Cable defect early warning method and device, terminal equipment and storage medium

Abstract

The invention discloses a cable defect early warning method and device, terminal equipment and a storage medium, and belongs to the technical field of cable defect early warning, and the method comprises the steps: carrying out the frequency sweeping test of an equivalent circuit model, generating a reflection coefficient spectrum, separating a low-frequency component from the reflection coefficient spectrum, and taking the low-frequency component as a head-end reflection coefficient, through combination of the head end reflection coefficient, the internal resistance of the test equipment and the cable impedance, equivalent impedance at the joint of the test fixture and the head end of the cable is obtained through quantification, and an original reflection coefficient spectrum is corrected according to the equivalent impedance, so that impedance mismatch of the test fixture in the test process is eliminated. The corrected reflection coefficient spectrum can reflect the impedance of the cable body more accurately, so that the subsequently obtained time domain response can reflect the defect condition of the cable body more truly, and the accuracy of cable defect early warning is improved. The problem that the accuracy of cable defect early warning is low due to the fact that the original reflection coefficient spectrum cannot be corrected in the prior art can be solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of cable defect early warning, and particularly relates to a cable defect early warning method and device, a terminal device and a storage medium. BACKGROUND

[0002] Detecting and early warning of cable defects refers to identifying internal defects of a cable by analyzing a reflection signal of the cable. When the cable has defects such as breakage, dampness, and insulation aging, local impedance will be abruptly changed, thereby abnormal characteristics are shown in the reflection signal. Early warning is performed according to the detected abnormal characteristics to avoid serious consequences such as power interruption and equipment damage caused by cable failure.

[0003] In a traditional cable defect detection process, a time domain reflection method (TDR) and a frequency domain reflection method (FDR) are usually used to collect a reflection coefficient spectrum of the cable, and characteristics of the reflection coefficient spectrum are analyzed to determine defects. Generally, the original reflection coefficient spectrum is directly used for analysis, and signal attenuation is compensated. However, in the test process, impedance mismatch between a test device and a cable body will cause distortion of the reflection coefficient spectrum. For example, when the output impedance of the test device does not match the input impedance of the cable body, reflection will occur at the connection between the two. However, the traditional technology does not fully consider the reflection interference caused by impedance mismatch of the test fixture and the cable head connection. The equivalent impedance of the connection between the test fixture and the cable head cannot be quantified, so the original reflection coefficient spectrum cannot be corrected to eliminate the influence of impedance mismatch of the test fixture on the test result (such as the time domain response of the cable defect), and the test result cannot truly reflect the defect condition of the cable body, which easily leads to misjudgment or omission, resulting in low accuracy and reliability of cable defect early warning. SUMMARY

[0004] The embodiments of the present application provide a cable defect early warning method, device, terminal device and storage medium. The low-frequency component is extracted as the head reflection coefficient, and the equivalent impedance of the connection between the test fixture and the cable head is quantified in combination with the internal resistance of the test device and the cable impedance. The original reflection coefficient spectrum is corrected according to the equivalent impedance to eliminate the impedance mismatch of the test fixture in the test process. The corrected reflection coefficient spectrum can more accurately reflect the impedance of the cable body, improve the accuracy and reliability of the cable defect early warning, and effectively solve the problem that the original reflection coefficient spectrum cannot be corrected to eliminate the influence of impedance mismatch of the test fixture on the test result (such as the time domain response of the cable defect) in the prior art, so that the test result cannot truly reflect the defect condition of the cable body, resulting in low accuracy and reliability of the cable defect early warning.

[0005] An embodiment of the present application provides a cable defect early warning method, comprising:

[0006] The swept-frequency test is performed on an equivalent circuit model comprising a test device, a test line, a test clamp and a cable connected in sequence to generate a reflection coefficient spectrum; wherein the reflection coefficient spectrum is used to reflect signal reflection characteristics in the cable test process;

[0007] The reflection coefficient spectrum is separated to extract a low-frequency component with a frequency less than a preset frequency threshold, and the low-frequency component is taken as a head-end reflection coefficient; an equivalent impedance corresponding to a connection between the test clamp and a head end of the cable is generated according to the head-end reflection coefficient, an internal resistance of the test device and an impedance of the cable; wherein the head-end reflection coefficient is used to represent a reflection coefficient caused by impedance mismatch between the head end of the cable and a body of the cable;

[0008] The reflection coefficient spectrum is corrected according to an input impedance of the cable during the swept-frequency test, the equivalent impedance and an impedance of the test device to determine a corrected reflection coefficient spectrum;

[0009] An attenuation term corresponding to a signal attenuation amount between a defect of the cable and the head end of the cable is compensated according to a linear relationship between an attenuation coefficient corresponding to the cable and a test frequency of the swept-frequency test to generate a compensated attenuation term;

[0010] A time-domain response corresponding to the defect of the cable is determined according to the corrected reflection coefficient spectrum and the compensated attenuation term, and defect early warning information corresponding to an amplitude of the defect in the time-domain response is generated.

[0011] Preferably, the separating of the reflection coefficient spectrum to extract the low-frequency component with the frequency less than the preset frequency threshold comprises:

[0012] A preset frequency threshold is generated according to a preset proportion value and a length of the cable;

[0013] The preset frequency threshold is taken as a cutoff frequency of a low-pass filter;

[0014] The low-pass filter is used to filter out a high-frequency component not less than the cutoff frequency in the reflection coefficient spectrum to output the low-frequency component with the frequency less than the preset frequency threshold.

[0015] Preferably, the generating of the equivalent impedance corresponding to the connection between the test clamp and the head end of the cable according to the head-end reflection coefficient, the internal resistance of the test device and the impedance of the cable comprises:

[0016] The equivalent impedance is calculated according to the following formula:

[0017]

[0018] wherein, Z wR0 is the internal resistance of the test equipment, and p'1 is the reflection coefficient of the cable head end.

[0019] Preferably, the reflection coefficient spectrum is corrected according to the input impedance of the cable during the sweep test, the equivalent impedance, and the impedance of the test equipment, and a corrected reflection coefficient spectrum is determined, including:

[0020] The corrected reflection coefficient spectrum is determined according to the following formula:

[0021]

[0022] Where Γ'0(ω) is the corrected reflection coefficient spectrum, ω is the angular frequency during the sweep test, Z' in is the input impedance of the cable during the sweep test, and Z w R0 is the internal resistance of the test equipment.

[0023] Preferably, the attenuation term is compensated according to the linear relationship between the attenuation coefficient corresponding to the cable and the test frequency of the sweep test, and a compensated attenuation term is generated, including:

[0024] According to the cable model of the cable, an attenuation relationship corresponding to the cable is obtained; wherein the attenuation relationship is used to represent the linear relationship between the attenuation coefficient of the cable and the test frequency of the sweep test;

[0025] According to the target distance between the defect of the cable and the cable head end, and the attenuation relationship, a to-be-processed attenuation term is generated;

[0026] The to-be-processed attenuation term is Fourier transformed to generate a compensated attenuation term.

[0027] Preferably, the time-domain response corresponding to the defect of the cable is determined according to the corrected reflection coefficient spectrum and the compensated attenuation term, including:

[0028] The corrected reflection coefficient spectrum and the compensated attenuation term are deconvoluted and the modulus value is taken to generate a reflection coefficient spectrum that has been compensated for distance attenuation;

[0029] The input voltage of the sweep test and the reflection coefficient spectrum that has been compensated for distance attenuation are frequency domain point multiplied, and then inverse Fourier transformed according to the frequency domain point multiplication result to generate a time-domain response corresponding to the defect of the cable.

[0030] Preferably, the corresponding defect warning information is generated according to the amplitude of the defect in the time-domain response, including:

[0031] acquiring an amplitude at the defect in the time domain response;

[0032] when it is determined that the amplitude is greater than the preset amplitude threshold value, and a ratio value between the amplitude and the preset amplitude threshold value is less than a first ratio value, then generating defect early warning information for representing that the cable has a slight defect;

[0033] when it is determined that the amplitude is greater than the preset amplitude threshold value, and a ratio value between the amplitude and the preset amplitude threshold value is greater than the first ratio value and less than a second ratio value, then generating defect early warning information for representing that the cable has a moderate defect;

[0034] when it is determined that the amplitude is greater than the preset amplitude threshold value, and a ratio value between the amplitude and the preset amplitude threshold value is greater than the second ratio value and less than a third ratio value, then generating defect early warning information for representing that the cable has a serious defect.

[0035] On the basis of the method embodiments described above, the application provides corresponding device embodiments.

[0036] An embodiment of the application provides a defect early warning device of a cable, comprising a reflection coefficient spectrum generation module, an equivalent impedance generation module, a reflection coefficient spectrum correction module, an attenuation term compensation module and a defect early warning information generation module.

[0037] The reflection coefficient spectrum generation module is configured to perform frequency sweep testing on an equivalent circuit model comprising a test device, a test line, a test clamp and the cable connected in sequence, and generate a reflection coefficient spectrum; wherein the reflection coefficient spectrum is used to reflect signal reflection characteristics in the cable testing process.

[0038] The equivalent impedance generation module is configured to separate the reflection coefficient spectrum, extract a low-frequency component with a frequency less than a preset frequency threshold value, and take the low-frequency component as a first-end reflection coefficient; and generate an equivalent impedance corresponding to a connection between the test clamp and a first end of the cable according to the first-end reflection coefficient, an internal resistance of the test device and an impedance of the cable; wherein the first-end reflection coefficient is used to represent a reflection coefficient caused by impedance mismatch between the first end of the cable and a body of the cable.

[0039] The reflection coefficient spectrum correction module is configured to correct the reflection coefficient spectrum according to an input impedance of the cable during the frequency sweep testing, the equivalent impedance and an impedance of the test device, and determine a corrected reflection coefficient spectrum.

[0040] The attenuation term compensation module is configured to compensate an attenuation term according to a linear relationship between an attenuation coefficient corresponding to the cable and a test frequency of the frequency sweep testing, and generate a compensated attenuation term; wherein the attenuation term is a signal attenuation amount between the defect of the cable and the first end of the cable.

[0041] The defect early warning information generation module is configured to determine a time domain response corresponding to the cable defect according to the corrected reflection coefficient spectrum and the compensated attenuation term, and generate corresponding defect early warning information according to an amplitude of the defect in the time domain response.

[0042] Based on the method embodiments described above, the application further provides terminal device embodiments.

[0043] Another embodiment of the application provides a terminal device, which comprises a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor, and the processor executes the computer program to implement the cable defect early warning method described in the above embodiments of the application.

[0044] Based on the method embodiments described above, the application further provides storage medium embodiments.

[0045] Another embodiment of the application provides a storage medium, which comprises a stored computer program, and when the computer program is executed, the device where the computer readable storage medium is located executes the cable defect early warning method described in the above embodiments of the application.

[0046] By implementing the application, the following beneficial effects can be achieved:

[0047] The embodiment of the present application provides a kind of cable defect early warning method, device, terminal equipment and storage medium, the present application is scanned to the equivalent circuit model, after generating the reflection coefficient spectrum, low frequency component that the frequency of separation from the reflection coefficient spectrum is lower than preset frequency threshold, since at lower frequency, signal wavelength is much larger than cable length and fixture size, reflection coefficient is caused by the first end impedance mismatch at this time, not cable internal defect or distributed parameter effect, therefore, the present application can obtain the first end reflection coefficient corresponding to impedance mismatch directly reflecting the connection of cable first end and fixture by extracting low frequency component, to further combine first end reflection coefficient, test equipment internal resistance and cable impedance, the equivalent impedance of test fixture and cable first end is calculated, the impedance of test fixture and cable first end connection is quantified, then the original reflection coefficient spectrum is corrected using the cable input impedance obtained by sweep frequency test, the equivalent impedance quantified and test equipment impedance;After compensating attenuation term according to the linear relationship between the attenuation coefficient corresponding to cable and the test frequency of sweep frequency test, the time domain response corresponding to cable defect can be determined according to the corrected reflection coefficient spectrum and the compensated attenuation term, so as to generate corresponding defect early warning information according to the amplitude of defect in the time domain response.Compared with prior art, the present application extracts low frequency component as first end reflection coefficient, and combines test equipment internal resistance and cable impedance, to quantify the equivalent impedance of test fixture and cable first end connection, and corrects the original reflection coefficient spectrum according to the equivalent impedance, to eliminate the impedance mismatch of test fixture in the test process, so that the corrected reflection coefficient spectrum can more accurately reflect the impedance of cable body, so that the subsequent obtained time domain response can more truly reflect the defect condition of cable body, to further improve the accuracy and reliability of cable defect early warning. BRIEF DESCRIPTION OF DRAWINGS

[0048] Figure 1 It is a kind of cable defect early warning method flow chart provided by the embodiment of the present application.

[0049] Figure 2 It is the schematic diagram of cable distributed parameter equivalent model provided by the embodiment of the present application.

[0050] Figure 3 It is the schematic diagram of cable propagation characteristic provided by the embodiment of the present application containing first end impedance mismatch.

[0051] Figure 4 It is the first end impedance mismatch model of cable provided by the embodiment of the present application.

[0052] Figure 5 It is the structure schematic diagram of a kind of cable defect early warning device provided by the embodiment of the present application. DETAILED DESCRIPTION

[0053] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0054] like Figure 1 As shown, to address the problem that existing technologies do not adequately consider reflection interference caused by impedance mismatch between the test fixture and the cable end connection, thus failing to quantify the impedance at the connection point and consequently unable to correct the original reflection coefficient spectrum to eliminate the impact of impedance mismatch on test results (such as the time-domain response of cable defects), resulting in low accuracy and reliability of cable defect early warning, an embodiment of the present invention provides a cable defect early warning method, comprising:

[0055] Step S1: Perform a frequency sweep test on the equivalent circuit model containing the test equipment, test leads, test fixtures and cable connected in sequence to generate a reflection coefficient spectrum; wherein, the reflection coefficient spectrum is used to reflect the signal reflection characteristics during the cable test.

[0056] In illustrative terms, embodiments of the present invention can use testing equipment such as a network analyzer to inject a full-band sweep signal (e.g., 100Hz to 1GHz) into an equivalent circuit model consisting of "test equipment → test lines → test fixtures → cables", collect and record the intensity of reflected signals at each frequency point, and generate a reflection coefficient spectrum (the horizontal axis is frequency, and the vertical axis is reflection coefficient amplitude / phase).

[0057] Understandably, frequency sweep testing can capture impedance changes in cables at different frequencies. High-frequency bands are sensitive to minor defects (such as microcracks), while low-frequency bands can reflect the connection status at the cable's inlet. The reflection coefficient spectrum contains amplitude and phase information, providing the initial data basis for subsequent separation of inlet interference from defects in the cable itself.

[0058] Step S2: Separate the reflection coefficient spectrum, extract the low-frequency components with frequencies lower than a preset frequency threshold, and use the low-frequency components as the first-end reflection coefficient; generate the equivalent impedance corresponding to the connection between the test fixture and the cable first end based on the first-end reflection coefficient, the internal resistance of the test equipment, and the impedance of the cable; wherein, the first-end reflection coefficient is used to characterize the reflection coefficient caused by the impedance mismatch between the cable first end and the cable body.

[0059] In a schematic manner, a preset frequency threshold can be set, and a low-pass filter can be used to extract low-frequency components with frequencies below this threshold. These low-frequency components only reflect the impedance mismatch between the test fixture and the cable end (because the wavelength of the low-frequency signal is much longer than the cable length, defect reflection can be ignored). The cable's distributed parameters have a smaller impact at low frequencies, the signal wavelength is longer, and the contribution of defect reflection signals to the overall reflection coefficient is weak. Furthermore, the impedance characteristics of the connection point between the test fixture and the cable are closer to the static resistance at low frequencies. Therefore, the equivalent impedance at the connection point can be further derived using the low-frequency component data.

[0060] The equivalent impedance at the connection between the test fixture and the cable head end is obtained by using the head-end reflection coefficient. This decouples the impedance effect of the test fixture from the signal of the cable itself. For example, by frequency separation, head-end contact problems (such as fixture oxidation or loosening) are decoupled from cable defects. This solves the problem of test fixture interference masking the real defects in traditional methods, so that the subsequent corrected reflection coefficient spectrum only reflects the characteristics of the cable itself, significantly improving the accuracy of subsequent defect warning.

[0061] Step S3: Based on the input impedance of the cable, the equivalent impedance, and the impedance of the test equipment during the frequency sweep test, the reflection coefficient spectrum is corrected to determine the corrected reflection coefficient spectrum.

[0062] Indicatively, the cable input impedance obtained using a frequency sweep test can be understood as the impedance value presented by the cable and its connection system (including test leads, test clamps, etc.) when viewed from the input end of the test equipment during a frequency sweep test (i.e., scanning tests on signals of different frequencies). The cable input impedance reflects the impedance characteristics of the cable system to the input signal at different frequencies, and is also the overall impedance characteristic of the cable system (including clamps, test leads, etc.).

[0063] By using the input impedance obtained from the frequency sweep test, combined with the quantized equivalent impedance of the test fixture and the internal resistance of the test equipment, the original reflection coefficient spectrum can be reverse-corrected through the impedance network cascade theory. This eliminates the influence of impedance mismatch at the beginning, so that the corrected reflection coefficient spectrum only contains the impedance change information of the cable body (such as the local impedance change at the defect), eliminating the interference of external links such as test equipment and fixtures, and allowing subsequent analysis to focus on the cable body.

[0064] Step S4: Based on the linear relationship between the attenuation coefficient of the cable and the test frequency of the sweep frequency test, compensate for the attenuation term to generate a compensated attenuation term; wherein, the attenuation term is the signal attenuation between the defect of the cable and the beginning of the cable.

[0065] Indicatively, the attenuation coefficient represents the energy loss per unit length of signal transmission in a cable. The attenuation term (signal attenuation) refers to the energy loss due to attenuation as the signal travels from the cable's beginning to the defect. Attenuation directly affects the amplitude of the reflected signal at the defect; the greater the attenuation, the weaker the signal reflected back to the cable's beginning, potentially leading to decreased defect detection sensitivity. Therefore, attenuation compensation is necessary to eliminate the impact of attenuation on the reflected signal amplitude during transmission, ensuring that the defect amplitude in the time-domain response reflects only the impedance mismatch, not the energy loss caused by attenuation. Without compensation, high-frequency defect reflection signals may be excessively attenuated, leading to distortion of the defect amplitude in the time-domain response (e.g., small defects may be misjudged as large defects, or large defects may be missed). This step, through linear compensation, uniformly corrects the attenuation of signals at different frequencies, restoring the true reflection intensity of the defect.

[0066] Step S5: Based on the corrected reflection coefficient spectrum and the compensated attenuation term, determine the time domain response corresponding to the cable defect, and generate the corresponding defect warning information based on the amplitude of the defect in the time domain response.

[0067] Indicatively, the present invention can convert the compensated reflection coefficient spectrum and the compensated attenuation term into a time-domain response waveform, with the horizontal axis representing time (corresponding to distance) and the vertical axis representing amplitude (corresponding to reflection intensity).

[0068] This allows for the generation of corresponding warnings based on the amplitude of the peak position in the time domain response, such as "minor / moderate / serious" defect warnings.

[0069] For step S1, in a preferred embodiment, the present invention can perform a frequency sweep test on the equivalent circuit model based on the time-frequency domain re-flectometry (TFDR) method to obtain the reflection coefficient spectrum. Due to the random impedance mismatch of the test fixture at the cable end and the signal attenuation during propagation, the obtained reflection coefficient spectrum will have a large error. Therefore, it is necessary to eliminate the influence of the test fixture at the cable end and the signal propagation distance.

[0070] Understandably, transmission line theory dictates that, in order to accurately describe the energy transfer characteristics of signals within a cable, at high frequencies, the cable must be equivalent to countless lines such as... Figure 2 The differential segmented distributed parameter equivalent circuit shown is the cable distributed parameter equivalent model, where R, G, C, and L are the resistance, conductance, capacitance, and inductance per unit length Δx of the cable, respectively.

[0071] Let the total length of the cable be l. The voltage U(x) and current I(x) at a distance x from the cable's beginning can be expressed by Kirchhoff's voltage law and current law:

[0072]

[0073] Among them, U + U - Let Z0 and γ represent the forward and reverse voltages of the cable. Equation (1) shows that the voltage at any location can be composed of the forward signal propagating from the test head to the cable end and the reverse signal propagating from the cable end to the test head. In equation (1), parameters Z0 and γ represent the characteristic impedance and propagation coefficient of the cable, respectively, which are the inherent and changing characteristics of electromagnetic waves propagating in the cable. Their expressions can be derived from equations (2) and (3), respectively:

[0074]

[0075]

[0076] From formula (2), it can be seen that ω is the angular frequency during the sweep frequency test, j is the imaginary unit, and under high frequency conditions, ωL>>R, ωC>>G, Z0 is approximately a constant, and its value is determined by L and C. It can be derived from formula (2) to obtain (4):

[0077]

[0078] In formula (3), α is the attenuation constant, which characterizes the signal amplitude attenuation characteristic per unit length of the cable; β is the phase constant, which characterizes the signal phase lag characteristic per unit length of the cable; and v is the propagation speed of electromagnetic waves in the cable.

[0079] To express the signal propagation characteristics of a cable with impedance mismatch at the beginning, such as Figure 3 The diagram showing the cable propagation characteristics assumes that the total length of the tested line, including the test fixture, is d+l (end load Z). L =∞), where d is the length of the impedance mismatch section at the beginning, and l is the total length of the cable after removing the cable termination at one end, then Figure 3 The process of signal propagation in the cable is described.

[0080] like Figure 3 As shown, R0 represents the internal resistance of the test equipment, and ρ0 is the reflection coefficient caused by the impedance mismatch between the test fixture and the terminal. ρ0 = (R0 - Z0) / (R0 + Z0). This is illustrative. The terminal mentioned above refers to the other end (not the beginning end) of the cable when the equivalent internal resistance of the test equipment is connected to the cable.

[0081] ρ1 is the reflection coefficient caused by impedance mismatch between the cable end and the cable body. U0 is the injected signal, U1 is the reflected signal from the impedance mismatch section at the cable head, and U2 is the reflected signal from the cable end, which is set to open circuit. U'0 is the sum of the reflected signals from the cable head in the frequency domain, which can be expressed as:

[0082]

[0083] Where γ1 is the propagation coefficient of the signal at the beginning of the cable (corresponding to attenuation coefficient α1, phase coefficient β1, and wave velocity v1), and γ2 is the propagation coefficient of the cable body (corresponding to attenuation coefficient α2, phase coefficient β2, and wave velocity v2). Since the end of the cable is in an open circuit state, the end reflection coefficient is 1. If the cable is extended and the original end position is replaced by a defect point, the corresponding reflection coefficient is ρ2. Then, U2 in equation (5) needs to be multiplied by a term ρ2.

[0084] It is easy to see from the expression of U2 that the reflected signal U2 is affected by the impedance mismatch section at the beginning of the cable. That is, the reflection point at the beginning of the cable will affect the amplitude of the reflected signal at the reflection point at the end. Therefore, the amplitude at this time cannot intuitively reflect the change of impedance at the reflection point.

[0085] In addition to the ρ term related to the reflection coefficient, the distance factor (d and l in the reflected signal U2) in its exponential decay term also affects the magnitude of U2. Even with the same defect, the reflected signal will have different attenuations depending on the distance between the defect location and the head end.

[0086] In summary, the propagation characteristics of the reflected signal at the defect in the cable are determined by the impedance of the defect itself, as well as by the impedance mismatch at the cable head and the propagation distance. Therefore, in order to quantitatively assess the degree of impedance change at each defect from the reflected signal, it is necessary to compensate for the cable head mismatch and the signal propagation distance after generating the reflection coefficient spectrum, thereby correcting the reflection coefficient spectrum.

[0087] For steps S2 and S3, as can be seen from step S1, based on the time-frequency domain reflection method, the injected signal U0 is known, and the reflected signal U'0 can be measured by the acquisition module. Therefore, by injecting signals U0 with different center frequencies and simultaneously acquiring their corresponding reflected signals U'0, the transfer function T0 of the cable can be fitted, T0 = U'0 / U0. Based on equation (5), T0 can be written as:

[0088]

[0089] Expanding equation (6) according to Euler's formula and extracting its real part, we can obtain:

[0090]

[0091] As can be seen from equation (7), the transfer function T0 describes the overall transformation characteristics of the signal from injection to reflection, reflecting the response of the cable system to signals of different frequencies. This transfer function consists of a constant term and two exponentially decaying oscillatory terms. The first exponentially decaying oscillatory term is caused by the head-end mismatch, where α1 refers to the attenuation coefficient of the cable at point d. The second exponentially decaying oscillatory term is caused by the cable tail, where α2 refers to the attenuation coefficient of the cable at point l. As can be seen from equation (7), an exponentially decaying oscillatory term appears for each impedance mismatch point in the cable, with an equivalent frequency f. x Since the location is related to the defect, the defect location and corresponding energy information can be obtained by performing an FFT (Fast Fourier Transform) on the transfer function. The distance calculation formula is as follows:

[0092]

[0093] Taking the exponentially decayed oscillation term at the end of the cable in equation (7) as an example, its amplitude is not only related to its own reflection coefficient (the open-circuit reflection coefficient at the end is 1), but also to the reflection coefficient of the preceding reflection point, that is, the reflection coefficient of the cable head and the intermediate joint. The reflection coefficient of the intermediate joint has a relatively small impact on the exponentially decayed oscillation term at the end of the cable.

[0094] It is understandable that after performing an FFT transformation on the transfer function, each peak in the spectrum corresponds to a specific frequency. The reflection at the beginning of the cable corresponds to the low-frequency component (short round-trip time of the signal), while the reflection at the end of the cable corresponds to the high-frequency component (the signal needs to travel a longer distance).

[0095] Therefore, in this step, the obtained reflection coefficient spectrum can be separated to extract low-frequency components with frequencies lower than a preset frequency threshold. Based on these low-frequency components (i.e., the first-end reflection coefficient), combined with the internal resistance of the test equipment and the cable impedance, the equivalent impedance at the connection between the test fixture and the first end of the cable can be generated. This can effectively eliminate interference from fixtures and other components in the test system, allowing the reflection coefficient spectrum to be corrected using the equivalent impedance. This corrected reflection coefficient spectrum can then focus on the impedance characteristics of the cable itself, thus more accurately reflecting the cable's condition.

[0096] In a preferred embodiment, separating the reflection coefficient spectrum and extracting low-frequency components with frequencies less than a preset frequency threshold includes:

[0097] A preset frequency threshold is generated based on a preset ratio value and the length of the cable;

[0098] The preset frequency threshold is used as the cutoff frequency of the low-pass filter;

[0099] The low-pass filter filters out high-frequency components in the reflection coefficient spectrum that are not less than the cutoff frequency, and outputs low-frequency components with frequencies less than a preset frequency threshold.

[0100] Schematic, as shown in equation (7), the first exponentially decaying oscillation term is caused by impedance mismatch at the cable's head end, and its equivalent frequency f x The frequency of the reflected signal is lower than the equivalent frequency of the reflected signal produced at a location farther from the cable head. Therefore, by filtering out the high-frequency components of the initial reflection coefficient spectrum, the remaining low-frequency components can be used as the head-end reflection coefficient caused by impedance mismatch at the cable head.

[0101] Furthermore, based on the obtained head-end reflection coefficient, the equivalent impedance corresponding to the connection between the test fixture and the cable head-end can be generated by combining the internal resistance of the test equipment and the impedance of the cable.

[0102] Specifically, in order to eliminate the head-end reflection caused by impedance mismatch, embodiments of the present invention can treat the test lead and the cable terminal as a whole, thereby quantifying the equivalent impedance Z corresponding to the connection between the test fixture and the cable head-end. w ,like Figure 4 The cable termination impedance mismatch model shown replaces the impedances of the test leads and cable terminations with a variable impedance Z. w For illustrative purposes, the cable termination mentioned above does not refer to the end of the cable, but rather to the equivalent load end of the cable head in the testing system, i.e., the connection point between the test fixture and the cable body. The impedance at this connection point is affected by factors such as the contact resistance of the fixture and parasitic capacitance / inductance, exhibiting non-ideal characteristics. Therefore, a variable impedance Z is required. w express.

[0103] The above-described cable termination impedance mismatch model is, in fact, the equivalent circuit model of this invention. This equivalent circuit model allows the impedance of the test leads and cable terminations to be replaced with a variable impedance Z. w Its core is to construct an equivalent circuit model to simulate the connection characteristics between the test fixture and the cable end, so as to quantify the variable impedance Z. w .

[0104] In a preferred embodiment, the equivalent impedance can be calculated according to the following formula:

[0105]

[0106] Among them, Z w R0 is the equivalent impedance at the connection between the test fixture and the cable end, ρ'1 is the reflection coefficient at the cable end, and Z0 is the impedance of the cable.

[0107] Specifically, during frequency sweep testing, the impedance frequency response of the entire system, as seen from the input of the test equipment (such as a network analyzer), is Z'. in This can be used as the input impedance of the cable during frequency sweep testing. Assuming a perfect match between the test fixture and the cable end (no contact resistance, parasitic reactance), the impedance frequency response of the cable body is Z. in (This can be understood as the impedance spectrum of an ideal input). However, due to the non-ideal characteristics at the connection between the test fixture and the cable end, the connection between the test fixture and the cable end can be equivalent to a variable impedance Z. w Therefore, the input impedance Z' of the cable during the frequency sweep test is... in It is Z in and Z w The sum of these can be used to determine the corrected reflection coefficient spectrum using the following formula:

[0108]

[0109] Where Γ'0(ω) is the corrected reflection coefficient spectrum, ω is the angular frequency during the sweep frequency test, and Z' in Z represents the input impedance of the cable during frequency sweep testing. w R0 is the equivalent impedance at the connection between the test fixture and the cable end, and R0 is the internal resistance of the test equipment.

[0110] Therefore, the head-end reflection coefficient ρ'1 caused by the head-end impedance mismatch can be expressed as:

[0111]

[0112] Transforming equation (10), we obtain the variable impedance Z. w The expression is:

[0113]

[0114] From formula (11), it can be seen that if ρ'1 and Z0 are known, then Z w It can be calculated, and the resulting Z can be... w Substituting into formula (9), the corrected reflection coefficient spectrum is obtained. Then we have:

[0115]

[0116] Furthermore, substituting equation (11) into equation (12) yields:

[0117]

[0118] In equation (13), for a known cable type, the characteristic impedance of the cable body can be obtained by calculation (i.e., by formula (4)). Therefore, the calculation of ρ'1 is to obtain the corrected reflection. Given the coefficient spectrum, in this step, a low-pass filter can be used to filter out the high-frequency components in Γ'0, leaving the low-frequency components as the reflection coefficient ρ'1 caused by the head end. Illustratively, if the preset frequency threshold is 5%, then the cutoff frequency of the digital low-pass filter can be set to the equivalent frequency corresponding to 5% of the cable length. If the cutoff frequency of the digital low-pass filter can be set to the equivalent frequency corresponding to 5% of the cable length, then:

[0119] ρ'1=LPF(Γ'0) (14)

[0120] Substituting the obtained ρ'1 into equation (13) yields the corrected reflection coefficient spectrum, thus reducing the impact of the cable head end on the test results.

[0121] For step S4, since the amplitude of long-distance defects in the cable is underestimated due to high-frequency attenuation, distance attenuation distortion can be eliminated by compensating for attenuation, so that the time-domain response amplitude can truly reflect the severity of the defect.

[0122] In a preferred embodiment, the step of compensating for the attenuation term based on the linear relationship between the attenuation coefficient of the cable and the test frequency of the sweep frequency test, to generate a compensated attenuation term, includes:

[0123] Based on the cable model, obtain the corresponding attenuation formula for the cable; wherein, the attenuation formula is used to characterize the linear relationship between the cable's attenuation coefficient and the test frequency of the sweep frequency test;

[0124] Based on the target distance between the cable defect and the cable head, and the attenuation relationship, an attenuation term to be processed is generated;

[0125] Perform a Fourier transform on the attenuation term to be processed to generate a compensated attenuation term.

[0126] Schematic, as can be seen from formula (7), when processing data using FFT transformation, the attenuation term e -2αl Fourier transform and modulus calculations were also performed, so the signal attenuation can be compensated simply by eliminating the influence of the attenuation term. The attenuation term is affected by both the attenuation coefficient α0 and the signal propagation distance l1. Eliminating the influence of the attenuation term will eliminate the influence of the attenuation coefficient and the signal propagation distance.

[0127] When the cable under test is fixed, the distance of its defect and the distance of its end are also fixed. The attenuation coefficient is a variable that changes with frequency. We need to obtain its variable relationship with frequency and then substitute this relationship into the original attenuation term to compensate for the signal attenuation according to the magnitude of the test frequency.

[0128] Because different types of cables have different materials and structures (such as conductor cross-sectional area and insulation thickness), their attenuation coefficients have different relationships with frequency. Therefore, the attenuation relationship between α0 and the test frequency f can be approximated as:

[0129] α0≈kf (15)

[0130] Where k is a coefficient, the value of which is determined by the cable type. The attenuation relationship of the cable can be obtained based on the cable type. Substituting equation (15) into the attenuation term, the attenuation term can be obtained as follows:

[0131]

[0132] Where α0 represents the attenuation coefficient of the attenuation term at l1. Formula (16) is the attenuation term to be processed obtained based on the target distance l1 between the defect and the cable head and the attenuation relationship;

[0133] Furthermore, performing a Fourier transform on the attenuation term S yields:

[0134] S f =FFT(S) (17)

[0135] Finally, S is obtained according to formula (17). f , as the attenuation term after compensation.

[0136] Therefore, by using the linear relationship between the attenuation coefficient of the cable and the test frequency of the sweep frequency test to compensate for the attenuation term, the influence of distance attenuation on the test results can be eliminated, the accuracy of defect detection can be improved, and better early warning can be provided.

[0137] For step S5, in a preferred embodiment, determining the time-domain response corresponding to the cable defect based on the corrected reflection coefficient spectrum and the compensated attenuation term includes:

[0138] The corrected reflection coefficient spectrum and the compensated attenuation term are deconvolved and the modulus is taken to generate the reflection coefficient spectrum after distance attenuation compensation.

[0139] The input voltage of the frequency sweep test is multiplied in the frequency domain with the reflection coefficient spectrum after distance attenuation compensation, and then an inverse Fourier transform is performed based on the frequency domain multiplication result to generate the time domain response corresponding to the cable defect.

[0140] Schematic, in this step, the reflection coefficient spectrum D after distance attenuation compensation can be obtained by deconvolving equation (17) and equation (13) and then taking the modulus:

[0141]

[0142] in Representing deconvolution, abs() is a function that stands for absolute value, often used to obtain the absolute value of a number or expression.

[0143] After obtaining the attenuation-compensated reflection coefficient spectrum D, the attenuation-compensated TFDR time-domain waveform is obtained by combining it with the incident signal, i.e., by combining it with abs(), and thus the time-domain response y(t) is obtained:

[0144]

[0145] Wherein, U0 is the original input waveform of TFDR, and its frequency can be any frequency within the frequency range of the reflection coefficient spectrum. By convolving the frequency domain characteristics of U0 with the attenuation-compensated reflection coefficient spectrum D (frequency domain dot product), and then performing an inverse Fourier transform (IFFT) based on the frequency domain dot product result, the time domain response y(t) of U0 in the cable after end impedance adaptation and distance compensation can be obtained. At this time, the amplitude of the reflection peak at the defect of the time domain response y(t) can represent the magnitude of the reflection coefficient without considering line attenuation, and can be used to directly compare with the reflection peaks at other defects.

[0146] Furthermore, after obtaining the time-domain response, corresponding defect warning information can be generated based on the amplitude at the defect location in the time-domain response, resulting in:

[0147] Obtain the amplitude at the defect location in the time-domain response;

[0148] When it is determined that the amplitude is greater than a preset amplitude threshold and the ratio between the amplitude and the preset amplitude threshold is less than a first ratio value, a defect warning message is generated to characterize the cable for having a minor defect.

[0149] When it is determined that the amplitude is greater than a preset amplitude threshold, and the ratio between the amplitude and the preset amplitude threshold is greater than a first ratio and less than a second ratio, a defect warning message is generated to characterize the cable as having a moderate defect.

[0150] When it is determined that the amplitude is greater than a preset amplitude threshold, but the ratio between the amplitude and the preset amplitude threshold is greater than a second ratio and less than a third ratio, a defect warning message is generated to characterize that the cable has a serious defect.

[0151] For illustrative purposes, if the amplitude is determined to be no greater than a preset amplitude threshold, no defect warning information will be generated.

[0152] In this embodiment of the invention, operations such as deconvolution, attenuation compensation, frequency domain multiplication, and inverse Fourier transform can be used to achieve a precise conversion from the frequency domain reflection coefficient spectrum to the time domain response, and different levels of defect warning information can be generated through amplitude grading.

[0153] like Figure 5 As shown, based on the embodiments of the above-mentioned defect early warning methods for various cables, the present invention provides corresponding device embodiments;

[0154] An embodiment of the present invention provides a cable defect early warning device, comprising: a reflection coefficient spectrum generation module, an equivalent impedance generation module, a reflection coefficient spectrum correction module, an attenuation term compensation module, and a defect early warning information generation module;

[0155] The reflection coefficient spectrum generation module is used to perform frequency sweep testing on an equivalent circuit model containing sequentially connected test equipment, test leads, test fixtures, and cables to generate a reflection coefficient spectrum; wherein, the reflection coefficient spectrum is used to reflect the signal reflection characteristics during cable testing.

[0156] The equivalent impedance generation module is used to separate the reflection coefficient spectrum, extract low-frequency components with frequencies lower than a preset frequency threshold, and use the low-frequency components as the head-end reflection coefficient; based on the head-end reflection coefficient, the internal resistance of the test equipment, and the impedance of the cable, the equivalent impedance corresponding to the connection between the test fixture and the cable head-end is generated; wherein, the head-end reflection coefficient is used to characterize the reflection coefficient caused by the impedance mismatch between the cable head-end and the cable body.

[0157] The reflection coefficient spectrum correction module is used to correct the reflection coefficient spectrum based on the input impedance of the cable, the equivalent impedance, and the impedance of the test equipment during the frequency sweep test, and to determine the corrected reflection coefficient spectrum.

[0158] The attenuation compensation module is used to compensate for the attenuation term based on the linear relationship between the attenuation coefficient of the cable and the test frequency of the sweep frequency test, and generate a compensated attenuation term; wherein, the attenuation term is the signal attenuation between the defect point of the cable and the beginning of the cable.

[0159] The defect warning information generation module is used to determine the time domain response corresponding to the cable defect based on the corrected reflection coefficient spectrum and the compensated attenuation term, and to generate corresponding defect warning information based on the amplitude of the defect in the time domain response.

[0160] It should be noted that the device embodiments described above are merely illustrative. The modules described as separate components may or may not be physically separate, and the components shown as modules may or may not be physical modules; they may be located in one place or distributed across multiple network modules. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Furthermore, in the accompanying drawings of the device embodiments provided by this invention, the connection relationships between modules indicate that they have communication connections, which can be specifically implemented as one or more communication buses or signal lines. Those skilled in the art can understand and implement this without any creative effort.

[0161] Those skilled in the art will clearly understand that, for convenience and simplicity, the specific working process of the device described above can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0162] Based on the above embodiments of various cable defect early warning methods, the present invention provides corresponding embodiments of terminal equipment.

[0163] One embodiment of the present invention provides a terminal device, including a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor. When the processor executes the computer program, it implements a cable defect early warning method according to any embodiment of the present invention.

[0164] The terminal device may be a desktop computer, laptop, handheld computer, or cloud server, etc. The terminal device may include, but is not limited to, a processor and a memory.

[0165] The processor can be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor can be a microprocessor or any conventional processor. The processor is the control center of the terminal device, connecting all parts of the terminal device via various interfaces and lines.

[0166] The memory can be used to store the computer program. The processor implements various functions of the terminal device by running or executing the computer program stored in the memory and calling data stored in the memory. The memory may mainly include a program storage area and a data storage area. The program storage area may store the operating system, at least one application program required for a function, etc.; the data storage area may store data created based on the use of the mobile phone, etc. In addition, the memory may include high-speed random access memory, and may also include non-volatile memory, such as hard disk, RAM, plug-in hard disk, smart media card (SMC), secure digital (SD) card, flash card, at least one disk storage device, flash memory device, or other volatile solid-state storage device.

[0167] Based on the above embodiments of various cable defect early warning methods, the present invention provides corresponding embodiments of storage media.

[0168] One embodiment of the present invention provides a storage medium including a stored computer program, wherein, when the computer program is executed, it controls the device where the computer-readable storage medium is located to execute a cable defect early warning method according to any embodiment of the present invention.

[0169] The storage medium is a computer-readable storage medium, and the computer program is stored in the computer-readable storage medium. When executed by a processor, the computer program can implement the steps of the various method embodiments described above. The computer program includes computer program code, which can be in the form of source code, object code, executable file, or some intermediate form. The computer-readable medium can include: any entity or device capable of carrying the computer program code, recording media, USB flash drive, portable hard drive, magnetic disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signals, telecommunication signals, and software distribution media, etc. It should be noted that the content included in the computer-readable medium can be appropriately added or removed according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, the computer-readable medium does not include electrical carrier signals and telecommunication signals.

[0170] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A method for early warning of cable defects, characterized in that, include: A frequency sweep test is performed on an equivalent circuit model containing sequentially connected test equipment, test leads, test fixtures, and cables to generate a reflection coefficient spectrum; wherein, the reflection coefficient spectrum is used to reflect the signal reflection characteristics during cable testing. The reflection coefficient spectrum is separated to extract low-frequency components with frequencies lower than a preset frequency threshold, and these low-frequency components are used as the first-end reflection coefficient. Based on the first-end reflection coefficient, the internal resistance of the test equipment, and the impedance of the cable, the equivalent impedance corresponding to the connection between the test fixture and the cable first end is generated. The first-end reflection coefficient is used to characterize the reflection coefficient caused by the impedance mismatch between the cable first end and the cable body. The reflection coefficient spectrum is corrected based on the input impedance of the cable, the equivalent impedance, and the impedance of the test equipment during the frequency sweep test, and the corrected reflection coefficient spectrum is determined. Based on the linear relationship between the cable's attenuation coefficient and the test frequency of the sweep frequency test, the attenuation term is compensated to generate a compensated attenuation term; wherein, the attenuation term is the signal attenuation between the defect point and the cable's beginning. Based on the corrected reflection coefficient spectrum and the compensated attenuation term, the time-domain response corresponding to the cable defect is determined, and the corresponding defect warning information is generated based on the amplitude of the defect in the time-domain response.

2. The cable defect early warning method as described in claim 1, characterized in that, The step of separating the reflection coefficient spectrum and extracting low-frequency components with frequencies lower than a preset frequency threshold includes: A preset frequency threshold is generated based on a preset ratio value and the length of the cable; The preset frequency threshold is used as the cutoff frequency of the low-pass filter; The low-pass filter filters out high-frequency components in the reflection coefficient spectrum that are not less than the cutoff frequency, and outputs low-frequency components with frequencies less than a preset frequency threshold.

3. The cable defect early warning method as described in claim 2, characterized in that, The step of generating the equivalent impedance corresponding to the connection between the test fixture and the cable head end based on the reflection coefficient at the head end, the internal resistance of the test equipment, and the impedance of the cable includes: The equivalent impedance is calculated using the following formula: Among them, Z w R0 is the equivalent impedance at the connection between the test fixture and the cable end, ρ'1 is the reflection coefficient at the cable end, and Z0 is the impedance of the cable.

4. The cable defect early warning method as described in claim 3, characterized in that, The step of correcting the reflection coefficient spectrum based on the cable's input impedance, the equivalent impedance, and the impedance of the testing equipment during the frequency sweep test, and determining the corrected reflection coefficient spectrum, includes: The corrected reflection coefficient spectrum is determined using the following formula: Where Γ'0(ω) is the corrected reflection coefficient spectrum, ω is the angular frequency during the sweep frequency test, and Z' in Z represents the input impedance of the cable during frequency sweep testing. w R0 is the equivalent impedance at the connection between the test fixture and the cable end, and R0 is the internal resistance of the test equipment.

5. A cable defect early warning method as described in claim 4, characterized in that, The attenuation term is compensated based on the linear relationship between the cable's attenuation coefficient and the test frequency of the sweep frequency test, generating a compensated attenuation term, including: Based on the cable model, obtain the corresponding attenuation formula for the cable; wherein, the attenuation formula is used to characterize the linear relationship between the cable's attenuation coefficient and the test frequency of the sweep frequency test; Based on the target distance between the cable defect and the cable head, and the attenuation relationship, an attenuation term to be processed is generated; Perform a Fourier transform on the attenuation term to be processed to generate a compensated attenuation term.

6. A cable defect early warning method as described in claim 5, characterized in that, The step of determining the time-domain response corresponding to the cable defect based on the corrected reflection coefficient spectrum and the compensated attenuation term includes: The corrected reflection coefficient spectrum and the compensated attenuation term are deconvolved and the modulus is taken to generate the reflection coefficient spectrum after distance attenuation compensation. The input voltage of the frequency sweep test is multiplied in the frequency domain with the reflection coefficient spectrum after distance attenuation compensation, and then an inverse Fourier transform is performed based on the frequency domain multiplication result to generate the time domain response corresponding to the cable defect.

7. A cable defect early warning method as described in claim 6, characterized in that, The step of generating corresponding defect warning information based on the amplitude at the defect location in the time-domain response includes: Obtain the amplitude at the defect location in the time-domain response; When it is determined that the amplitude is greater than a preset amplitude threshold and the ratio between the amplitude and the preset amplitude threshold is less than a first ratio value, a defect warning message is generated to characterize the cable for having a minor defect. When it is determined that the amplitude is greater than a preset amplitude threshold, and the ratio between the amplitude and the preset amplitude threshold is greater than a first ratio and less than a second ratio, a defect warning message is generated to characterize the cable as having a moderate defect. When it is determined that the amplitude is greater than a preset amplitude threshold, but the ratio between the amplitude and the preset amplitude threshold is greater than a second ratio and less than a third ratio, a defect warning message is generated to characterize that the cable has a serious defect.

8. A defect early warning device for cables, characterized in that, include: The module includes a reflection coefficient spectrum generation module, an equivalent impedance generation module, a reflection coefficient spectrum correction module, an attenuation term compensation module, and a defect early warning information generation module. The reflection coefficient spectrum generation module is used to perform frequency sweep testing on an equivalent circuit model containing sequentially connected test equipment, test leads, test fixtures, and cables to generate a reflection coefficient spectrum; wherein, the reflection coefficient spectrum is used to reflect the signal reflection characteristics during cable testing. The equivalent impedance generation module is used to separate the reflection coefficient spectrum, extract low-frequency components with frequencies lower than a preset frequency threshold, and use the low-frequency components as the head-end reflection coefficient; based on the head-end reflection coefficient, the internal resistance of the test equipment, and the impedance of the cable, the equivalent impedance corresponding to the connection between the test fixture and the cable head-end is generated; wherein, the head-end reflection coefficient is used to characterize the reflection coefficient caused by the impedance mismatch between the cable head-end and the cable body. The reflection coefficient spectrum correction module is used to correct the reflection coefficient spectrum based on the input impedance of the cable, the equivalent impedance, and the impedance of the test equipment during the frequency sweep test, and to determine the corrected reflection coefficient spectrum. The attenuation compensation module is used to compensate for the attenuation term based on the linear relationship between the attenuation coefficient of the cable and the test frequency of the sweep frequency test, and generate a compensated attenuation term; wherein, the attenuation term is the signal attenuation between the defect point of the cable and the beginning of the cable. The defect warning information generation module is used to determine the time domain response corresponding to the cable defect based on the corrected reflection coefficient spectrum and the compensated attenuation term, and to generate corresponding defect warning information based on the amplitude of the defect in the time domain response.

9. A terminal device, characterized in that, The device includes a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor, wherein the processor, when executing the computer program, implements a cable defect early warning method as described in any one of claims 1 to 7.

10. A storage medium, characterized in that, The storage medium includes a stored computer program, wherein, when the computer program is executed, it controls the device where the storage medium is located to perform a cable defect early warning method as described in any one of claims 1 to 7.

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