Cable accessory defect echo detection method and system

Abstract

The invention discloses a cable accessory defect echo detection method and system. The method comprises the following steps: deploying an ultrasonic probe at a lead sealing position of a to-be-detected cable accessory and guaranteeing the probe level; the excitation source emits a sine wave ultrasonic excitation signal and injects the signal into the high-voltage cable accessory sealing lead through the ultrasonic probe; echo signals of ultrasonic detection are synchronously received after set delay time, and fitting and self-adaptive smooth denoising are carried out; and judging the lead sealing defect of the high-voltage cable accessory according to the echo signal amplitude of the ultrasonic detection after fitting and self-adaptive smooth denoising, adjusting the position of the probe, and continuing to detect. According to the invention, internal and external defects of the lead seal of the high-voltage cable accessory can be detected, defect positions can be given, high-voltage cable operation and maintenance units are guided to find the defects in time, and faults are avoided.

Description

Technical Field

[0001] The invention belongs to the technical field of operation and maintenance of high-voltage cable accessories, and relates to a cable accessory defect echo detection method and system. Background Art

[0002] In recent years, among the failures of high-voltage cables caused by improper installation technology, failures caused by defects in the lead seals of cable terminals and intermediate joints accounted for more than 60%, which exposed the problem of low skill levels of some operators and the lack of quality supervision means by operation and maintenance units.

[0003] High-voltage cable lead seal is an important installation process applied to high-voltage cable accessories, and plays an important role in connection. The quality of the lead seal directly determines whether the grounding system of the high-voltage cable can operate safely and stably. If the lead seal has problems such as cold welding, loose welding, and gradual loosening of the lead seal due to external force, the lead seal part of the high-voltage cable accessory will induce a higher suspended potential, and generate a potential difference with the low-potential cable accessory tail pipe, forming air breakdown discharge, resulting in high-voltage cable operation failure.

[0004] However, there are few and imperfect detection methods for high-voltage cable accessory lead seal defects. The main method is eddy current detection. The eddy current detection method is a high-voltage cable accessory lead seal defect detection technology based on eddy current flaw detection technology. The test verification results show that this method has a significant detection effect on the cracking defects on the surface of the seal structure. However, this method has great limitations and cannot effectively detect the cracking defects inside the lead seal of high-voltage cable accessories. Summary of the invention

[0005] In order to solve the deficiencies in the prior art, the present invention provides a new non-destructive detection method and system for lead seal defects of high-voltage cable accessories, which can detect internal and external defects of lead seals of high-voltage cable accessories and give the defect locations, guiding the high-voltage cable operation and maintenance units to find defects in time and avoid failures.

[0006] The present invention adopts the following technical solution.

[0007] A first aspect of the present invention provides a cable accessory defect echo detection method, comprising:

[0008] Place the ultrasonic probe at the lead seal of the high-voltage cable accessories to be tested and ensure that the probe is level;

[0009] The excitation source sends out a sinusoidal ultrasonic excitation signal and injects it into the lead seal of the high-voltage cable accessories through the ultrasonic probe;

[0010] After a set delay time, the echo signal of ultrasonic detection is synchronously received and fitted and adaptively smoothed to remove noise;

[0011] Based on the amplitude of the echo signal of the ultrasonic test after fitting and adaptive smoothing and denoising, the lead seal defects and defect locations of the high-voltage cable accessories are identified, the probe position is adjusted, and the test is continued.

[0012] Preferably, the sinusoidal ultrasonic excitation signal emitted by the excitation source is:

[0013]

[0014] Where s(t) is the sinusoidal ultrasonic excitation signal at time t, f 0 Set the frequency for the excitation signal, T 0 is the period of the sine wave, D i is the delay time of the ith excitation source sending out the sinusoidal ultrasonic excitation signal.

[0015] Preferably, the step of injecting lead seals into high-voltage cable accessories through an ultrasonic probe comprises:

[0016] In an ultrasonic probe detection plane, sinusoidal ultrasonic excitation signals are injected into the lead seals of high-voltage cable accessories from left to right.

[0017] Preferably, the synchronously receiving the echo signal of ultrasonic detection after the set delay time and performing fitting and adaptive smoothing and denoising includes:

[0018] After the set delay time T, the ultrasonic detection echo signal is synchronously received until T+D i After the end, the received ultrasonic echo signal is fitted and the signal is denoised using the adaptive smoothing denoising method, where D i is the delay time of the ith excitation source sending out the sinusoidal ultrasonic excitation signal.

[0019] Preferably, the fitting formula of the ultrasonic detection echo signal is:

[0020]

[0021] Where g(t) is the echo signal of ultrasonic detection obtained by fitting at time t, A is the amplitude of the echo signal; f 0 Set the frequency for the excitation signal, T 0 is the period of the sine wave, D i is the delay time of the ith excitation source sending out the sinusoidal ultrasonic excitation signal.

[0022] Preferably, the adaptive smoothing denoising method is specifically as follows:

[0023] (1) Calculate the local mean and local standard deviation:

[0024]

[0025] Among them, μ(t) and μ(t-1) are the local means at time t and t-1;

[0026] σ(t) and σ(t-1) are the local standard deviations at time t and t-1;

[0027] is t+i, The signal value to be denoised at any moment;

[0028] N is the length of the sliding window;

[0029] (2) Set the adaptive threshold T(t) according to the local mean and standard deviation, and judge whether the signal to be denoised x(t) is noise, and obtain the signal x′(t) after adaptive denoising:

[0030] T(t)=μ(t)+k·σ(t)

[0031]

[0032] Where k is the adaptive coefficient;

[0033] (3) Based on the adaptive denoising signal x′(t), the arithmetic average is performed to obtain the adaptive smooth denoising signal:

[0034]

[0035] Among them, y(t) is the adaptive smoothed denoised signal;

[0036] x′(t+i) is the signal value after adaptive denoising at time t+i.

[0037] Preferably, the echo signal amplitude of the ultrasonic test after fitting and adaptive smoothing and denoising is used to determine the lead seal defect and defect position of the high-voltage cable accessories, adjust the probe position, and continue the test, which specifically includes:

[0038] If the change of the echo signal amplitude A in the detection plane of an ultrasonic probe does not exceed the threshold value, the lead seal of the high-voltage cable accessory to be detected is located in the current detection plane of the ultrasonic probe without defects;

[0039] If the change of the echo signal amplitude A in the detection plane of an ultrasonic probe exceeds the threshold, the lead seal of the high-voltage cable accessory to be detected is defective in the current ultrasonic probe detection plane, and the delay time D of the sinusoidal ultrasonic excitation signal emitted by the i-th excitation source is obtained by fitting and adaptive smoothing and denoising the ultrasonic detection echo signal. i , according to the delay time D i Determine the defect location.

[0040] Preferably, the delay time D iThe method for determining the defect location is as follows:

[0041] The material to be tested is divided into several planes, and each excitation signal is adjusted so that each ultrasonic signal reaches a fixed plane at each time. Then, the ith excitation source sends a sinusoidal ultrasonic excitation signal at the ith plane of the material. According to the delay time D of the ith excitation source sending a sinusoidal ultrasonic excitation signal i Determine the defect location.

[0042] A second aspect of the present invention provides a cable accessory defect echo detection system, comprising:

[0043] The probe deployment module is used to deploy the ultrasonic probe at the lead sealing part of the high-voltage cable accessories to be tested and ensure the probe is level;

[0044] An excitation signal injection module is used for the excitation source to emit a sinusoidal ultrasonic excitation signal and inject it into the lead seal of the high-voltage cable accessories through the ultrasonic probe;

[0045] An echo signal receiving module is used to synchronously receive the echo signal of ultrasonic detection after a set delay time and perform fitting and adaptive smoothing and denoising;

[0046] The defect detection module is used to identify the lead seal defects and defect locations of high-voltage cable accessories based on the amplitude of the ultrasonic detection echo signal after fitting and adaptive smoothing and denoising, and return to the probe deployment module to adjust the probe position and continue detection.

[0047] A third aspect of the present invention provides a terminal, comprising a processor and a storage medium; the storage medium is used to store instructions; the processor is used to operate according to the instructions to execute the steps of the method.

[0048] A fourth aspect of the present invention provides a computer-readable storage medium having a computer program stored thereon, which implements the steps of the method when executed by a processor.

[0049] Compared with the prior art, the beneficial effects of the present invention include at least:

[0050] The present invention can not only detect external defects of cable accessory seals, but sound waves can also penetrate metal or non-metal surfaces to reach the inside. When encountering an interface with discontinuous acoustic impedance, acoustic phenomena such as reflection, diffraction, and transmission will occur at the interface. Therefore, the acoustic characteristic information of the internal structure of the object is obtained through the interaction between ultrasonic waves and defects, thereby realizing non-destructive detection of defects in cable accessory seals.

[0051] The adaptive smoothing denoising method of the present invention processes the ultrasonic signal, avoids noise interference and smoothes the image, so that the direction of defects in the image is more in line with the actual situation, which is convenient for predicting the development trend of defects. When calculating the local standard deviation, it uses the recursive nature of the sliding window to avoid recalculating the data of the entire window, and uses the standard deviation σ at the previous moment to calculate the local standard deviation. 2 (t-1), mean μ(t-1), combined with the newly added data points and remove data points Only the two newly added and removed data points need to be updated each time without traversing the entire window, which effectively improves the updating efficiency of the local standard deviation.

[0052] The present invention can judge whether a defect occurs by the echo amplitude A, and can control the time D of the ith excitation source to send out the sinusoidal ultrasonic excitation signal. i Send out a sinusoidal ultrasonic excitation signal at regular intervals, and adjust it so that each ultrasonic signal reaches a fixed plane at each time, so as to facilitate passing through D i Determine the defect location, and accurately give the defect location, and guide the cable operation and maintenance unit to find the defect in time and avoid failure. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 It is a flow chart of a method for detecting lead seal defects of high-voltage cable accessories of the present invention;

[0054] Figure 2 Schematic diagram of defect detection in an embodiment of the present invention. DETAILED DESCRIPTION

[0055] In order to make the purpose, technical scheme and advantages of the present invention clearer, the technical scheme of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. The embodiments described in this application are only part of the embodiments of the present invention, not all of them. Based on the spirit of the present invention, other embodiments obtained by ordinary technicians in this field without creative work are all within the scope of protection of the present invention.

[0056] Embodiment 1 of the present invention provides a cable accessory defect echo detection method. Based on the ultrasonic phased array principle, an ultrasonic probe is deployed at the lead seal of a high-voltage cable accessory to be detected, a sinusoidal ultrasonic excitation signal is excited, and after a time delay, an ultrasonic detection echo signal is synchronously received. The existence of defects can be determined based on the material, defects, etc. of the lead seal of the high-voltage cable accessory to be detected in the plane where the probe is deployed, and the synchronously received ultrasonic detection echo signal is used to determine whether a defect exists. Figure 1 As shown, the high-voltage cable accessory lead seal defect detection method specifically includes:

[0057] Step 1: Place the ultrasonic probe at the lead seal of the high-voltage cable accessories to be tested and ensure that the probe is level;

[0058] Further preferably, the probe deployment steps are specifically as follows:

[0059] 1) Deploy the ultrasonic probe for detection at the lead sealing part of the high-voltage cable accessories to be detected;

[0060] 2) Adjust the ultrasonic probe to ensure that it is level and record the position of the probe at this time.

[0061] Step 2: The excitation source sends out a sinusoidal ultrasonic excitation signal s(t) and injects it into the sealing lead of the high-voltage cable accessories through the ultrasonic probe;

[0062] Further preferably, the step of sending the sinusoidal wave ultrasonic excitation signal is specifically as follows:

[0063] 1) Keep the ultrasonic probe fixed and start the ultrasonic excitation source;

[0064] 2) Sine wave ultrasonic excitation signals are emitted in sequence through the ultrasonic excitation source. The expression of the sinusoidal ultrasonic signal is:

[0065]

[0066] In the formula, f 0 Set the frequency for the excitation signal, T 0 is the period of the sine wave, D i is the delay time of the signal emitted by the i-th excitation source.

[0067] 3) The ultrasonic probe is placed at the lead seal of the high-voltage cable accessory to be tested, that is, within a detection plane of the ultrasonic probe, and ultrasonic excitation signals are injected into the lead seal of the high-voltage cable accessory from left to right.

[0068] Step 3: After the set delay time, the echo signal of the ultrasonic detection is synchronously received and fitted and adaptively smoothed to remove noise;

[0069] Further preferably, the step of synchronously receiving the echo signal of ultrasonic detection is specifically:

[0070] 1) Set a fixed delay time T. After time T, start receiving echo signals until T+D i After the end;

[0071] 2) Fit the received echo signal and use the adaptive smoothing denoising method to denoise the signal.

[0072] Among them, the fitting formula of ultrasonic detection echo signal is:

[0073]

[0074] Where A is the ultrasonic echo amplitude, which includes the energy loss caused by attenuation when the ultrasonic wave propagates in the medium; f 0 Set the frequency for the excitation signal, T 0 is the period of the sine wave, D i is the delay time of the signal emitted by the i-th excitation source.

[0075] The adaptive smoothing denoising method is as follows:

[0076] (1) Calculate the local mean and local standard deviation:

[0077]

[0078] Among them, μ(t) and μ(t-1) are the local means at time t and t-1;

[0079] σ(t) and σ(t-1) are the local standard deviations at time t and t-1;

[0080] for The signal value to be denoised at any moment;

[0081] N is the length of the sliding window;

[0082] In specific implementation, the initial value of the local standard deviation is calculated using the following formula:

[0083]

[0084] (2) Set the adaptive threshold T(t) according to the local mean and standard deviation, and judge whether the signal to be denoised x(t) is noise, and obtain the signal x′(t) after adaptive denoising:

[0085] T(t)=μ(t)+k·σ(t)

[0086]

[0087] Where k is the adaptive coefficient;

[0088] (3) Based on the adaptive denoising signal x′(t), the arithmetic average is performed to obtain the adaptive smooth denoising signal:

[0089]

[0090] Among them, y(t) is the adaptive smoothed denoised signal;

[0091] x′(t+i) is the signal value after adaptive denoising at time t+i.

[0092] Step 4: Based on the amplitude of the ultrasonic detection echo signal after fitting and adaptive smoothing and denoising, the lead seal defect and defect position of the high-voltage cable accessories are determined, and the probe position is adjusted back to step 1 to continue the detection.

[0093] Further preferably, the steps for distinguishing the lead seal defects of high-voltage cable accessories are specifically as follows:

[0094] Considering the influence of the receiving material of the ultrasonic echo signal, different materials have different acoustic impedances, and the echo signal expression of the lead seal of the high-voltage cable accessory is analyzed, where A is the ultrasonic echo amplitude. Different materials have different attenuation effects and are strongly correlated with the acoustic impedance of the material. Therefore, at the lead seal of the high-voltage cable accessory to be detected, that is, within an ultrasonic probe detection plane, if A is that the ultrasonic echo amplitude is basically consistent, then there is no defect in the ultrasonic probe detection plane at the lead seal of the high-voltage cable accessory to be detected; if A is that the ultrasonic echo amplitude has a large change, then there is no defect in the ultrasonic probe detection plane at the lead seal of the high-voltage cable accessory to be detected, and by fitting the received echo signal, the signal time sent by the i-th excitation source (that is, the delay time D of the i-th excitation source to send a sinusoidal ultrasonic excitation signal) can be obtained. i ), determine the defect location, such as Figure 2 shown.

[0095] The material to be tested is divided into several planes, and each excitation signal is adjusted so that each ultrasonic signal reaches a fixed plane at each time. Then, the ith excitation source sends a sinusoidal ultrasonic excitation signal at the ith plane of the material. According to the delay time D of the ith excitation source sending a sinusoidal ultrasonic excitation signal i Determine the defect location. A delay time D i Corresponding to a detection surface, when the change of the amplitude A of a certain echo signal exceeds the threshold, the D of the echo signal i The corresponding detection surface is the defect location.

[0096] Adjust the probe position and repeat the above process again, and finally the lead sealing state of the entire high-voltage cable accessory can be obtained.

[0097] Embodiment 2 of the present invention provides a cable accessory defect echo detection system, including:

[0098] The probe deployment module is used to deploy the ultrasonic probe at the lead sealing part of the high-voltage cable accessories to be tested and ensure the probe is level;

[0099] An excitation signal injection module is used for the excitation source to emit a sinusoidal ultrasonic excitation signal s(t) and inject it into the lead seal of the high-voltage cable accessories through the ultrasonic probe;

[0100] An echo signal receiving module is used to synchronously receive the echo signal of ultrasonic detection after a set delay time and perform fitting and adaptive smoothing and denoising;

[0101] The defect detection module is used to identify the lead seal defects and defect locations of high-voltage cable accessories based on the amplitude of the ultrasonic detection echo signal after fitting and adaptive smoothing and denoising, and return to the probe deployment module to adjust the probe position and continue detection.

[0102] Embodiment 3 of the present invention provides a terminal, including a processor and a storage medium; the storage medium is used to store instructions;

[0103] The processor is configured to operate according to the instructions to execute the steps of the method.

[0104] Embodiment 4 of the present invention provides a computer-readable storage medium having a computer program stored thereon, which implements the steps of the method when executed by a processor.

[0105] Compared with the prior art, the beneficial effects of the present invention include at least:

[0106] The present invention can not only detect external defects of cable accessory seals, but sound waves can also penetrate metal or non-metal surfaces to reach the inside. When encountering an interface with discontinuous acoustic impedance, acoustic phenomena such as reflection, diffraction, and transmission will occur at the interface. Therefore, the acoustic characteristic information of the internal structure of the object is obtained through the interaction between ultrasonic waves and defects, thereby realizing non-destructive detection of defects in cable accessory seals.

[0107] The adaptive smoothing denoising method of the present invention processes the ultrasonic signal, avoids noise interference and smoothes the image, so that the direction of defects in the image is more in line with the actual situation, which is convenient for predicting the development trend of defects. When calculating the local standard deviation, it uses the recursive nature of the sliding window to avoid recalculating the data of the entire window, and uses the standard deviation σ at the previous moment to calculate the local standard deviation. 2 (t-1), mean μ(t-1), combined with the newly added data points and remove data points Only the two newly added and removed data points need to be updated each time without traversing the entire window, which effectively improves the updating efficiency of the local standard deviation.

[0108] The present invention can judge whether a defect occurs by the echo amplitude A, and can control the time D of the ith excitation source to send out the sinusoidal ultrasonic excitation signal. i Send out a sinusoidal ultrasonic excitation signal at regular intervals, and adjust it so that each ultrasonic signal reaches a fixed plane at each time, so as to facilitate passing through D i Determine the defect location, and accurately give the defect location, and guide the cable operation and maintenance unit to find the defect in time and avoid failure.

[0109] The present disclosure may be a system, a method and / or a computer program product. The computer program product may include a computer-readable storage medium carrying computer-readable program instructions for causing a processor to implement various aspects of the present disclosure.

[0110] A computer-readable storage medium may be a tangible device that can hold and store instructions used by an instruction execution device. A computer-readable storage medium may be, for example, but not limited to, an electrical storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any suitable combination of the foregoing. More specific examples of computer-readable storage media (a non-exhaustive list) include: a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), a static random access memory (SRAM), a portable compact disk read-only memory (CD-ROM), a digital versatile disk (DVD), a memory stick, a floppy disk, a mechanical encoding device, such as a punch card or a raised structure in a groove on which instructions are stored, and any suitable combination of the foregoing. As used herein, a computer-readable storage medium is not to be interpreted as a transient signal per se, such as a radio wave or other freely propagating electromagnetic wave, an electromagnetic wave propagating through a waveguide or other transmission medium (e.g., a light pulse through a fiber optic cable), or an electrical signal transmitted through a wire.

[0111] The computer-readable program instructions described herein can be downloaded from a computer-readable storage medium to each computing / processing device, or downloaded to an external computer or external storage device via a network, such as the Internet, a local area network, a wide area network, and / or a wireless network. The network can include copper transmission cables, optical fiber transmissions, wireless transmissions, routers, firewalls, switches, gateway computers, and / or edge servers. The network adapter card or network interface in each computing / processing device receives the computer-readable program instructions from the network and forwards the computer-readable program instructions for storage in the computer-readable storage medium in each computing / processing device.

[0112] The computer program instructions for performing the operation of the present disclosure may be assembly instructions, instruction set architecture (ISA) instructions, machine instructions, machine-related instructions, microcode, firmware instructions, state setting data, or source code or object code written in any combination of one or more programming languages, including object-oriented programming languages, such as Smalltalk, C++, etc., and conventional procedural programming languages, such as "C" language or similar programming languages. Computer-readable program instructions may be executed completely on a user's computer, partially on a user's computer, as an independent software package, partially on a user's computer, partially on a remote computer, or completely on a remote computer or server. In the case of a remote computer, the remote computer may be connected to the user's computer via any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computer (e.g., using an Internet service provider to connect via the Internet). In some embodiments, an electronic circuit, such as a programmable logic circuit, a field programmable gate array (FPGA), or a programmable logic array (PLA), may be customized by utilizing the state information of the computer-readable program instructions, and the electronic circuit may execute the computer-readable program instructions, thereby realizing various aspects of the present disclosure.

[0113] 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 it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents, and any modifications or equivalent replacements that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A cable accessory defect echo detection method, characterized in that: include: Place the ultrasonic probe at the lead seal of the high-voltage cable accessories to be tested and ensure that the probe is level; The excitation source sends out a sinusoidal ultrasonic excitation signal and injects it into the lead seal of the high-voltage cable accessories through the ultrasonic probe; After a set delay time, the echo signal of ultrasonic detection is synchronously received and fitted and adaptively smoothed to remove noise; Based on the amplitude of the echo signal of the ultrasonic test after fitting and adaptive smoothing and denoising, the lead seal defects and defect locations of the high-voltage cable accessories are identified, the probe position is adjusted, and the test is continued.

2. A cable accessory defect echo detection method according to claim 1, characterized in that: The sinusoidal ultrasonic excitation signal emitted by the excitation source is: Where s(t) is the sinusoidal ultrasonic excitation signal at time t, f0 is the set frequency of the excitation signal, T0 is the period of the sinusoidal wave, and D i is the delay time of the ith excitation source sending out the sinusoidal ultrasonic excitation signal.

3. A cable accessory defect echo detection method according to claim 1, characterized in that: The method of injecting lead seal into high-voltage cable accessories through an ultrasonic probe comprises: In an ultrasonic probe detection plane, sinusoidal ultrasonic excitation signals are injected into the lead seals of high-voltage cable accessories from left to right.

4. A cable accessory defect echo detection method according to claim 1, characterized in that: The synchronously receiving the echo signal of ultrasonic detection after the set delay time and performing fitting and adaptive smoothing and denoising includes: After the set delay time T, the ultrasonic detection echo signal is synchronously received until T+D i After the end, the received ultrasonic echo signal is fitted and the signal is denoised using the adaptive smoothing denoising method, where D i is the delay time of the ith excitation source sending out the sinusoidal ultrasonic excitation signal.

5. A cable accessory defect echo detection method according to claim 4, characterized in that: The fitting formula of ultrasonic detection echo signal is: Where g(t) is the echo signal of ultrasonic detection obtained by fitting at time t, A is the amplitude of the echo signal; f0 is the set frequency of the excitation signal, T0 is the period of the sine wave, and D i is the delay time of the ith excitation source sending out the sinusoidal ultrasonic excitation signal.

6. A cable accessory defect echo detection method according to claim 4, characterized in that: The adaptive smoothing denoising method is as follows: (1) Calculate the local mean and local standard deviation: Among them, μ(t) and μ(t-1) are the local means at time t and t-1; σ(t) and σ(t-1) are the local standard deviations at time t and t-1; x(t+i), is t+i, The signal value to be denoised at any moment; N is the length of the sliding window; (2) Set the adaptive threshold T(t) according to the local mean and standard deviation, and judge whether the signal to be denoised x(t) is noise, and obtain the signal x′(t) after adaptive denoising: T(t)=μ(t)+k·σ(t) Where k is the adaptive coefficient; (3) Based on the adaptive denoising signal x′(t), the arithmetic average is performed to obtain the adaptive smooth denoising signal: Among them, y(t) is the adaptive smoothed denoised signal; x′(t+i) is the signal value after adaptive denoising at time t+i.

7. A cable accessory defect echo detection method according to claim 1, characterized in that: The method of judging the lead seal defect and defect position of the high-voltage cable accessory based on the amplitude of the echo signal of the ultrasonic detection after fitting and adaptive smoothing and denoising, adjusting the probe position, and continuing the detection specifically includes: If the change of the echo signal amplitude A in the detection plane of an ultrasonic probe does not exceed the threshold value, the lead seal of the high-voltage cable accessory to be detected is located in the current detection plane of the ultrasonic probe without defects; If the change of the echo signal amplitude A in the detection plane of an ultrasonic probe exceeds the threshold, the lead seal of the high-voltage cable accessory to be detected is defective in the current ultrasonic probe detection plane, and the delay time D of the sinusoidal ultrasonic excitation signal emitted by the i-th excitation source is obtained by fitting and adaptive smoothing and denoising the ultrasonic detection echo signal. i , according to the delay time D i Determine the defect location.

8. A cable accessory defect echo detection method according to claim 7, characterized in that: The delay time D i The method for determining the defect location is as follows: The material to be tested is divided into several planes, and each excitation signal is adjusted so that each ultrasonic signal reaches a fixed plane at each time. Then, the ith excitation source sends a sinusoidal ultrasonic excitation signal at the ith plane of the material. According to the delay time D of the ith excitation source sending a sinusoidal ultrasonic excitation signal i Determine the defect location.

9. A cable accessory defect echo detection system, using the method according to any one of claims 1 to 8, characterized in that: The system comprises: The probe deployment module is used to deploy the ultrasonic probe at the lead sealing part of the high-voltage cable accessories to be tested and ensure the probe is level; An excitation signal injection module is used for the excitation source to emit a sinusoidal ultrasonic excitation signal and inject it into the lead seal of the high-voltage cable accessories through the ultrasonic probe; An echo signal receiving module is used to synchronously receive the echo signal of ultrasonic detection after a set delay time and perform fitting and adaptive smoothing and denoising; The defect detection module is used to identify the lead seal defects and defect locations of high-voltage cable accessories based on the amplitude of the ultrasonic detection echo signal after fitting and adaptive smoothing and denoising, and return to the probe deployment module to adjust the probe position and continue detection.

10. A terminal comprising a processor and a storage medium; characterized in that: The storage medium is used to store instructions; The processor is configured to operate according to the instructions to execute the steps of the method according to any one of claims 1-8.

11. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the steps of the method according to any one of claims 1 to 8 are implemented.

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