Cable defect evaluation method, device and medium based on positioning curve attenuation compensation

Abstract

The application discloses a cable defect evaluation method and device based on positioning curve attenuation compensation and a medium, to solve the problem that the existing FDR technology cannot determine the defect degree of each position when evaluating the cable defect due to signal attenuation with propagation distance. The method comprises the following steps: collecting cable frequency domain dielectric impedance data of the measured cable to calculate attenuation coefficient and phase shift coefficient; calculating the frequency domain distribution average value of the attenuation coefficient and the frequency domain distribution average value of the cable wave speed based on the phase shift coefficient; positioning the converted cable frequency domain dielectric impedance data to obtain the original positioning curve of the cable and determine the specified defect peak and the defect peak coordinates of the specified defect peak; calculating the attenuation law function of the original positioning curve of the cable based on the frequency domain distribution average value of the attenuation coefficient and the defect peak coordinates to perform attenuation compensation on the original positioning curve; determining the cable end positioning peak of the compensated positioning curve to normalize the positioning curve and determine the cable defect degree of the measured cable through the processed defect peak amplitude.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of cable defect evaluation, and in particular to a cable defect evaluation method and device based on positioning curve attenuation compensation and a medium. BACKGROUND

[0002] At present, with the continuous development of the power system, the safety and stability of the cable, as an important tool for power transmission and distribution, are crucial. However, various types of degradation defects will gradually appear in the cable during long-term operation, which seriously threatens the normal operation of the power system. In order to realize the timely diagnosis and state evaluation of the cable defects, the frequency domain reflectometry (FDR) is widely used in cable detection. In the frequency domain reflectometry, according to the different data processing algorithms, there are currently mainly several methods such as the line resonance analysis (LIRA), the integral transformation based on the kernel function (IT), the fast Fourier transform (FFT), and the like. These methods can all realize the detection and positioning of the weak defects in the cable, and the principle is that the more serious the defect is, the higher the defect peak amplitude in the positioning curve is. Therefore, the existing research mainly qualitatively evaluates the severity of the defect by comparing the size of the defect peak amplitude.

[0003] However, these methods have a common problem in actual application: the signal will gradually attenuate with the increase of the propagation distance when propagating in the cable. This causes the defect peak amplitude in the positioning curve obtained by using the LIRA, IT, FFT and the like to decrease with the increase of the distance between the defect position and the cable head. This attenuation phenomenon seriously affects the accurate evaluation of the severity of the defect. Even if the types and severity of two defects are exactly the same, if they appear at different positions of the cable, the defect peak amplitude in their positioning curves will also be different. This makes the method of evaluating the severity of the defect only by the defect peak amplitude unreliable, and further limits the accuracy and application range of the FDR method in the evaluation of the cable defect. SUMMARY

[0004] In order to solve the above problems, the present application proposes a cable defect evaluation method based on positioning curve attenuation compensation, which comprises:

[0005] Based on the pre-deployed equipment, the cable frequency domain dielectric impedance data of the measured cable are collected, and the attenuation coefficient and the phase shift coefficient of the measured cable are calculated according to the cable frequency domain dielectric impedance data;

[0006] Calculating a frequency domain distribution average value of the attenuation coefficient according to the attenuation coefficient of the tested cable, and calculating a frequency domain distribution average value of the cable wave velocity of the tested cable based on the phase shift coefficient;

[0007] Performing positioning conversion processing on the cable frequency-domain dielectric impedance data to obtain a corresponding cable original positioning curve, and determining a designated defect peak and defect peak coordinates corresponding to the designated defect peak in the cable original positioning curve;

[0008] Calculating an attenuation law function corresponding to the original positioning curve of the cable based on the frequency domain distribution average value of the attenuation coefficient and the defect peak coordinates, and performing attenuation compensation on the original positioning curve according to the attenuation law corresponding to the attenuation law function;

[0009] A cable end positioning peak is determined in the compensated positioning curve, and based on the cable end positioning peak, the compensated positioning curve is normalized to determine the cable defect degree of the tested cable through the processed defect peak amplitude.

[0010] In one implementation of the present application, collecting the cable frequency domain dielectric impedance data of the tested cable based on the pre-deployed equipment specifically includes:

[0011] Establish a connection between the industrial computer and the impedance analyzer, and establish a connection between the impedance analyzer and the head end of the cable under test based on the test fixture of the impedance analyzer; wherein the positive pole of the test fixture is connected to the head end core of the cable under test, and the negative pole of the test fixture is connected to the cable metal shielding layer of the cable under test;

[0012] When the end core of the tested cable is disconnected from the metal shielding layer of the cable and no load is connected, collecting the disconnected cable frequency domain dielectric impedance data corresponding to the tested cable by the impedance analyzer;

[0013] When the end core of the tested cable is connected to the metal shielding layer of the cable, the impedance analyzer is used to collect the frequency domain dielectric impedance data of the connected cable corresponding to the tested cable.

[0014] In one implementation of the present application, calculating the attenuation coefficient and phase shift coefficient of the tested cable according to the cable frequency-domain dielectric impedance data specifically includes:

[0015] The attenuation coefficient of the tested cable is calculated using the following formula:

[0016]

[0017] wherein f represents the incident signal frequency, l represents the full length of the measured cable, A(f) represents the frequency domain dielectric impedance data of the disconnected cable, B(f) represents the frequency domain dielectric impedance data of the connected cable, Re represents taking the real part, a represents the attenuation coefficient, which is a function of frequency, written as a(f);

[0018] The phase shift coefficient of the measured cable is calculated by the following formula:

[0019]

[0020] wherein Im represents taking the imaginary part, β represents the phase shift coefficient, which is a function of frequency, written as β(f).

[0021] In an implementation manner of the present application, the calculation of the frequency domain distribution average value of the attenuation coefficient according to the attenuation coefficient of the measured cable specifically includes:

[0022] The frequency domain distribution average value of the attenuation coefficient is calculated by the following formula:

[0023]

[0024] wherein a f-avg represents the frequency domain distribution average value of the attenuation coefficient, a(f) represents the attenuation coefficient, f min represents the sweep start frequency, f max represents the sweep end frequency.

[0025] In an implementation manner of the present application, the calculation of the frequency domain distribution average value of the cable wave speed of the measured cable based on the phase shift coefficient specifically includes:

[0026] The frequency domain distribution average value corresponding to the cable wave speed of the measured cable is calculated by the following formula:

[0027] v(f) = 2p f / β(f)

[0028]

[0029] wherein v(f) represents the cable wave speed, v f-avg represents the frequency domain distribution average value of the cable wave speed, β(f) represents the phase shift coefficient.

[0030] In an implementation manner of the present application, the positioning conversion processing of the cable frequency domain dielectric impedance data is performed to obtain the corresponding cable original positioning curve, and the specified defect peak and the defect peak coordinate corresponding to the specified defect peak are determined in the cable original positioning curve, specifically including:

[0031] The following formula is used to perform positioning conversion on the frequency-domain dielectric impedance data of the disconnected cable to obtain the original cable positioning curve:

[0032] y(x)=FFT{angle[A(f)·Chebwin(N)]}

[0033]

[0034] x=v f-avg t / 2

[0035] Where y(x) represents the original cable positioning function, FFT represents fast Fourier transform, angle represents the phase angle of the complex number, Chebwin(N) represents the Chebyshev window function, N represents the window length, which is equal to the number of sampling points of the impedance analyzer, t represents the time variable sequence, Δf represents the frequency interval between adjacent sweep points, x represents the position variable sequence, the curve of y(x) changing with respect to x represents the original cable positioning curve, A(f) represents the frequency domain dielectric impedance data of the disconnected cable, and v f-avg Indicates the average value of the frequency domain distribution of the cable wave velocity;

[0036] In the original cable positioning curve, determining at least one defect peak between the cable head end and the cable tail end, and determining the distance between the at least one defect peak and the cable head end;

[0037] A designated defect peak closest to the cable head end is determined from the at least one defect peak, and defect peak coordinates corresponding to the designated defect peak in the original cable positioning curve are obtained.

[0038] In one implementation of the present application, the attenuation law function corresponding to the original cable positioning curve is calculated based on the frequency domain distribution average value of the attenuation coefficient and the defect peak coordinates, specifically including:

[0039] The attenuation law function of the original cable positioning curve is calculated using the following formula:

[0040]

[0041] Wherein, s(x) represents the attenuation law function of the original cable positioning curve, s0 represents the parameter of the attenuation law function, (x1, y1) represents the defect peak coordinates corresponding to the specified defect peak closest to the cable head end in the original cable positioning curve, α f-avg represents the average value of the frequency domain distribution of the attenuation coefficient.

[0042] In one implementation of the present application, performing attenuation compensation on the original positioning curve according to the attenuation law corresponding to the attenuation law function specifically includes:

[0043] The original positioning curve is attenuated and compensated using the following formula:

[0044] y bc (x) = y(x) / s(x)

[0045] Among them, y bc The curve of the change of (x) with respect to x represents the positioning curve after compensation, y(x) represents the original positioning function of the cable, and s(x) represents the attenuation law function of the original positioning curve of the cable.

[0046] On the other hand, an embodiment of the present application further provides a cable defect assessment device based on positioning curve attenuation compensation, the device comprising:

[0047] at least one processor; and a memory communicatively coupled to the at least one processor;

[0048] The memory stores instructions that can be executed by the at least one processor, and the instructions are executed by the at least one processor to enable the at least one processor to perform the cable defect assessment method based on positioning curve attenuation compensation as described above.

[0049] On the other hand, an embodiment of the present application further provides a non-volatile computer storage medium storing computer executable instructions, which, when executed, implements the above-mentioned cable defect assessment method based on positioning curve attenuation compensation.

[0050] The embodiments of the present application provide a cable defect assessment method, device, and medium based on positioning curve attenuation compensation, which have at least the following beneficial effects:

[0051] The attenuation effect in the original cable positioning curve is compensated, so that the defect peak amplitude no longer changes with the change of the defect position in the cable, and is normalized based on the amplitude of the positioning peak at the end of the compensated cable. The size of the normalized defect peak amplitude can intuitively and quantitatively characterize the severity of the defect, effectively realizing a unified quantitative assessment of the degree of cable defects. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0053] Figure 1 A schematic flow chart of a cable defect assessment method based on positioning curve attenuation compensation provided in an embodiment of the present application;

[0054] Figure 2The device connection schematic diagram of the cable defect evaluation method based on positioning curve attenuation compensation provided by the embodiment of the present application is shown in the following figure.

[0055] Figure 3 The original positioning curve schematic diagram provided by the embodiment of the present application is shown in the following figure.

[0056] Figure 4 The compensated positioning curve schematic diagram provided by the embodiment of the present application is shown in the following figure.

[0057] Figure 5 The original positioning curve schematic diagram before compensation of the experimental group one provided by the embodiment of the present application is shown in the following figure.

[0058] Figure 6 The compensated positioning curve schematic diagram of the experimental group one provided by the embodiment of the present application is shown in the following figure.

[0059] Figure 7 The original positioning curve schematic diagram before compensation of the experimental group two provided by the embodiment of the present application is shown in the following figure.

[0060] Figure 8 The compensated positioning curve schematic diagram of the experimental group two provided by the embodiment of the present application is shown in the following figure.

[0061] Figure 9 The internal structure schematic diagram of the cable defect evaluation device based on positioning curve attenuation compensation provided by the embodiment of the present application is shown in the following figure. DETAILED DESCRIPTION

[0062] In order to make the objectives, technical solutions and advantages of the present application clearer, the technical solutions of the present application will be described in detail below in combination with the embodiments of the present application and the corresponding drawings. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0063] The technical solutions provided by the embodiments of the present application will be described in detail below in combination with the drawings.

[0064] Figure 1 The flowchart of the cable defect evaluation method based on positioning curve attenuation compensation provided by the embodiment of the present application is shown in the following figure.

[0065] The implementation of the analysis method related by the embodiments of the present application can be a terminal device or a server, and the present application does not make special limitation thereon. In order to facilitate understanding and description, the following embodiments are described in detail by taking the server as an example. It should be noted that the server can be a single device, or a system composed of multiple devices, i.e., a distributed server, and the present application does not make specific limitation thereon.

[0066] As Figure 1 As shown, the cable defect assessment method based on positioning curve attenuation compensation provided by the embodiment of the present application includes:

[0067] 101. Based on the pre-deployed equipment, the cable frequency domain dielectric impedance data of the tested cable is collected, and the attenuation coefficient and phase shift coefficient of the tested cable are calculated based on the cable frequency domain dielectric impedance data.

[0068] Industrial computers are computers designed specifically for industrial automation and control systems. They typically operate in industrial environments and are used to monitor, control, and manage various industrial processes and equipment. Impedance analyzers are primarily used to measure and analyze the impedance characteristics of circuits, electronic components, or materials. The impedance analyzer first generates a test signal of one or more frequencies, which is applied to the cable under test via a test fixture. The impedance analyzer then simultaneously measures the voltage and current flowing through the cable at both ends, as well as the phase difference between them. Finally, by calculating the voltage-current ratio and the phase difference, the impedance parameters of the cable under test are determined.

[0069] Specifically, the server establishes a connection between the industrial computer, the impedance analyzer, and the cable under test. Figure 2 This is a schematic diagram of the equipment connection of the cable defect assessment method based on positioning curve attenuation compensation provided in the embodiment of the present application. Figure 2 As shown, first, the test fixture leading out from the impedance analyzer is connected to the head end of the cable under test, the positive pole of the test fixture is connected to the head end core of the cable under test, and the negative pole of the test fixture is connected to the metal shielding layer of the cable.

[0070] An impedance analyzer was used to collect frequency-domain dielectric impedance data for the cable, with the end core of the cable connected or disconnected from the metal shield. First, with the end core of the cable disconnected from the metal shield and no load connected, the disconnected cable frequency-domain dielectric impedance (A(f)) was measured. Next, the end core of the cable was connected to the metal shield using a metal conductor, and the connected cable frequency-domain dielectric impedance (B(f)) was measured.

[0071] In one specific cable defect assessment scenario, an operator first connects an industrial computer to an impedance analyzer via a USB or network interface. Next, the operator uses the impedance analyzer's test fixture to connect the head end of the cable under test to the analyzer. During this process, the positive terminal of the test fixture is clamped onto the core of the cable under test to ensure good electrical contact, while the negative terminal of the test fixture is connected to the cable's metal shield.

[0072] After completing the connections, the operator performs the first measurement. At the end of the cable under test, the operator ensures that the core is disconnected from the cable's metallic shield and that no load is connected. At this point, the operator initiates the measurement using the impedance analyzer's software interface, collecting frequency-domain dielectric impedance data for the disconnected cable. This data is recorded by an industrial computer for subsequent analysis and processing.

[0073] Next, the operator performed a second measurement. This time, at the end of the cable under test, the core and metal shield were connected. The impedance analyzer was used again to collect frequency-domain dielectric impedance data in the connected state. This data was also recorded by the industrial computer and compared and analyzed with the data from the disconnected state. The data from these two measurements provided the basis for subsequent calculations of the attenuation coefficient and phase shift coefficient, as well as further cable defect assessment.

[0074] In one embodiment of the present application, when calculating the attenuation coefficient and phase shift coefficient of the tested cable, the server first needs to determine the frequency of the incident signal and the total length of the tested cable, and calculate the attenuation coefficient and phase shift coefficient based on the frequency domain dielectric impedance data of the disconnected cable and the frequency domain dielectric impedance data of the connected cable using the following formulas (1)-(2):

[0075]

[0076]

[0077] It should be noted that f in the embodiment of the present application represents the frequency of the incident signal, l represents the total length of the cable under test, A(f) represents the frequency domain dielectric impedance data of the disconnected cable, B(f) represents the frequency domain dielectric impedance data of the connected cable, Re represents the real part, Im represents the imaginary part, α represents the attenuation coefficient, β represents the phase shift coefficient, α and β are functions that change with frequency, written as α(f) and β(f).

[0078] In one embodiment, during the cable defect assessment process, the above two calculation formulas (1) and (2) are used to accurately calculate the attenuation coefficient and phase shift coefficient of the tested cable. These calculations are based on the frequency domain dielectric impedance data A(f) of the disconnected cable and the frequency domain dielectric impedance data B(f) of the connected cable collected by the impedance analyzer.

[0079] First, to calculate the attenuation coefficient α(f), we need the frequency f of the incident signal, the total length l of the cable under test, the frequency-domain dielectric impedance data A(f) for the disconnected state, and the frequency-domain dielectric impedance data B(f) for the connected state. Substituting these values ​​into the attenuation coefficient calculation formula yields a frequency-dependent attenuation coefficient function α(f). This coefficient reflects the attenuation of the signal as it propagates through the cable and is an important indicator for evaluating cable performance.

[0080] Next, to calculate the phase shift coefficient, β(f), we need the frequency f of the incident signal, the frequency-domain dielectric impedance data A(f) for the disconnected state, and the frequency-domain dielectric impedance data B(f) for the connected state. Substituting these values ​​into the phase shift coefficient calculation formula yields a frequency-dependent phase shift coefficient function, β(f). This coefficient describes the phase change of a signal as it propagates through a cable and is crucial for analyzing the cable's transmission characteristics.

[0081] In practice, programming the above formulas automatically processes collected data and outputs the attenuation coefficient and phase shift coefficient. These results are then used in subsequent cable defect assessment and location analysis, helping engineers accurately determine the cable's performance and defects. For example, in one cable defect assessment, an impedance analyzer was used to collect frequency-domain dielectric impedance data in both disconnected and connected states. This data was then input into a pre-written MATLAB script to automatically calculate the attenuation coefficient and phase shift coefficient.

[0082] 102. According to the attenuation coefficient of the tested cable, the frequency domain distribution average value of the attenuation coefficient is calculated, and based on the phase shift coefficient, the frequency domain distribution average value of the cable wave velocity of the tested cable is calculated.

[0083] Specifically, the frequency domain distribution average value of the attenuation coefficient is calculated using the following formula (3):

[0084]

[0085] It should be noted that the α in the embodiment of the present application f-avg represents the frequency domain distribution average value of the attenuation coefficient, α(f) represents the attenuation coefficient, f min Indicates the sweep start frequency, f max Indicates the sweep cutoff frequency.

[0086] In one embodiment, in the application scenario of cable performance evaluation, in order to more comprehensively understand the attenuation characteristics of the cable, it is necessary to calculate the frequency domain distribution average of the attenuation coefficient. First, we calculate the frequency domain distribution average of the attenuation coefficient according to the formula provided in the claim. In this formula, α f-avg Represents the average value of the frequency domain distribution of the attenuation coefficient, α(f) is the attenuation coefficient that changes with frequency, f min is the sweep start frequency, f max is the sweep cutoff frequency. The specific calculation steps are as follows:

[0087] Determine the sweep frequency range, that is, set f min and f max These two values ​​are usually set and determined on the impedance analyzer based on actual application requirements and the length of the cable being tested.

[0088] Within the set frequency sweep range, the attenuation coefficient α(f) at each frequency point is obtained by calculation in step 101, substituted into the formula, and an integral operation is performed.

[0089] According to the integration results, the frequency domain distribution average value α of the attenuation coefficient is calculated f-avg .

[0090] For example, in a cable performance evaluation, engineers set the frequency sweep range to 0.1 MHz to 50 MHz and measured the cable's frequency-domain dielectric impedance data in both disconnected and connected states within this range. They then calculated the attenuation coefficient and phase shift coefficient of the tested cable based on the frequency-domain dielectric impedance data, and calculated the frequency-domain distribution average of the attenuation coefficient using formula (3).

[0091] In one embodiment of the present application, the frequency domain distribution average value corresponding to the cable wave velocity of the tested cable is calculated based on the phase shift coefficient, the sweep start frequency, and the sweep cutoff frequency using the following formulas (4)-(5):

[0092] v(f)=2πf / β(f) (4)

[0093]

[0094] It should be noted that v(f) in the embodiment of the present application represents the cable wave velocity, v f-avg It represents the average value of the frequency domain distribution of the cable wave velocity, and β(f) represents the phase shift coefficient.

[0095] In one embodiment, in the field of cable performance testing, cable wave velocity is a key parameter that affects the transmission efficiency and stability of the signal in the cable. In order to accurately evaluate the transmission performance of the cable, it is necessary to calculate the frequency domain distribution average value of the cable wave velocity. Substitute the cable wave velocity v(f) at all frequency points into formula (5), integrate it and divide it by the sweep frequency range to obtain the frequency domain distribution average value v of the cable wave velocity. f-avg This average value represents the average performance of the cable's wave velocity over the entire frequency sweep range.

[0096] 103. Perform positioning conversion processing on the cable frequency domain dielectric impedance data to obtain a corresponding cable original positioning curve, and determine a designated defect peak and defect peak coordinates corresponding to the designated defect peak in the cable original positioning curve.

[0097] After obtaining the original cable positioning curve, find the defect peak closest to the head end by observing the original cable positioning curve, and record the coordinates (x1, y1) of the peak point.

[0098] Specifically, in one embodiment of the present application, the frequency-domain dielectric impedance data of the disconnected cable is subjected to positioning conversion processing by the following formulas (6)-(8), thereby obtaining the original cable positioning curve:

[0099] y(x)=FFT{angle[A(f)·Chebwin(N)]} (6)

[0100]

[0101] x=v f-avg ·t / 2 (8)

[0102] It should be noted that y(x) in the embodiment of the present application represents the original positioning function of the cable, FFT represents fast Fourier transform, angle represents the phase angle of the complex number, Chebwin(N) represents the Chebyshev window function, N represents the window length, which is equal to the number of sampling points of the impedance analyzer, t represents the time variable sequence, Δf represents the frequency interval between adjacent scanning points, x represents the position variable sequence, and the change curve of y(x) with respect to x represents the original positioning curve of the cable.

[0103] In one embodiment, a cable defect location application uses a location conversion method based on frequency-domain dielectric impedance data to accurately locate local defects in the cable. This method uses techniques such as fast Fourier transform (FFT) and Chebyshev window function to convert the frequency-domain dielectric impedance data of the disconnected cable into the original cable location curve, thereby intuitively identifying the defect location.

[0104] First, an impedance analyzer is used to perform a swept frequency measurement on the disconnected cable to obtain frequency-domain dielectric impedance data, which contains information about the electrical characteristics of the cable along the cable. Next, a fast Fourier transform (FFT) is performed on this acquired frequency-domain dielectric impedance data. FFT is an efficient algorithm that converts time-domain signals into frequency-domain signals, or vice versa. Here, FFT is used to convert frequency-domain data into spatial-domain data for further analysis.

[0105] After the FFT conversion, spatial domain data is obtained in the form of complex numbers. To extract useful positioning information, the amplitudes of these complex numbers must be calculated. Furthermore, when converting the cable frequency-domain dielectric impedance data into the original cable positioning curve, a Chebyshev window function is introduced to weight the signal. The Chebyshev window function has excellent sidelobe suppression performance, effectively reducing spectral leakage and aliasing, and improving positioning accuracy. The length of the window function is determined based on the number of sampling points N of the impedance analyzer, and the shape of the window function must match the characteristics of the sampled data.

[0106] After the above processing, a complex amplitude sequence related to the position variable sequence x is obtained. By converting these amplitude sequences into position information and plotting the y(x) curve with respect to x, the original positioning curve of the cable is obtained. This curve intuitively shows the impedance characteristic changes of the cable at each point along the line, thereby accurately identifying the location of the local defect. For example, in a cable defect positioning task, the engineer first uses the impedance analyzer to collect the frequency domain dielectric impedance data of the disconnected cable. Then, the data is processed according to the above steps, and the original positioning curve of the cable is generated.

[0107] 104、Based on the average value of the frequency domain distribution of the attenuation coefficient and the defect peak coordinates, the attenuation law function corresponding to the original positioning curve of the cable is calculated, and the original positioning curve is compensated for attenuation according to the attenuation law corresponding to the attenuation law function.

[0108] Specifically, in an embodiment of the present application, based on the average value of the frequency domain distribution of the attenuation coefficient and the defect peak coordinates, the attenuation law function corresponding to the original positioning curve of the cable is calculated by the following formulas (9)-(10):

[0109]

[0110] It should be noted that s(x) in the embodiment of the present application represents the attenuation law function of the original positioning curve of the cable, s0 represents the parameter of the attenuation law function, and (x1, y1) represents the coordinates of the nearest defect peak to the head end in the original positioning curve of the cable.

[0111] In an embodiment, in a cable defect detection and positioning system, in order to more accurately describe the attenuation characteristics of the cable, based on the average value of the frequency domain distribution of the attenuation coefficient and the defect peak coordinates, the attenuation law function corresponding to the original positioning curve of the cable is calculated.

[0112] First, the calculation process of the attenuation law function is understood according to the formula provided in the claim. In this formula, s(x) represents the attenuation law function, which describes the attenuation of the cable at each point along the line; s0 is the parameter of the attenuation law function, which is related to the specific attenuation characteristics of the cable; and (x1, y1) represents the coordinates of the nearest defect peak to the head end in the original positioning curve of the cable.

[0113] According to the previously measured or calculated attenuation coefficient data, the average value of the frequency domain distribution is calculated. This average value reflects the average attenuation level of the cable in the entire sweep frequency range. By analyzing the original positioning curve of the cable, the nearest defect peak to the head end in the original positioning curve can be found. By substituting the average value of the frequency domain distribution of the attenuation coefficient and the specified defect peak coordinates into the formula, the attenuation law function s(x) can be calculated. This function describes the attenuation of the cable at each point along the line in the original positioning curve, providing more detailed cable performance information.

[0114] For example, during a cable defect inspection, engineers analyzed the original cable location curve to determine the coordinates of the defect peak. They then plugged this data into a formula to calculate the cable's attenuation function. This function not only helped engineers more accurately understand the cable's attenuation characteristics but also provided strong support for subsequent defect severity assessments.

[0115] 105. Determine the cable end positioning peak in the compensated positioning curve, and perform normalization processing on the compensated positioning curve based on the cable end positioning peak to determine the cable defect degree of the tested cable through the processed defect peak amplitude.

[0116] Specifically, in one embodiment of the present application, the original positioning curve is attenuated and compensated according to the attenuation law corresponding to the attenuation law function by the following formula (11):

[0117] y bc (x)=y(x) / s(x) (11)

[0118] It should be noted that, in the embodiment of the present application, bc (x) The curve of the change in x represents the positioning curve after compensation.

[0119] In one embodiment, a simulation was conducted to verify the above technical solution. The simulation object was a 300m long RG-58 coaxial cable. Local defects were placed at 30m, 60m, 90m, 120m, 150m, 180m, 210m, 240m, and 270m, respectively. The defect location curves at different locations were compared. The defect type and severity remained the same, and the frequency sweep range was set to 0.01 to 50MHz.

[0120] Figure 3 The original positioning curve diagram provided in the embodiment of this application is as follows: Figure 3 As shown, it can be seen that as the distance between the defect location and the cable head end increases, the defect peak amplitude in the positioning curve decreases exponentially. Obviously, this is not conducive to uniformly judging the severity of defects at different locations.

[0121] Figure 4 The compensation curve diagram provided in the embodiment of the present application is as follows: Figure 4 As shown in the figure, it can be seen that the defect peak amplitudes at different positions after compensation are basically on the same horizontal line, which is consistent with the Figure 3 The original positioning curve in the simulation is significantly different. As shown in Table 1 below, the coordinates of the defect peaks at different defect locations in the compensated positioning curve are shown.

[0122] Table 1

[0123]

[0124]

[0125] As shown in Table 1, the maximum difference in the peak amplitude of defects at different positions after compensation is 0.0166. Fitting the peak points of each defect can obtain the following linear function curve:

[0126] s bc (x) = -0.00007x + 0.115 (12)

[0127] The slope of the fitted curve is -0.00007, approaching 0, and the curve is approximately horizontal. This indicates that after compensation, for defects of the same type and severity, when they occur at different locations in the cable, the defect peak amplitude remains essentially the same and no longer varies with the defect's location, indicating good compensation. In this case, the defect's severity can be uniformly assessed by reading the defect peak amplitude.

[0128] In one embodiment, the above technical solution was experimentally verified. Experimental Group 1: RG-58 coaxial cable with a total length of 130m. Two experiments were conducted, with a high-resistance ground fault at 30m and 100m respectively. The ground resistance was 500Ω in both cases. The frequency sweep range was set to 0.1-50MHz. The location curves of different defect locations were compared before and after compensation.

[0129] Figure 5 This is a schematic diagram of the original positioning curve before compensation in the experimental group 1 provided in the embodiment of this application. Figure 5 As shown in the figure, for high-resistance ground faults of the same severity, when the fault locations are 30m and 100m, the defect peak amplitudes in the original location curves differ significantly, making it impossible to accurately determine the severity of the fault based on the defect peak amplitudes. Table 2 below shows the defect peak coordinates for different defect locations in experimental group 1 before compensation.

[0130] Table 2

[0131]

[0132] Figure 6 This is a schematic diagram of the positioning curve after compensation of the experimental group 1 provided in the embodiment of this application. Figure 6 As shown in the figure, the fault peak amplitudes of two ground faults of equal severity, located at 30m and 100m, are close to the same level after compensation. Table 3 below shows the fault peak coordinates at different fault locations in experimental group 1 after compensation.

[0133] Table 3

[0134]

[0135] Table 3 shows that compensation did not affect the cable defect and end location results. Normalized using the end amplitude as a reference, only the defect peak amplitude changed. Calculations show that the difference in the defect peak amplitude at the two locations after compensation is only 2.0%. At this point, the severity of the two faults can be considered equal.

[0136] In one embodiment, experimental group 2 maintains the cable model, total length, fault type, and fault location of experimental group 1 unchanged, changes the grounding resistance to 1000Ω, and sets the sweep frequency range to 0.1-50MHz. The positioning curves of different defect locations before and after compensation are compared.

[0137] Figure 7 This is a schematic diagram of the original positioning curve before compensation of the experimental group 2 provided in the embodiment of this application. Figure 7 As shown in the figure, before compensation, for a 1000Ω ground fault, the original location curves for fault locations at 30m and 100m showed significant differences in the defect peak amplitudes, making it difficult to accurately determine the severity of the fault based on the defect peak amplitudes. Table 4 below shows the defect peak coordinates for different defect locations in Experimental Group 2 before compensation.

[0138] Table 4

[0139]

[0140] Figure 8 This is a schematic diagram of the positioning curve after compensation for the experimental group 2 provided in the embodiment of this application. Figure 8 As shown, the fault peak amplitudes of two ground faults of equal severity, located at 30m and 100m, approach the same level after compensation. Table 5 below shows the fault peak coordinates for different fault locations in experimental group 2 after compensation.

[0141] Table 5

[0142]

[0143] According to the data in Table 5, the difference in the defect peak amplitudes at the two locations after compensation is 7.1% (within 10.0%). It can be approximately considered that the severity of the two faults is the same and the compensation effect is achieved.

[0144] According to the positioning results after compensation in "Experimental Group 1" and "Experimental Group 2":

[0145] The defect peak amplitudes of the two 500Ω ground faults in “experimental group 1” are 0.0503 and 0.0493 respectively;

[0146] The defect peak amplitudes of the two 1000Ω ground faults in “Experimental Group 2” are 0.0253 and 0.0235 respectively.

[0147] It can be seen that the defect peak amplitude of the 500Ω grounding fault in the compensated positioning result is about equal to 2 times of the 1000Ω grounding fault, which is consistent with the actual defect severity. It is proved that the method of the patent can overcome the attenuation, realize compensation, and realize unified quantitative evaluation of defect severity for defects at different positions.

[0148] The above is the method embodiment of the present application. Based on the same inventive concept, the present application also provides a cable defect evaluation device based on positioning curve attenuation compensation, which has a structure as shown in Figure 9 .

[0149] Figure 9 The internal structure diagram of the cable defect evaluation device based on positioning curve attenuation compensation provided by the present application is shown in Figure 9 . The device includes:

[0150] at least one processor 901;

[0151] and a memory 902 in communication connection with the at least one processor 901;

[0152] The memory 902 stores instructions executable by the at least one processor 901, and the instructions are executed by the at least one processor 901 to enable the at least one processor 901 to:

[0153] Based on the pre-deployed device, the cable frequency domain dielectric impedance data of the measured cable is collected, and the attenuation coefficient and the phase shift coefficient of the measured cable are calculated according to the cable frequency domain dielectric impedance data;

[0154] According to the attenuation coefficient of the measured cable, the frequency domain distribution average value of the attenuation coefficient is calculated, and based on the phase shift coefficient, the frequency domain distribution average value of the cable wave speed of the measured cable is calculated;

[0155] The cable frequency domain dielectric impedance data is subjected to positioning conversion processing to obtain the corresponding cable original positioning curve, and the specified defect peak and the defect peak coordinates corresponding to the specified defect peak are determined in the cable original positioning curve;

[0156] Based on the frequency domain distribution average value of the attenuation coefficient and the defect peak coordinates, the attenuation law function corresponding to the cable original positioning curve is calculated, and the original positioning curve is subjected to attenuation compensation according to the attenuation law of the attenuation law function;

[0157] The cable end positioning peak is determined in the compensated positioning curve, and the compensated positioning curve is subjected to normalization processing based on the cable end positioning peak, so as to determine the cable defect degree of the measured cable through the processed defect peak amplitude.

[0158] The present application also provides a non-volatile computer storage medium storing computer-executable instructions. When the computer-executable instructions are executed, they can:

[0159] Based on pre-deployed equipment, the cable frequency domain dielectric impedance data of the tested cable is collected, and the attenuation coefficient and phase shift coefficient of the tested cable are calculated based on the cable frequency domain dielectric impedance data;

[0160] According to the attenuation coefficient of the tested cable, the frequency domain distribution average value of the attenuation coefficient is calculated, and based on the phase shift coefficient, the frequency domain distribution average value of the cable wave velocity of the tested cable is calculated;

[0161] Performing positioning conversion processing on the cable frequency domain dielectric impedance data to obtain the corresponding cable original positioning curve, and determining the specified defect peak and the defect peak coordinates corresponding to the specified defect peak in the cable original positioning curve;

[0162] Based on the frequency domain distribution average value of the attenuation coefficient and the defect peak coordinates, the attenuation law function corresponding to the original cable positioning curve is calculated, and the attenuation compensation is performed on the original positioning curve according to the attenuation law corresponding to the attenuation law function;

[0163] The cable end positioning peak is determined in the compensated positioning curve, and based on the cable end positioning peak, the compensated positioning curve is normalized to determine the cable defect degree of the tested cable through the processed defect peak amplitude.

[0164] The various embodiments in this application are described in a progressive manner. Similar portions between the various embodiments can be referred to in conjunction with each other. Each embodiment focuses on the differences between the other embodiments. In particular, the device and medium embodiments are generally similar to the method embodiments, so their descriptions are relatively simple. For relevant portions, refer to the descriptions of the method embodiments.

[0165] The foregoing description describes specific embodiments of the present application. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recited in the claims can be performed in an order different from that described in the embodiments and still achieve the desired results. Furthermore, the processes depicted in the accompanying drawings do not necessarily require the specific order shown or the sequential order to achieve the desired results. In certain embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0166] The devices and media provided in the embodiments of the present application correspond one-to-one to the methods. Therefore, the devices and media also have similar beneficial technical effects to 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.

[0167] Those skilled in the art will appreciate that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the present application can adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application can adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code.

[0168] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the steps in the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0169] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0170] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 The steps for the function specified in one or more boxes.

[0171] In a typical configuration, a computing device includes one or more processors (CPUs), input / output interfaces, network interfaces, and memory.

[0172] Memory may include non-permanent storage in a computer-readable medium, random access memory (RAM) and / or non-volatile memory in the form of read-only memory (ROM) or flash RAM. Memory is an example of a computer-readable medium.

[0173] Computer-readable media includes permanent and non-permanent, removable and non-removable media that can be implemented by any method or technology to store information. The information can be computer-readable instructions, data structures, program modules 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 technology, compact disc read-only memory (CD-ROM), digital versatile disc (DVD) or other optical storage, magnetic cassettes, magnetic disk storage or other magnetic storage devices or any other non-transmission media that can be used to store information that can be accessed by a computing device. As defined herein, computer-readable media does not include transitory computer-readable media (transitory media), such as modulated data signals and carrier waves.

[0174] It should also be noted that the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, commodity, or apparatus that includes a series of elements includes not only those elements but also other elements not explicitly listed, or includes elements inherent to such process, method, commodity, or apparatus. In the absence of further limitations, an element defined by the phrase "comprises a ..." does not exclude the presence of other identical elements in the process, method, commodity, or apparatus that includes the element.

[0175] The foregoing is merely an embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application should all be included within the scope of the claims of the present application.

Claims

1. A cable defect assessment method based on positioning curve attenuation compensation is characterized by: The method comprises: Based on pre-deployed equipment, the cable frequency domain dielectric impedance data of the tested cable is collected, and the attenuation coefficient and phase shift coefficient of the tested cable are calculated according to the cable frequency domain dielectric impedance data; Calculating a frequency domain distribution average value of the attenuation coefficient according to the attenuation coefficient of the tested cable, and calculating a frequency domain distribution average value of the cable wave velocity of the tested cable based on the phase shift coefficient; Performing positioning conversion processing on the cable frequency-domain dielectric impedance data to obtain a corresponding cable original positioning curve, and determining a designated defect peak and defect peak coordinates corresponding to the designated defect peak in the cable original positioning curve; Calculating an attenuation law function corresponding to the original positioning curve of the cable based on the frequency domain distribution average value of the attenuation coefficient and the defect peak coordinates, and performing attenuation compensation on the original positioning curve according to the attenuation law corresponding to the attenuation law function; Determining a cable end positioning peak in the compensated positioning curve, and performing normalization processing on the compensated positioning curve based on the cable end positioning peak, so as to determine the cable defect degree of the tested cable through the processed defect peak amplitude; Calculating the attenuation law function corresponding to the original cable positioning curve based on the frequency domain distribution average value of the attenuation coefficient and the defect peak coordinates specifically includes: The attenuation law function of the original cable positioning curve is calculated using the following formula: Wherein, s(x) represents the attenuation law function of the original cable positioning curve, s0 represents the parameter of the attenuation law function, (x1, y1) represents the defect peak coordinates corresponding to the specified defect peak closest to the cable head end in the original cable positioning curve, α f-avg represents the average value of the frequency domain distribution of the attenuation coefficient.

2. The cable defect assessment method based on positioning curve attenuation compensation according to claim 1 is characterized in that: The method of collecting the cable frequency domain dielectric impedance data of the tested cable based on the pre-deployed equipment specifically includes: Establish a connection between the industrial computer and the impedance analyzer, and establish a connection between the impedance analyzer and the head end of the cable under test based on the test fixture of the impedance analyzer; wherein the positive pole of the test fixture is connected to the head end core of the cable under test, and the negative pole of the test fixture is connected to the cable metal shielding layer of the cable under test; When the end core of the tested cable is disconnected from the metal shielding layer of the cable and no load is connected, collecting the disconnected cable frequency domain dielectric impedance data corresponding to the tested cable by the impedance analyzer; When the end core of the tested cable is connected to the metal shielding layer of the cable, the impedance analyzer is used to collect the frequency-domain dielectric impedance data of the connected cable corresponding to the tested cable.

3. The cable defect assessment method based on positioning curve attenuation compensation according to claim 1 is characterized in that: Calculating the attenuation coefficient and phase shift coefficient of the tested cable according to the cable frequency domain dielectric impedance data specifically includes: The attenuation coefficient of the tested cable is calculated using the following formula: Where f is the incident signal frequency, l is the total length of the cable under test, A(f) is the frequency-domain dielectric impedance data of the disconnected cable, B(f) is the frequency-domain dielectric impedance data of the connected cable, Re is the real part, and α is the attenuation coefficient, which is a function that changes with frequency and is written as α(f). The phase shift coefficient of the tested cable is calculated using the following formula: Here, Im represents the imaginary part, and β represents the phase shift coefficient, which is a function that changes with frequency and is written as β(f).

4. The cable defect assessment method based on positioning curve attenuation compensation according to claim 1, characterized in that: Calculating the frequency domain distribution average value of the attenuation coefficient according to the attenuation coefficient of the tested cable specifically includes: The frequency domain distribution average value of the attenuation coefficient is calculated using the following formula: Among them, α f-avg represents the frequency domain distribution average value of the attenuation coefficient, α(f) represents the attenuation coefficient, f min Indicates the sweep start frequency, f max Indicates the sweep cutoff frequency.

5. The cable defect assessment method based on positioning curve attenuation compensation according to claim 1 is characterized in that: Calculating the frequency domain distribution average value of the cable wave velocity of the tested cable based on the phase shift coefficient specifically includes: The frequency domain distribution average value of the cable wave velocity of the tested cable is calculated using the following formula: v(f)=2πf / β(f) Where, v(f) represents the cable wave velocity, v f-avg It represents the average value of the frequency domain distribution of the cable wave velocity, and β(f) represents the phase shift coefficient.

6. The cable defect assessment method based on positioning curve attenuation compensation according to claim 1 is characterized in that: The performing positioning conversion processing on the cable frequency-domain dielectric impedance data to obtain a corresponding cable original positioning curve, and determining a specified defect peak and a defect peak coordinate corresponding to the specified defect peak in the cable original positioning curve, specifically includes: The following formula is used to perform positioning conversion on the frequency-domain dielectric impedance data of the disconnected cable to obtain the original cable positioning curve: y(x)=FFT{angle[A(f)·Chebwin(N)]} x=v f-avg ·t / 2 Where y(x) represents the original cable positioning function, FFT represents fast Fourier transform, angle represents the phase angle of the complex number, Chebwin(N) represents the Chebyshev window function, N represents the window length, which is equal to the number of sampling points of the impedance analyzer, t represents the time variable sequence, Δf represents the frequency interval between adjacent sweep points, x represents the position variable sequence, the curve of y(x) changing with respect to x represents the original cable positioning curve, A(f) represents the frequency domain dielectric impedance data of the disconnected cable, and v f-avg Indicates the average value of the frequency domain distribution of the cable wave velocity; In the original cable positioning curve, determining at least one defect peak between the cable head end and the cable tail end, and determining the distance between the at least one defect peak and the cable head end; A designated defect peak closest to the cable head end is determined from the at least one defect peak, and defect peak coordinates corresponding to the designated defect peak in the original cable positioning curve are obtained.

7. The cable defect assessment method based on positioning curve attenuation compensation according to claim 1, characterized in that: The performing attenuation compensation on the original positioning curve according to the attenuation law corresponding to the attenuation law function specifically includes: The original positioning curve is attenuated and compensated using the following formula: y bc (x)=y(x) / s(x) Among them, y bc The curve of the change of (x) with respect to x represents the positioning curve after compensation, y(x) represents the original positioning function of the cable, and s(x) represents the attenuation law function of the original positioning curve of the cable.

8. Cable defect assessment equipment based on positioning curve attenuation compensation, characterized in that: The device comprises: at least one processor; and, a memory communicatively coupled to the at least one processor; The memory stores instructions that can be executed by the at least one processor, and the instructions are executed by the at least one processor so that the at least one processor can execute the cable defect assessment method based on positioning curve attenuation compensation as described in any one of claims 1 to 7.

9. A non-volatile computer storage medium storing computer executable instructions, characterized in that: When the computer executable instructions are executed, the cable defect assessment method based on positioning curve attenuation compensation according to any one of claims 1 to 7 is implemented.

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