Cable fault positioning method and device, electronic equipment and storage medium

Abstract

The invention discloses a cable fault positioning method and device, electronic equipment and a storage medium. Relates to the technical field of power grids, and the method comprises the steps: obtaining the impedance spectrum of a to-be-detected cable, and determining a target positioning spectrogram according to the impedance spectrum, the target positioning spectrogram being used for representing the impedance abnormal state of the to-be-detected cable; sliding on the target positioning spectrogram by using a first preset window, and processing the spectrogram region during each sliding by using a window function corresponding to the first preset window to obtain a first positioning spectrogram; and determining the fault position of the to-be-detected cable according to the first positioning spectrogram. According to the scheme provided by the invention, the sensitivity of fault identification can be improved, and misjudgment and missed judgment of weak faults are avoided, so that global evaluation of the cable is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of power grids, and in particular to a cable fault locating method, device, electronic equipment and storage medium. Background Art

[0002] There are a large number of cables in the construction of power grids. Affected by various factors (such as cable laying environment, cable aging, etc.), cables may fail, seriously affecting the stable operation of the power system and causing inconvenience and losses to residents. Therefore, the location of cable faults is of great significance to ensure the stable operation of the power system and extend the service life of cables.

[0003] At present, the methods for locating cable faults mainly include: Time Domain Reflectometry (TDR) and Frequency Domain Reflectometry (FDR). However, since the time domain reflectometry injects narrow pulse signals into the cable, the narrow pulse signals attenuate quickly when propagating in the time domain, resulting in low sensitivity of fault identification; and the frequency domain reflectometry, due to the interference of environmental noise, limits the fault identification accuracy of the cable when it is used in the early stage or when the cable is long, and cannot achieve global evaluation of the cable. Summary of the invention

[0004] The present invention provides a cable fault location method, device, electronic device and storage medium, which can improve the sensitivity of fault identification, avoid misjudgment and missed judgment of weak faults, and thus realize global evaluation of the cable.

[0005] According to one aspect of the present invention, a cable fault location method is provided, comprising: obtaining an impedance spectrum of a cable to be tested, and determining a target location spectrum based on the impedance spectrum, wherein the target location spectrum is used to characterize the impedance abnormality state of the cable to be tested; sliding a first preset window on the target location spectrum, and using a window function corresponding to the first preset window to process the spectrum area at each sliding to obtain a first location spectrum; and determining the fault position of the cable to be tested based on the first location spectrum.

[0006] Optionally, a vector network analyzer is provided at the head end of the cable to be tested; obtaining the impedance spectrum of the cable to be tested includes: inputting incident waves of different frequencies from the head end of the cable to be tested, and collecting the impedance spectrum measured by the vector network analyzer, wherein the frequency range of the incident wave is 100KHz-50MHz.

[0007] Optionally, a target positioning spectrum is determined based on the impedance spectrum, including: performing discrete Fourier transform on the imaginary part of the impedance spectrum to obtain multiple impedance mutation points; normalizing all impedance mutation points based on an impedance mutation point with the largest reflection peak value to obtain an original positioning spectrum; and performing wavelet transform on the original positioning spectrum to obtain a target positioning spectrum.

[0008] Optionally, after obtaining the first positioning spectrum, it also includes: using a second preset window to slide on the target positioning spectrum, and using the window function corresponding to the second preset window to process the spectrum area at each sliding to obtain a second positioning spectrum; determining whether the similarity between the first positioning spectrum and the second positioning spectrum is greater than or equal to a preset threshold; if the similarity between the first positioning spectrum and the second positioning spectrum is greater than or equal to the preset threshold, continuing to execute the step of determining the fault position of the cable to be tested according to the first positioning spectrum; if the similarity between the first positioning spectrum and the second positioning spectrum is less than the preset threshold, returning to execute the step of obtaining the impedance spectrum of the cable to be tested, or using the second positioning spectrum to correct the first positioning spectrum, and then continuing to execute the step of determining the fault position of the cable to be tested according to the first positioning spectrum.

[0009] Optionally, the first preset window is a Blackman window; the second preset window is any one of the following: a Cassel window, a Gaussian window, a flat-top window, a rectangular window, a Hanning window, or a Hamming window.

[0010] Optionally, the window function corresponding to the Blackman window is the Blackman window function, and the Blackman window function is Wherein, n=1, 2, ..., N-1, N represents the total length of the Blackman window function, and M represents the effective length of the Blackman window function.

[0011] Optionally, determining the fault position of the cable under test according to the first positioning spectrum includes: obtaining a peak point in the first positioning spectrum; determining the distance of the peak point relative to the head end of the cable under test, and using the distance as the fault position of the cable under test.

[0012] According to another aspect of the present invention, a cable fault locating device is provided, comprising: a measuring module, a spectrum determination module, a windowing module and a positioning module; wherein the measuring module is used to obtain the impedance spectrum of the cable to be tested; the spectrum determination module is used to determine the target positioning spectrum according to the impedance spectrum, wherein the target positioning spectrum is used to characterize the impedance abnormality state of the cable to be tested; the windowing module is used to slide on the target positioning spectrum using a first preset window, and use the window function corresponding to the first preset window to process the spectrum area at each sliding to obtain a first positioning spectrum; the positioning module is used to determine the fault position of the cable to be tested according to the first positioning spectrum.

[0013] According to another aspect of the present invention, an electronic device is provided, the electronic device comprising: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores a computer program executable by the at least one processor, and the computer program is executed by the at least one processor so that the at least one processor can execute the cable fault location method of any embodiment of the present invention.

[0014] According to another aspect of the present invention, a computer-readable storage medium is provided. The computer-readable storage medium stores computer instructions, and the computer instructions are used to enable a processor to implement the cable fault location method of any embodiment of the present invention when executed.

[0015] The technical solution of the embodiment of the present invention obtains the impedance spectrum of the cable to be tested and determines the target positioning spectrum used to characterize the abnormal impedance state of the cable to be tested, thereby sliding on the target positioning spectrum using a first preset window, and using the window function corresponding to the first preset window to process the spectrum area at each sliding to obtain a first positioning spectrum, and further determine the fault position of the cable to be tested based on the first positioning spectrum. On the one hand, the cable fault locating method determines the target positioning spectrum through the impedance spectrum of the cable to be tested, which can realize the extraction of the abnormal impedance state of the cable to be tested and provide data support for subsequent processes. On the other hand, by performing a windowing operation on the target positioning spectrum, since the window function has the characteristics of simple form and low sidelobe peak, it can enhance the waveform of the fault position without increasing the difficulty of implementation, and suppress the high-frequency sidelobe interference in the waveform diagram, thereby improving the sensitivity of subsequent fault identification, avoiding misjudgment and missed judgment of weak faults, and realizing the global evaluation of the cable, which has good scalability.

[0016] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0018] Figure 1 It is a flow chart of a cable fault location method provided by an embodiment of the present invention;

[0019] Figure 2 This is a schematic diagram of a model for locating a fault in a cable under test provided by an embodiment of the present invention;

[0020] Figure 3 It is a flow chart of another cable fault location method provided by an embodiment of the present invention;

[0021] Figure 4 is a time domain characteristic diagram of a Blackman window provided by an embodiment of the present invention;

[0022] Figure 5 is a Blackman window normalized frequency characteristic diagram provided by an embodiment of the present invention;

[0023] Figure 6 It is a comparison diagram of the results after Blackman window processing and without Blackman window processing provided by an embodiment of the present invention;

[0024] Figure 7 It is a flow chart of another cable fault location method provided by an embodiment of the present invention;

[0025] Figure 8 is a structural schematic diagram of a cable fault locating device provided by an embodiment of the present invention;

[0026] Fig. 9 It is a structural schematic diagram of an electronic device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0027] 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.

[0028] It should be noted that the terms "first", "second", "target", "original", 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 interchangeable 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, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0029] Figure 1This is a flow chart of a cable fault location method provided by an embodiment of the present invention. This embodiment is applicable to the situation of locating the fault position of the cable. The method can be executed by a cable fault location device. The cable fault location device can be implemented in the form of hardware and / or software. The cable fault location device can be configured in an electronic device (such as a computer device, a server, etc.). Figure 1 As shown, the method includes:

[0030] S110, obtaining an impedance spectrum of the cable to be tested, and determining a target positioning spectrum according to the impedance spectrum, wherein the target positioning spectrum is used to characterize an abnormal impedance state of the cable to be tested.

[0031] The cable fault location method provided by the present invention is applicable to the situation of locating the fault position of a cable in an offline state. The cable being in an offline state means that the cable is in a state of power failure and suspension of operation. In this state, the cable does not carry current to ensure safety and positioning accuracy. The cable to be tested refers to any cable that needs to be fault located. The present invention does not limit the length and model of the cable to be tested.

[0032] Figure 2 1 is a schematic diagram of a model for locating a fault in a cable under test provided by an embodiment of the present invention. Figure 2 As shown, the cable to be tested includes two ends, one end is the head end of the cable, and the other end is the end of the cable, and the cable length of the cable to be tested is l. Assuming that there is a fault point on the cable to be tested, then based on the transmission line theory, the incident wave input from the head end of the cable to be tested will change the transmission characteristics at the fault point, and the impedance spectrum of the cable to be tested will also change accordingly. Therefore, the fault type identification and positioning of the cable to be tested can be realized based on the impedance spectrum of the cable to be tested. In one embodiment, the fault type includes but is not limited to insulation aging, insulation breakdown, joint failure, and conductor breakage.

[0033] In one embodiment, the impedance spectrum of the cable to be tested can be directly measured by a vector network analyzer (VNA), which is a radio frequency measuring instrument used to measure the performance parameters of high-frequency devices, circuits and systems. Specifically, since the cable to be tested is in an offline state, the head end of the cable to be tested can be directly connected to the vector network analyzer, and the impedance spectrum of the cable to be tested can be obtained by inputting incident waves of different frequencies from the head end of the cable to be tested and directly collecting the impedance spectrum measured by the vector network analyzer.

[0034] Optionally, the frequency of the incident wave can be selected according to actual needs, such as selecting the signal frequency when the cable to be tested is working.

[0035] After obtaining the impedance spectrum, the impedance spectrum can be analyzed by Fourier transform to determine the target positioning spectrum, which is used to characterize the impedance abnormality of the cable under test. That is, if the cable under test has a fault point, the impedance abnormality of the fault point will be reflected in the target positioning spectrum.

[0036] Fourier transform is a method of converting a time (or space) function into a frequency function, thereby being able to analyze the frequency components of a signal. In the present invention, Fourier transform can be any one of inverse Fourier transform, continuous Fourier transform, discrete Fourier transform, and fast Fourier transform.

[0037] S120, using a first preset window to slide on the target positioning spectrum, and using a window function corresponding to the first preset window to process the spectrum area during each sliding to obtain a first positioning spectrum.

[0038] The preset window mentioned in the embodiment of the present invention is a tool for performing localized processing on a signal in the frequency domain, which can reduce the impact of discontinuity at both ends of the signal, thereby reducing spectrum leakage.

[0039] Exemplarily, the first preset window can be any one of the following: Blackman window, Cassel window, Gaussian window, flat-top window, rectangular window, Hanning window, Hamming window. Each window has its advantages and disadvantages, and can be selected according to actual needs. For example, if you need to reduce spectrum leakage, you may choose a Hanning window or a Hamming window; if you need a smoother window edge, you may choose a Gaussian window.

[0040] Preferably, the first preset window is a Blackman window. The Blackman window has the characteristics of simple form and low sidelobe peak, so it can enhance the waveform of the target positioning spectrum (especially the fault location) without increasing the difficulty of implementation, while suppressing high-frequency sidelobe interference in the waveform.

[0041] In one embodiment, the window function corresponding to the Blackman window is the Blackman window function. The Blackman window function is Wherein, n=1, 2, ..., N-1, N represents the total length of the Blackman window function, and M represents the effective length of the Blackman window function.

[0042] S130: Determine the fault location of the cable to be tested according to the first positioning spectrum.

[0043] Specifically, the first positioning spectrum can be analyzed to determine whether there is a peak point in the first positioning spectrum. If there is a peak point in the first positioning spectrum, it means that there is a fault in the cable to be tested. At this time, the distance of the peak point relative to the head end of the cable to be tested is determined, and the distance is the fault position of the cable to be tested. On the contrary, if there is no peak point in the first positioning spectrum, it means that there is no fault in the cable to be tested, and the process ends.

[0044] The embodiment of the present invention provides a cable fault location method, including: obtaining an impedance spectrum of a cable to be tested, and determining a target location spectrum according to the impedance spectrum, wherein the target location spectrum is used to characterize the impedance abnormal state of the cable to be tested; sliding the target location spectrum using a first preset window, and using a window function corresponding to the first preset window to process the spectrum area at each sliding to obtain a first location spectrum; and determining the fault position of the cable to be tested according to the first location spectrum. The technical solution of the embodiment of the present invention, by obtaining the impedance spectrum of the cable to be tested, and determining a target location spectrum used to characterize the impedance abnormal state of the cable to be tested, thereby sliding the target location spectrum using a first preset window, and using a window function corresponding to the first preset window to process the spectrum area at each sliding to obtain a first location spectrum, and further determining the fault position of the cable to be tested according to the first location spectrum. The cable fault location method, on the one hand, can realize the extraction of the impedance abnormal state of the cable to be tested by determining the target location spectrum through the impedance spectrum of the cable to be tested, and provide data support for subsequent processes. On the other hand, by performing a windowing operation on the target positioning spectrum, due to the characteristics of the window function such as simple form and low sidelobe peak, it is possible to enhance the waveform at the fault location without increasing the difficulty of implementation, while suppressing high-frequency sidelobe interference in the waveform, thereby improving the sensitivity of subsequent fault identification and avoiding misjudgment and omission of weak faults, realizing a global evaluation of the cable with good generalizability.

[0045] In the first possible implementation, Figure 3 FIG. 1 is a flow chart of another cable fault location method provided by an embodiment of the present invention. Based on the above embodiment, this embodiment introduces an optimization mechanism for the target location spectrum and a verification mechanism for the first location spectrum. Figure 3 As shown, the method includes:

[0046] S301. Input incident waves of different frequencies from the head end of the cable to be tested, and collect impedance spectra measured by a vector network analyzer.

[0047] The cable fault location method provided by the present invention is implemented based on the transmission line theory. The transmission line is a part of the circuit and serves as a connection between the generator and the load. The performance of the transmission line depends on the ratio of its length to the wavelength λ of the electrical signal (i.e., the incident wave) entering it. λ=v / f, where v is the speed of the electrical signal in the cable (also called the phase velocity), and f is the frequency of the electrical signal. In the present invention, the frequency of the incident wave is usually within a wide frequency range, such as 100KHz-50MHz.

[0048] When the transmission line length is much shorter than the wavelength, such as when the cable is short (i.e., a few meters) and the signal frequency is low (i.e., a few kilohertz), the line has no effect on the behavior of the circuit. Then, from the power supply side, the circuit impedance is equal to the load impedance at all times.

[0049] However, if the line length is higher than the signal wavelength (l ≥ λ), the line characteristics play an important role and the circuit impedance seen from the source side does not match the load, except in some very special cases.

[0050] The voltage V and current I on the cable are determined by the following differential equations, which are called telegraph equations:

[0051]

[0052] Among them, ω is the signal angular frequency, R is the conductor resistance, L is the inductance, C is the capacitance, and G is the insulation conductivity, all of which are related to the cable length unit. When a high-frequency signal passes through the cable, these four parameters can fully describe the characteristics of the cable.

[0053] In transmission line theory, the behavior of a transmission line is usually described as a function of two complex numbers. The first is the propagation function The second is the characteristic impedance

[0054] The propagation function is usually written as γ = α + jβ; where the real part α is the line attenuation constant and the imaginary part β is the propagation constant, which is related to the phase velocity v, angular frequency ω, and wavelength λ.

[0055] According to the propagation function and characteristic impedance The telegraph equation can be solved to obtain the line impedance at a distance d from the cable head end: Among them, Γ d is the generalized reflection coefficient, Γ d =Γ L e -2γd , Γ L is the load reflection coefficient, Z L is the load impedance connected at the end of the line.

[0056] It can be seen that when the load matches the characteristic impedance, Γ d =Γ L =0, Z d =Z 0 =Z L ; In all other cases, line impedance is a complex variable.

[0057] By directly connecting a vector network analyzer to the head end of the cable to be tested, inputting incident waves of different frequencies from the head end of the cable to be tested, and directly collecting the amplitude and phase of the line impedance measured by the vector network analyzer, the impedance spectrum can be obtained, thereby realizing the acquisition of the impedance spectrum of the cable to be tested.

[0058] S302, performing discrete Fourier transform on the imaginary part of the impedance spectrum to obtain a plurality of impedance mutation points.

[0059] When performing Fourier transform on the impedance spectrum, the imaginary part of the impedance spectrum can be selected for discrete Fourier transform, which can reduce the computational complexity while ensuring data accuracy.

[0060] The multiple impedance mutation points obtained by performing discrete Fourier transform on the imaginary part of the impedance spectrum are caused by multiple refractions and reflections of the incident wave in the cable to be tested. The reflection peaks of the multiple impedance mutation points usually increase gradually.

[0061] S303, taking an impedance mutation point with the largest reflection peak as a reference, normalizing all impedance mutation points to obtain an original positioning spectrum.

[0062] The impedance discontinuity point with the largest reflection peak is usually located at the end of the cable to be tested.

[0063] S304, performing wavelet transform on the original positioning spectrum to obtain a target positioning spectrum.

[0064] Since the slight changes in the cable distribution parameters caused by the minor defects / latent defects in the normalized original positioning spectrum are difficult to be observed in the spectrum, it may cause misjudgment or missed judgment. Therefore, the original positioning spectrum can be subjected to wavelet transformation to eliminate the noise interference in the original positioning spectrum and obtain the target positioning spectrum.

[0065] S305 , slide the target positioning spectrum using the first preset window, and use the window function corresponding to the first preset window to process the spectrum area during each sliding to obtain a first positioning spectrum.

[0066] In this implementation, the first preset window is the Blackman window. Figure 4 is a time domain characteristic diagram of a Blackman window provided by an embodiment of the present invention, Figure 5This is a Blackman window normalized frequency characteristic diagram provided by an embodiment of the present invention.

[0067] The window function corresponding to the Blackman window is the Blackman window function. The Blackman window function is Wherein, n=1, 2, ..., N-1, N represents the total length of the Blackman window function, and M represents the effective length of the Blackman window function.

[0068] The Blackman window has the characteristics of simple form and low sidelobe peak, so it can enhance the waveform of the target positioning spectrum (especially the fault location) without increasing the difficulty of implementation, while suppressing high-frequency sidelobe interference in the waveform. Figure 6 1 is a comparison diagram of the results after Blackman window processing and without Blackman window processing provided by an embodiment of the present invention. Figure 6 As shown in the figure, after the Blackman window processing, two faults were located in the cable under test (such as Figure 6 The cable under test without Blackman window treatment has four faults located, that is, Figure 6 The part shown in the red circle. However, these two faults are actually misjudgments caused by high-frequency sidelobe interference. It can be seen that using the Blackman window to process the target positioning spectrum can significantly improve the recognition accuracy.

[0069] S306: Use the second preset window to slide on the target positioning spectrum, and use the window function corresponding to the second preset window to process the spectrum area during each sliding to obtain a second positioning spectrum.

[0070] In this implementation, the second preset window is any one of the following: Cassel window, Gaussian window, flat-top window, rectangular window, Hanning window, Hamming window.

[0071] By using the second preset window to obtain the second positioning spectrum, the first positioning spectrum obtained by using the first preset window can be verified to ensure the accuracy of positioning.

[0072] S307: Determine whether the similarity between the first positioning spectrum and the second positioning spectrum is greater than or equal to a preset threshold. If yes, execute S308; if no, return to execute S301.

[0073] When the similarity between the first positioning spectrum and the second positioning spectrum is greater than or equal to a preset threshold, it means that the first positioning spectrum and the second positioning spectrum are basically similar, and the same fault can be located. At this time, the subsequent steps of determining the fault position of the cable to be tested can be directly executed; when the similarity between the first positioning spectrum and the second positioning spectrum is less than the preset threshold, it means that the similarity between the first positioning spectrum and the second positioning spectrum is low, and different faults may be located. At this time, in order to achieve accurate positioning, it is necessary to return to the step of obtaining the impedance spectrum of the cable to be tested for re-positioning.

[0074] In one embodiment, the value of the preset threshold can be set according to actual needs, such as 60%, 70%, 75%, 80%, 85%, 90%, etc.

[0075] S308: Obtain peak points in the first positioning spectrum.

[0076] S309: Determine the distance between the peak point and the head end of the cable to be tested, and use the distance as the fault position of the cable to be tested.

[0077] Combining S308-S309, it can be known that by analyzing the first positioning spectrum, it is determined whether there is a peak point in the first positioning spectrum. If there is a peak point in the first positioning spectrum, it means that there is a fault in the cable to be tested. At this time, the distance of the peak point relative to the head end of the cable to be tested is determined, and the distance is the fault position of the cable to be tested. On the contrary, if there is no peak point in the first positioning spectrum, it means that there is no fault in the cable to be tested, and the process ends.

[0078] In the second possible implementation, Figure 7 FIG. 1 is a flow chart of another cable fault location method provided by an embodiment of the present invention. Based on the above embodiment, this embodiment introduces an optimization mechanism for the target location spectrum and another verification mechanism for the first location spectrum. Figure 7 As shown, the method includes:

[0079] S701. Input incident waves of different frequencies from the head end of the cable to be tested, and collect impedance spectra measured by a vector network analyzer.

[0080] Among them, the frequency range of the incident wave is 100KHz-50MHz.

[0081] S702, performing discrete Fourier transform on the imaginary part of the impedance spectrum to obtain multiple impedance mutation points.

[0082] S703, taking an impedance mutation point with the largest reflection peak as a reference, normalizing all impedance mutation points to obtain an original positioning spectrum.

[0083] S704, performing wavelet transform on the original positioning spectrum to obtain a target positioning spectrum.

[0084] S705 , slide the target positioning spectrum using the first preset window, and use the window function corresponding to the first preset window to process the spectrum area during each sliding to obtain a first positioning spectrum.

[0085] S706: Use the second preset window to slide on the target positioning spectrum, and use the window function corresponding to the second preset window to process the spectrum area during each sliding to obtain a second positioning spectrum.

[0086] The related technologies of steps S701-S706 are similar to those of the above steps S301-S306, and can refer to the description of the above steps S301-S306. For the sake of brevity, they will not be repeated here.

[0087] S707: Determine whether the similarity between the first positioning spectrum and the second positioning spectrum is greater than or equal to a preset threshold. If not, execute S708; if yes, execute S709.

[0088] When the similarity between the first positioning spectrum and the second positioning spectrum is greater than or equal to a preset threshold, it means that the first positioning spectrum and the second positioning spectrum are basically similar, and the same fault can be located. At this time, the subsequent steps of determining the fault position of the cable to be tested can be directly executed; when the similarity between the first positioning spectrum and the second positioning spectrum is less than the preset threshold, it means that the similarity between the first positioning spectrum and the second positioning spectrum is low, and different faults may be located. At this time, in order to achieve accurate positioning, the first positioning spectrum can be corrected.

[0089] In one embodiment, the value of the preset threshold can be set according to actual needs, such as 60%, 70%, 75%, 80%, 85%, 90%, etc.

[0090] S708: Use the second positioning spectrum to correct the first positioning spectrum.

[0091] Specifically, the method of correcting the first positioning spectrum using the second positioning spectrum may include but is not limited to: fusing the second positioning spectrum with the first positioning spectrum and retaining only the fault waveforms common to the second positioning spectrum and the first positioning spectrum.

[0092] S709: Obtain peak points in the first positioning spectrum.

[0093] S710: Determine the distance between the peak point and the head end of the cable to be tested, and use the distance as the fault position of the cable to be tested.

[0094] Combining S709-S710, it can be known that by analyzing the first positioning spectrum, it is determined whether there is a peak point in the first positioning spectrum. If there is a peak point in the first positioning spectrum, it means that there is a fault in the cable to be tested. At this time, the distance of the peak point relative to the head end of the cable to be tested is determined, and the distance is the fault position of the cable to be tested. On the contrary, if there is no peak point in the first positioning spectrum, it means that there is no fault in the cable to be tested, and the process ends.

[0095] The embodiment of the present invention provides a cable fault location method, including: obtaining an impedance spectrum of a cable to be tested, and determining a target location spectrum according to the impedance spectrum, wherein the target location spectrum is used to characterize the impedance abnormal state of the cable to be tested; sliding the target location spectrum using a first preset window, and using a window function corresponding to the first preset window to process the spectrum area at each sliding to obtain a first location spectrum; and determining the fault position of the cable to be tested according to the first location spectrum. The technical solution of the embodiment of the present invention, by obtaining the impedance spectrum of the cable to be tested, and determining a target location spectrum used to characterize the impedance abnormal state of the cable to be tested, thereby sliding the target location spectrum using a first preset window, and using a window function corresponding to the first preset window to process the spectrum area at each sliding to obtain a first location spectrum, and further determining the fault position of the cable to be tested according to the first location spectrum. The cable fault location method, on the one hand, can realize the extraction of the impedance abnormal state of the cable to be tested by determining the target location spectrum through the impedance spectrum of the cable to be tested, and provide data support for subsequent processes. On the other hand, by performing a windowing operation on the target positioning spectrum, due to the characteristics of the window function such as simple form and low sidelobe peak, it is possible to enhance the waveform at the fault location without increasing the difficulty of implementation, while suppressing high-frequency sidelobe interference in the waveform, thereby improving the sensitivity of subsequent fault identification and avoiding misjudgment and omission of weak faults, realizing a global evaluation of the cable with good generalizability.

[0096] Figure 8 Schematic diagram of the structure of a cable fault location device provided by an embodiment of the present invention. Figure 8 As shown, the device includes: a measuring module 801, a spectrum determination module 802, a windowing module 803 and a positioning module 804.

[0097] The measuring module 801 is used to obtain the impedance spectrum of the cable to be tested;

[0098] The spectrum determination module 802 is used to determine the target positioning spectrum according to the impedance spectrum, wherein the target positioning spectrum is used to characterize the impedance abnormality state of the cable to be tested;

[0099] The windowing module 803 is used to slide the target positioning spectrum using the first preset window, and use the window function corresponding to the first preset window to process the spectrum area at each sliding to obtain a first positioning spectrum;

[0100] The positioning module 804 is used to determine the fault location of the cable to be tested according to the first positioning spectrum.

[0101] Optionally, a vector network analyzer is provided at the head end of the cable to be tested; the measurement module 801 is specifically used to input incident waves of different frequencies from the head end of the cable to be tested, and collect the impedance spectrum measured by the vector network analyzer, wherein the frequency range of the incident wave is 100KHz-50MHz.

[0102] Optionally, the spectrum determination module 802 is specifically used to perform discrete Fourier transform on the imaginary part of the impedance spectrum to obtain multiple impedance mutation points; normalize all impedance mutation points based on an impedance mutation point with the largest reflection peak value to obtain an original positioning spectrum; and perform wavelet transform on the original positioning spectrum to obtain a target positioning spectrum.

[0103] Optionally, the windowing module 803 is also used to use a second preset window to slide on the target positioning spectrum, and use the window function corresponding to the second preset window to process the spectrum area at each sliding to obtain a second positioning spectrum; determine whether the similarity between the first positioning spectrum and the second positioning spectrum is greater than or equal to a preset threshold; if the similarity between the first positioning spectrum and the second positioning spectrum is greater than or equal to the preset threshold, the positioning module 804 continues to execute the step of determining the fault position of the cable to be tested according to the first positioning spectrum; if the similarity between the first positioning spectrum and the second positioning spectrum is less than the preset threshold, the measurement module 801 returns to execute the step of obtaining the impedance spectrum of the cable to be tested, or after correcting the first positioning spectrum using the second positioning spectrum, the positioning module 804 continues to execute the step of determining the fault position of the cable to be tested according to the first positioning spectrum.

[0104] Optionally, the first preset window is a Blackman window;

[0105] The second preset window is any one of the following: Cassel window, Gaussian window, flat-top window, rectangular window, Hanning window, Hamming window.

[0106] Optionally, the window function corresponding to the Blackman window is the Blackman window function, and the Blackman window function is

[0107] Wherein, n=1, 2, ..., N-1, N represents the total length of the Blackman window function, and M represents the effective length of the Blackman window function.

[0108] Optionally, the positioning module 804 is specifically used to obtain a peak point in the first positioning spectrum; determine the distance of the peak point relative to the head end of the cable to be tested, and use the distance as the fault position of the cable to be tested.

[0109] The cable fault locating device provided in the embodiment of the present invention can execute the cable fault locating method provided in any embodiment of the present invention, and has the corresponding functional modules and beneficial effects of the execution method.

[0110] Fig. 9 A schematic diagram of the structure of an electronic device 10 that can be used to implement an embodiment of the present invention is shown. The electronic device is intended to represent various forms of digital computers, such as laptop computers, desktop computers, workstations, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. The electronic device can also represent various forms of mobile devices, such as personal digital processing, cellular phones, smart phones, wearable devices (such as helmets, glasses, watches, etc.) and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely examples and are not intended to limit the implementation of the present invention described and / or required herein.

[0111] like Fig. 9 As shown, the electronic device 10 includes at least one processor 11, and a memory connected to the at least one processor 11, such as a read-only memory (ROM) 12, a random access memory (RAM) 13, etc., wherein the memory stores a computer program that can be executed by at least one processor, and the processor 11 can perform various appropriate actions and processes according to the computer program stored in the read-only memory (ROM) 12 or the computer program loaded from the storage unit 18 to the random access memory (RAM) 13. In the RAM 13, various programs and data required for the operation of the electronic device 10 can also be stored. The processor 11, the ROM 12, and the RAM 13 are connected to each other through a bus 14. An input / output (I / O) interface 15 is also connected to the bus 14.

[0112] A number of components in the electronic device 10 are connected to the I / O interface 15, including: an input unit 16, such as a keyboard, a mouse, etc.; an output unit 17, such as various types of displays, speakers, etc.; a storage unit 18, such as a disk, an optical disk, etc.; and a communication unit 19, such as a network card, a modem, a wireless communication transceiver, etc. The communication unit 19 allows the electronic device 10 to exchange information / data with other devices through a computer network such as the Internet and / or various telecommunication networks.

[0113] The processor 11 may be a variety of general and / or special processing components with processing and computing capabilities. Some examples of the processor 11 include, but are not limited to, a central processing unit (CPU), a graphics processing unit (GPU), various special artificial intelligence (AI) computing chips, various processors running machine learning model algorithms, a digital signal processor (DSP), and any appropriate processor, controller, microcontroller, etc. The processor 11 executes the various methods and processes described above, such as a cable fault location method.

[0114] In some embodiments, the cable fault location method may be implemented as a computer program, which is tangibly contained in a computer-readable storage medium, such as a storage unit 18. In some embodiments, part or all of the computer program may be loaded and / or installed on the electronic device 10 via the ROM 12 and / or the communication unit 19. When the computer program is loaded into the RAM 13 and executed by the processor 11, one or more steps of the cable fault location method described above may be performed. Alternatively, in other embodiments, the processor 11 may be configured to execute the cable fault location method in any other appropriate manner (e.g., by means of firmware).

[0115] Various implementations of the systems and techniques described above herein can be implemented in digital electronic circuit systems, integrated circuit systems, field programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), application specific standard products (ASSPs), systems on chips (SOCs), load programmable logic devices (CPLDs), computer hardware, firmware, software, and / or combinations thereof. These various implementations can include: being implemented in one or more computer programs that can be executed and / or interpreted on a programmable system including at least one programmable processor, which can be a special purpose or general purpose programmable processor that can receive data and instructions from a storage system, at least one input device, and at least one output device, and transmit data and instructions to the storage system, the at least one input device, and the at least one output device.

[0116] Computer programs for implementing the methods of the present invention may be written in any combination of one or more programming languages. These computer programs may be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device, so that when the computer program is executed by the processor, the functions / operations specified in the flow chart and / or block diagram are implemented. The computer program may be executed entirely on the machine, partially on the machine, partially on the machine and partially on a remote machine as a stand-alone software package, or entirely on a remote machine or server.

[0117] In the context of the present invention, a computer-readable storage medium may be a tangible medium that may contain or store a computer program for use by or in combination with an instruction execution system, device or equipment. A computer-readable storage medium may include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, devices or equipment, or any suitable combination of the foregoing. Alternatively, a computer-readable storage medium may be a machine-readable signal medium. A more specific example of a machine-readable storage medium may include an electrical connection based on one or more lines, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0118] To provide interaction with a user, the systems and techniques described herein may be implemented on an electronic device having: a display device (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor) for displaying information to the user; and a keyboard and a pointing device (e.g., a mouse or trackball) through which the user can provide input to the electronic device. Other types of devices may also be used to provide interaction with the user; for example, the feedback provided to the user may be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user may be received in any form (including acoustic input, voice input, or tactile input).

[0119] The systems and techniques described herein may be implemented in a computing system that includes backend components (e.g., as a data server), or a computing system that includes middleware components (e.g., an application server), or a computing system that includes frontend components (e.g., a user computer with a graphical user interface or a web browser through which a user can interact with implementations of the systems and techniques described herein), or a computing system that includes any combination of such backend components, middleware components, or frontend components. The components of the system may be interconnected by any form or medium of digital data communication (e.g., a communication network). Examples of communication networks include: a local area network (LAN), a wide area network (WAN), a blockchain network, and the Internet.

[0120] A computing system may include a client and a server. The client and the server are generally remote from each other and usually interact through a communication network. The client and server relationship is generated by computer programs running on the corresponding computers and having a client-server relationship with each other. The server may be a cloud server, also known as a cloud computing server or cloud host, which is a host product in the cloud computing service system to solve the defects of difficult management and weak business scalability in traditional physical hosts and VPS services.

[0121] An embodiment of the present invention further provides a computer program product, including a computer program. When the computer program is executed by a processor, the computer program implements the cable fault locating method provided by any embodiment of the present invention.

[0122] In the process of implementation, the computer program product can be written in one or more programming languages ​​or a combination thereof to perform the computer program code of the present invention, including object-oriented programming languages, such as Java, Smalltalk, C++, and conventional procedural programming languages, such as "C" language or similar programming languages. The program code can be executed entirely on the user's computer, partially on the user's computer, as a separate software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In the case of a remote computer, the remote computer can be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or can be connected to an external computer (for example, using an Internet service provider to connect through the Internet).

[0123] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the present invention can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solution of the present invention can be achieved, and this document does not limit this.

[0124] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A cable fault location method, characterized in that: include: Acquire an impedance spectrum of the cable to be tested, and determine a target positioning spectrum according to the impedance spectrum, wherein the target positioning spectrum is used to characterize an abnormal impedance state of the cable to be tested; Slide the target positioning spectrum using a first preset window, and process the spectrum area at each sliding using a window function corresponding to the first preset window to obtain a first positioning spectrum; The fault location of the cable to be tested is determined according to the first positioning spectrum.

2. The cable fault location method according to claim 1, characterized in that: The head end of the cable to be tested is provided with a vector network analyzer; the step of obtaining the impedance spectrum of the cable to be tested comprises: Incident waves of different frequencies are input from the head end of the cable to be tested, and the impedance spectrum measured by the vector network analyzer is collected, wherein the frequency range of the incident wave is 100KHz-50MHz.

3. The cable fault location method according to claim 1, characterized in that: Determining a target positioning spectrum according to the impedance spectrum includes: Performing discrete Fourier transform on the imaginary part of the impedance spectrum to obtain a plurality of impedance mutation points; Taking the impedance mutation point with the largest reflection peak as the benchmark, all impedance mutation points are normalized to obtain the original positioning spectrum; The original positioning spectrum is subjected to wavelet transformation to obtain the target positioning spectrum.

4. The cable fault location method according to claim 1, characterized in that: After obtaining the first positioning spectrum, the method further includes: Slide the target positioning spectrum using a second preset window, and process the spectrum area at each sliding using a window function corresponding to the second preset window to obtain a second positioning spectrum; Determine whether the similarity between the first positioning spectrum and the second positioning spectrum is greater than or equal to a preset threshold; If the similarity between the first positioning spectrum and the second positioning spectrum is greater than or equal to a preset threshold, then continue to perform the step of determining the fault location of the cable to be tested according to the first positioning spectrum; If the similarity between the first positioning spectrum and the second positioning spectrum is less than a preset threshold, return to the step of obtaining the impedance spectrum of the cable to be tested, or use the second positioning spectrum to correct the first positioning spectrum and continue to perform the step of determining the fault location of the cable to be tested according to the first positioning spectrum.

5. The cable fault location method according to claim 4, characterized in that: The first preset window is a Blackman window; The second preset window is any one of the following: Cassel window, Gaussian window, flat-top window, rectangular window, Hanning window, and Hamming window.

6. The cable fault location method according to claim 5, characterized in that: The window function corresponding to the Blackman window is the Blackman window function, and the Blackman window function is: Wherein, n=1, 2, ..., N-1, N represents the total length of the Blackman window function, and M represents the effective length of the Blackman window function.

7. The cable fault location method according to claim 1, characterized in that: Determining the fault position of the cable to be tested according to the first positioning spectrum includes: Obtaining a peak point in the first positioning spectrum; The distance between the peak point and the head end of the cable to be tested is determined, and the distance is used as the fault position of the cable to be tested.

8. A cable fault locating device, characterized in that: include: Measurement module, spectrum determination module, windowing module and positioning module; wherein, The measuring module is used to obtain the impedance spectrum of the cable to be tested; The spectrum determination module is used to determine a target positioning spectrum according to the impedance spectrum, wherein the target positioning spectrum is used to characterize the impedance abnormality state of the cable to be tested; The windowing module is used to slide the target positioning spectrum using a first preset window, and use a window function corresponding to the first preset window to process the spectrum area during each sliding to obtain a first positioning spectrum; The positioning module is used to determine the fault location of the cable to be tested according to the first positioning spectrum.

9. An electronic device, characterized in that: The electronic device comprises: at least one processor; and a memory in communication with the at least one processor; wherein, The memory stores a computer program executable by the at least one processor, and the computer program is executed by the at least one processor so that the at least one processor can execute the cable fault locating method according to any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer instructions, and the computer instructions are used to enable a processor to implement the cable fault location method according to any one of claims 1 to 7 when executed.

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