Method and device for detecting interface pressure of combined prefabricated intermediate joint of high-voltage cable

Abstract

The invention discloses a method and a device for detecting the interface pressure of a combined prefabricated intermediate joint of a high-voltage cable. The method comprises the following steps: acquiring an ultrasonic echo signal of an intermediate joint of a to-be-detected cable; performing spectral analysis on the ultrasonic echo signal to obtain a fundamental wave amplitude and a second harmonic amplitude; calculating a nonlinear coefficient according to the fundamental wave amplitude and the second harmonic amplitude; and according to the nonlinear coefficient and a pressure calibration curve constructed through a pressure loading experiment, determining the interface pressure of the intermediate joint of the to-be-tested cable.

Description

Technical Field

[0001] The present invention relates to the technical field of prefabricated intermediate joint interface pressure detection, and more particularly to a method and device for detecting the interface pressure of a prefabricated intermediate joint of a high-voltage cable assembly. Background Art

[0002] The pressure at the silicone rubber-cable interface of prefabricated intermediate joints in high-voltage cable assemblies directly affects insulation performance. Insufficient pressure can easily trigger partial discharge, while overpressure can damage the insulation layer. Currently, engineering projects primarily rely on contact-based testing (such as embedded pressure sensors or mechanical probes), but the former damages the structural integrity of the joint, while the latter has low accuracy (error >20%). Indirect methods (such as electrical parameter inversion) are susceptible to environmental interference and lack quantitative analysis. In recent years, ultrasonic technology has been explored for interface testing due to its non-invasive nature, but it has significant drawbacks: conventional linear ultrasonic parameters (sound velocity, attenuation coefficient) can only qualitatively determine the contact state and cannot distinguish between material nonlinearity and interface pressure effects; conventional detection systems are difficult to adapt to complex joint structures, and the second harmonic signal-to-noise ratio is low (<10dB); existing technologies lack experimentally supported quantitative calibration methods and can only achieve a binary "pass / fail" judgment, which cannot guide installation process optimization. Therefore, there is an urgent need to develop a non-destructive, high-precision interface pressure detection solution based on experimental verification to address the destructive nature, poor interference resistance, and insufficient quantitative analysis capabilities of traditional methods. Summary of the Invention

[0003] In view of the deficiencies in the prior art, the present invention provides a method and device for detecting the interface pressure of a prefabricated intermediate joint of a high-voltage cable assembly.

[0004] According to one aspect of the present invention, a method for detecting interface pressure of a prefabricated intermediate joint of a high-voltage cable assembly is provided, comprising:

[0005] Collect the ultrasonic echo signal of the middle joint of the cable to be tested;

[0006] Perform spectrum analysis on the ultrasonic echo signal to obtain the fundamental wave amplitude and the second harmonic amplitude;

[0007] Calculate the nonlinear coefficient based on the fundamental wave amplitude and the second harmonic amplitude;

[0008] The interface pressure of the middle joint of the cable to be tested is determined based on the nonlinear coefficient and the pressure calibration curve constructed through the pressure loading experiment.

[0009] Optionally, collecting an ultrasonic echo signal of an intermediate joint of the cable to be tested includes:

[0010] A high-voltage pulse generator is used to drive the transmitting probe to align vertically with the center area of ​​the interface of the middle joint of the cable to be tested to collect ultrasonic echo signals.

[0011] Optionally, performing spectrum analysis on the ultrasonic echo signal to obtain the fundamental wave amplitude and the second harmonic amplitude includes:

[0012] The ultrasonic echo signal is pre-processed with wavelet threshold noise reduction algorithm to obtain a noise-free ultrasonic echo signal.

[0013] A duplex filter is used to separate the noise-free ultrasonic echo signal to obtain the fundamental wave amplitude and the second harmonic amplitude.

[0014] Optionally, the calculation expression of the nonlinear coefficient is:

[0015]

[0016] Where A1 is the fundamental wave amplitude; A2 is the second harmonic amplitude; β is the nonlinear coefficient, K1 is the linear contact stiffness, K2 is the nonlinear contact stiffness, ρ is the medium density, c is the speed of ultrasound in the medium, ω is the fundamental wave angular frequency, P is the contact section pressure, and m is a coefficient related to the interface roughness characteristics.

[0017] Optionally, the pressure calibration curve is constructed as follows:

[0018] A preset number of standard 110kV high-voltage cable prefabricated intermediate joint samples were selected as experimental samples;

[0019] After cleaning the cable cross section of the test sample, fix it on a hydraulic press and apply pressure with a preset step length to obtain the preset pressure test nonlinear coefficient;

[0020] A pressure calibration curve is constructed based on the preset pressure and the preset pressure test nonlinear coefficient.

[0021] According to another aspect of the present invention, there is provided a device for detecting interface pressure of a prefabricated intermediate joint of a high-voltage cable assembly, comprising:

[0022] An acquisition module is used to acquire ultrasonic echo signals from the middle joint of the cable to be tested;

[0023] An analysis module is used to perform spectrum analysis on the ultrasonic echo signal to obtain the fundamental wave amplitude and the second harmonic amplitude;

[0024] A calculation module, used for calculating a nonlinear coefficient according to a fundamental wave amplitude and a second harmonic amplitude;

[0025] The determination module is used to determine the interface pressure of the middle joint of the cable to be tested according to the nonlinear coefficient and the pressure calibration curve constructed through the pressure loading experiment.

[0026] According to another aspect of the present invention, a computer-readable storage medium is provided, wherein the storage medium stores a computer program, and the computer program is used to execute the method according to any one of the above aspects of the present invention.

[0027] According to another aspect of the present invention, an electronic device is provided, comprising: a processor; a memory for storing instructions executable by the processor; and the processor for reading the executable instructions from the memory and executing the instructions to implement the method described in any one of the above aspects of the present invention.

[0028] The present invention collects ultrasonic echo signals from the cable's intermediate joint under test; performs spectrum analysis on the ultrasonic echo signals to obtain the fundamental and second harmonic amplitudes; calculates the nonlinear coefficient based on the fundamental and second harmonic amplitudes; and determines the interface pressure of the cable's intermediate joint under test based on the nonlinear coefficient and a pressure calibration curve constructed through pressure loading experiments. This method can accurately guide the optimization of intermediate joint crimping process parameters and the evaluation of operating status, significantly improving the installation quality and maintenance efficiency of cable accessories. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] A more complete understanding of exemplary embodiments of the present invention may be obtained by referring to the following drawings:

[0030] Figure 1 This is a flow chart of a method for detecting interface pressure of a prefabricated intermediate joint of a high-voltage cable assembly provided by an exemplary embodiment of the present invention;

[0031] Figure 2 This is another flow chart of a method for detecting interface pressure of a prefabricated intermediate joint of a high-voltage cable assembly provided by an exemplary embodiment of the present invention;

[0032] Figure 3 This is a schematic diagram of a sample structure of a high-voltage cable intermediate joint provided by an exemplary embodiment of the present invention;

[0033] Figure 4 is a connection block diagram of an ultrasonic detection system provided by an exemplary embodiment of the present invention;

[0034] Figure 5 is a schematic diagram of a typical ultrasonic echo time domain waveform provided by an exemplary embodiment of the present invention;

[0035] Figure 6 is a spectrum analysis diagram provided by an exemplary embodiment of the present invention;

[0036] Figure 7 is a schematic diagram of a calibration curve of β value and interface pressure provided by an exemplary embodiment of the present invention;

[0037] Figure 8It is a structural schematic diagram of a high-voltage cable combined prefabricated intermediate joint interface pressure detection device provided by an exemplary embodiment of the present invention;

[0038] Figure 9 This is a structure of an electronic device provided by an exemplary embodiment of the present invention. DETAILED DESCRIPTION

[0039] Below, the exemplary embodiments according to the present invention will be described in detail with reference to the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments of the present invention, and it should be understood that the present invention is not limited to the exemplary embodiments described herein.

[0040] It should be noted that the relative arrangement of components and steps, the numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present invention unless specifically stated otherwise.

[0041] Those skilled in the art will understand that the terms "first" and "second" in the embodiments of the present invention are only used to distinguish different steps, devices or modules, and neither represent any specific technical meaning nor indicate the necessary logical order between them.

[0042] It should also be understood that, in the embodiments of the present invention, “a plurality of” may refer to two or more than two, and “at least one” may refer to one, two or more than two.

[0043] It should also be understood that any component, data or structure mentioned in the embodiments of the present invention can generally be understood as one or more, unless explicitly limited or otherwise indicated in the context.

[0044] In addition, the term "and / or" in this invention merely describes an association relationship between related objects, indicating that three possible relationships exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. Furthermore, the character " / " in this invention generally indicates that the related objects are in an "or" relationship.

[0045] It should also be understood that the description of the various embodiments of the present invention focuses on the differences between the various embodiments, and the same or similar aspects thereof can be referenced with each other. For the sake of brevity, they will not be described one by one.

[0046] At the same time, it should be understood that for the convenience of description, the sizes of the various parts shown in the drawings are not drawn according to the actual proportional relationship.

[0047] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses.

[0048] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered part of the specification.

[0049] It should be noted that like reference numerals and letters refer to like items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0050] Embodiments of the present invention can be applied to electronic devices such as terminal devices, computer systems, and servers, and can operate in conjunction with numerous other general-purpose or specialized computing system environments or configurations. Examples of well-known terminal devices, computing systems, environments, and / or configurations suitable for use with terminal devices, computer systems, servers, and other electronic devices include, but are not limited to, personal computer systems, server computer systems, thin clients, thick clients, handheld or laptop devices, microprocessor-based systems, set-top boxes, programmable consumer electronics, network personal computers, minicomputer systems, mainframe computer systems, and distributed cloud computing technology environments including any of the above.

[0051] Electronic devices such as terminal devices, computer systems, and servers can be described in the general context of computer system-executable instructions (such as program modules) executed by a computer system. Generally, program modules can include routines, programs, object programs, components, logic, data structures, etc., which perform specific tasks or implement specific abstract data types. Computer systems / servers can be implemented in a distributed cloud computing environment, where tasks are performed by remote processing devices linked via a communication network. In a distributed cloud computing environment, program modules can be located on local or remote computing system storage media, including storage devices.

[0052] Exemplary Methods

[0053] Figure 1 This is a flow chart of a method for detecting interface pressure of a prefabricated intermediate joint of a high-voltage cable assembly provided by an exemplary embodiment of the present invention. This embodiment can be applied to electronic devices, such as Figure 1 As shown, the method 100 for detecting the interface pressure of a prefabricated intermediate joint of a high-voltage cable assembly includes the following steps:

[0054] Step 101, collecting the ultrasonic echo signal of the middle joint of the cable to be tested;

[0055] Step 102: Perform spectrum analysis on the ultrasonic echo signal to obtain the fundamental wave amplitude and the second harmonic amplitude;

[0056] Step 103, calculating the nonlinear coefficient according to the fundamental wave amplitude and the second harmonic amplitude;

[0057] Step 104 : determining the interface pressure of the middle joint of the cable to be tested according to the nonlinear coefficient and the pressure calibration curve constructed through the pressure loading experiment.

[0058] Specifically, the present invention aims to provide a method and apparatus for nondestructive testing of the interface pressure of prefabricated intermediate joints of high-voltage cable assemblies based on ultrasonic nonlinear parameters, addressing the challenges of traditional testing technologies, such as high destructiveness, low accuracy, and the inability to perform quantitative assessments. Specific objectives are as follows:

[0059] 1. Non-destructive, high-precision testing: By experimentally calibrating the direct relationship between ultrasonic nonlinear parameters (the relationship between the fundamental and second harmonic amplitudes) and interface pressure, this method replaces contact sensors or probe penetration methods, enabling non-destructive testing and avoiding damage to insulation structures.

[0060] 2. Design of a dedicated anti-interference system: Develop a highly sensitive detection device adapted to the complex geometry of the intermediate joint. Using high-voltage pulse excitation (such as a 400V Hamming window modulation signal), duplex filtering and noise reduction technology, and a dual-transmitter-receiver probe layout, we can increase the second harmonic signal-to-noise ratio to >25dB, ensuring effective extraction of weak signals in strong electromagnetic environments.

[0061] 3. Experiment-driven pressure quantification: Based on experimental data, a joint analysis mechanism for the fundamental wave amplitude drop rate (1.89% to 14.38%) and the second harmonic attenuation trend is established to achieve quantitative analysis of the interface pressure state (resolution 0.1 MPa), providing a direct basis for installation process parameter optimization and operation and maintenance inspection.

[0062] The present invention fills the technical gap of non-destructive and quantitative evaluation of interface pressure of intermediate joints of high-voltage cables through the non-linear ultrasonic detection technology verified by experiments.

[0063] The present invention relates to a method for detecting the interface pressure of a prefabricated intermediate joint of a high-voltage cable assembly based on ultrasonic nonlinear parameters. The quantitative relationship between the ultrasonic nonlinear response and the interface pressure is experimentally calibrated to achieve non-destructive and high-precision detection. A high-voltage pulse excitation module is used to generate a 400V Hamming window modulation signal to drive the transmitting probe, and ultrasonic waves with a center frequency of 5MHz are directionally transmitted to the silicone rubber-cable interface; the receiving probe captures the interface reflected echo signal at an angle of 30°, and then separates the fundamental wave (4-6MHz) and the second harmonic (10-12MHz) components through a duplex filter, and then records the time domain waveform through a high-speed data acquisition card. In the signal processing stage, the echo signal is Fourier transformed to extract the fundamental wave amplitude A1 and the second harmonic amplitude A2, and the nonlinear coefficient β is calculated as (A2 / A1 2), and combined with experimental data to establish a pressure calibration curve: in the pressure range of 0.1 to 3.0 MPa, the fundamental wave amplitude shows a downward trend with increasing pressure (the rate of decrease is 1.89% to 14.38%), while the β value shows a nonlinear change law of first rapidly rising and then slowing down with increasing pressure. The joint analysis of the two can achieve quantitative analysis of the pressure state. The detection device includes a high-sensitivity transceiver probe, a high-voltage pulse generator, a duplex noise reduction module and a signal analysis terminal. The dual probe adopts a one-transmitter and one-receiver layout to eliminate the nonlinear interference of the silicone rubber material itself. The duplex filter is combined with the wavelet threshold noise reduction algorithm to increase the second harmonic signal-to-noise ratio to more than 25dB. Through laboratory simulation and engineering field verification, this method can still maintain a pressure resolution of 0.1MPa in a strong electromagnetic interference environment. The deviation between the detection results and the measured data of the thin film sensor is less than 5%. It can accurately guide the optimization of the intermediate joint crimping process parameters and the evaluation of the operating status, significantly improving the installation quality and operation and maintenance efficiency of cable accessories.

[0064] refer to Figure 2 As shown, the present invention provides a specific embodiment as follows:

[0065] Step 1: Experimental sample preparation and pressure loading:

[0066] Select 10 sets of standard 110kV high voltage cable prefabricated intermediate joint samples (structure as Figure 3 After cleaning the silicone rubber-cable interface, it was secured to a hydraulic press. A pressure controller applied a preset pressure of 0.1 to 3.0 MPa (in 0.2 MPa steps) to the interface. Three load-unload cycles were repeated for each pressure setting. A high-precision thin-film pressure sensor (Tekscan 5101B, range 0-5 MPa, accuracy ±1%) was used to monitor the actual contact pressure in real time. The data were recorded in Table 1 (Pressure Calibration Comparison Table) to ensure an experimental pressure error of less than 3%.

[0067] Table 1 Comparison table of preset pressure and β value experimental data

[0068]

[0069] Step 2: Ultrasonic detection system construction

[0070] according to Figure 4 Connect the detection device as shown:

[0071] Transmitter module: A high-voltage pulse generator (parameters: 400V Hamming window modulation, pulse width 200ns, repetition rate 1kHz) drives a transmitter probe (Olympus V156-RB, center frequency 5MHz), which is vertically aligned with the center area of ​​the connector interface;

[0072] Receiving module: The receiving probe (same model) is fixed at a 30° angle to the transmitting probe. The echo signal is separated by a duplex filter (bandwidth: fundamental wave 4-6 MHz, second harmonic 10-12 MHz) and input into a high-speed data acquisition card (NIPXIe-5162, sampling rate 1 GS / s, bandwidth 250 MHz).

[0073] Noise reduction unit: The wavelet threshold noise reduction algorithm (sym8 wavelet base, threshold 0.1) is used to preprocess the original signal and suppress the environmental noise (laboratory background noise <40dB).

[0074] Step 3: Ultrasonic signal acquisition and processing

[0075] Start the detection system and collect the ultrasonic echo signal under each pressure group (typical time domain waveform is as follows Figure 5 The signal is processed as follows:

[0076] 1. Spectrum analysis: Perform 2048-point Fourier transform on the time domain signal to obtain the amplitude of the fundamental wave (5MHz±0.5MHz) and the second harmonic (10MHz±1MHz) (see the spectrum diagram Figure 6 );

[0077] 2. Calculation of nonlinear coefficient: Calculate the β value according to formula (1) (A1 and A2 are the amplitudes of the fundamental wave and the second harmonic, respectively), and record the results in Table 1;

[0078]

[0079] Among them, A1 is the fundamental wave amplitude, A2 is the second harmonic amplitude, β is the nonlinear coefficient, K1 is the linear contact stiffness, K2 is the nonlinear contact stiffness, ρ is the medium density, c is the speed of ultrasound in the medium, ω is the fundamental wave angular frequency, P is the contact section pressure, and m is a coefficient related to the interface roughness characteristics.

[0080] Step 4: Establish pressure calibration curve

[0081] According to the data in Table 1, the relationship curve between β value and interface pressure is drawn (such as Figure 7 ), and the empirical formula is obtained by least square fitting:

[0082]

[0083] Step 5: Project site verification

[0084] Five newly installed intermediate joints were selected in a 220kV cable tunnel. Figure 4 System connection method for on-site testing:

[0085] 1. Signal acquisition: Select 3 detection points for each connector (see Figure 1Mark), collect ultrasonic echo signals;

[0086] 2. Pressure analysis: check according to β value Figure 5 The calibration curve shows that the interface pressure distribution is 1.3-1.7 MPa (installation requirement: 1.5±0.3 MPa);

[0087] 3. Comparison of results: A joint was randomly selected for dissection and a thin film sensor was implanted for re-measurement. The measured pressure was 1.52 MPa, which deviated from the ultrasonic detection value of 1.55 MPa by less than 2%, verifying the reliability of this method.

[0088] Thus, the present invention has achieved a technological breakthrough in the interface pressure assessment of the intermediate joints of high-voltage cables through the experimentally calibrated ultrasonic nonlinear parameter detection technology. Compared with the traditional contact detection method, its non-invasive characteristics completely avoid the risk of insulation structure damage caused by embedded sensors or mechanical probe puncture, and at the same time solve the problem that the indirect evaluation method is greatly disturbed by the ambient temperature and humidity and cannot be quantified. Experiments show that based on the joint analysis mechanism of the fundamental wave amplitude drop rate and the second harmonic nonlinear coefficient, a high-resolution detection of 0.1MPa can be achieved in the pressure range of 0.1~3.0MPa. The maximum deviation between the test results and the measured data of the thin film pressure sensor is less than 5%, and the signal-to-noise ratio is improved to more than 25dB, which is significantly better than the traditional ultrasonic detection technology (signal-to-noise ratio <10dB). This improvement in accuracy makes it possible to visualize the interface pressure distribution, providing a direct basis for the refined control of the cable accessories installation process.

[0089] At the engineering application level, the dedicated detection system of the present invention overcomes the difficulty of extracting weak second harmonic signals in strong electromagnetic interference environments through high-voltage pulse excitation, duplex filtering noise reduction, and a one-transmitter-one-receiver probe layout design. Field tests have shown that the detection time of a single intermediate joint can be shortened to less than 3 minutes, which is more than 80% more efficient than traditional anatomical detection, and can be implemented without power outages. For example, in a 220kV cable project, two joints with an interface pressure of less than 1.0MPa were quickly screened out using this method. After re-tightening, the local discharge was reduced to less than 5pC, effectively avoiding potential operational failures. In addition, long-term monitoring data of fundamental and harmonic parameters can also be used to evaluate the aging status of joints, provide support for predictive maintenance, and are expected to extend the service life of joints by more than 20%.

[0090] From the perspective of economic and social benefits, the present invention significantly reduces the cable failure rate caused by improper installation through non-destructive and quantitative detection. Statistics show that projects using this technology can reduce the joint rework rate from 15% to below 3%, saving more than 500,000 yuan in construction costs for a single 10-kilometer cable line. At the same time, its high reliability reduces power outages caused by joint failures and improves the reliability index of urban power grid power supply (RS-3 can reach 99.99%). At present, this technology has been applied in multiple UHV project pilots, with a cumulative detection of more than 1,200 joints and a defect identification accuracy rate of 98.7%, providing an innovative solution for the intelligent operation and maintenance of power equipment.

[0091] Exemplary devices

[0092] Figure 8 FIG. 1 is a schematic diagram of a high-voltage cable assembly prefabricated intermediate joint interface pressure detection device provided by an exemplary embodiment of the present invention. Figure 8 As shown, the apparatus 800 includes:

[0093] The acquisition module 810 is used to acquire the ultrasonic echo signal of the middle joint of the cable to be tested;

[0094] The analysis module 820 is used to perform spectrum analysis on the ultrasonic echo signal to obtain the fundamental wave amplitude and the second harmonic amplitude;

[0095] A calculation module 830 is used to calculate a nonlinear coefficient based on the fundamental wave amplitude and the second harmonic amplitude;

[0096] The determination module 840 is configured to determine the interface pressure of the middle joint of the cable to be tested according to the nonlinear coefficient and the pressure calibration curve constructed through the pressure loading experiment.

[0097] Optionally, the acquisition module 810 includes:

[0098] The acquisition submodule is used to use a high-voltage pulse generator to drive the transmitting probe to vertically align with the center area of ​​the interface of the middle joint of the cable to be tested to collect ultrasonic echo signals.

[0099] Optionally, the analysis module 820 includes:

[0100] The denoising submodule is used to perform denoising preprocessing on the ultrasonic echo signal using a wavelet threshold denoising algorithm to obtain a noise-free ultrasonic echo signal;

[0101] The separation submodule is used to separate the noise-free ultrasonic echo signal using a duplex filter to obtain the fundamental wave amplitude and the second harmonic amplitude.

[0102] Optionally, the calculation expression of the nonlinear coefficient is:

[0103]

[0104] Where A1 is the fundamental wave amplitude; A2 is the second harmonic amplitude; β is the nonlinear coefficient, K1 is the linear contact stiffness, K2 is the nonlinear contact stiffness, ρ is the medium density, c is the speed of ultrasound in the medium, ω is the fundamental wave angular frequency, P is the contact section pressure, and m is a coefficient related to the interface roughness characteristics.

[0105] Optionally, the process of constructing the pressure calibration curve in the determination module 840 is as follows:

[0106] A preset number of standard 110kV high-voltage cable prefabricated intermediate joint samples were selected as experimental samples;

[0107] After cleaning the cable cross section of the test sample, fix it on a hydraulic press and apply pressure with a preset step length to obtain the preset pressure test nonlinear coefficient;

[0108] A pressure calibration curve is constructed based on the preset pressure and the preset pressure test nonlinear coefficient.

[0109] Exemplary electronic devices

[0110] Figure 9 This is the structure of an electronic device provided by an exemplary embodiment of the present invention. Figure 9 As shown, the electronic device 90 includes one or more processors 91 and a memory 92 .

[0111] The processor 91 may be a central processing unit (CPU) or other forms of processing units having data processing capabilities and / or instruction execution capabilities, and may control other components in the electronic device to perform desired functions.

[0112] The memory 92 may include one or more computer program products, which may include various forms of computer-readable storage media, such as volatile memory and / or non-volatile memory. The volatile memory may, for example, include random access memory (RAM) and / or cache memory (cache), etc. The non-volatile memory may, for example, include read-only memory (ROM), a hard disk, a flash memory, etc. One or more computer program instructions may be stored on the computer-readable storage medium, and the processor 91 may execute the program instructions to implement the methods of the software programs of the various embodiments of the present invention described above and / or other desired functions. In one example, the electronic device may further include: an input device 93 and an output device 94, which are interconnected via a bus system and / or other forms of connection mechanisms (not shown).

[0113] In addition, the input device 93 may also include, for example, a keyboard, a mouse, and the like.

[0114] The output device 94 can output various information to the outside. The output device 94 can include, for example, a display, a speaker, a printer, a communication network and a remote output device connected thereto.

[0115] Of course, to simplify, Figure 9 Only some of the components related to the present invention in the electronic device are shown, and components such as a bus, an input / output interface, etc. are omitted. In addition, the electronic device may further include any other appropriate components according to specific application conditions.

[0116] Exemplary computer program products and computer-readable storage media

[0117] In addition to the above-mentioned methods and devices, an embodiment of the present invention may also be a computer program product, which includes computer program instructions, which, when executed by a processor, enable the processor to perform the steps of the method according to various embodiments of the present invention described in the above "Exemplary Method" section of this specification.

[0118] The computer program product may be written in any combination of one or more programming languages ​​to implement the operations of embodiments of the present invention, including object-oriented programming languages ​​such as Java, C++, and conventional procedural programming languages ​​such as C or similar programming languages. The program code may be executed entirely on the user's computing device, partially on the user's computing device, as a stand-alone software package, partially on the user's computing device and partially on a remote computing device, or entirely on a remote computing device or server.

[0119] In addition, an embodiment of the present invention may also be a computer-readable storage medium having computer program instructions stored thereon, which, when executed by a processor, enable the processor to execute the steps of the method according to various embodiments of the present invention described in the above "Exemplary Method" section of this specification.

[0120] The computer-readable storage medium can adopt any combination of one or more readable media. The readable medium can be a readable signal medium or a readable storage medium. The readable storage medium can, for example, include but is not limited to a system, system or device of electricity, magnetism, light, electromagnetic, infrared, or semiconductor, or any combination thereof. More specific examples (non-exhaustive list) of readable storage media include: an electrical connection with one or more wires, a portable disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination thereof.

[0121] The basic principles of the present invention have been described above in conjunction with specific embodiments. However, it should be noted that the advantages, strengths, and effects mentioned in the present invention are merely illustrative and non-limiting, and should not be construed as necessarily possessed by each embodiment of the present invention. Furthermore, the specific details disclosed above are provided for illustrative purposes and to facilitate understanding, and are not intended to be limiting. These details do not necessarily limit the present invention to being implemented using these specific details.

[0122] Each embodiment in this specification is described in a progressive manner, with each embodiment focusing on its differences from the other embodiments. Reference can be made to the descriptions of the identical or similar parts between the various embodiments. The system embodiments are described briefly because they largely correspond to the method embodiments. For relevant parts, refer to the descriptions of the method embodiments.

[0123] The block diagrams of the devices, systems, equipment, and systems involved in the present invention are merely illustrative examples and are not intended to require or imply that they must be connected, arranged, or configured in the manner shown in the block diagrams. As will be appreciated by those skilled in the art, these devices, systems, equipment, and systems can be connected, arranged, or configured in any manner. Words such as "including," "comprising," "having," and the like are open-ended words, meaning "including but not limited to," and can be used interchangeably therewith. The words "or" and "and" used herein refer to the words "and / or" and can be used interchangeably therewith, unless the context clearly indicates otherwise. The word "such as" used herein refers to the phrase "such as but not limited to," and can be used interchangeably therewith.

[0124] The method and system of the present invention may be implemented in many ways. For example, the method and system of the present invention may be implemented by software, hardware, firmware, or any combination of software, hardware, and firmware. The above sequence of steps for the method is for illustration only, and the steps of the method of the present invention are not limited to the sequence specifically described above, unless otherwise specified. In addition, in some embodiments, the present invention may also be implemented as a program recorded in a recording medium, which includes machine-readable instructions for implementing the method according to the present invention. Thus, the present invention also covers recording media that store programs for executing the method according to the present invention.

[0125] It should also be noted that, in the system, device and method of the present invention, each component or each step can be decomposed and / or recombined. These decompositions and / or recombinations should be regarded as equivalent schemes of the present invention. The above description of the disclosed aspects is provided to enable any technician in this field to make or use the present invention. Various modifications to these aspects will be very obvious to those skilled in the art, and the general principles defined here can be applied to other aspects without departing from the scope of the present invention. Therefore, the present invention is not intended to be limited to the aspects shown here, but according to the widest scope consistent with the principles disclosed here and novel features.

[0126] The above description has been presented for purposes of illustration and description. Furthermore, this description is not intended to limit the embodiments of the present invention to the forms disclosed herein. Although a number of example aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, alterations, additions, and sub-combinations thereof.

Claims

1. A method for detecting interface pressure of a prefabricated intermediate joint of a high-voltage cable assembly, characterized in that: include: Collect the ultrasonic echo signal of the middle joint of the cable to be tested; Performing spectrum analysis on the ultrasonic echo signal to obtain the fundamental wave amplitude and the second harmonic amplitude; Calculating a nonlinear coefficient based on the fundamental wave amplitude and the second harmonic amplitude; The interface pressure of the intermediate joint of the cable to be tested is determined according to the nonlinear coefficient and a pressure calibration curve constructed through a pressure loading experiment.

2. The method according to claim 1, characterized in that Collect the ultrasonic echo signal of the middle joint of the cable to be tested, including: A high-voltage pulse generator is used to drive a transmitting probe to be vertically aligned with the center area of ​​the interface of the middle joint of the cable to be tested to collect ultrasonic echo signals.

3. The method according to claim 2, characterized in that Performing spectrum analysis on the ultrasonic echo signal to obtain the fundamental wave amplitude and the second harmonic amplitude includes: Performing noise reduction preprocessing on the ultrasonic echo signal using a wavelet threshold noise reduction algorithm to obtain a noise-free ultrasonic echo signal; A duplex filter is used to separate the noise-free ultrasonic echo signal to obtain the fundamental wave amplitude and the second harmonic amplitude.

4. The method according to claim 1, wherein The calculation expression of the nonlinear coefficient is: Where A1 is the fundamental wave amplitude; A2 is the second harmonic amplitude; β is the nonlinear coefficient, K1 is the linear contact stiffness, K2 is the nonlinear contact stiffness, ρ is the medium density, c is the speed of ultrasound in the medium, ω is the fundamental wave angular frequency, P is the contact section pressure, and m is a coefficient related to the interface roughness characteristics.

5. The method according to claim 1, wherein The construction process of the pressure calibration curve is as follows: A preset number of standard 110kV high-voltage cable prefabricated intermediate joint samples were selected as experimental samples; The cable cross section of the test sample is cleaned and fixed on a hydraulic press to apply pressure of a preset step length to obtain a preset pressure test nonlinear coefficient; The pressure calibration curve is constructed based on the preset pressure and the nonlinear coefficient of the preset pressure test.

6. A high-voltage cable combined prefabricated intermediate joint interface pressure detection device, characterized in that: include: An acquisition module is used to acquire ultrasonic echo signals from the middle joint of the cable to be tested; An analysis module, configured to perform spectrum analysis on the ultrasonic echo signal to obtain a fundamental wave amplitude and a second harmonic amplitude; A calculation module, configured to calculate a nonlinear coefficient based on the fundamental wave amplitude and the second harmonic amplitude; The determination module is used to determine the interface pressure of the intermediate joint of the cable to be tested according to the nonlinear coefficient and the pressure calibration curve constructed through the pressure loading experiment.

7. The device according to claim 6, characterized in that Acquisition module, including: The acquisition submodule is used to use a high-voltage pulse generator to drive the transmitting probe to vertically align with the center area of ​​the interface of the middle joint of the cable to be tested to collect ultrasonic echo signals.

8. The device according to claim 7, characterized in that Analysis modules, including: a denoising submodule, configured to perform denoising preprocessing on the ultrasonic echo signal using a wavelet threshold denoising algorithm to obtain a noise-free ultrasonic echo signal; The separation submodule is used to separate the noise-free ultrasonic echo signal by using a duplex filter to obtain the fundamental wave amplitude and the second harmonic amplitude.

9. The device according to claim 6, characterized in that The calculation expression of the nonlinear coefficient is: Where A1 is the fundamental wave amplitude; A2 is the second harmonic amplitude; β is the nonlinear coefficient, K1 is the linear contact stiffness, K2 is the nonlinear contact stiffness, ρ is the medium density, c is the speed of ultrasound in the medium, ω is the fundamental wave angular frequency, P is the contact section pressure, and m is a coefficient related to the interface roughness characteristics.

10. The device according to claim 6, characterized in that The construction process of the pressure calibration curve in the determination module is as follows: A preset number of standard 110kV high-voltage cable prefabricated intermediate joint samples were selected as experimental samples; The cable cross section of the test sample is cleaned and fixed on a hydraulic press to apply pressure of a preset step length to obtain a preset pressure test nonlinear coefficient; The pressure calibration curve is constructed based on the preset pressure and the nonlinear coefficient of the preset pressure test.

11. A computer-readable storage medium, characterized in that The storage medium stores a computer program, and the computer program is used to execute the method according to any one of claims 1 to 5.

12. An electronic device, characterized in that: The electronic device comprises: processor; a memory for storing instructions executable by the processor; The processor is configured to read the executable instructions from the memory and execute the instructions to implement the method according to any one of claims 1 to 5.

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