A cable defect diagnosis method based on sine pulse segmentation technology

Abstract

The application discloses a cable defect diagnosis method based on a sinusoidal pulse segmentation technology, and the method comprises the following steps: injecting a frequency-increased sinusoidal pulse signal; detecting a cable head-end signal, performing time domain alignment, and obtaining a time-frequency matrix; processing the time-frequency matrix based on a Teager-Kaiser operator, obtaining a sinusoidal pulse energy distribution, and performing time domain segmentation; determining a transfer function of each reflected pulse signal and a corresponding spatial position; determining two impedance mismatch points closest to the head end in the cable and reflection coefficients of the two impedance mismatch points; constructing a multiple reflection transfer function, filtering out sinusoidal pulses corresponding to multiple reflections in the time domain; determining that a spatial position corresponding to a to-be-determined reflected wave first arriving at the cable head end after filtering is a new impedance mismatch point and calculating a reflection coefficient of the new impedance mismatch point; repeating the above steps to determine the new impedance mismatch point until the new impedance mismatch point is the cable tail end and calculating a reflection coefficient of the new impedance mismatch point; and constructing a final cable defect positioning map and a diagnosis map. The method can effectively avoid inherent defects of a traditional traveling wave reflection method.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of cable defect detection, and particularly relates to a cable defect diagnosis method based on sinusoidal pulse segmentation technology. BACKGROUND

[0002] In modern industrial systems, cables bear the role of information and power transmission, and their importance is self-evident. However, due to the needs of industrial production, cables are often affected by harsh environments during operation, such as heat, electricity, radiation, etc. These factors will cause local defects in the cable, and if not treated immediately, the local defects will turn into permanent faults, seriously affecting the safe and stable operation of the industrial system.

[0003] At present, the traveling wave reflection method used in practical cable detection mainly includes time domain reflection method and frequency domain reflection method. The time domain reflection method obtains the time delay of the reflected wave through correlation calculation, and this method is subject to the time domain broadening of correlation calculation; the frequency domain reflection method obtains the time delay of the reflected wave through spectrum analysis, and this method is subject to spectrum leakage. Time domain broadening and spectrum leakage seriously affect the accuracy of the time domain reflection method and the frequency domain reflection method in defect positioning, and the traditional traveling wave reflection method cannot avoid the influence of multiple reflections. SUMMARY

[0004] In order to solve the above problems, the present application provides a cable defect diagnosis method based on sinusoidal pulse segmentation technology, wherein the method comprises:

[0005] Injecting a time-limited triggered frequency-increasing sinusoidal pulse signal into a cable to be detected; detecting a cable head signal, and performing time domain alignment on the time domain pulse according to the frequency point to obtain a time-frequency matrix; the cable head signal includes the incident frequency-increasing sinusoidal pulse signal and a reflected pulse signal; processing the time-frequency matrix based on a Teager-Kaiser operator to obtain a sinusoidal pulse energy distribution, and performing time domain segmentation on the frequency-increasing sinusoidal pulse signal according to the sinusoidal pulse energy distribution to obtain a segmented sinusoidal pulse signal; based on the segmented sinusoidal pulse signal, constructing a cable defect positioning map and a diagnosis map based on sinusoidal pulse segmentation technology.

[0006] In one example, based on the segmented sinusoidal pulse signal, a cable defect positioning map and a diagnosis map based on the sinusoidal pulse segmentation technology are constructed, specifically comprising: determining the transfer function of each reflected pulse signal of the sinusoidal pulse signal and the corresponding spatial position; determining the impedance mismatch point closest to the cable head end in the cable according to the cable head end impedance matching state and the spatial position; repeatedly performing a diagnosis action based on the time-frequency matrix until the newly determined impedance mismatch point is located at the cable end of the cable to be detected; constructing a cable defect positioning map and a diagnosis map based on the sinusoidal pulse segmentation technology according to the parameters of all impedance mismatch points obtained in the diagnosis action; wherein the diagnosis action comprises: determining the reflection coefficient of the impedance mismatch point according to the relationship between the transfer function and the reflection coefficient of the impedance mismatch point; constructing a multiple reflection transfer function through the parameters of the impedance mismatch point, and filtering out the sinusoidal pulse corresponding to the multiple reflection in the time-frequency matrix based on the multiple reflection transfer function; determining the position corresponding to the to-be-determined reflected wave that first arrives at the cable head end in the filtered time-frequency matrix as a new impedance mismatch point.

[0007] In one example, based on the segmented sinusoidal pulse signal, a cable defect positioning map and a diagnosis map based on the sinusoidal pulse segmentation technology are constructed, specifically comprising: determining the transfer function of each reflected pulse signal of the sinusoidal pulse signal and the corresponding spatial position; determining the impedance mismatch point closest to the cable head end in the cable according to the cable head end impedance matching state and the spatial position; repeatedly performing a diagnosis action based on the time-frequency matrix until the newly determined impedance mismatch point is located at the cable end of the cable to be detected; constructing a cable defect positioning map and a diagnosis map based on the sinusoidal pulse segmentation technology according to the parameters of all impedance mismatch points obtained in the diagnosis action; wherein the diagnosis action comprises: determining the reflection coefficient of the impedance mismatch point according to the relationship between the transfer function and the reflection coefficient of the impedance mismatch point; constructing a multiple reflection transfer function through the parameters of the impedance mismatch point, and filtering out the sinusoidal pulse corresponding to the multiple reflection in the time-frequency matrix based on the multiple reflection transfer function; determining the position corresponding to the to-be-determined reflected wave that first arrives at the cable head end in the filtered time-frequency matrix as a new impedance mismatch point.

[0008] In one example, the signal expression of the frequency-increasing sinusoidal pulse signal is: Wherein, f(t) is a time-limited trigger frequency-increasing sinusoidal pulse signal; N is the number of frequency points; A is the amplitude of the signal; ω=ω0+i·Δω is the signal angular frequency; ω0 and Δω are the initial angular frequency and angular frequency interval; T is the pulse period; τ is the pulse duration; rec(t) is a unit rectangular pulse.

[0009] In one example, the time-frequency matrix is processed based on the Teager-Kaiser operator to obtain a sinusoidal pulse energy distribution, specifically comprising: processing the time-frequency matrix through the following formula: 2 Ψ(m,q)=g(m,q) -g(m,q-1)g(m,q+1); Ψ(m, q) = g(m, q) * E(q) wherein, Ψ(m, q) is a sinusoidal pulse energy distribution, g(m, q) is a time-frequency matrix; m is an index of a frequency axis of the time-frequency matrix, q is an index of a time axis of the time-frequency matrix, and E(q) is a sinusoidal pulse energy distribution after frequency dimension reduction.

[0010] In one example, the calculating the impedance mismatch compensation coefficient corresponding to the frequency-increased sinusoidal pulse signal based on the source signal corresponding to the frequency-increased sinusoidal pulse signal and the incident pulse signal specifically comprises: calculating the impedance mismatch compensation coefficient corresponding to the frequency-increased sinusoidal pulse signal by the following formula: wherein, η imc is the impedance mismatch compensation coefficient, U S is the source signal, and U in is the incident signal. wherein, is a transfer function of a reflected wave, d re is a second amplitude, d in is a first amplitude, is a second phase, is a first phase, and τ raw is an initial time delay of the reflected pulse signal.

[0011] In one example, the spatial position corresponding to each transfer function is: D(l) = D max ; wherein, x is a distance from a cable head end, and D(x) is a spatial position function. is a phase spectrum of the transfer function, β is a phase constant of an intact cable, Δf is a frequency interval, and D max is a peak value of the spatial position function, and l is an abscissa corresponding to the peak value of the spatial position function.

[0012] In one example, the expression of the impedance matching state of the cable head end is: The determining the impedance mismatch point closest to the cable head end in the cable according to the impedance matching state of the cable head end and the spatial position specifically comprises: if the impedance matching state of the cable head end is zero, two reflected waves first reaching the cable head end are single-reflected waves and the positions corresponding to the transfer functions of the two reflected waves are two impedance mismatch points; and if the impedance matching state of the cable head end is not zero, one reflected wave first reaching the cable head end is a single-reflected wave and the position corresponding to the transfer function of the reflected wave is one impedance mismatch point.

[0013] In one example, determining the reflection coefficient of the impedance mismatch point based on the relationship between the transfer function and the reflection coefficient specifically includes: determining the reflection coefficient of the impedance mismatch point using the following formula: In the formula, γ is the reflection coefficient; p is the transmission index: p = 2 for distributed defects and p = 1 for lumped defects; l(n) is the location of the impedance mismatch point; γ is the propagation coefficient of the intact cable; Let n be the transfer function of a single reflection at the nth impedance mismatch point closest to the cable start end. When n = 0, the corresponding impedance mismatch point is the cable start end.

[0014] In one example, constructing the multiple reflection transfer function using the parameters of the impedance mismatch point specifically includes the following: the function expression of the multiple reflection transfer function is as follows: In the formula, Let be the multiple reflection transfer function, where k is the order of multiple reflections and k≥1.

[0015] This application also provides a cable defect diagnosis device based on sinusoidal pulse segmentation technology, comprising: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, the instructions being executed by the at least one processor to enable the at least one processor to perform the method as described in any of the above examples.

[0016] The method proposed in this application offers the following advantages: it enables precise defect localization by avoiding the limitations imposed by spectral leakage and time-domain broadening. The multiple reflection suppression technology proposed in this application effectively identifies reflected waves generated by multiple reflections, significantly reducing interference from multiple reflections in cable defect localization results. The cable defect diagnosis method based on sinusoidal pulse segmentation technology can assess the severity of cable defects. Attached Figure Description

[0017] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0018] Figure 1 This is a flowchart illustrating a cable defect diagnosis method based on sinusoidal pulse segmentation technology in an embodiment of this application.

[0019] Figure 2 This is a flowchart illustrating a cable defect diagnosis method according to an embodiment of this application;

[0020] Figure 3This is a schematic diagram illustrating the application scenario of the defect diagnosis method in the embodiments of this application;

[0021] Figure 4 This is a schematic diagram of the sinusoidal pulse energy distribution in an embodiment of this application;

[0022] Figure 5 This is a schematic diagram illustrating the location of defects in a cable to be inspected, as described in an embodiment of this application.

[0023] Figure 6 This is a schematic diagram illustrating defect diagnosis of a cable to be tested in an embodiment of this application;

[0024] Figure 7 This is a diagnostic diagram illustrating a correlation calculation in an embodiment of this application;

[0025] Figure 8 This is a diagnostic diagram of a spectrum analysis in an embodiment of this application. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0027] The technical solutions provided by the various embodiments of this application are described in detail below with reference to the accompanying drawings.

[0028] Figure 1 This diagram illustrates a cable defect diagnosis method based on sinusoidal pulse segmentation technology, provided for one or more embodiments of this specification. The process can be executed by a computing device in the relevant field, and certain input parameters or intermediate results can be manually adjusted to help improve accuracy.

[0029] The analysis method involved in the embodiments of this application can be implemented by a terminal device or a server, and this application does not impose any special limitations on it. For ease of understanding and description, the following embodiments are all described in detail using a server as an example.

[0030] It should be noted that the server can be a single device or a system composed of multiple devices, i.e., a distributed server. This application does not make any specific limitations in this regard.

[0031] like Figure 1 As shown in the figure, this application provides a cable defect diagnosis method based on sinusoidal pulse segmentation technology, including:

[0032] S101: Injects a time-triggered, frequency-enhanced sinusoidal pulse signal into the cable to be tested.

[0033] A time-triggered, frequency-enhanced sinusoidal pulse signal is injected into the cable under test, which is open at the end. The signal expression is as follows:

[0034]

[0035] In the formula, f(t) is a time-triggered frequency-enhanced sinusoidal pulse signal; N is the number of frequency points; A is the amplitude of the signal; ω=ω0+i·Δω is the angular frequency of the signal; ω0 and Δω are the initial angular frequency and the angular frequency interval, respectively; T is the pulse period; τ is the pulse duration; rec(t) is a unit rectangular pulse;

[0036] S102: Detect the signal at the beginning of the cable and align the time-domain pulses according to the frequency points based on the pulse period to obtain a time-frequency matrix; the signal at the beginning of the cable includes the frequency-enhanced sinusoidal pulse signal and the reflected pulse signal.

[0037] Here, the time-frequency matrix is ​​expressed as g(ω,t). Where ω∈(ω0,ω0+(N-1)·Δω),t∈(0,T).

[0038] S103: Process the time-frequency matrix based on the Teager-Kaiser operator to obtain the sinusoidal pulse energy distribution, and perform time-domain segmentation on the frequency-enhanced sinusoidal pulse signal according to the sinusoidal pulse energy distribution to obtain the segmented sinusoidal pulse signal.

[0039] The expression for calculating the energy distribution of a sinusoidal pulse is as follows:

[0040] ψ(m,q)=g(m,q) 2 -g(m,q-1)g(m,q+1)

[0041]

[0042] In the formula, Ψ(m,q) is the sinusoidal pulse energy distribution, g(m,q) is the time-frequency matrix; m is the index of the frequency axis of the time-frequency matrix, q is the index of the time axis of the time-frequency matrix, and E(q) is the sinusoidal pulse energy distribution after frequency dimensionality reduction.

[0043] S104: Based on the segmented sinusoidal pulse signal, construct a cable defect location map and a diagnostic map based on sinusoidal pulse segmentation technology.

[0044] Specifically, to construct the defect location map and diagnostic map, S104 includes:

[0045] S1041: Based on the sinusoidal pulse signal, determine the transfer function and corresponding spatial position of each reflected pulse signal of the sinusoidal pulse signal.

[0046] Specifically, S1041 includes the following steps:

[0047] S10411: Based on the source signal and incident pulse signal corresponding to the frequency-enhanced sinusoidal pulse signal, calculate the impedance mismatch compensation coefficient η corresponding to the frequency-enhanced sinusoidal pulse signal. imc The calculation formula is:

[0048]

[0049] In the formula, U S U is the source signal; in This is the incident signal.

[0050] S10412: Perform correlation calculation on the incident and reflected signals to obtain the initial time delay τ of the reflected pulse signal. raw .

[0051] S10413: Fitting the first amplitude d of the incident signal using the least squares method in With the first phase With the second amplitude d of each reflected signal re With the second phase

[0052] S10414: Reconstruct the transfer function of each reflected wave using the impedance mismatch compensation coefficient and the least squares fitting result. The calculation formula is:

[0053]

[0054] S10415: Perform spectral analysis on the phase spectrum of each transfer function to determine the spatial location corresponding to each transfer function:

[0055]

[0056] D(l)=D max

[0057] Where x is the distance from the beginning of the cable; D(x) is the spatial position function; The phase spectrum of the transfer function; β is the phase constant of the intact cable; Δf is the frequency interval; D max is the peak value of the spatial position function; l is the x-coordinate corresponding to the peak value of the spatial position function.

[0058] S1042: Based on the impedance matching status of the cable head and the spatial location, determine the impedance mismatch point in the cable closest to the head.

[0059] When determining the impedance mismatch point closest to the cable's beginning end based on the impedance matching state of the cable's beginning end, the expression for the impedance matching state of the cable's beginning end is:

[0060]

[0061] like Then, the cable head end is impedance matched, and the first two reflected waves arriving at the cable head end are single-reflection waves, and the locations corresponding to their transfer functions are the two impedance mismatch points; if If there is an impedance mismatch at the beginning of the cable, the first reflected wave to reach the beginning of the cable is a single reflected wave, and the position corresponding to its transfer function is an impedance mismatch point.

[0062] S1043: Determine the reflection coefficient of the impedance mismatch point based on the relationship between the transfer function and the reflection coefficient of the impedance mismatch point.

[0063] Based on the relationship between the transfer function and the reflection coefficient at the impedance mismatch point, the reflection coefficient at the impedance mismatch point can be determined:

[0064]

[0065] In the formula, γ is the reflection coefficient; p is the transmission index: p = 2 for distributed defects and p = 1 for lumped defects; l(n) is the location of the impedance mismatch point; γ is the propagation coefficient of the intact cable. It should be noted that, except when n = 0, the reflection coefficient at this impedance mismatch point is... The value of is related to the transfer function of each reflected wave in S1044. Similarly, when n = 0, at this time... The value is as described above.

[0066] S1044: Construct a multiple reflection transfer function using the parameters of the impedance mismatch point, and filter out the sinusoidal pulses corresponding to the multiple reflections in the time-frequency matrix based on the multiple reflection transfer function.

[0067] The transfer function for multiple reflections is:

[0068]

[0069] In the formula Let be the transfer function for multiple reflections, and k be the order of multiple reflections, where k ≥ 1. It can be understood that when k = 0,

[0070] The amplitude and occurrence time of the sinusoidal pulse corresponding to the multiple reflections in the time domain are determined by the amplitude and phase of the constructed multiple reflection transfer function, and then filtered out in the time-frequency matrix obtained in S102.

[0071] S1045: The location corresponding to the undetermined reflected wave that first arrives at the cable head in the filtered time-frequency matrix is ​​the new impedance mismatch point.

[0072] S1046: Repeat the diagnostic actions of S1043-S1045 above until the latest determined impedance mismatch point is located at the end of the cable under test.

[0073] S1047: Based on the parameters of all impedance mismatch points obtained in the diagnostic action, construct a cable defect location map and a diagnostic map based on sinusoidal pulse segmentation technology.

[0074] The following is a case study of the application of this invention in the detection of defective cables. Figure 3 This is a schematic diagram of a test scenario for a defective cable. The cable model is RG58, and the length is 100m. A parallel defect is set at 20m, and a series defect is set at 40m. The parameters of the timed sinusoidal pulse signal injected into the cable end are: amplitude of 4V, frequency range of 20-60MHz, frequency interval of 0.2MHz, pulse interval of 6μs, and pulse duration of 100ns.

[0075] Figure 4 The diagram shows the energy distribution of a sinusoidal pulse. It can be seen that the six square wave responses correspond to the incident signal, the parallel defect reflection signal, the series defect reflection signal, two sets of multiple reflection signals, and the cable end reflection signal, respectively. After using multiple reflection suppression technology, the energy of the multiple reflections is effectively suppressed. Figure 5 As shown in the defect location diagram, due to the use of pulse segmentation technology, different impedance mismatch points will appear on different spatial axes. Therefore, even if there is spectral leakage, they will not interfere with each other. Figure 5 The main lobe is preserved and its amplitude is replaced with the reflection coefficient of the defect to obtain... Figure 6 , Figure 6 This is the final diagnostic diagram of the present invention.

[0076] Figure 6 It reflects both the location of the cable defect and its severity. Figure 7 A diagnostic graph calculated using correlation on a sinusoidal pulse. Figure 8 The diagram shows a diagnostic plot using spectral analysis. It's easy to see that due to time-domain broadening and spectral leakage, the results of correlation calculations and spectral analysis can easily lead to misjudgments of defects, and neither method can avoid interference from multiple reflections.

[0077] This application also provides a cable defect diagnosis device based on sinusoidal pulse segmentation technology, including: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, the instructions being executed by the at least one processor to enable the at least one processor to perform the steps of the method described in any of the above embodiments.

[0078] This application also provides a non-volatile computer storage medium storing computer-executable instructions configured to perform the steps of the method described in any of the above embodiments.

[0079] The various embodiments in this application are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, the device and medium embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the description of the method embodiments.

[0080] The devices and media provided in this application are one-to-one with the methods. Therefore, the devices and media also have similar beneficial technical effects as their corresponding methods. Since the beneficial technical effects of the methods have been described in detail above, the beneficial technical effects of the devices and media will not be repeated here.

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

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

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

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

[0085] In a typical configuration, a computing device includes one or more processors (CPU), input / output interfaces, network interfaces, and memory.

[0086] Memory may include non-persistent storage in computer-readable media, such as random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash memory. Memory is an example of computer-readable media.

[0087] Computer-readable media include both permanent and non-permanent, removable and non-removable media that can store information by any method or technology. Information can be computer-readable instructions, data structures, modules of programs, or other data. Examples of computer storage media include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, CD-ROM, digital versatile optical disc (DVD) or other optical storage, magnetic tape, magnetic magnetic disk storage or other magnetic storage devices, or any other non-transfer medium that can be used to store information accessible by a computing device. As defined herein, computer-readable media do not include transient computer-readable media, such as modulated data signals and carrier waves.

[0088] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0089] The above description is merely an embodiment of this application and is not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. A cable defect diagnosis method based on sinusoidal pulse segmentation technology, characterized in that, include: Inject a time-triggered, frequency-enhanced sinusoidal pulse signal into the cable under test; The signal at the beginning of the cable is detected, and the time-domain pulses are aligned according to their frequency points based on the pulse period to obtain the time-frequency matrix; The signal at the beginning of the cable includes an incident frequency-enhanced sinusoidal pulse signal and a reflected pulse signal; The time-frequency matrix is ​​processed based on the Teager-Kaiser operator to obtain the sinusoidal pulse energy distribution, and the frequency-enhanced sinusoidal pulse signal is divided in the time domain according to the sinusoidal pulse energy distribution to obtain the segmented sinusoidal pulse signal. Based on the segmented sinusoidal pulse signal, a cable defect location map and a diagnostic map based on sinusoidal pulse segmentation technology are constructed. Based on the segmented sinusoidal pulse signal, a cable defect location map and a diagnostic map based on sinusoidal pulse segmentation technology are constructed, specifically including: Determine the transfer function and corresponding spatial position of each reflected pulse signal of the sinusoidal pulse signal; Based on the impedance matching status at the cable head and the spatial location, determine the impedance mismatch point in the cable closest to the head; Based on the time-frequency matrix, the diagnostic action is repeated until the latest determined impedance mismatch point is located at the end of the cable under test. Based on the parameters of all impedance mismatch points obtained in the diagnostic process, a cable defect location map and a diagnostic map based on sinusoidal pulse segmentation technology are constructed.

2. The method according to claim 1, characterized in that, The diagnostic action includes: determining the reflection coefficient of the impedance mismatch point based on the relationship between the transfer function and the reflection coefficient of the impedance mismatch point; A multiple reflection transfer function is constructed using the parameters of the impedance mismatch point, and based on the multiple reflection transfer function, the sinusoidal pulses corresponding to the multiple reflections are filtered out in the time-frequency matrix; The location corresponding to the undetermined reflected wave that first arrives at the cable head in the filtered time-frequency matrix is ​​identified as the new impedance mismatch point.

3. The method according to claim 2, characterized in that, The step of determining the transfer function and corresponding spatial position of each reflected pulse signal of the sinusoidal pulse signal based on the sinusoidal pulse signal specifically includes: Based on the source signal and incident pulse signal corresponding to the frequency-enhanced sinusoidal pulse signal, calculate the impedance mismatch compensation coefficient corresponding to the frequency-enhanced sinusoidal pulse signal; The initial time delay of the reflected pulse signal is obtained by calculating the correlation between the incident signal and the reflected signal. The first amplitude and first phase of the incident pulse signal and the second amplitude and second phase of each reflected pulse signal were obtained by fitting using the least squares method. Based on the impedance mismatch compensation coefficient and the least squares fitting result, the transfer function of each reflected pulse signal is reconstructed. Spectral analysis is performed on the phase spectrum of the transfer function corresponding to each reflected pulse signal to determine the spatial location of each transfer function.

4. The method according to claim 2, characterized in that, The signal expression of the frequency-enhanced sinusoidal pulse signal is: in, It is a time-limited triggered frequency-increased sinusoidal pulse signal; The number of frequency points is A; A is the amplitude of the signal. , where is the signal angular frequency; and The initial angular frequency and the angular frequency interval; It is the pulse period; It is the pulse duration; A unit rectangular pulse.

5. The method according to claim 4, characterized in that, The process of processing the time-frequency matrix based on the Teager-Kaiser operator to obtain the sinusoidal pulse energy distribution specifically includes: The time-frequency matrix is ​​processed using the following formula: In the formula, The energy distribution of a sinusoidal pulse. It is a time-frequency matrix; For the frequency axis index of the time-frequency matrix, This is the index of the time axis of the time-frequency matrix. This represents the energy distribution of a sinusoidal pulse after frequency dimensionality reduction.

6. The method according to claim 5, characterized in that, The calculation of the impedance mismatch compensation coefficient corresponding to the frequency-enhanced sinusoidal pulse signal based on the source signal and the incident pulse signal specifically includes: The impedance mismatch compensation coefficient corresponding to the frequency-enhanced sinusoidal pulse signal is calculated using the following formula: In the formula, This is the impedance mismatch compensation factor. The source signal; For the incident signal; The transfer function of each reflected pulse signal is reconstructed based on the impedance mismatch compensation coefficient and the least squares fitting result, specifically including: in, Let be the transfer function of the reflected wave. The second value, The first value, For the second phase, For the first phase, This represents the initial time delay of the reflected pulse signal.

7. The method according to claim 6, characterized in that, The spatial location corresponding to each transfer function is: in, The distance from the beginning of the cable; It is a spatial position function; The phase spectrum of the transfer function; For the phase constant of an intact cable; Frequency interval; The peak value of the spatial location function; is the x-coordinate corresponding to the peak value of the spatial location function.

8. The method according to claim 7, characterized in that, The expression for the impedance matching state at the cable's beginning is: The step of determining the impedance mismatch point closest to the cable's beginning end based on the impedance matching state at the cable's beginning end and the spatial location specifically includes: If the impedance matching state at the beginning of the cable is zero, then the first two reflected waves to reach the beginning of the cable are single reflected waves and the positions corresponding to their transfer functions are two impedance mismatch points. If the impedance matching state at the beginning of the cable is not zero, then the first reflected wave to reach the beginning of the cable is a single reflected wave and the position corresponding to its transfer function is an impedance mismatch point.

9. The method according to claim 8, characterized in that, The step of determining the reflection coefficient of the impedance mismatch point based on the relationship between the transfer function and the reflection coefficient specifically includes: The reflection coefficient at the impedance mismatch point is determined using the following formula: In the formula, The reflection coefficient; Transmission index: for distributed defects Regarding the lumpedity defect ; This indicates the location of the impedance mismatch point; The propagation coefficient of a healthy cable; Let n be the transfer function of a single reflection at the nth impedance mismatch point closest to the cable start end. When n=0, the corresponding impedance mismatch point is the cable start end.

10. The method according to claim 9, characterized in that, The construction of the multiple reflection transfer function using the parameters at the impedance mismatch point specifically includes: The functional expression of the multiple reflection transfer function is as follows: In the formula, For multiple reflection transfer functions, The number of multiple reflections and .

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