Cable defect positioning precision improving method and system based on beat signal phase information

Abstract

The invention discloses a method and system for improving cable defect positioning precision based on beat signal phase information, and belongs to the technical field of cable defect positioning, and the method comprises the steps: obtaining a beat signal containing cable defect position information, and carrying out the normalization of the beat signal, and obtaining a normalized beat signal; decomposing the normalized beat signal to obtain two beat signal subsequences; carrying out DFT (Discrete Fourier Transform) after carrying out zero padding on the beat signal subsequences to obtain DFT discrete points corresponding to amplitude spectrum peak values of the beat signal subsequences; calculating the phase difference at the DFT discrete point corresponding to the amplitude spectrum peak value of the beat signal sub-sequence; and correcting a DFT-based defect positioning result by using the phase difference. According to the invention, the distance measurement precision of the DFT-based cable defect positioning method is effectively improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of cable defect positioning, and relates to a method for improving cable defect positioning accuracy, and specifically to a method and system for improving cable defect positioning accuracy based on beat signal phase information. Background Art

[0002] Power cables are gradually becoming a major component of urban power transmission and distribution networks due to their small footprint and high operational reliability. However, cables in operation are prone to permanent faults, which, once occurring, may damage electrical equipment or even cause power outages, leading to serious economic losses and social impacts. Permanent cable faults usually begin with local defects. If these defects are not promptly and effectively eliminated, they will pose a major threat to the safe and stable operation of the power system. Therefore, it is of great significance to accurately locate local defects in cables.

[0003] At present, the main method for locating cable defects is the traveling wave method. Among them, the frequency domain reflection method is widely used due to its high sensitivity in defect detection. This method injects a series of sweep frequency signals into the head end of the cable to obtain frequency domain reflection data such as the input impedance spectrum or reflection coefficient spectrum of the cable, and uses mathematical methods such as discrete Fourier transform (DFT) to convert the frequency domain data into the spatial domain, thereby locating the cable defects. However, the frequency domain reflection method is susceptible to interference from on-site noise, and the positioning accuracy of local defects in practical applications still needs to be further improved. Although some studies have been conducted to improve the distance measurement accuracy by zeroing the measurement data, this method has certain limitations. Specifically, when the distance measurement accuracy is doubled, the number of DFT points also needs to be doubled accordingly, resulting in a significant increase in the amount of calculation. The increase in the spectral lines in the main lobe of the spectrum of the defect location peak makes it more difficult to determine the maximum amplitude spectral line. Coupled with the interference of on-site noise, the improvement effect of distance measurement accuracy is limited. Summary of the invention

[0004] The purpose of the present invention is to provide a method and system for improving the positioning accuracy of cable defects based on the phase information of a beat signal, so as to solve the problem of low positioning accuracy in the detection of local defects in cables by the traditional frequency domain reflection method.

[0005] In order to achieve the above object, the present invention adopts the following technical scheme:

[0006] The method for improving the cable defect positioning accuracy based on the beat signal phase information comprises the following steps:

[0007] Obtaining a beat signal containing the cable defect position information, and normalizing it to obtain a normalized beat signal;

[0008] Decomposing the normalized beat signal to obtain two beat signal subsequences;

[0009] Perform DFT on the beat signal subsequence after zero padding to obtain the DFT discrete point number corresponding to the peak value of the amplitude spectrum of the beat signal subsequence;

[0010] Calculate the phase difference at the DFT discrete points corresponding to the peak value of the amplitude spectrum of the beat signal subsequence;

[0011] The phase difference is used to correct the defect location results based on DFT.

[0012] Further, the obtaining of the beat signal is specifically as follows:

[0013] The frequency modulated continuous wave voltage signal with sawtooth wave modulation is used as the incident signal for locating cable defects. In one modulation cycle, the instantaneous frequency f(t) of the incident signal is:

[0014] f(t)=f0+St

[0015] Where f0 is the initial frequency; S=B / T is the FM slope, B is the FM bandwidth, and T is the FM period;

[0016] The incident signal T(t) is:

[0017]

[0018] Where A is the effective value of the incident signal;

[0019] The incident signal is reflected at the impedance discontinuity point such as the defect in the cable. Using the phasor method, the reflected signal R(t) detected at the signal injection end is derived as:

[0020]

[0021] Where l is the actual distance from the impedance discontinuity point to the signal injection end; ρ l is the reflection coefficient at the impedance discontinuity point, ρ l =(Z s -Z0) / (Z s +Z0), where Z s is the characteristic impedance at the impedance discontinuity point, Z0 is the characteristic impedance of the sound line segment; α is the attenuation constant; τ is the time delay of the reflected signal relative to the incident signal, τ = 2l / v, where v is the average propagation speed of the signal in the cable;

[0022] The incident signal and the reflected signal are mixed to obtain the beat signal s(t), which is expressed as:

[0023]

[0024] Further, the normalized beat signal s(n) is expressed as:

[0025]

[0026] Where N is the number of sampling points in the modulation period, Δt = T / N is the sampling interval, and the sampling frequency is f s =1 / Δt=N / T.

[0027] Furthermore, the decomposition and normalization of the beat signal obtains two beat signal subsequences, specifically:

[0028] Decompose the normalized beat signal s(n) into two subsequences, wherein the first N1 points of s(n) constitute the first subsequence s1(n), and the last N1 points of s(n) constitute the second subsequence s2(n), and the first subsequence s1(n) and the second subsequence s2(n) can partially overlap, that is, 2N1≥N;

[0029]

[0030] Further, the DFT is performed after zero padding the beat signal subsequence, specifically:

[0031] The first subsequence s1(n) is padded with zeros. 1e (n) is:

[0032]

[0033] Where, M is the length of the sequence after zero padding, M>N1;

[0034] s 1e The M-point DFT of (n) is:

[0035]

[0036] The second subsequence s2(n) is the sequence s after zero padding 2e (n) is:

[0037]

[0038] s 2e The M-point DFT of (n) is:

[0039]

[0040] The number of DFT discrete points corresponding to the peak values ​​of the amplitude spectra of s1(k) and s2(k) in [0,M-1] is the same, denoted as k1:

[0041]

[0042] Where round[x] means taking the integer closest to x; ΔR is the distance resolution unit; ΔR1 is the distance resolution unit corresponding to the M-point DFT;

[0043]

[0044] Furthermore, the phase difference at the DFT discrete points corresponding to the peak value of the amplitude spectrum of the beat signal subsequence is calculated, specifically:

[0045] The phases of s1(k) and s2(k) are different. At the discrete frequency corresponding to k1, the phases of s1(k1) and s2(k1) are recorded as and It is expressed as follows:

[0046]

[0047] The phase difference between the two is:

[0048]

[0049] use The cable defect distance is accurately measured within a distance resolution unit ΔR1.

[0050] Furthermore, the use of phase difference to correct the defect location result based on DFT is specifically as follows:

[0051] In a distance resolution unit ΔR1, the distance correction of the cable defect is calculated as:

[0052]

[0053] make is the defect distance calculated from the discrete spectrum of the subsequence, and we have:

[0054]

[0055] Then the distance from the cable defect location to the signal injection end is calculated as:

[0056]

[0057] The cable defect positioning accuracy improvement system based on the beat signal phase information includes:

[0058] Signal acquisition module: used to acquire the beat signal containing the cable defect location information and normalize it to obtain a normalized beat signal;

[0059] Decomposition module: used for decomposing the normalized beat signal to obtain two beat signal subsequences;

[0060] DFT module: used to perform DFT on the beat signal subsequence after zero padding, and obtain the DFT discrete points corresponding to the peak value of the amplitude spectrum of the beat signal subsequence;

[0061] Calculation module: used to calculate the phase difference at the DFT discrete points corresponding to the peak value of the amplitude spectrum of the beat signal subsequence;

[0062] Correction module: used to correct the DFT-based defect location results using phase difference.

[0063] A computer device comprises a memory, a processor and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the steps of the method for improving the cable defect positioning accuracy based on the phase information of the beat signal are implemented.

[0064] A computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the method for improving the cable defect positioning accuracy based on beat signal phase information are implemented.

[0065] Compared with the prior art, the present invention has the following beneficial technical effects:

[0066] The method of the present invention decomposes the sampling sequence of the beat signal into two subsequences, and performs DFT after zero padding on each subsequence to improve the frequency measurement accuracy of the subsequence; the phase difference at the DFT discrete points corresponding to the subsequence DFT amplitude spectrum peak is used to calculate the correction amount of the defect distance within a distance resolution unit. The present invention can effectively solve the whole cycle ambiguity problem in phase measurement by using the phase difference of the subsequence, and can correct the defect distance measurement error caused by the DFT fence effect, and correct the defect positioning result within a distance resolution unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0067] The drawings in the specification are used to provide further understanding of the present invention and constitute a part of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0068] Figure 1 This is the cable defect location result based on DFT;

[0069] Figure 2 is the DFT amplitude spectrum of the first subsequence of the beat signal;

[0070] Figure 3 It is the phase spectrum of the first subsequence DFT part of the beat signal;

[0071] Figure 4 is the DFT amplitude spectrum of the second subsequence of the beat signal;

[0072] Figure 5 is the DFT partial phase spectrum of the second subsequence of the beat signal;

[0073] Figure 6 It is a flow chart of a method for improving the cable defect positioning accuracy based on the beat signal phase information of the present invention;

[0074] Figure 7 It is a schematic diagram of the structure of the cable defect positioning accuracy improvement system based on the beat signal phase information of the present invention. DETAILED DESCRIPTION

[0075] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0076] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0077] Embodiment 1

[0078] See also Figure 6 The present invention provides a method for improving the accuracy of cable defect positioning based on the phase information of the beat signal, comprising the following steps:

[0079] Obtaining a beat signal containing the cable defect position information, and normalizing it to obtain a normalized beat signal;

[0080] Decomposing the normalized beat signal to obtain two beat signal subsequences;

[0081] Perform DFT on the beat signal subsequence after zero padding to obtain the DFT discrete point number corresponding to the peak value of the amplitude spectrum of the beat signal subsequence;

[0082] Calculate the phase difference at the DFT discrete points corresponding to the peak value of the amplitude spectrum of the beat signal subsequence;

[0083] The phase difference is used to correct the defect location results based on DFT.

[0084] The method of the present invention decomposes the sampling sequence of the beat signal into two subsequences, and performs DFT on each subsequence after zero padding to improve the frequency measurement accuracy of the subsequence; the phase difference at the DFT discrete point corresponding to the subsequence DFT amplitude spectrum peak is used to calculate the correction amount of the defect distance in a distance resolution unit. The method of the present invention can correct the defect ranging error caused by the DFT fence effect, and effectively improve the ranging accuracy of the DFT-based cable defect positioning method.

[0085] Embodiment 2

[0086] The present invention provides a method for improving the positioning accuracy of cable defects based on beat signal phase information, comprising:

[0087] (1) Obtaining the beat signal

[0088] The present invention uses a frequency modulated continuous wave voltage signal in a sawtooth wave modulation mode as an incident signal for locating cable defects. In one modulation cycle, the instantaneous frequency f(t) of the incident signal is:

[0089] f(t)=f0+St

[0090] Where f0 is the initial frequency; S=B / T is the FM slope, B is the FM bandwidth, and T is the FM period.

[0091] The incident signal T(t) is:

[0092]

[0093] Where A is the effective value of the incident signal.

[0094] The incident signal is reflected at the impedance discontinuity point such as the defect in the cable. Using the phasor method, the reflected signal R(t) detected at the signal injection end is derived as:

[0095]

[0096] Where l is the actual distance from the impedance discontinuity point to the signal injection end; ρ l is the reflection coefficient at the impedance discontinuity point, ρ l =(Z s -Z0) / (Z s +Z0), where Z s is the characteristic impedance at the impedance discontinuity point, Z0 is the characteristic impedance of the sound line segment; α is the attenuation constant; τ is the time delay of the reflected signal relative to the incident signal, τ = 2l / v, where v is the average propagation speed of the signal in the cable.

[0097] The incident signal and the reflected signal are mixed to obtain the beat signal s(t), which can be expressed as:

[0098]

[0099] In order to simplify the subsequent calculations, the amplitude of the beat signal is normalized, and we have:

[0100]

[0101] In practical applications, the beat signal is usually sampled, and then the sampling sequence is subjected to DFT to locate the cable defects. Assume that the number of sampling points in a modulation cycle is N, the sampling interval is Δt = T / N, and the sampling frequency is f s =1 / Δt=N / T. The normalized beat signal s(n) after sampling is:

[0102]

[0103] (2) Decomposition of the beat signal

[0104] The sampled beat signal s(n) is decomposed into two subsequences, wherein the first N1 points of s(n) constitute the first subsequence s1(n), and the last N1 points of s(n) constitute the second subsequence s2(n). The subsequence s1(n) and the subsequence s2(n) may partially overlap, that is, 2N1≥N.

[0105]

[0106] (3) Perform DFT after zero padding the beat signal subsequence

[0107] The sequence s after the subsequence s1(n) is padded with zeros 1e (n) is:

[0108]

[0109] Where M is the length of the sequence after zero padding, M>N1.

[0110] s 1e The M-point DFT of (n) is:

[0111]

[0112] The sequence s after the subsequence s2(n) is padded with zeros 2e (n) is:

[0113]

[0114] s 2e The M-point DFT of (n) is:

[0115]

[0116] The number of DFT discrete points corresponding to the peak values ​​of the amplitude spectra of s1(k) and s2(k) in [0,M-1] is the same, denoted as k1, and we have:

[0117]

[0118] Wherein, round[x] means taking the integer closest to x; ΔR is the distance resolution unit; ΔR1 is the distance resolution unit corresponding to the M-point DFT.

[0119]

[0120] (4) Calculate the phase difference at the DFT discrete points corresponding to the peak value of the amplitude spectrum of the beat signal subsequence

[0121] The phases of s1(k) and s2(k) are different. At the discrete frequency corresponding to k1, the phases of s1(k1) and s2(k1) are recorded as and have:

[0122]

[0123] The phase difference between the two is:

[0124]

[0125] It changes linearly with distance. As long as N, N1 and M are selected appropriately, The change within a distance resolution unit ΔR1 will not exceed 2π, that is The measurement of will not have the 2π ambiguity problem. Therefore, it can be used The cable defect distance is measured more accurately within one distance resolution unit ΔR1.

[0126] (5) Correction of defect location results

[0127] In a distance resolution unit ΔR1, the distance correction of cable defects can be calculated as:

[0128]

[0129] make is the defect distance calculated from the discrete spectrum of the subsequence, and we have:

[0130]

[0131] Then, the distance from the cable defect location to the signal injection end can be calculated as:

[0132]

[0133] Embodiment 3

[0134] Based on the MATLAB simulation platform, a 1500m 330kV single-core cable is simulated with a 500Ω high-resistance grounding at 500m away from the signal injection end. The incident signal amplitude is 2.5V, f0=0.5MHz, B=10MHz, T=1ms, N=10000, N1=5000, and M=20000 to illustrate the effectiveness of the defect location accuracy improvement method based on the beat signal phase information.

[0135] Using the original sampling sequence of the beat signal, the cable defect location results based on DFT are as follows: Figure 1 As shown, the discrete frequency corresponding to the defect characteristic peak at the maximum spectrum amplitude is 52, and the defect distance is calculated to be 506.01m, and the relative positioning error is 1.2%.

[0136] The original sampling sequence of the beat signal is split, the first 5000 points of the beat signal constitute the first subsequence, and the 5000 points after the beat signal constitute the second subsequence. After the first subsequence is padded with zeros, a 20,000-point DFT is performed, and the amplitude spectrum simulation results are as follows: Figure 2 The simulation results of the phase spectrum are shown in Figure 3 The second subsequence is also subjected to 20,000-point DFT after zero padding, and its amplitude spectrum simulation results are shown in Figure 4 The simulation results of the phase spectrum are shown in Figure 5 shown.

[0137] In the amplitude spectra of the first subsequence and the second subsequence, the discrete frequencies corresponding to the defect characteristic peaks at the maximum spectrum amplitude are the same, both 102. The phase corresponding to the discrete frequency 102 of the first subsequence is -2.95668 rad, and the phase corresponding to the discrete frequency 102 of the second subsequence is -0.92748 rad. The corrected cable defect distance is 500.565m, and the relative positioning error is 0.11%. Therefore, compared with the cable defect positioning method based on DFT, the method proposed in the present invention can effectively improve the cable defect positioning accuracy.

[0138] Embodiment 4

[0139] See also Figure 7 The present invention provides a cable defect positioning accuracy improvement system based on beat signal phase information, comprising:

[0140] Signal acquisition module: used to acquire the beat signal containing the cable defect location information and normalize it to obtain a normalized beat signal;

[0141] Decomposition module: used for decomposing the normalized beat signal to obtain two beat signal subsequences;

[0142] DFT module: used to perform DFT on the beat signal subsequence after zero padding, and obtain the DFT discrete points corresponding to the peak value of the amplitude spectrum of the beat signal subsequence;

[0143] Calculation module: used to calculate the phase difference at the DFT discrete points corresponding to the peak value of the amplitude spectrum of the beat signal subsequence;

[0144] Correction module: used to correct the DFT-based defect location results using phase difference.

[0145] Embodiment 5

[0146] The present invention provides a computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the steps of the method for improving the cable defect positioning accuracy based on the beat signal phase information are implemented.

[0147] Embodiment 6

[0148] The present invention provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and is characterized in that when the computer program is executed by a processor, the steps of the method for improving the cable defect positioning accuracy based on the beat signal phase information are implemented.

[0149] Those skilled in the art will appreciate that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0150] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks 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 processes in the flowchart and / or block diagram. 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.

[0151] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate 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 A function specified in one or more boxes.

[0152] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0153] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit its protection scope. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the field should understand that after reading the present invention, those skilled in the art can still make various changes, modifications or equivalent substitutions to the specific implementation methods of the invention, but these changes, modifications or equivalent substitutions are all within the protection scope of the pending claims of the invention.

Claims

1. A method for improving the accuracy of cable defect positioning based on beat signal phase information, characterized in that: The steps include: Obtaining a beat signal containing the cable defect position information, and normalizing it to obtain a normalized beat signal; Decomposing the normalized beat signal to obtain two beat signal subsequences; Perform DFT on the beat signal subsequence after zero padding to obtain the DFT discrete point number corresponding to the peak value of the amplitude spectrum of the beat signal subsequence; Calculate the phase difference at the DFT discrete points corresponding to the peak value of the amplitude spectrum of the beat signal subsequence; The phase difference is used to correct the defect location results based on DFT.

2. The method for improving the cable defect positioning accuracy based on the beat signal phase information according to claim 1, characterized in that: The obtaining of the beat signal is specifically as follows: The frequency modulated continuous wave voltage signal with sawtooth wave modulation is used as the incident signal for locating cable defects. In one modulation cycle, the instantaneous frequency f(t) of the incident signal is: f(t)=f0+St Where f0 is the initial frequency; S=B / T is the FM slope, B is the FM bandwidth, and T is the FM period; The incident signal T(t) is: Where A is the effective value of the incident signal; The incident signal is reflected at the impedance discontinuity point such as the defect in the cable. Using the phasor method, the reflected signal R(t) detected at the signal injection end is derived as: Where l is the actual distance from the impedance discontinuity point to the signal injection end; ρ l is the reflection coefficient at the impedance discontinuity point, ρ l =(Z s -Z0) / (Z s +Z0), where Z s is the characteristic impedance at the impedance discontinuity point, Z0 is the characteristic impedance of the sound line segment; α is the attenuation constant; τ is the time delay of the reflected signal relative to the incident signal, τ = 2l / v, where v is the average propagation speed of the signal in the cable; The incident signal and the reflected signal are mixed to obtain the beat signal s(t), which is expressed as:

3. The method for improving the cable defect positioning accuracy based on the beat signal phase information according to claim 2 is characterized in that: The normalized beat signal s(n) is expressed as: Where N is the number of sampling points in the modulation period, Δt = T / N is the sampling interval, and the sampling frequency is f s =1 / Δt=N / T.

4. The method for improving the cable defect positioning accuracy based on the beat signal phase information according to claim 3 is characterized in that: The decomposition and normalization of the beat signal obtains two beat signal subsequences, specifically: Decompose the normalized beat signal s(n) into two subsequences, wherein the first N1 points of s(n) constitute the first subsequence s1(n), and the last N1 points of s(n) constitute the second subsequence s2(n), and the first subsequence s1(n) and the second subsequence s2(n) can partially overlap, that is, 2N1≥N; 5. The method for improving the cable defect positioning accuracy based on the beat signal phase information according to claim 4 is characterized in that: The DFT is performed after zero padding of the beat signal subsequence, specifically: The first subsequence s1(n) is padded with zeros. 1e (n) is: Where, M is the length of the sequence after zero padding, M>N1; s 1e The M-point DFT of (n) is: The second subsequence s2(n) is the sequence s after zero padding 2e (n) is: s 2e The M-point DFT of (n) is: The number of DFT discrete points corresponding to the peak values ​​of the amplitude spectra of s1(k) and s2(k) in [0,M-1] is the same, denoted as k1: Where round[x] means taking the integer closest to x; ΔR is the distance resolution unit; ΔR1 is the distance resolution unit corresponding to the M-point DFT; 6. The method for improving the cable defect positioning accuracy based on the beat signal phase information according to claim 5, characterized in that: The phase difference at the DFT discrete points corresponding to the peak value of the amplitude spectrum of the beat signal subsequence is calculated as follows: The phases of s1(k) and s2(k) are different. At the discrete frequency corresponding to k1, the phases of s1(k1) and s2(k1) are recorded as and It is expressed as follows: The phase difference between the two is: use The cable defect distance is accurately measured within a distance resolution unit ΔR1.

7. The method for improving the cable defect positioning accuracy based on the beat signal phase information according to claim 6, characterized in that: The defect location result based on DFT is corrected by using phase difference, specifically: In a distance resolution unit ΔR1, the distance correction of the cable defect is calculated as: make is the defect distance calculated from the discrete spectrum of the subsequence, and we have: Then the distance from the cable defect location to the signal injection end is calculated as:

8. A cable defect positioning accuracy improvement system based on beat signal phase information, characterized in that: include: Signal acquisition module: used to acquire the beat signal containing the cable defect location information and normalize it to obtain a normalized beat signal; Decomposition module: used for decomposing the normalized beat signal to obtain two beat signal subsequences; DFT module: used to perform DFT on the beat signal subsequence after zero padding, and obtain the DFT discrete points corresponding to the peak value of the amplitude spectrum of the beat signal subsequence; Calculation module: used to calculate the phase difference at the DFT discrete points corresponding to the peak value of the amplitude spectrum of the beat signal subsequence; Correction module: used to correct the DFT-based defect location results using phase difference.

9. A computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the steps of the method for improving the cable defect positioning accuracy based on the beat signal phase information as described in any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the steps of the method for improving the cable defect positioning accuracy based on the beat signal phase information as described in any one of claims 1 to 7 are implemented.

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