Ultrasonic-based nondestructive testing method and system for cable protection pipe

Abstract

The invention relates to the technical field of nondestructive testing, and provides an ultrasonic-based nondestructive testing method and system for a cable protection tube, an ultrasonic signal is transmitted through a signal capturing module, an echo signal reflected from the cable protection tube is received, any damage to a detected object is avoided, detection can be carried out without shutdown, and the detection efficiency is improved. The maintenance cost and the safety risk are reduced; the signal processing module is used for processing the received echo signals and extracting the characteristics of the echo signals, so that the recognition accuracy and reliability can be improved by training a large amount of data, and the nondestructive testing system is more advanced and efficient; and the defect identification module analyzes and judges the characteristics of the echo signals, and determines the integrity and defect type of the cable protection tube. The whole process realizes an automatic detection process, manual intervention is reduced, the detection efficiency and accuracy are improved, potential problems can be timely found and processed, and the maintenance cost and the safety risk are reduced.

Description

Technical Field

[0001] The present application relates to the technical field of nondestructive testing, and in particular to a method and system for nondestructive testing of cable protection tubes based on ultrasound. Background Art

[0002] Ultrasonic pipeline in-pipeline detection technology has become an important method for pipeline non-destructive testing due to its advantages such as fast detection speed, reliability, accuracy and no need to strip the outer sheath of the pipeline. Foreign ultrasonic pipeline detection technology has a history of several decades of development.

[0003] The ultrasonic nondestructive testing method of cable protection tube is mainly used for the damage detection of high-voltage multi-core cables in power systems, as well as the real-time detection of pipe wall thickness and internal defects of pipes. In addition, this method is also widely used in the fields of oil and gas pipelines, urban water supply and heating pipe networks, etc. Ultrasonic testing is a non-destructive testing method that will not cause any damage to the object being tested. Compared with traditional manual inspection methods, ultrasonic testing can complete the testing task more quickly and improve the testing efficiency. Ultrasonic testing can accurately identify the defects and damage inside the pipeline, providing a reliable basis for maintenance work. However, most of them have not solved how to determine the integrity and defect type of the cable protection tube by receiving and processing the echo signal.

[0004] For example, a Chinese patent with publication number CN117347489A discloses an ultrasonic rapid detection method and system for the Vicat softening temperature of a cable protection tube, comprising: collecting ultrasonic raw A-scan data through a longitudinal wave probe, extracting ultrasonic key parameters as feature quantities, establishing a training set with the Vicat softening temperature as the output quantity, performing Gaussian process regression on the data, performing Bayesian optimization on the model using the minimum square error as the evaluation quantity, obtaining a Vicat softening temperature prediction model, collecting ultrasonic longitudinal wave signals of the cable protection tube to be inspected, extracting corresponding ultrasonic parameters and inputting them into the prediction model, obtaining a predicted value of the Vicat softening temperature, and when the predicted value differs greatly from the actual value, adding the measured data to the training set to retrain and correct the model, thereby improving the universality of the model. Compared with traditional detection methods, the portability and detection efficiency are significantly improved, non-destructive detection is realized, and the detection needs of engineering sites are better adapted, with great market application prospects and promotion value.

[0005] For example, a Chinese patent with the authorization announcement number CN116577413B discloses an ultrasonic nondestructive testing device and a testing method, which includes a shell, a console fixedly connected to the top of the shell, a control box arranged inside the console, a fixed frame arranged on one side of the control box and located on the top of the console, a clamping block arranged on the side opposite to the fixed frame, a mounting block fixedly connected to the inside of the fixed frame, a cylinder fixedly installed inside the mounting block, and one end of the cylinder fixedly connected to the clamping block near the fixed frame. Through the coordinated use of the driving device, the fixed block, the moving rod, the rectangular frame, the connecting column, the detection ring and the cleaning block, the cleaning block moves back and forth on the outside of the pipe while rotating, which is convenient for comprehensive cleaning of the outer surface of the pipe body, and prevents dust and impurities adhering to the surface of the pipe from affecting the detection effect of the detection head.

[0006] The above patents have the problem raised by the background technology: the above two patents do not solve the problem of how to determine the integrity and defect type of the cable protection tube by receiving and processing the echo signal. Summary of the invention

[0007] In view of the deficiencies in the prior art, the present application provides an ultrasonic-based nondestructive testing method and system for cable protection tubes.

[0008] In a first aspect, the present application provides an ultrasound-based nondestructive testing system for a cable protection tube, the system comprising: a signal capture module, a signal processing module, and a defect identification module;

[0009] The signal capture module is used to transmit ultrasonic signals and receive echo signals reflected from the cable protection tube;

[0010] The signal processing module is used to process the received echo signal and extract the characteristics of the echo signal;

[0011] The defect recognition module is used to analyze and judge the characteristics of the echo signal to determine the integrity and defect type of the cable protection tube.

[0012] As an optional embodiment, the signal capture module includes at least one ultrasonic transmitter and at least one ultrasonic receiver, the ultrasonic transmitter is used to transmit ultrasonic signals, the ultrasonic signals penetrate the cable protection tube and propagate inside the cable protection tube, and the ultrasonic receiver is used to receive echo signals caused by defects inside the cable protection tube.

[0013] As an optional implementation, the ultrasonic transmitter and the ultrasonic receiver are distributed along the axial direction or the circumferential direction of the cable protection tube.

[0014] As an optional implementation manner, the logic of processing the received echo signal includes:

[0015] The frequency of receiving the echo signal is configured to be at least twice the bandwidth of the echo signal, the echo signal is denoised, and the arrangement positions of the ultrasonic transmitter and the ultrasonic receiver are adjusted according to the time delay of the echo signal.

[0016] As an optional implementation manner, the function expression of the delay of the echo signal is as follows:

[0017]

[0018] Where t represents the time delay of the echo signal, d represents the distance between the cable protection tube and the ultrasonic receiver, and c represents the propagation speed of the echo signal.

[0019] As an optional implementation manner, the feature of the echo signal is extracted, and the feature of the echo signal includes an amplitude feature, a time domain feature, and a frequency domain feature, and the amplitude feature includes an average amplitude of the echo signal, which is used to represent the overall strength of the echo signal;

[0020] The time domain feature includes the change time of the echo signal, which is used to indicate the change rate of the echo signal;

[0021] The frequency domain feature includes a main frequency component of the echo signal, which is used to indicate the location of the main energy of the echo signal.

[0022] As an optional implementation, the logic for determining the integrity of the cable protection tube includes:

[0023] Configure the amplitude threshold, compare the average amplitude of the echo signal with the amplitude threshold to obtain the amplitude state. If the average amplitude of the echo signal is less than or equal to the amplitude threshold, the amplitude state is the signal amplitude base value.

[0024] If the average amplitude of the echo signal is greater than the amplitude threshold, the amplitude state is the signal amplitude extreme value;

[0025] The change time of the echo signal includes the rise time and the fall time. The change state is judged according to the rise time and the fall time. If the changes of the rise time and the fall time are consistent, the change state is consistent with the signal change;

[0026] If the changes in the rise time and the fall time are inconsistent, the change state is inconsistent signal changes;

[0027] Configure the frequency threshold, compare the main frequency component of the echo signal with the frequency threshold to obtain the frequency state. If the main frequency component of the echo signal is less than or equal to the frequency threshold, the frequency state is the signal frequency base value.

[0028] If the main frequency component of the echo signal is greater than the frequency threshold, the frequency state is the signal frequency extreme value;

[0029] The integrity of the cable protection tube is determined comprehensively according to the amplitude state, change state and frequency state. If the amplitude state is the signal amplitude extreme value and the frequency state is the signal frequency base value, the cable protection tube has no defects.

[0030] If the amplitude state is the signal amplitude base value and the frequency state is the signal frequency extreme value, the cable protection tube is defective. The degree of the defect of the cable protection tube is determined according to the change state. If the change state is inconsistent with the signal change, the cable protection tube is at the defect base value.

[0031] If the change state is consistent with the signal change, the cable protection tube is a defect extreme value.

[0032] In a second aspect, the present application provides an ultrasonic-based nondestructive testing method for a cable protection tube, the method comprising: S1, transmitting an ultrasonic signal, and receiving an echo signal reflected from the cable protection tube;

[0033] S2. Processing the received echo signal and extracting the features of the echo signal;

[0034] S3. Analyze and judge the characteristics of the echo signal to determine the integrity and defect type of the cable protection tube.

[0035] In a third aspect, an optional implementation of the present application further provides a computer device, a memory and a processor, wherein the memory is used to store instructions; the processor is used to execute the instructions, so that the computer device executes the above-mentioned second aspect.

[0036] In a fourth aspect, an optional implementation of the present application further provides a computer-readable storage medium having a computer program stored thereon, and the computer program executes the above-mentioned second aspect when executed.

[0037] Compared with the prior art, the beneficial effects of the present application are as follows: the ultrasonic signal is emitted through the signal capture module, and the echo signal reflected from the cable protection tube is received, which will not cause any damage to the object being detected, and the detection can be carried out without stopping the machine, reducing maintenance costs and safety risks; the signal processing module processes the received echo signal and extracts the characteristics of the echo signal, which can improve the accuracy and reliability of recognition by training a large amount of data, and the non-destructive testing system is more advanced and efficient; the defect recognition module analyzes and judges the characteristics of the echo signal to determine the integrity and defect type of the cable protection tube. The entire process realizes an automated detection process, reduces manual intervention, improves the efficiency and accuracy of detection, can continuously monitor the status of the cable protection tube, and immediately issues a warning signal once an abnormality is found. This real-time monitoring function helps to timely discover and deal with potential problems, prevent accidents, reduce maintenance costs and safety risks, and promote the intelligent development of cable protection tube detection technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor. Among them:

[0039] Figure 1 A system structure diagram of an ultrasonic-based nondestructive testing system for cable protection tubes provided in an embodiment of the present application;

[0040] Figure 2 A signal processing logic diagram of the ultrasonic-based nondestructive testing system for cable protection tubes provided in an embodiment of the present application;

[0041] Figure 3 A flow chart of a method for nondestructive testing of cable protection tubes based on ultrasound provided in an embodiment of the present application. DETAILED DESCRIPTION

[0042] In order to make the objectives, technical solutions and advantages of the embodiments of the present application more obvious and easy to understand, the technical solutions in the embodiments of the present application are clearly and completely described below in conjunction with the drawings in the specification. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments.

[0043] Example 1

[0044] like Figure 1 As shown, a system structure diagram of an ultrasonic-based nondestructive testing system for cable protection tubes is provided for an embodiment of the present application. The system includes a signal capture module, a signal processing module and a defect recognition module.

[0045] The signal capture module is used to transmit ultrasonic signals and receive echo signals reflected from the cable protection tube.

[0046] The signal capture module includes at least one ultrasonic transmitter and at least one ultrasonic receiver. The ultrasonic transmitter is used to transmit ultrasonic signals that penetrate the cable protection tube and propagate inside the cable protection tube. The ultrasonic receiver is used to receive echo signals caused by defects inside the cable protection tube.

[0047] The ultrasonic transmitter and the ultrasonic receiver are distributed along the axial direction or the circumferential direction of the cable protection tube.

[0048] Exemplarily, at least one ultrasonic transmitter and at least one ultrasonic receiver are arranged outside the cable protection tube. The ultrasonic transmitter transmits an ultrasonic signal, which penetrates the cable protection tube and propagates to the inside of the cable protection tube. The ultrasonic signal is reflected at defects in the cable protection tube or outside the cable protection tube to form an echo signal. The echo signal is sent to a signal processing module for processing to identify the integrity and defect type of the cable protection tube.

[0049] Exemplarily, a multi-channel design is adopted, including multiple ultrasonic transmitters and ultrasonic receivers, and the multiple ultrasonic transmitters and ultrasonic receivers are arranged on the outside of the cable protection tube in different ways, thereby covering multiple detection areas at the same time, which significantly improves the detection efficiency and coverage.

[0050] For example, in order to further improve the sensitivity and accuracy of detection, the array design of ultrasonic transmitters and ultrasonic receivers can enhance the reception effect of echo signals, especially when facing the complex internal structure of the cable protection tube, this design can effectively improve the efficiency of signal capture.

[0051] The signal processing module is used to process the received echo signal and extract the characteristics of the echo signal.

[0052] The logic for processing the received echo signal is as follows: Figure 2 As shown, specifically including:

[0053] The frequency of receiving the echo signal is configured to be at least twice the bandwidth of the echo signal, the echo signal is denoised, and the arrangement positions of the ultrasonic transmitter and the ultrasonic receiver are adjusted according to the time delay of the echo signal.

[0054] The function expression of the time delay of the echo signal is as follows:

[0055]

[0056] Where t represents the time delay of the echo signal, d represents the distance between the cable protection tube and the ultrasonic receiver, and c represents the propagation speed of the echo signal.

[0057] It should be noted that: the distance d between the cable protection tube and the ultrasonic receiver refers to the actual distance between the cable protection tube and the ultrasonic receiver, and the value is a non-negative value; the propagation speed c of the echo signal depends on the type of echo signal and the medium in which it is located. For example, the propagation speed of ultrasonic waves depends on the properties of the medium. At normal temperature and pressure, the propagation speed of ultrasonic waves in air is 343 meters per second.

[0058] Exemplarily, the echo signal is received by an ultrasonic receiver, and it is ensured that the frequency of the received echo signal is twice the bandwidth of the echo signal to avoid aliasing.

[0059] Exemplarily, the received echo signal is denoised. Common methods include low-pass filtering, band-pass filtering, Kalman filtering and wavelet denoising, etc. The purpose is to remove irrelevant noise components to make the echo signal purer. At the same time, in some cases, the echo signal may be weak and it is necessary to enhance the strength of the echo signal through gain control (such as automatic gain control AGC) to ensure the effectiveness of the echo signal.

[0060] Exemplarily, an ultrasonic transmitter transmits an ultrasonic signal to a cable protection tube. The ultrasonic signal propagates at a certain speed and is reflected back after encountering the cable protection tube to form an echo signal. Therefore, the distance between the cable protection tube and the ultrasonic receiver is directly related to the time delay of the echo signal. By calculating the time delay of the echo signal, the distance between the cable protection tube and the ultrasonic receiver can be accurately measured, and the position of the cable protection tube can be accurately known, thereby adjusting the layout of the ultrasonic transmitter and the ultrasonic receiver; and adjusting the layout of the ultrasonic transmitter and the ultrasonic receiver by calculating the time delay of the echo signal is more efficient and automated than traditional measurement methods; and the accuracy of measuring the distance between the cable protection tube and the ultrasonic receiver can be optimized and errors can be reduced by adjusting the transmission power and frequency of the ultrasonic signal.

[0061] The features of the echo signal are extracted. The features of the echo signal include amplitude features, time domain features and frequency domain features. The amplitude features include the average amplitude of the echo signal, which is used to represent the overall strength of the echo signal.

[0062] The time domain characteristics include the changing time of the echo signal, which is used to indicate the changing rate of the echo signal.

[0063] The frequency domain features include the main frequency components of the echo signal, which are used to indicate the location of the main energy of the echo signal.

[0064] Exemplarily, by obtaining the time domain representation of the echo signal, the absolute value of the time domain representation of the echo signal is calculated (because the echo signal may contain positive and negative oscillations, the absolute value can reflect the actual strength of the echo signal), the absolute value of the time domain representation of the echo signal is integrated over the total duration of the echo signal to obtain the total intensity value of the echo signal, and the average amplitude of the echo signal is obtained by dividing the total intensity value of the echo signal by the total duration of the echo signal, thereby evaluating the overall strength of the echo signal, helping to determine whether the echo signal is strong enough, and at the same time reflecting the stability of the echo signal and whether there is valid information. A higher average amplitude of the echo signal usually indicates that the echo signal is of better quality.

[0065] Exemplarily, the start and end times of the echo signal are determined (usually by detecting the edges of the echo signal), the time when the amplitude of the echo signal reaches its maximum value is identified, and the peak time is obtained (this is the moment when the echo signal undergoes the largest change in the time domain), and the rise time is calculated. The rise time is equal to the time difference from the start time of the echo signal to the peak time (the rise time reflects the time required for the echo signal to grow from zero amplitude to the maximum amplitude). The fall time is calculated. The fall time is equal to the time difference from the peak time to the end time of the echo signal (the fall time reflects the rate at which the echo signal falls from the maximum amplitude back to zero amplitude). The rise time and fall time can effectively describe the speed of change of the echo signal, and can also determine whether the waveform of the echo signal is smooth and whether there is oscillation and distortion.

[0066] Exemplarily, the time domain representation of the echo signal is converted into a frequency domain signal through Fourier transform, and the amplitude of the frequency domain signal, that is, the intensity of the echo signal on each frequency component, is calculated (the absolute value of the frequency component is usually used to determine the contribution of different frequencies), and the frequency position with the largest amplitude is found, that is, the main frequency of the echo signal (this main frequency is the position where the energy of the echo signal is most concentrated). This can help identify the main frequency components of the echo signal, and then understand the source or physical characteristics of the echo signal, and distinguish the echo signal from noise or interference.

[0067] The defect recognition module is used to analyze and judge the characteristics of the echo signal to determine the integrity and defect type of the cable protection tube.

[0068] The logic for determining the integrity of the cable protection tube includes:

[0069] Configure the amplitude threshold, compare the average amplitude of the echo signal with the amplitude threshold to obtain the amplitude state. If the average amplitude of the echo signal is less than or equal to the amplitude threshold, the amplitude state is the signal amplitude base value.

[0070] If the average amplitude of the echo signal is greater than the amplitude threshold, the amplitude state is the signal amplitude extreme value.

[0071] The change time of the echo signal includes the rise time and the fall time. The change state is judged according to the rise time and the fall time. If the changes of the rise time and the fall time are consistent, the change state is consistent with the signal change;

[0072] If the changes in the rise time and the fall time are inconsistent, the change state is that the signal changes are inconsistent.

[0073] Configure the frequency threshold, compare the main frequency component of the echo signal with the frequency threshold to obtain the frequency state. If the main frequency component of the echo signal is less than or equal to the frequency threshold, the frequency state is the signal frequency base value.

[0074] If the main frequency component of the echo signal is greater than the frequency threshold, the frequency state is the signal frequency extreme value.

[0075] The integrity of the cable protection tube is determined comprehensively according to the amplitude state, change state and frequency state. If the amplitude state is the signal amplitude extreme value and the frequency state is the signal frequency base value, the cable protection tube has no defects.

[0076] If the amplitude state is the signal amplitude base value and the frequency state is the signal frequency extreme value, the cable protection tube is defective. The degree of the defect of the cable protection tube is determined according to the change state. If the change state is inconsistent with the signal change, the cable protection tube is at the defect base value.

[0077] If the change state is consistent with the signal change, the cable protection tube is a defect extreme value.

[0078] For example, if the average amplitude of the echo signal is lower than the normal range, it means that the echo signal is attenuated or interfered by noise, which may be caused by local damage or breakage of the cable protection tube; if the average amplitude of the echo signal is high and there is no significant noise interference, it usually indicates that the integrity of the cable protection tube is good; if the rise time and the fall time are consistent (for example, the rise time is longer and the fall time is longer), it means that the cable protection tube is defective and the defect is more serious; if the rise time and the fall time are inconsistent (for example, the rise time is longer but the fall time is shorter), it means that the cable protection tube is defective but the defect is relatively minor; if the main frequency component of the echo signal is significantly offset, deformation, friction, corrosion or other structural losses may have occurred in the cable protection tube.

[0079] Exemplarily, after it is determined that the cable protection tube has defects, the defect type is determined by the changing state. When the cable protection tube is at the defect base value, it means that there is local damage, blockage, cracks or bubbles in the cable protection tube, which affects the propagation of the echo signal; when the cable protection tube is at the defect extreme value, it means that the cable protection tube has undergone deformation or corrosion damage or large-area holes.

[0080] Example 2

[0081] like Figure 3 As shown, a method flow chart of a nondestructive testing method for a cable protection tube based on ultrasound is provided for an embodiment of the present application, and the method comprises:

[0082] S1, transmit ultrasonic signals and receive echo signals reflected from the cable protection tube;

[0083] S2. Processing the received echo signal and extracting the features of the echo signal;

[0084] S3. Analyze and judge the characteristics of the echo signal to determine the integrity and defect type of the cable protection tube.

[0085] Since the principle of solving the problem by the method in the embodiment of the present application is similar to that of the system described above in the embodiment of the present application, the implementation of the method refers to the implementation of the system, and the repeated parts will not be repeated.

[0086] Example 3

[0087] In this embodiment, a computer device is provided, including a memory and a processor, wherein the memory is used to store instructions, and the processor is used to execute the instructions, so that the computer device executes the steps in the above method embodiment.

[0088] Example 4

[0089] In this embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed, the steps in the above method embodiment are implemented.

[0090] The computer-readable storage medium includes: a U disk, a mobile hard disk, a read-only memory, a random access memory, a magnetic disk or an optical disk, and other media for storing program codes.

[0091] In the description of this specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0092] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present application and are not intended to limit the present application. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present application, which should be included in the scope of the claims of the present application.

Claims

1. Ultrasonic-based nondestructive testing system for cable protection tubes, characterized in that: include: Signal capture module, signal processing module and defect identification module; The signal capture module is used to transmit ultrasonic signals and receive echo signals reflected from the cable protection tube; The signal processing module is used to process the received echo signal and extract the characteristics of the echo signal; The defect recognition module is used to analyze and judge the characteristics of the echo signal to determine the integrity and defect type of the cable protection tube.

2. The system according to claim 1, characterized in that: The signal capture module includes at least one ultrasonic transmitter and at least one ultrasonic receiver. The ultrasonic transmitter is used to transmit ultrasonic signals that penetrate the cable protection tube and propagate inside the cable protection tube. The ultrasonic receiver is used to receive echo signals caused by defects inside the cable protection tube.

3. The system according to claim 2, characterized in that: The ultrasonic transmitters and the ultrasonic receivers are distributed along the axial direction or the circumferential direction of the cable protection tube.

4. The system according to claim 3, characterized in that: The logic of processing the received echo signal includes: The frequency of receiving the echo signal is configured to be at least twice the bandwidth of the echo signal, the echo signal is denoised, and the arrangement positions of the ultrasonic transmitter and the ultrasonic receiver are adjusted according to the time delay of the echo signal.

5. The system according to claim 4, characterized in that: The function expression of the time delay of the echo signal is as follows: Where t represents the time delay of the echo signal, d represents the distance between the cable protection tube and the ultrasonic receiver, and c represents the propagation speed of the echo signal.

6. The system according to claim 5, characterized in that: The feature of the echo signal is extracted, the feature of the echo signal includes amplitude feature, time domain feature and frequency domain feature, the amplitude feature includes the average amplitude of the echo signal, which is used to represent the overall strength of the echo signal; The time domain feature includes the change time of the echo signal, which is used to indicate the change rate of the echo signal; The frequency domain feature includes a main frequency component of the echo signal, which is used to indicate the location of the main energy of the echo signal.

7. The system according to claim 6, characterized in that: The logic for determining the integrity of the cable protection tube includes: Configure the amplitude threshold, compare the average amplitude of the echo signal with the amplitude threshold to obtain the amplitude state. If the average amplitude of the echo signal is less than or equal to the amplitude threshold, the amplitude state is the signal amplitude base value. If the average amplitude of the echo signal is greater than the amplitude threshold, the amplitude state is the signal amplitude extreme value; The change time of the echo signal includes the rise time and the fall time. The change state is judged according to the rise time and the fall time. If the changes of the rise time and the fall time are consistent, the change state is consistent with the signal change; If the changes in the rise time and the fall time are inconsistent, the change state is inconsistent signal changes; Configure the frequency threshold, compare the main frequency component of the echo signal with the frequency threshold to obtain the frequency state. If the main frequency component of the echo signal is less than or equal to the frequency threshold, the frequency state is the signal frequency base value. If the main frequency component of the echo signal is greater than the frequency threshold, the frequency state is the signal frequency extreme value; The integrity of the cable protection tube is determined comprehensively according to the amplitude state, change state and frequency state. If the amplitude state is the signal amplitude extreme value and the frequency state is the signal frequency base value, the cable protection tube has no defects. If the amplitude state is the signal amplitude base value and the frequency state is the signal frequency extreme value, the cable protection tube is defective. The degree of the defect of the cable protection tube is determined according to the change state. If the change state is inconsistent with the signal change, the cable protection tube is at the defect base value. If the change state is consistent with the signal change, the cable protection tube is a defect extreme value.

8. An ultrasonic nondestructive testing method for a cable protection tube, implemented based on the ultrasonic nondestructive testing system for a cable protection tube according to any one of claims 1 to 7, characterized in that: include: S1, transmit ultrasonic signals and receive echo signals reflected from the cable protection tube; S2. Processing the received echo signal and extracting the features of the echo signal; S3. Analyze and judge the characteristics of the echo signal to determine the integrity and defect type of the cable protection tube.

9. A computer device, characterized in that: include: A memory for storing instructions; A processor is used to execute the instructions so that the computer device executes the ultrasonic-based nondestructive testing method for cable protection tubes as described in claim 8.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed, the ultrasonic-based nondestructive testing method for cable protection tubes as claimed in claim 8 is implemented.

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