteristics of the vibration signal, but also reflects the inherent pattern of the ground wire structure. This analysis method that integrates data statistics and physical modalities ensures the accuracy and reliability of modal parameter identification. The current modal parameters determined according to the covariance matrix are compared with the standard modal parameters, and any structural changes beyond the normal range can be accurately located, especially minor damage such as broken strands of solid wires. This comparative analysis based on modal parameters enhances the sensitivity and specificity of fault identification, can discover potential problems at a very early stage, and improves the accuracy of detecting broken strand faults of overhead ground wires, thereby solving the technical problem of inaccurate detection of broken strand faults of overhead ground wires. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0019] Figure 1 is a flow chart of a method for detecting a broken strand fault of an overhead ground wire according to an embodiment of the present invention;

[0020] Figure 2 is a flow chart of another method for detecting a broken strand fault of an overhead ground wire according to an embodiment of the present invention.

[0021] Figure 3 is a schematic diagram of a state space model according to an embodiment of the present application;

[0022] Figure 4 It is a schematic diagram of a device for detecting a broken strand fault of an overhead ground wire according to an embodiment of the present invention. DETAILED DESCRIPTION

[0023] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0024] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, functional component or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, functional components or devices.

[0025] Example 1

[0026] According to an embodiment of the present invention, an embodiment of a method for detecting a broken strand fault of an overhead ground wire is provided. It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and although a logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0027] Figure 1 is a flow chart of a method for detecting a broken strand fault of an overhead ground wire according to an embodiment of the present invention. Figure 1 As shown, the method may include the following steps:

[0028] Step S101, collecting vibration signals generated by the overhead ground wire at a fixed point.

[0029] In the technical solution provided in the above step S101 of the present invention, the vibration signal is used to characterize the instant response result of the overhead ground wire under the external excitation. The overhead ground wire will be subjected to various external excitations during operation, such as wind, lightning strikes, temperature changes, etc. These excitations will cause it to produce a specific vibration response. The vibration signal can directly reflect the physical and mechanical state of the overhead ground wire. Any structural damage, such as broken strands, will cause changes in the vibration characteristics. The fixed point is used to indicate the location of the tower that fixes the overhead ground wire.

[0030] In this embodiment, in order to accurately capture the vibration response of the overhead ground wire, acceleration sensors are usually installed at the fixed points of the tower. These sensors can monitor and record the vibration acceleration of the ground wire in real time to form time series data, i.e., vibration signals. The fixed points of the towers are selected as the collection locations because the connection points between the ground wire and the towers are the key locations for detecting changes in the structural state, and can more accurately reflect the vibration characteristics of the ground wire.

[0031] Step S102: at least establishing a historical response matrix and a future response matrix based on the vibration signal.

[0032] In the technical solution provided in the above step S102 of the present invention, the historical response matrix is ​​used to characterize the dynamic response characteristics of the overhead ground wire in the historical stage, and the future response matrix is ​​used to predict the dynamic response characteristics of the overhead ground wire in the future stage.

[0033] In this embodiment, the historical response matrix contains the dynamic response characteristics of the vibration signal in the historical stage, that is, the changes in the signal over a period of time in the past. These data provide a record of the dynamic behavior of the overhead ground wire at historical time points after being stimulated by external factors. The construction of the historical response matrix helps to identify patterns and trends in the vibration signal and provide a basis for the calculation of subsequent modal parameters. The future response matrix focuses on the dynamic response characteristics of the vibration signal in the future stage. It should be noted that the "future" here does not mean predicting the response at future time points, but refers to building a matrix that can reflect the future dynamic behavior of the structure based on current and historical data. The design of the future response matrix is ​​to capture information related to future dynamic responses in the vibration signal, which helps to understand the possible response of the structure at subsequent time points, and then more comprehensively evaluate the dynamic characteristics of the structure.

[0034] Optionally, after collecting the vibration signals of the overhead ground wire at a fixed point, these signals are usually stored in the form of a time series, and each data point corresponds to the vibration acceleration at a specific moment. Before performing modal analysis, these time series data need to be preprocessed to eliminate noise and unnecessary interference to ensure the accuracy of subsequent analysis. After preprocessing the collected vibration signals, the preprocessed vibration signals can be used to construct a historical response matrix and a future response matrix.

[0035] Optionally, after obtaining the historical response matrix and the future response matrix, the historical response matrix and the future response matrix can be used to jointly construct a Hankel matrix. Through the Hankel matrix, we can use the random subspace method to identify the modal parameters.

[0036] In this step, by establishing a historical response matrix and a future response matrix, the complete dynamic response information of the overhead ground wire can be obtained from the vibration signal.

[0037] Step S103: determining the covariance matrix of the vibration signal based on the historical response matrix and the future response matrix.

[0038] In the technical solution provided in the above step S103 of the present invention, the covariance matrix is ​​used to characterize the statistical characteristics of the vibration signal.

[0039] In this embodiment, the covariance matrix is ​​a matrix used in statistics to describe the degree of linear dependence between multidimensional random variables. The covariance matrix can be used to understand the correlation between different sampling points in the vibration signal. In the context of fault identification of broken overhead ground wires, the covariance matrix can reflect the statistical characteristics of the vibration signal changing over time, including the autocorrelation and cross-correlation of the signal.

[0040] Optionally, the calculation of the covariance matrix depends on the historical response matrix and the future response matrix. The data in the historical matrix and the future matrix can obtain the covariance of the output data by calculating the autocorrelation and cross-correlation of the path. In the random subspace method, this process involves the construction of two Toeplitz matrices, where the Toeplitz matrix is ​​a special form of matrix whose diagonal elements are constant. Through these two matrices, multiple blocks of the covariance matrix of the output data can be calculated to obtain the entire covariance matrix.

[0041] Optionally, the covariance matrix reveals the autocorrelation and cross-correlation characteristics of the vibration signal at different time delays, which is crucial for understanding the dynamic behavior of the overhead ground wire. By analyzing the characteristics of the covariance matrix, patterns and structures in the signal can be identified, which helps to understand the modal characteristics of the overhead ground wire. Even a tiny broken strand can leave a statistical trace in the signal.

[0042] Optionally, after the covariance matrix is ​​determined, the covariance matrix will serve as the basis for calculating the state matrix A and the output matrix C in the subsequent steps. The state matrix A and the output matrix C are key elements for identifying modal parameters in the random subspace algorithm, and their accurate calculation depends on high-quality covariance matrix data.

[0043] Step S104: determining current modal parameters of the vibration signal based on the covariance matrix.

[0044] In the technical solution provided in the above step S104 of the present invention, the current modal parameters are used to characterize the internal structural properties of the overhead ground wire in the current operating state.

[0045] In this embodiment, after obtaining the covariance matrix, the random subspace identification for output-COVar iance (SSI-COV) technology in the random subspace method can be used. Based on the state space model of the system, the modal parameters of the system are extracted from the statistical characteristics of the output data. The modal parameters include natural frequency, damping ratio and modal vibration shape. These modal parameters are key parameters for describing the inherent characteristics of the structure and can reflect the internal structural properties of the overhead ground wire under the current operating state. Optionally, by performing singular value decomposition on the Toep litz matrix, the state matrix A and the output matrix C can be obtained, and then the modal parameters related to the vibration characteristics of the overhead ground wire can be solved.

[0046] Optionally, the modal parameters obtained in the random subspace method provide important information about the health of the overhead ground wire structure. The natural frequency reflects the natural frequency of the structure's vibration, the damping ratio describes the degree of attenuation of the vibration energy, and the modal vibration shape represents the deformation mode of the overhead ground wire when it vibrates. When there is damage to the overhead ground wire, such as a broken strand, these modal parameters will change. By monitoring the changes in these parameters, it can be determined whether the ground wire is in a normal state.

[0047] Optionally, after obtaining the current modal parameters, they can be compared with the standard modal parameters of the ground wire in an undamaged state. If there is a significant difference between the current modal parameters and the standard modal parameters, this may indicate that the overhead ground wire has suffered damage, such as a broken strand. By observing the position change of the modal parameters on the stability diagram, it can be further confirmed whether the difference is caused by real structural damage, thereby realizing the identification of the overhead ground wire broken strand fault.

[0048] In this step, the current modal parameters are determined based on the covariance matrix, and then the health status of the overhead ground wire can be monitored in real time according to the current modal parameters, which is of great significance for preventing and promptly repairing potential broken strand damage and ensuring the safe operation of the power system.

[0049] Step S105: Determine the detection result of the broken strand fault of the overhead ground wire based on the current modal parameters and the standard modal parameters.

[0050] In the technical solution provided in the above step S105 of the present application, the standard modal parameters are the modal parameters of the vibration signal generated when the overhead ground wire is in normal operation, and the detection result is used to indicate that there is a broken strand fault in the overhead ground wire, or the detection result is used to indicate that there is no broken strand fault in the overhead ground wire.

[0051] In this embodiment, modal parameters are key indicators for describing the dynamic characteristics of the structure, including natural frequency, damping ratio and modal vibration type. These parameters can reveal the natural vibration characteristics of the structure, and when the structure is intact, the modal parameters remain relatively stable. Optionally, when the overhead ground wire is operating normally, a set of stable modal parameters, i.e., standard modal parameters, can be obtained by performing modal analysis on the vibration signal. These parameters are used as a reference for the health state, and are usually data obtained by performing modal analysis on the ground wire at the initial stage of ground wire installation or during regular maintenance. The recording and analysis of standard modal parameters provide a comparative benchmark for subsequent fault detection. During the detection process, the vibration signal collected in real time by the acceleration sensor is used to calculate the current modal parameters using the random subspace method (Subspace System Identification, referred to as SSI). This parameter reflects the instantaneous vibration characteristics of the overhead ground wire at the time of detection, including the natural frequency, damping ratio and modal vibration type at that time.

[0052] Optionally, after obtaining the current modal parameters, the next step is to compare them with the standard modal parameters. The purpose of the comparative analysis is to identify whether the dynamic characteristics of the overhead ground wire have changed significantly, which may be caused by structural damage such as broken strands. The comparison process usually includes calculating the difference or deviation between the current modal parameters and the standard modal parameters, such as the change in frequency and damping ratio.

[0053] Optionally, if it is found that some values ​​in the current modal parameters are significantly different from the standard modal parameters and exceed a preset threshold, this may indicate that a strand break fault has occurred in the overhead ground wire. For example, a decrease in the natural frequency or an increase in the damping ratio is usually associated with structural damage, especially when the ground wire is broken, its mass distribution and stiffness will change, thereby affecting the vibration characteristics.

[0054] Optionally, based on the results of the comparative analysis, if the difference between the current modal parameters and the standard modal parameters is within the threshold range, that is, the change is not significant, then it can be determined that there is no broken strand fault in the overhead ground wire, indicating that the structure of the ground wire remains in a normal operating state. On the contrary, if the difference exceeds the threshold, the detection result will indicate that there is a broken strand fault in the overhead ground wire.

[0055] In this step, by comparing and analyzing the current modal parameters with the standard modal parameters, it is possible to effectively identify whether the overhead ground wire has structural damage such as broken strands. This process is based on modal analysis of vibration signals and combines the principles of structural dynamics. It provides a scientific basis for the monitoring and maintenance of the power system, and helps to ensure the safe and stable operation of the power network.

[0056] In the above steps S101 to S104, by collecting the vibration signal generated by the overhead ground wire at the fixed point, the dynamic response of the ground wire under external excitation can be reflected in real time. The historical response matrix and the future response matrix are constructed based on the vibration signal, which can not only understand the dynamic characteristics of the ground wire based on past behavior, but also predict its future response mode. This dual-matrix construction strategy combining history and prediction greatly enhances the foresight and responsiveness of fault identification. Based on the historical response matrix and the future response matrix, the covariance matrix of the vibration signal is determined. The covariance matrix not only captures the random fluctuation characteristics of the vibration signal, but also reflects the inherent pattern of the ground wire structure. This analysis method that integrates data statistics and physical modalities ensures the accuracy and reliability of modal parameter identification. By comparing the current modal parameters determined according to the covariance matrix with the standard modal parameters, any structural changes beyond the normal range can be accurately located, especially minor damage such as broken solid wire strands. This comparative analysis based on modal parameters enhances the sensitivity and specificity of fault identification, can discover potential problems at a very early stage, and improves the accuracy of detecting broken strand faults in overhead ground wires, thereby solving the technical problem of inaccurate detection of broken strand faults in overhead ground wires.

[0057] The above method of this embodiment is further introduced below.

[0058] As an optional implementation method, step S102, based on the vibration signal, at least a historical response matrix and a future response matrix are established, including: arranging the vibration signals in order of collection time to obtain a time series; constructing a historical response matrix based on a first number of row data in the time series, and constructing a future response matrix based on a second number of column data in the time series, wherein the first number is greater than the second number.

[0059] In this embodiment, the collected vibration signals are arranged in chronological order to form a time series. Each item of the time series data corresponds to the vibration acceleration value recorded by the acceleration sensor at a specific time point. After the time series is formed, two parts of data need to be extracted from the time series to construct a historical response matrix and a future response matrix. The historical response matrix is ​​composed of a first number of row data in the time series, which reflects the dynamic behavior of the structure in the past; and the future response matrix is ​​composed of a second number of column data in the time series, which is used to predict the dynamic behavior of the structure in the future. It is worth noting that the first number is usually larger than the second number. This is because historical data usually requires a longer time period to fully reflect the dynamic characteristics of the structure, while future predictions may be based on data within a shorter time window.

[0060] Optionally, the historical response matrix and the future response matrix are integrated in the order of the time series to form a Hankel matrix. The Hankel matrix is ​​a special matrix whose main characteristic is that the element values ​​of the matrix are constants along the diagonal direction. In the random subspace method, the Hankel matrix is ​​used to capture the autocorrelation and cross-correlation characteristics of the signal, thereby extracting the dynamic modal information of the system (overhead ground wire). The construction of this matrix fully considers the time-varying characteristics of the signal, integrates the information of past and future responses, and is an important input for subsequent modal parameter identification.

[0061] Optionally, when constructing the Hankel matrix, a larger first number (number of rows) means a longer historical data window, which usually improves the accuracy of modal identification, but also increases the complexity and time consumption of the calculation. The second number (number of columns) is usually smaller and is used to construct the future response matrix, which is crucial for predicting future dynamic behavior. Choosing the appropriate parameter value requires finding a balance between accuracy and efficiency.

[0062] For example, the collected vibration signals are arranged in a Hankel matrix according to the time series (establishing a Hankel matrix), and the Hankel matrix contains 2i blocks of rows and j columns. The Hankel matrix can be divided into two parts: the past response matrix (2i blocks of rows) and the future response matrix (j columns), with Y f With Y p Refers to, its expression is:

[0063]

[0064] In the formula, y k is the output at a certain moment (the data collected by the acceleration sensor), i, j are the row and column values ​​of the Hanke l matrix.

[0065] In addition, there is another partitioning method for the Hankel matrix, which can be expressed as:

[0066]

[0067] It can be seen from the above formula that when the response signal length is s, the size of the Hankel matrix should satisfy s=2i+j-1, and based on usage experience, when j and i are selected to satisfy formula (3) and formula (4), the calculation efficiency will be higher.

[0068] j>20i (3)

[0069]

[0070] Optionally, the rows and columns of the Hankel matrix are pre-set parameters. The larger the value i is, the greater the calculation accuracy of the random subspace is, and the longer the calculation time is. The selection can be made according to actual conditions.

[0071] Through this step, the overhead ground wire broken strand fault identification method can extract key dynamic information from the original vibration signal, laying a solid foundation for subsequent modal analysis and fault detection. The construction and use of the Hankel matrix is ​​an important part of this process. It not only reflects the statistical characteristics of the signal, but also provides the necessary data structure for the accurate identification of modal parameters.

[0072] As an optional implementation method, step S104, based on the covariance matrix, determines the current modal parameters of the vibration signal, including: constructing a first Toeplitz matrix and a second Toeplitz matrix based on the covariance matrix, wherein the first Toeplitz matrix is ​​used to characterize the autocorrelation of the dynamic response of the overhead ground line in the historical stage, and the second Toeplitz matrix is ​​used to characterize the autocorrelation of the dynamic response of the overhead ground line in the future stage; based on the first Toeplitz matrix and the second Toeplitz matrix, determines the current modal parameters of the vibration signal.

[0073] In this embodiment, the first Toeplitz matrix is ​​constructed based on the historical response signal, which can reflect the dynamic response autocorrelation of the overhead ground wire in the past time period. Specifically, the first Toeplitz matrix extracts the part of the covariance matrix associated with the historical response data and arranges it in the form of a Toeplitz matrix. The characteristic of the Toeplitz matrix is ​​that the elements of each row and column are the same along the diagonal direction, which makes the structure of the matrix very suitable for processing and analyzing the autocorrelation characteristics of time series data.

[0074] Optionally, the second Toeplitz matrix focuses on the autocorrelation of the future response signal. It is constructed based on the part of the covariance matrix associated with the predicted future response data. It should be noted that the "future" here does not refer to the actual future time point, but to the subsequent time point relative to the historical response data. The construction of the second Toeplitz matrix also follows the rules of the Toeplitz matrix. In this way, the dynamic response characteristics of the ground line at subsequent time points can be analyzed and predicted.

[0075] Optionally, the current modal parameters of the vibration signal may be determined by using the first Toeplitz matrix and the second Toeplitz matrix.

[0076] Through this step, the first Toeplitz matrix and the second Toeplitz matrix are constructed based on the covariance matrix, which is an important step in extracting modal parameters in the overhead ground wire broken strand fault identification method. Through this series of matrix operations, key information reflecting the health status of the ground wire can be mined from the original vibration signal, providing a scientific basis for real-time monitoring and accurate diagnosis of faults.

[0077] As an optional implementation, based on the first Toeplitz matrix and the second Toeplitz matrix, the current modal parameters of the vibration signal are determined, including: performing singular value decomposition on the second Toeplitz matrix to obtain a singular value decomposition result; based on the singular value decomposition result and the first Toeplitz matrix, determining a discrete state matrix and an observation mapping matrix; based on the discrete state matrix and the observation mapping matrix, determining the current modal parameters.

[0078] In this embodiment, singular value decomposition is a matrix decomposition method used to reveal the structure and characteristics of the matrix, and is particularly suitable for processing noisy data. Here, the second Toeplitz matrix is ​​subjected to singular value decomposition to extract the main information in the matrix, reduce the influence of noise, and provide clean data for the subsequent identification of modal parameters.

[0079] Optionally, the second Toeplitz matrix is ​​decomposed into the product of three matrices, namely, a left singular vector matrix, a diagonal singular value matrix, and the transpose of a right singular vector matrix, wherein the diagonal singular value matrix contains the singular values ​​of the matrix, and the order of the magnitude of these singular values ​​reflects the importance of the information in the matrix.

[0080] Optionally, in the random subspace method, the discrete state matrix describes the law of change of the system state over time. For the overhead ground wire, it reflects the dynamic characteristics of the ground wire state evolving over time. Through the singular value decomposition results of the second Toeplitz matrix and the specific operation of the first Toeplitz matrix, the discrete state matrix can be solved, and then the internal structural properties of the overhead ground wire can be analyzed. The observation mapping matrix links the system state and the output signal, that is, the vibration signal collected by the acceleration sensor. In modal parameter identification, the observation mapping matrix helps to understand how the system state is observed and is a bridge connecting the model and the actual measurement data. The calculation of the observation prediction matrix also depends on the singular value decomposition results and the first Toeplitz matrix. Through this matrix, the model prediction can be compared with the actual observation data.

[0081] Optionally, the modal parameters include natural frequency, damping ratio and modal vibration shape, which are key parameters for characterizing the inherent characteristics of the system in structural dynamics analysis. These modal parameters can be obtained by performing eigenvalue decomposition on the discrete state matrix.

[0082] Optionally, the eigenvalue decomposition result of the discrete state matrix provides information about the system's natural frequency and damping ratio. The real and imaginary parts of the eigenvalues ​​are related to the damping ratio and natural frequency, respectively, and are important indicators for assessing the health of overhead ground wires.

[0083] Optionally, the modal vibration shape describes the shape change of the overhead ground wire when it vibrates, which is calculated from the observation mapping matrix and the corresponding eigenvector. The modal vibration shape can reflect the physical structure and damage state of the ground wire, which is the key information for the broken strand fault diagnosis.

[0084] Through the above steps, by performing complex operations on the first Toeplitz matrix and the second Toeplitz matrix, including singular value decomposition and eigenvalue decomposition, the current modal parameters of the vibration signal can be accurately determined, and then the health status of the overhead ground wire can be evaluated based on these parameters, and the broken wire fault can be discovered and repaired in time to ensure the safe operation of the power system.

[0085] As an optional implementation method, current modal parameters are determined based on a discrete state matrix and an observation mapping matrix, including: performing eigenvalue decomposition on the discrete state matrix to obtain an eigenvalue decomposition result, wherein the eigenvalue decomposition result includes at least eigenvalues ​​and eigenvectors; determining the vibration frequency and damping ratio of the overhead ground wire based on the eigenvalues, and determining the vibration form of the overhead ground wire in different modes based on the eigenvectors and the observation mapping matrix; and determining the vibration frequency of the overhead ground wire, the damping ratio of the overhead ground wire, and the vibration form of the overhead ground wire in different modes as the current modal parameters.

[0086] In this embodiment, the eigenvalue decomposition of the discrete state matrix is ​​the first step to obtain the modal parameters. Eigenvalue decomposition is an important concept in linear algebra, which decomposes the discrete state matrix into eigenvalues ​​and corresponding eigenvectors, where the eigenvalues ​​represent the expansion and contraction factors of the matrix, and the eigenvectors represent the expansion and contraction directions under the action of the matrix. In the modal analysis of overhead ground wires, eigenvalue decomposition can reveal the inherent characteristics of the system, including key parameters such as vibration frequency and damping ratio.

[0087] Optionally, complex eigenvalues ​​can be extracted from the eigenvalue decomposition results, which contain information about the vibration frequency and damping ratio of the overhead ground wire. The vibration frequency is a discrete representation of the natural frequency, which determines the periodicity of the vibration of the overhead ground wire, while the damping ratio reflects the degree of attenuation of the vibration energy. Through the mathematical conversion of discrete eigenvalues ​​to continuous eigenvalues, the vibration frequency and damping ratio of the overhead ground wire can be calculated from the eigenvalues ​​of the discrete state matrix.

[0088] Optionally, the modal vibration shape is a parameter that describes the vibration shape of the overhead ground wire in different modes, reflecting the actual displacement and deformation of each part of the overhead ground wire when it vibrates. The modal vibration shape can be calculated by combining the eigenvector with the observation mapping matrix. The observation mapping matrix describes the mapping relationship from the state space to the output space, that is, how the state vector of the overhead ground wire is mapped to the actual observation value of the acceleration sensor. Combining the eigenvector and the observation mapping matrix, the actual vibration shape of the overhead ground wire in different modes can be calculated.

[0089] Optionally, the vibration frequency, damping ratio and modal vibration shape calculated above are combined to form the current modal parameters of the overhead ground wire. These parameters are key indicators for describing the dynamic characteristics of the overhead ground wire in the current operating state, and can reflect whether the ground wire has suffered damage such as broken strands.

[0090] Optionally, after determining the current modal parameters, the current modal parameters can be compared with standard modal parameters. It should be noted that the standard modal parameters are derived based on the vibration characteristics of the ground wire under normal operating conditions. By comparison, if it is found that there is a significant difference between the current modal parameters and the standard parameters, this may indicate that the structural health of the overhead ground wire has changed, and the possibility of faults such as broken strands has increased.

[0091] For example, if the vibration frequency in the current modal parameters decreases, the damping ratio increases, or the modal vibration shape changes, these are typical characteristics of a broken overhead ground wire. Therefore, through comparative analysis, it is possible to determine whether there is a broken overhead ground wire fault, thereby providing timely and accurate information for maintenance and troubleshooting of the power system.

[0092] Through this step, the process of determining the current modal parameters based on the discrete state matrix and the observation mapping matrix involves eigenvalue decomposition, calculation of vibration frequency and damping ratio, and determination of modal vibration shape. This series of mathematical processing can deeply analyze the vibration signal and reveal the internal dynamic characteristics of the overhead ground wire, which is of great significance for fault identification and health monitoring.

[0093] As an optional implementation, step S105, based on the current modal parameters and the standard modal parameters, determines the detection result of the broken strand fault of the overhead ground wire, including: constructing a stability diagram based on the current modal parameters, wherein the stability diagram is used to characterize the stability of the modal parameters; identifying abnormal modal parameters in the stability diagram, and removing the abnormal modal parameters from the current modal parameters to obtain the current true mode; based on the current true modal parameters and the standard modal parameters, determines the detection result of the broken strand fault of the overhead ground wire.

[0094] In this embodiment, the stability diagram is a commonly used graphical representation method in modal parameter identification, which can intuitively show the stability of modal parameters in different analyses. On the stability diagram, each point represents the result of a modal parameter identification. Through multiple identifications, the distribution of points on the stability diagram can be observed to judge the stability and consistency of the modal parameters. Specifically, if the modal parameters remain consistent in multiple analyses, then on the stability diagram, the corresponding points will be gathered at or near the same position, which indicates that the modal parameters are stable and can reflect the true state of the structure.

[0095] Optionally, abnormal modal parameters generally refer to modal parameters that deviate far from other points on the stability diagram, which may be caused by data noise, algorithm errors, or real structural damage. The process of identifying abnormal modal parameters includes comparing the current modal parameters with previously identified parameters, and using statistical methods or machine learning algorithms to identify those parameters that deviate from the normal distribution. For example, a dynamic clustering method can be used to set a threshold to determine which modal parameter points have a significant distance difference from other points, and these points may be abnormal.

[0096] Optionally, after the abnormal modal parameters are identified from the steady-state diagram, they are removed from the current modal parameters to reduce their impact on subsequent analysis. This step is critical to ensure the accuracy and reliability of the analysis. After removing the abnormal values, the remaining modal parameters are called "current true modes", which are closer to the true dynamic characteristics of the overhead ground wire under the current operating state.

[0097] Optionally, the current true modal parameters are compared with the standard modal parameters to determine the broken strand fault detection result of the overhead ground wire. The standard modal parameters are the modal parameters measured when the overhead ground wire is in normal operation, usually obtained at the beginning of installation or during maintenance. By comparing the current true modal parameters with the standard modal parameters, any significant differences can be detected. If the modal parameters such as the natural frequency, damping ratio or mode vibration shape have changed significantly compared with the standard value, this may indicate that the overhead ground wire has a broken strand or other damage. On the contrary, if the modal parameters remain within the standard range, it can be considered that the overhead ground wire currently has no obvious damage.

[0098] Optionally, based on the above comparative analysis, a judgment can be made as to whether there is a strand break fault in the overhead ground wire. If the detected modal parameters are significantly different from the standard modal parameters, especially the change in the natural frequency or damping ratio, this will usually serve as a significant indicator of a strand break fault. At this time, the test result will indicate the presence of a strand break fault. Conversely, if the modal parameters match the standard values, the test result will indicate that the overhead ground wire is currently in good operating condition and there is no strand break fault.

[0099] Through the above steps, the overhead ground wire broken strand fault identification method based on random subspace can accurately judge the health status of the overhead ground wire, timely discover potential structural damage, and provide strong guarantee for the safe operation of the power system. This process not only reflects the in-depth understanding and analysis of modal parameters, but also integrates knowledge from multiple fields such as signal processing, statistics and structural dynamics. It is a typical application of modern fault diagnosis technology.

[0100] As an optional implementation method, step S105, based on the current true modal parameters and the standard modal parameters, determines the detection result of the broken strand fault of the overhead ground wire, including: comparing the current true modal parameters with the standard modal parameters to obtain a comparison result; in response to the comparison result indicating that the difference between the current true modal parameters and the standard modal parameters is greater than or equal to a preset threshold, determining that there is a broken strand fault in the overhead ground wire; in response to the comparison result indicating that the difference between the current true modal parameters and the standard modal parameters is less than the preset threshold, determining that there is no broken strand fault in the overhead ground wire.

[0101] In this embodiment, after completing the automatic recognition process of the modal parameters, the current real modal parameters reflecting the current dynamic characteristics of the overhead ground wire are obtained, including the natural frequency, damping ratio and modal vibration shape, etc. Based on this, the standard modal parameter record under the normal operating conditions of the overhead ground wire can be used. By comparing the two sets of parameters one by one, the difference of each parameter can be calculated to form a comparison result. The comparison result usually includes a set of differences, which represents the degree of difference between the current modal parameters and the standard modal parameters.

[0102] Optionally, in order to determine whether this difference is sufficient to indicate a broken strand fault, a preset threshold needs to be set in advance. This threshold is determined based on historical data and professional knowledge, and represents the maximum possible deviation of the structural modal parameters in a healthy state and a damaged state. The selection of the preset threshold is critical. A threshold that is too low may cause normal fluctuations to be misjudged as a fault, while a threshold that is too high may prevent the actual fault from being discovered in time.

[0103] Optionally, the comparison between the difference indicated by the comparison result and the preset threshold is the key to determining whether the overhead ground wire is broken. If the difference in any one or more of the natural frequency, damping ratio or modal vibration type is greater than or equal to the preset threshold, this indicates that the dynamic characteristics of the ground wire have changed significantly, which may be caused by structural damage caused by broken strands. At this point, it can be determined that the overhead ground wire has a broken strand fault. On the contrary, if the difference in all modal parameters is less than the preset threshold, it means that the dynamic characteristics of the ground wire have not changed beyond the normal fluctuation range, and it can be considered that the overhead ground wire is currently in a healthy state and there is no broken strand fault.

[0104] Optionally, based on the comparison between the current real modal parameters obtained by real-time monitoring and the standard modal parameters, real-time monitoring of overhead ground wire broken strand faults can be achieved. Once the detected modal parameter difference exceeds the preset threshold, the system can immediately issue an early warning and initiate the corresponding fault handling process, such as dispatching maintenance personnel for on-site inspection and repair, thereby avoiding power system operation safety problems caused by overhead ground wire broken strands.

[0105] This step is to compare the current real modal parameters of the overhead ground wire with the standard modal parameters and make judgments based on the preset thresholds, which is an effective method to achieve real-time identification and early warning of broken wire faults. This process not only relies on accurate modal parameter identification technology, but also requires reasonable threshold settings and comprehensive analysis capabilities to ensure the accuracy and timeliness of fault judgment.

[0106] The technical solution of the embodiment of the present invention is illustrated below in conjunction with preferred implementation modes.

[0107] At present, overhead ground wires are important protective facilities for high-voltage transmission lines and are one of the most basic and effective lightning protection measures for lines. Ground wires are mostly in harsh line conditions and meteorological conditions. Due to factors such as lightning strikes, line vibrations, and device wear, the outer layer may be broken or scattered, which will reduce the electrical and mechanical properties of the overhead ground wires, affect the safe operation of the transmission lines below, and even cause line flashover discharges, thereby causing large-scale power outages. Therefore, it is necessary to identify the faults of overhead ground wires in a timely manner, repair the broken ground wires, and prevent greater problems. However, the existing algorithms are inefficient and there are many problems that cannot detect the location of the faults. With the reform of the power system and the improvement of the marketization of power operations, traditional fault detection algorithms have been unable to meet the needs of modern power system reliability monitoring. In summary, it is necessary to adopt a new fault identification algorithm to solve this problem.

[0108] The embodiment of the present invention proposes a method for detecting a broken strand fault of an overhead ground wire. An acceleration sensor collects acceleration data of a pole tower, establishes a Hankel matrix and a state space model of conductor structure vibration based on the collected data, and outputs a covariance matrix; divides the Hankel matrix to establish a past response matrix and two future response parts, and establishes two Toeplitz matrices; performs singular value decomposition on one of the Toeplitz matrices, and calculates it together with the other Toeplitz matrix to obtain a random discrete state system matrix; solves the modal parameters of the structure through the discrete state matrix and the output matrix; automatically identifies the modal parameters, uses a stability diagram, extracts stable points of the modal parameters, and removes false poles; obtains actual modal parameters, and compares the positions of the actual modal parameters on the stability diagram to determine whether there is a fault. That is, in the present application, a method for identifying a broken strand fault of an overhead ground wire based on a random subspace solves the modal parameters of the structure, and realizes real-time monitoring of the broken strand of the overhead ground wire by comparing the states of the modal parameters on the stability diagram, thereby better promoting the safe and stable operation of the power grid.

[0109] Next, the random subspace identification algorithm is introduced.

[0110] Random subspace identification is a method for identifying the modal parameters of system structures, and modal analysis can be performed using environmental excitation signals. The modal parameter uncertainty quantification method of random subspace identification can effectively estimate the variance of modal parameters, but because it needs to explicitly represent the Jacobian matrix when calculating each intermediate variable, the matrix operation dimension is high and the calculation efficiency is low. For this reason, the application adopts a covariance-based random subspace identification method (SSI-COV), and the modal parameter identification of this method has the advantages of strong robustness and high precision, and is widely used in structural working modal analysis. The random subspace method based on covariance is a random subspace method that calculates the structural modal parameters by solving the covariance of the output data.

[0111] Next, the method for detecting a broken strand fault of an overhead ground wire in the present application is further introduced with examples.

[0112] Figure 2 is a flow chart of a method for detecting a broken strand fault of an overhead ground wire according to an embodiment of the present invention. Figure 2 As shown, the method comprises the following steps:

[0113] Step S201, collecting vibration response data of the overhead ground wire.

[0114] In this embodiment, the acceleration data of the pole tower is collected by an acceleration sensor.

[0115] Step S202, establishing a Hankel matrix.

[0116] In this embodiment, the collected data is arranged in a Hankel matrix (building a Hankel matrix), which includes 2i blocks of rows and j columns, and each block consists of l rows (l is the number of output channels). The matrix is ​​usually divided into two parts: the "past matrix" and the "future matrix", with Y f With Y p It refers to that its expression is the above formula (1) or formula (2).

[0117] Step S203: Establish a state space model of the conductor structure vibration and output a covariance matrix.

[0118] In this embodiment, the signals actually collected are all discrete signals. Assuming that the initial collection time is t0, for the discrete time state space system, its dynamic equation is:

[0119]

[0120] Optionally, let the time interval for each data collection be Δt, and each sampling time point be 0, Δt, 2Δt…, kΔt, where k=1, 2, 3…. To express the state equation under discrete state, the time interval in equation (5) can be transformed into a single time interval, let t0=kΔt, t=(k+1)Δt, then equation (5) can be converted to:

[0121]

[0122] After integration, formula (6) can be expressed as:

[0123] x k+1 =Ax k +Bu k (7)

[0124] Then the observation equation can be transformed into:

[0125] y k =Cx k +Du k (8)

[0126] In formula (7) and formula (8), x k is the state vector of the conductor system at time k, u k is the input vector of the conductor system at time k, A is the state matrix, B is the input matrix, C is the output matrix, and D is the transfer coefficient matrix. The expressions of each matrix are shown in equations (9) and (10):

[0127]

[0128] C=C c ,D=D c (10)

[0129] Optionally, the discrete state space model lacks the input of the interference term in the environment, that is, lacks the input of the noise term, and the measurement noise vector v is added to the observation equation and the state equation respectively. k The noise vector w caused by poor structural construction k , we can get the state space model expression and model diagram, as shown in equation (11) and Figure 3 As shown:

[0130] x k+1 =Ax k +Bu k +w k

[0131] y k =Cx k +Du k +v k (11)

[0132] Figure 3 is a schematic diagram of a state space model according to an embodiment of the present application, such as Figure 3 As shown, the coherence between the state equation and the observation equation is demonstrated, that is, the state xk and output yk of the system are associated through the state matrix A and the output matrix C, and the input uk also affects the output yk through the input matrix B and the direct transfer matrix D. Figure 2 In , A is the state matrix, which describes the evolution of the system state over time; B is the input matrix, which describes the impact of the system input on the state; wk is the noise vector related to the system construction difference and environmental excitation, which is assumed to be white noise; uk represents the input of the system, which can be any external excitation that causes the structural response, and yk represents the output of the system, that is, the tower acceleration data collected by the acceleration sensor. The input and output data are the basis for constructing the Hanke l matrix and performing subsequent modal parameter identification.

[0133] Alternatively, in the random subspace method, the noise term is usually assumed to be white noise, where the covariance matrix of the noise term can be expressed as:

[0134]

[0135] In the above formula, E is the mathematical expectation operator; δ pq is the Kroneck delta function (where p and q are arbitrary time points, when p = q, δ pq =1, otherwise δ pq = 0), when the environmental excitation is used as the structural input, since the input signal cannot be measured, it is usually considered that the impact of the environmental excitation is similar to the impact of noise, that is, the structural input term u k and the noise term v k With can k can be combined, and the discrete time state space model expression is obtained as follows:

[0136]

[0137] From the above formula, we can see that both the state equation and the observation equation will excite the term u k Hidden, that is, the state vector of the system that changes over time and the system output vector are only related to the state matrix A and the output matrix C.

[0138] Optionally, in order to obtain the state matrix A and the output matrix C from the output data, it is necessary to further analyze the statistical characteristics of the output data.

[0139] From formula (12), we can know that:

[0140]

[0141] From the discrete time state space model, we know that the input term wk With v k All belong to white noise, that is, the state vector x k With w k 、v k The covariance between is 0, and its expression is:

[0142]

[0143] From the state equation and observation equation, we can know that the output vector of the system consists of three parts: output matrix, state vector and excitation. The covariance of the state vector is:

[0144]

[0145] Then the covariance matrix G between the state vector and the output vector is:

[0146]

[0147] Therefore, the covariance of the output vector is:

[0148]

[0149] In the above formula, i is the time delay value, that is, y k+1 With y k There is a time interval difference of i between them. i is classified and discussed. When i = 0 and i ≠ 0, formula (17) can be transformed into:

[0150]

[0151]

[0152] From the above formula, we can see that when the time delay of the two output vectors is 0 and the time delay is 1, the covariance expression of the two differs by a state matrix A. Based on this principle, the state matrix A can be solved, and then the state matrix A of the continuous-time system can be solved. c According to the relationship among the mass matrix, stiffness matrix and damping matrix in its composition, the modal parameters of the structure can be solved by combining the output matrix.

[0153] Step S204, constructing a covariance matrix.

[0154] In this embodiment, the covariance matrix of the output vector is constructed by using formula (20) to establish a Toep litz matrix, which is expressed as follows:

[0155]

[0156] When the random subspace method assumes a stationary random process, the mathematical expectation of the sample can be expressed by the following formula:

[0157]

[0158] In actual engineering, due to the limited number of measurement points, the estimated value of the output covariance Λ' can be used for calculation, and the calculation formula is:

[0159]

[0160] Step S205, establishing a Toeplitz matrix.

[0161] In this embodiment, by transforming formula (22), we can get:

[0162]

[0163] In the above formula, A is the state matrix; C is the output matrix; G is the covariance matrix; O is the generalized observation matrix; Γ is the extended controllable matrix. It can be deduced from formula (22) that Γ 2|i+1 As shown below:

[0164]

[0165] Optionally, in order to solve the state matrix A and the output matrix C, it is necessary to further perform singular value decomposition on Toep litz, as shown below:

[0166]

[0167] Where S1 is a diagonal matrix with a matrix dimension of n×n, where n is the system order.

[0168] Step S206, solving the state matrix.

[0169] In this embodiment, according to formula (24), the observation matrix O i and the expansion matrix Γ i It can be expressed as:

[0170]

[0171] In the above formula, T s is a non-singular matrix, we can take T s =I, then equation (28) and equation (29) can be transformed into equation (30) and equation (31), and the output matrix C is the first n rows of the observation matrix O.

[0172]

[0173] Combining equation (30) and equation (31), the expression of the state matrix A can be expressed as:

[0174]

[0175] Step S207, calculating modal parameters.

[0176] In this embodiment, in order to obtain the modal parameters, it is necessary to perform eigenvalue decomposition on the state matrix A, and its expression can be expressed as:

[0177] A=ΨΛΨ -1 (33)

[0178] In the above formula, A is a diagonal matrix, which is composed of complex eigenvalues ​​μ i is composed of; ψ is the eigenvector.

[0179] Optionally, the discrete-time state matrix A and the continuous-time state matrix A c The relationship can be converted through formula (34).

[0180]

[0181] In the above formula, μ i is the discrete system eigenvalue; i is the eigenvalue of the continuous system; t is the sampling time interval. The modal vibration shape V in the modal parameters can be calculated by the observation matrix C and the eigenvector ψ, and its formula can be expressed as:

[0182] V=CΨ (35)

[0183] The system eigenvalue, system natural frequency and damping ratio expressions can be expressed as:

[0184]

[0185] Then the modal frequency ω i With damping ratio ξ i They can be expressed as:

[0186]

[0187]

[0188] In the above formula, λ l and λ R is the eigenvalue λ i The imaginary and real parts of .

[0189] Step S208: automatic identification of modal parameters.

[0190] In this embodiment, a stability diagram is used to extract stable points of modal parameters and remove false poles.

[0191] Optionally, the sampled breeze vibration signal is constructed into two Hankel matrices with different dimensions. Toeplitz matrices are constructed according to the two matrices, singular value decomposition is performed, and structural modal parameters are extracted.

[0192] Optionally, one of the results is selected as the benchmark and the other is compared with it. According to equation (39), whether the pole is a stable point is determined. If there is a point in the second group such that r ij ≤1, then the point in the first group is a stable point.

[0193]

[0194] In the above formula, W f ,W c ,W φ They represent the weights of natural frequency, damping ratio and modal vibration shape respectively. i corresponds to the first set of modal parameters, and j corresponds to the second set of modal parameters.

[0195] Optionally, for the extreme points calculated from the breeze vibration signal of the conductor, the amount of data is not large, and the dynamic clustering method can be used to classify the extreme points. The specific steps are as follows: First, the extreme points identified by the random subspace are used as samples. Assuming that the number of samples is n, each sample is a class; secondly, a distance threshold is set, the absolute distance between each sample is calculated, and the minimum distance and the distance less than the threshold are selected as a new class. The absolute distance is calculated according to formula (40).

[0196]

[0197] Optionally, the distance between the new categories is calculated, and the categories with the closest distance and less than the threshold are selected for merging again. This process is repeated until the distance is greater than the threshold and the classification is stopped.

[0198] Optionally, in the obtained classification, the number of extreme points in each category is determined, and the combination with more category elements is selected as the real mode according to the model order. The elements in the real mode combination are averaged to obtain the actual mode parameters.

[0199] Step S209, comparing the obtained actual modal parameters with the states on the stability diagram to determine whether there is a fault.

[0200] In the above steps S201 to S209, the random subspace algorithm is used to analyze the vibration signal of the overhead ground wire to realize the broken strand fault identification of the overhead ground wire, improve the fault detection and processing efficiency, and ensure the safe and stable operation of the power system.

[0201] According to an embodiment of the present invention, a device for detecting a strand break fault of an overhead ground wire is also provided. It should be noted that the device for detecting a strand break fault of an overhead ground wire can be used to execute the method for detecting a strand break fault of an overhead ground wire in the embodiment.

[0202] Figure 4 Schematic diagram of a device for detecting a broken strand fault of an overhead ground wire according to an embodiment of the present invention. Figure 4 As shown, the overhead ground wire broken fault detection device 400 may include: a collection unit 401 , an establishment unit 402 , a first determination unit 403 , a second determination unit 404 and a third determination unit 405 .

[0203] The collection unit 401 is used to collect the vibration signal generated by the overhead ground wire at the fixed point, wherein the vibration signal is used to characterize the instant response result of the overhead ground wire under the external excitation.

[0204] Establishing unit 402 is used to establish at least a historical response matrix and a future response matrix based on the vibration signal, wherein the historical response matrix is ​​used to characterize the dynamic response characteristics of the overhead ground wire in the historical stage, and the future response matrix is ​​used to predict the dynamic response characteristics of the overhead ground wire in the future stage.

[0205] The first determining unit 403 is configured to determine a covariance matrix of the vibration signal based on the historical response matrix and the future response matrix, wherein the covariance matrix is ​​used to characterize the statistical characteristics of the vibration signal.

[0206] The second determining unit 404 is used to determine the current modal parameters of the vibration signal based on the covariance matrix, wherein the current modal parameters are used to characterize the internal structural properties of the overhead ground wire in the current operating state.

[0207] The third determination unit 405 is used to determine the detection result of the broken strand fault of the overhead ground wire based on the current modal parameters and the standard modal parameters, wherein the standard modal parameters are the modal parameters of the vibration signal generated when the overhead ground wire is in normal operation, and the detection result is used to indicate that there is a broken strand fault in the overhead ground wire, or the detection result is used to indicate that there is no broken strand fault in the overhead ground wire.

[0208] Optionally, the establishing unit 402 is also used to: arrange the vibration signals in order of collection time to obtain a time series; construct a historical response matrix based on a first number of row data in the time series, and construct a future response matrix based on a second number of column data in the time series, wherein the first number is greater than the second number.

[0209] Optionally, the second determination unit 404 is also used to: construct a first Toeplitz matrix and a second Toeplitz matrix based on the covariance matrix, wherein the first Toeplitz matrix is ​​used to characterize the autocorrelation of the dynamic response of the overhead ground line in the historical stage, and the second Toeplitz matrix is ​​used to characterize the autocorrelation of the dynamic response of the overhead ground line in the future stage; based on the first Toeplitz matrix and the second Toeplitz matrix, determine the current modal parameters of the vibration signal.

[0210] Optionally, the second determination unit 404 is also used to: perform singular value decomposition on the second Toeplitz matrix to obtain a singular value decomposition result; determine a discrete state matrix and an observation mapping matrix based on the singular value decomposition result and the first Toeplitz matrix; and determine current modal parameters based on the discrete state matrix and the observation mapping matrix.

[0211] Optionally, the second determination unit 404 is also used to: perform eigenvalue decomposition on the discrete state matrix to obtain an eigenvalue decomposition result, wherein the eigenvalue decomposition result includes at least eigenvalues ​​and eigenvectors; determine the vibration frequency and damping ratio of the overhead ground wire based on the eigenvalues, and determine the vibration form of the overhead ground wire in different modes based on the eigenvectors and the observation mapping matrix; determine the vibration frequency of the overhead ground wire, the damping ratio of the overhead ground wire, and the vibration form of the overhead ground wire in different modes as current modal parameters.

[0212] Optionally, the third determination unit 405 is also used to: construct a stability diagram based on current modal parameters, wherein the stability diagram is used to characterize the stability of the modal parameters; identify abnormal modal parameters in the stability diagram, and remove the abnormal modal parameters from the current modal parameters to obtain the current true mode; and determine the detection result of the broken strand fault of the overhead ground wire based on the current true modal parameters and the standard modal parameters.

[0213] Optionally, the third determination unit 405 is also used to: compare the current true modal parameters with the standard modal parameters to obtain a comparison result; in response to the comparison result indicating that the difference between the current true modal parameters and the standard modal parameters is greater than or equal to a preset threshold, determine that there is a broken strand fault in the overhead ground wire; in response to the comparison result indicating that the difference between the current true modal parameters and the standard modal parameters is less than a preset threshold, determine that there is no broken strand fault in the overhead ground wire.

[0214] In this embodiment, by collecting the vibration signal generated by the overhead ground wire at the fixed point, the dynamic response of the ground wire under external excitation can be reflected in real time. The historical response matrix and the future response matrix are constructed based on the vibration signal, which can not only understand the dynamic characteristics of the ground wire based on past behavior, but also predict its future response mode. This dual-matrix construction strategy combining history and prediction greatly enhances the foresight and responsiveness of fault identification. Based on the historical response matrix and the future response matrix, the covariance matrix of the vibration signal is determined. The covariance matrix not only captures the random fluctuation characteristics of the vibration signal, but also reflects the inherent pattern of the ground wire structure. This analysis method that integrates data statistics and physical modalities ensures the accuracy and reliability of modal parameter identification. By comparing the current modal parameters determined according to the covariance matrix with the standard modal parameters, any structural changes beyond the normal range can be accurately located, especially minor damage such as solid wire broken strands. This comparative analysis based on modal parameters enhances the sensitivity and specificity of fault identification, can discover potential problems at a very early stage, and improves the accuracy of detecting the broken strand fault of the overhead ground wire, thereby solving the technical problem of inaccurate detection of the broken strand fault of the overhead ground wire.

[0215] According to an embodiment of the present invention, there is further provided a computer-readable storage medium, the storage medium comprising a stored program, wherein the program executes the method for detecting a broken strand fault of an overhead ground wire in the embodiment.

[0216] According to an embodiment of the present invention, a processor is further provided. The processor is used to run a program, wherein the method for detecting a broken strand fault of an overhead ground wire in the embodiment is executed when the program is run.

[0217] According to another aspect of the embodiments of the present invention, a computer program product is provided, which includes computer instructions, and when the computer instructions are executed by a processor, the method for detecting a broken strand fault of an overhead ground wire in the embodiments is implemented.

[0218] The serial numbers of the above embodiments of the present invention are only for description and do not represent the advantages or disadvantages of the embodiments.

[0219] In the above embodiments of the present invention, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0220] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. Among them, the device embodiments described above are only schematic. For example, the division of units can be a logical function division. There may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of units or modules, which can be electrical or other forms.

[0221] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed over multiple units. Some or all of the units may be selected according to actual needs to achieve the purpose of the present embodiment.

[0222] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0223] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent functional component, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software functional component, which is stored in a storage medium and includes several instructions for a computer device (which can be a personal computer, a server or a network device, etc.) to perform all or part of the steps of the methods of each embodiment of the present invention. The aforementioned storage medium includes: U disk, read-only memory (Read-Only Memory, referred to as ROM), random access memory (Random Access Memory, referred to as RAM), mobile hard disk, magnetic disk or optical disk and other media that can store program codes.

[0224] The above are only preferred embodiments of the present invention. It should be pointed out that, for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for detecting a broken strand fault of an overhead ground wire, characterized in that: include: Collecting a vibration signal generated by the overhead ground wire at a fixed point, wherein the vibration signal is used to characterize an instant response result of the overhead ground wire under external excitation; Based on the vibration signal, at least a historical response matrix and a future response matrix are established, wherein the historical response matrix is ​​used to characterize the dynamic response characteristics of the overhead ground wire in the historical stage, and the future response matrix is ​​used to predict the dynamic response characteristics of the overhead ground wire in the future stage; Determining a covariance matrix of the vibration signal based on the historical response matrix and the future response matrix, wherein the covariance matrix is ​​used to characterize statistical characteristics of the vibration signal; Based on the covariance matrix, determining current modal parameters of the vibration signal, wherein the current modal parameters are used to characterize internal structural properties of the overhead ground wire in a current operating state; Based on the current modal parameters and the standard modal parameters, the detection result of the broken strand fault of the overhead ground wire is determined, wherein the standard modal parameters are the modal parameters of the vibration signal generated when the overhead ground wire is in normal operation, and the detection result is used to indicate that the overhead ground wire has a broken strand fault, or the detection result is used to indicate that the overhead ground wire does not have a broken strand fault.

2. The method according to claim 1, characterized in that Based on the vibration signal, at least a historical response matrix and a future response matrix are established, including: Arranging the vibration signals in order of acquisition time to obtain a time series; The historical response matrix is ​​constructed based on a first number of row data in the time series, and the future response matrix is ​​constructed based on a second number of column data in the time series, wherein the first number is greater than the second number.

3. The method according to claim 1, characterized in that: Determining current modal parameters of the vibration signal based on the covariance matrix includes: Constructing a first Toeplitz matrix and a second Toeplitz matrix based on the covariance matrix, wherein the first Toeplitz matrix is ​​used to characterize the autocorrelation of the dynamic response of the overhead ground wire in a historical stage, and the second Toeplitz matrix is ​​used to characterize the autocorrelation of the dynamic response of the overhead ground wire in a future stage; The current modal parameters of the vibration signal are determined based on the first Toeplitz matrix and the second Toeplitz matrix.

4. The method according to claim 3, characterized in that Determining the current modal parameter of the vibration signal based on the first Toeplitz matrix and the second Toeplitz matrix includes: Performing singular value decomposition on the second Toeplitz matrix to obtain a singular value decomposition result; Determine a discrete state matrix and an observation mapping matrix based on the singular value decomposition result and the first Toeplitz matrix; The current modal parameters are determined based on the discrete state matrix and the observation mapping matrix.

5. The method according to claim 4, characterized in that Determining the current modal parameters based on the discrete state matrix and the observation mapping matrix includes: Performing eigenvalue decomposition on the discrete state matrix to obtain an eigenvalue decomposition result, wherein the eigenvalue decomposition result includes at least an eigenvalue and an eigenvector; Determine the vibration frequency and damping ratio of the overhead ground wire based on the eigenvalue, and determine the vibration form of the overhead ground wire in different modes based on the eigenvector and the observation mapping matrix; The vibration frequency of the overhead ground wire, the damping ratio of the overhead ground wire, and the vibration forms of the overhead ground wire in different modes are determined as the current modal parameters.

6. The method according to claim 1, characterized in that Determining a detection result of a broken strand fault of the overhead ground wire based on the current modal parameter and the standard modal parameter includes: Constructing a stability diagram based on the current modal parameters, wherein the stability diagram is used to characterize the stability of the modal parameters; Identifying abnormal modal parameters in the stability diagram, and removing the abnormal modal parameters from the current modal parameters to obtain a current true mode; Based on the current true modal parameters and the standard modal parameters, a detection result of the broken strand fault of the overhead ground wire is determined.

7. The method according to claim 6, characterized in that Determining a detection result of a broken strand fault of the overhead ground wire based on the current real modal parameter and the standard modal parameter includes: Comparing the current true modal parameters with the standard modal parameters to obtain a comparison result; In response to the comparison result indicating that the difference between the current real modal parameter and the standard modal parameter is greater than or equal to a preset threshold, determining that the overhead ground wire has the broken strand fault; In response to the comparison result indicating that the difference between the current true modal parameter and the standard modal parameter is smaller than the preset threshold, it is determined that the overhead ground wire does not have the broken strand fault.

8. A device for detecting a broken strand fault of an overhead ground wire, characterized in that: include: A collection unit, used to collect a vibration signal generated by the overhead ground wire at a fixed point, wherein the vibration signal is used to characterize an instant response result of the overhead ground wire under external excitation; An establishing unit, configured to establish at least a historical response matrix and a future response matrix based on the vibration signal, wherein the historical response matrix is ​​used to characterize the dynamic response characteristics of the overhead ground wire in a historical stage, and the future response matrix is ​​used to predict the dynamic response characteristics of the overhead ground wire in a future stage; a first determining unit, configured to determine a covariance matrix of the vibration signal based on the historical response matrix and the future response matrix, wherein the covariance matrix is ​​used to characterize a statistical characteristic of the vibration signal; A second determining unit, configured to determine current modal parameters of the vibration signal based on the covariance matrix, wherein the current modal parameters are used to characterize internal structural properties of the overhead ground wire in a current operating state; The third determination unit is used to determine the detection result of the broken strand fault of the overhead ground wire based on the current modal parameters and the standard modal parameters, wherein the standard modal parameters are the modal parameters of the vibration signal generated when the overhead ground wire is in normal operation, and the detection result is used to indicate that the overhead ground wire has a broken strand fault, or the detection result is used to indicate that the overhead ground wire does not have a broken strand fault.

9. A computer-readable storage medium, characterized in that: The computer-readable storage medium includes a stored program, wherein when the program is executed by a processor, the device where the storage medium is located is controlled to execute the method according to any one of claims 1 to 7.

10. An electronic device, characterized in that: include: A memory storing an executable program; A processor, configured to run the program, wherein the program executes the method according to any one of claims 1 to 7 when running.

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