High-voltage cable buffer layer ablation defect detection method and device based on heat source excitation

Abstract

The present invention relates to the field of electrical detection technology, and discloses a method and device for detecting ablation defects in a high-voltage cable buffer layer based on heat source excitation. The present invention adjusts the heat flux intensity applied by an external heat source to the outer sheath of a target high-voltage cable through a modulation signal meter, so that the heat flux intensity changes in a sinusoidal pattern, and detects the heat wave generated by the outer sheath of the target high-voltage cable under the excitation of the external heat source through an infrared thermal imager, and then analyzes and processes the thermal infrared image detected by the infrared thermal imager to obtain the reflected heat wave amplitude of each unit point on the outer sheath of the target high-voltage cable, and determines the location of the ablation defect based on the degree of change and / or size of the reflected heat wave amplitude. The present invention amplifies the local temperature rise of the outer sheath corresponding to the ablation defect of the cable buffer layer through an external excitation source to form a clear contrast with the surrounding non-defective positions, which can effectively improve the accuracy and efficiency of ablation defect detection.

Description

Technical Field

[0001] The present invention relates to the field of electrical detection technology, and in particular to a method and device for detecting ablation defects of a high-voltage cable buffer layer based on heat source excitation. Background Art

[0002] High-voltage cables are widely used in urban power grids, hydropower transmission, submarine power transmission, and resource and environmental protection, and are key components of new power systems. High-voltage cables are typically laid underground, making them vulnerable to damage from external forces such as municipal engineering projects, which can lead to moisture intrusion. To prevent moisture from forming on cable insulation, a semi-conductive buffer tape (i.e., a buffer layer) is often used as a longitudinal water-blocking structure (i.e., a buffer layer). The tape is filled with a sodium polyacrylate-based water-blocking powder.

[0003] Burning of the buffer layer of high-voltage cables can easily lead to failures in the cable itself, primarily manifesting as large-scale burns between the metal sheath and the insulation shield. This type of large-scale burnout, unlike previous high-voltage cable failures, occurs not in cable accessories or the main insulation, but rather between the cable's metal sheath and insulation shield. Numerous burnout points can be found on the insulation shield, buffer layer, and metal sheath. In some severe cases, the burns can even damage the main insulation.

[0004] Most of these faulty cables exhibit white powder (hereinafter referred to as "white powder") at the point where the water-blocking tape contacts the aluminum sheath. Industry analysts believe this powder is formed by a chemical reaction between the water-blocking tape and the aluminum sheath, as it expands when exposed to moisture. The white powder, a high-resistance insulating substance, is distributed between the normally conductive insulation shield and the aluminum sheath, resulting in poor electrical contact between the two. This can cause localized overheating after prolonged cable operation. This heat is then transferred through the aluminum sheath, manifesting as a localized temperature rise in the outer sheath. This heat then gradually develops into a burn defect in the conductor, scalding the main insulation and ultimately causing a breakdown in the cable itself.

[0005] Because white powder defects in high-voltage cables are very small, they accumulate very little heat. Field testing results show that the outer sheath temperature rise at the location of the white powder defect is typically no more than 1°C. Furthermore, due to the influence of external environmental factors such as room temperature, traditional temperature detection methods have difficulty detecting the specific location of ablation defects in the high-voltage cable buffer layer.

[0006] Currently, X-ray detection methods or direct infrared thermal imaging methods are often used to detect ablation defects in the buffer layer of high-voltage cables.

[0007] The X-ray detection method is based on the principle that X-rays will interact with the medium layer by layer when passing through an object. It uses the obvious difference in density between the ablation area and the water-blocking tape to characterize the characteristics of the ablation defects in the buffer layer with X-ray imaging. The X-ray detection method is limited by the cable laying environment. Most cables are laid in a herringbone structure. The X-ray machine has a limited shooting angle and cannot cover the entire cable in all directions. If the ablation defect appears between the three herringbone cables, it is easy to miss the detection due to inadequate shooting. In addition, the X-ray machine needs to adjust the exposure time, focal length, tube voltage, tube current and other parameters before shooting, and needs to be tested multiple times to find the optimal value. If the entire cable line needs to be inspected, it will consume a lot of manpower, material resources and time costs, greatly increasing the operation and maintenance workload of the inspection personnel. At the same time, the X-ray detection process has certain safety hazards.

[0008] The infrared thermal imaging method uses the fact that the temperature at the local overheating location of the ablation defect is transferred through the aluminum sheath to the outer sheath surface, resulting in a localized, point-like temperature rise on the outer sheath. The infrared thermal image captured is used to determine the temperature difference between the defect location and surrounding, undefected areas, thereby locating the buffer layer defect. This method is significantly limited by the instrument's detection accuracy and is affected by external environmental factors such as room temperature. The local temperature rise caused by the ablation defect can be overwhelmed by interference signals, resulting in missed detections.

[0009] It can be seen that the current high-voltage cable buffer layer ablation defect detection method still needs to be improved in terms of detection accuracy and efficiency. Summary of the Invention

[0010] The present invention provides a method and device for detecting ablation defects of a high-voltage cable buffer layer based on heat source excitation, which solves the technical problem of how to achieve high-precision and high-efficiency detection of ablation defects of a high-voltage cable buffer layer.

[0011] A first aspect of the present invention provides a method for detecting ablation defects in a high-voltage cable buffer layer based on heat source excitation, comprising:

[0012] Sending a heat source excitation instruction to the modulation signal instrument, so that the modulation signal instrument adjusts the heat flux intensity applied by the external heat source to the outer sheath of the target high-voltage cable according to the heat source excitation instruction according to the sine law;

[0013] controlling an infrared thermal imager to detect heat waves generated by the outer sheath of the target high-voltage cable under the excitation of an external heat source, and obtaining a thermal infrared image detected by the infrared thermal imager;

[0014] The thermal infrared image is analyzed and processed to obtain the reflected thermal wave amplitude of each unit point on the outer sheath of the target high-voltage cable, and the ablation defect position is determined according to the change degree and / or size of the reflected thermal wave amplitude.

[0015] According to one achievable manner of the first aspect of the present invention, the heat source excitation instruction includes the heating power and loading frequency of the external heat source, and the expression for the change of the heat flux intensity is:

[0016]

[0017] Where I(t) represents the heat flux intensity at time t, P is the heating power of the external heat source, and f e is the loading frequency of the external heat source.

[0018] According to one achievable method of the first aspect of the present invention, analyzing and processing the thermal infrared image to obtain the reflected thermal wave amplitude of each unit point on the outer sheath of the target high-voltage cable includes:

[0019] generating a temperature change curve of each unit point when the heat wave is transmitted through the outer sheath of the target high-voltage cable according to the thermal infrared image;

[0020] Perform fast Fourier transform on the temperature variation curve of each unit point to obtain the corresponding thermal wave amplitude curve;

[0021] According to the thermal wave amplitude curve, the reflected thermal wave amplitude of each unit point on the outer sheath of the target high-voltage cable is calculated using the infrared phase-locked method.

[0022] According to an achievable manner of the first aspect of the present invention, determining the location of the ablation defect according to the degree of change and / or size of the reflected thermal wave amplitude includes:

[0023] The reflected thermal wave amplitude of each unit point on the outer sheath of the target high-voltage cable at the end of the external heat source excitation is used as the reflected thermal wave amplitude to be detected, the amplitude average of the reflected thermal wave amplitude to be detected is calculated, and the unit point corresponding to the reflected thermal wave amplitude to be detected being greater than the amplitude average is regarded as the ablation defect point;

[0024] And / or, calculate the degree of change in the reflected thermal wave amplitude of each unit point on the outer sheath of the target high-voltage cable during the excitation of the external heat source, calculate the average value of the change degree based on the degree of change in the reflected thermal wave amplitude, and take the unit point corresponding to the degree of change in the reflected thermal wave amplitude greater than the average value of the change degree as the ablation defect point.

[0025] According to one implementation of the first aspect of the present invention, the method further includes:

[0026] Determine the current maximum temperature of the outer sheath of the target high-voltage cable according to the current thermal infrared image;

[0027] Calculating the temperature difference between the maximum temperature and the ambient temperature of the target high-voltage cable;

[0028] When the temperature difference is greater than a preset temperature difference threshold, the external heat source is controlled to be turned off.

[0029] A second aspect of the present invention provides a high-voltage cable buffer layer ablation defect detection device based on heat source excitation, comprising:

[0030] a sending module, configured to send a heat source excitation instruction to a modulation signal instrument, so that the modulation signal instrument adjusts the heat flux intensity applied by the external heat source to the outer sheath of the target high-voltage cable according to the heat source excitation instruction according to a sinusoidal law;

[0031] a control module, configured to control an infrared thermal imager to detect heat waves generated by the outer sheath of the target high-voltage cable under the excitation of an external heat source, and to obtain a thermal infrared image detected by the infrared thermal imager;

[0032] The analysis module is used to analyze and process the thermal infrared image to obtain the reflected thermal wave amplitude of each unit point on the outer sheath of the target high-voltage cable, and determine the location of the ablation defect according to the degree of change and / or size of the reflected thermal wave amplitude.

[0033] According to an achievable manner of the second aspect of the present invention, the heat source excitation instruction includes the heating power, loading frequency and heating time of the external heat source, and the variation expression of the heat flux intensity is:

[0034]

[0035] Where I(t) represents the heat flux intensity at time t, P is the heating power of the external heat source, and f e is the loading frequency of the external heat source.

[0036] According to one implementation of the second aspect of the present invention, the analysis module includes:

[0037] a first curve generating unit, configured to generate, based on the thermal infrared image, a temperature change curve of each unit point when the heat wave is transmitted through the outer sheath of the target high-voltage cable;

[0038] The second curve generating unit is used to perform fast Fourier transform on the temperature change curve of each unit point to obtain a corresponding thermal wave amplitude curve graph;

[0039] The calculation unit is used to calculate the reflected thermal wave amplitude of each unit point on the outer sheath of the target high-voltage cable using an infrared phase-locked method according to the thermal wave amplitude curve.

[0040] According to one implementation of the second aspect of the present invention, the analysis module includes:

[0041] The first ablation defect judgment unit is configured to use the reflected thermal wave amplitude of each unit point on the outer sheath of the target high-voltage cable at the end of the external heat source excitation as the reflected thermal wave amplitude to be detected, calculate the amplitude average of the reflected thermal wave amplitude to be detected, and use the unit point corresponding to the reflected thermal wave amplitude to be detected being greater than the amplitude average as the ablation defect point;

[0042] And / or, a second ablation defect judgment unit is used to calculate the degree of change in the reflected thermal wave amplitude of each unit point on the outer sheath of the target high-voltage cable during the excitation of the external heat source, calculate the average value of the change degree based on the degree of change in the reflected thermal wave amplitude, and take the unit point corresponding to the degree of change in the reflected thermal wave amplitude greater than the average value of the change degree as the ablation defect point.

[0043] According to one implementation of the second aspect of the present invention, the apparatus further includes:

[0044] a determination module, configured to determine a current maximum temperature of the outer sheath of the target high-voltage cable according to a current thermal infrared image;

[0045] A temperature difference calculation module, used to calculate the temperature difference between the maximum temperature and the ambient temperature of the target high-voltage cable;

[0046] The heat source control module is used to control the external heat source to be turned off when the temperature difference is greater than a preset temperature difference threshold.

[0047] A third aspect of the present invention provides a high-voltage cable buffer layer ablation defect detection device based on heat source excitation, comprising an ablation defect detection device, a modulation signal meter, an external heat source and an infrared thermal imager;

[0048] The ablation defect detection device is used to send a heat source excitation instruction to the modulation signal instrument;

[0049] The modulation signal instrument is used to adjust the heat flux intensity applied by the external heat source to the outer sheath of the target high-voltage cable according to the heat source excitation instruction according to the sine law;

[0050] The ablation defect detection equipment is also used to control the infrared thermal imager to detect the heat waves generated by the target high-voltage cable outer sheath under the excitation of the external heat source, and obtain the thermal infrared image detected by the infrared thermal imager; analyze and process the thermal infrared image to obtain the reflected heat wave amplitude of each unit point on the target high-voltage cable outer sheath, and determine the ablation defect position according to the degree of change and / or size of the reflected heat wave amplitude.

[0051] According to an achievable manner of the third aspect of the present invention, the heat source excitation instruction includes the heating power and loading frequency of the external heat source, and the expression for the change of the heat flux intensity is:

[0052]

[0053] Where I(t) represents the heat flux intensity at time t, P is the heating power of the external heat source, and f e is the loading frequency of the external heat source.

[0054] According to an achievable manner of the third aspect of the present invention, the ablation defect detection device is specifically used for:

[0055] generating a temperature change curve of each unit point when the heat wave is transmitted through the outer sheath of the target high-voltage cable according to the thermal infrared image;

[0056] Perform fast Fourier transform on the temperature variation curve of each unit point to obtain the corresponding thermal wave amplitude curve;

[0057] According to the thermal wave amplitude curve, the reflected thermal wave amplitude of each unit point on the outer sheath of the target high-voltage cable is calculated using the infrared phase-locked method.

[0058] According to an achievable manner of the third aspect of the present invention, the ablation defect detection device is specifically used for:

[0059] The reflected thermal wave amplitude of each unit point on the outer sheath of the target high-voltage cable at the end of the external heat source excitation is used as the reflected thermal wave amplitude to be detected, the amplitude average of the reflected thermal wave amplitude to be detected is calculated, and the unit point corresponding to the reflected thermal wave amplitude to be detected being greater than the amplitude average is regarded as the ablation defect point;

[0060] And / or, calculate the degree of change in the reflected thermal wave amplitude of each unit point on the outer sheath of the target high-voltage cable during the excitation of the external heat source, calculate the average value of the change degree based on the degree of change in the reflected thermal wave amplitude, and take the unit point corresponding to the degree of change in the reflected thermal wave amplitude greater than the average value of the change degree as the ablation defect point.

[0061] According to an achievable manner of the third aspect of the present invention, the ablation defect detection device is further used for:

[0062] Determine the current maximum temperature of the outer sheath of the target high-voltage cable according to the current thermal infrared image;

[0063] Calculating the temperature difference between the maximum temperature and the ambient temperature of the target high-voltage cable;

[0064] When the temperature difference is greater than a preset temperature difference threshold, the external heat source is controlled to be turned off.

[0065] The fourth aspect of the present invention provides an electronic device, comprising a memory, a processor, and a computer program stored on the memory and runnable on the processor, wherein when the processor executes the program, it implements the method for detecting ablation defects of a high-voltage cable buffer layer based on heat source excitation as described in any of the above methods.

[0066] A fifth aspect of the present invention provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the high-voltage cable buffer layer ablation defect detection method based on heat source excitation as described in any of the above-mentioned methods.

[0067] A sixth aspect of the present invention provides a computer program product, comprising a computer program, which, when executed by a processor, implements the high-voltage cable buffer layer ablation defect detection method based on heat source excitation as described in any of the above achievable methods.

[0068] It can be seen from the above technical solutions that the present invention has the following advantages:

[0069] The present invention adjusts the heat flux intensity applied to the target high-voltage cable outer sheath by an external heat source through a modulation signal meter, so that the heat flux intensity changes in a sinusoidal pattern, and detects the heat wave generated by the target high-voltage cable outer sheath under the excitation of the external heat source through an infrared thermal imager, and then analyzes and processes the thermal infrared image detected by the infrared thermal imager to obtain the reflected heat wave amplitude of each unit point on the target high-voltage cable outer sheath, and determines the location of the ablation defect according to the degree of change and / or size of the reflected heat wave amplitude; the present invention amplifies the local temperature rise of the outer sheath corresponding to the ablation defect of the cable buffer layer through an external excitation source to form a clear contrast with the surrounding defect-free positions, which can effectively improve the accuracy and efficiency of ablation defect detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0070] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0071] Figure 1 A flow chart of a method for detecting ablation defects in a high-voltage cable buffer layer based on heat source excitation provided in an embodiment of the first aspect of the present invention;

[0072] Figure 2 A structural connection block diagram of a high-voltage cable buffer layer ablation defect detection device based on heat source excitation is provided in an embodiment of the second aspect of the present invention.

[0073] Reference numerals:

[0074] 1-Sending module; 2-Detection and control module; 3-Analysis module. DETAILED DESCRIPTION

[0075] The embodiments of the present invention provide a method and apparatus for detecting ablation defects of a high-voltage cable buffer layer based on heat source excitation, which are used to solve the technical problem of how to achieve high-precision and high-efficiency detection of ablation defects of a high-voltage cable buffer layer.

[0076] In order to make the purpose, features, and advantages of the present invention more obvious and easy to understand, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described below are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0077] A first embodiment of the present invention provides a method for detecting ablation defects in a high-voltage cable buffer layer based on heat source excitation.

[0078] See also Figure 1 , Figure 1 A flow chart of a method for detecting ablation defects in a high-voltage cable buffer layer based on heat source excitation provided by an embodiment of the present invention is shown.

[0079] An embodiment of the present invention provides a method for detecting ablation defects of a high-voltage cable buffer layer based on heat source excitation, comprising steps S1-S3.

[0080] Step S1: sending a heat source excitation instruction to a modulation signal instrument, so that the modulation signal instrument adjusts the heat flux intensity applied by an external heat source to the outer sheath of a target high-voltage cable according to a sine law according to the heat source excitation instruction.

[0081] The target high-voltage cable outer sheath refers to the outer sheath of a high-voltage cable that requires buffer layer ablation defect detection.

[0082] The external heat source may be a light source or an ultrasonic source.

[0083] In one possible implementation, the heat source excitation instruction includes the heating power and loading frequency of the external heat source, and the expression for the change of the heat flux intensity is:

[0084]

[0085] Where I(t) represents the heat flux intensity at time t, P is the heating power of the external heat source, and f e is the loading frequency of the external heat source.

[0086] In the above embodiment of the present invention, a modulation signal instrument is used to control the intensity of the external heat source, so that the heat flux of the external heat source changes sinusoidally with time, that is, the heat flux intensity is a sinusoidal function that changes with time. The outer sheath of the target high-voltage cable is heated by the radiant energy of the external heat source, so that the surface temperature of the outer sheath oscillates with the loading frequency of the external heat source.

[0087] Step S2: controlling an infrared thermal imager to detect heat waves generated by the outer sheath of the target high-voltage cable under the excitation of an external heat source, and obtaining a thermal infrared image detected by the infrared thermal imager.

[0088] In a specific implementation process, the target high-voltage cable can be placed on a platform suitable for infrared thermal imaging, the positions of the infrared thermal imager and the target high-voltage cable can be adjusted, and the parameters of the infrared thermal imager can be set so that the infrared thermal imager can accurately obtain the temperature signal of the outer sheath of the target high-voltage cable in the measured area.

[0089] Step S3: analyzing and processing the thermal infrared image to obtain the reflected thermal wave amplitude of each unit point on the outer sheath of the target high-voltage cable, and determining the location of the ablation defect according to the degree of change and / or size of the reflected thermal wave amplitude.

[0090] In one achievable manner, analyzing and processing the thermal infrared image to obtain the reflected thermal wave amplitude of each unit point on the outer sheath of the target high-voltage cable includes:

[0091] generating a temperature change curve of each unit point when the heat wave is transmitted through the outer sheath of the target high-voltage cable according to the thermal infrared image;

[0092] Perform fast Fourier transform on the temperature variation curve of each unit point to obtain the corresponding thermal wave amplitude curve;

[0093] According to the thermal wave amplitude curve, the reflected thermal wave amplitude of each unit point on the outer sheath of the target high-voltage cable is calculated using the infrared phase-locked method.

[0094] It is understandable that the size of the so-called unit point can be set according to specific circumstances, and the target high-voltage cable outer sheath is composed of several unit points.

[0095] In the embodiment of the present invention, the existing infrared phase-locked method is used to calculate the reflected thermal wave amplitude of each unit point on the outer sheath of the target high-voltage cable.

[0096] In order to better understand the present invention, the relevant principles of the infrared phase-locking method are described in detail below.

[0097] The conduction process of heat waves in the outer sheath of high-voltage cables along the three-dimensional direction of space can be described by the Fourier heat diffusion equation, which is shown as follows:

[0098]

[0099] Where T is the temperature, k is the thermal conductivity of the high-voltage cable outer sheath, ρ is the density of the high-voltage cable outer sheath, c is the specific heat of the high-voltage cable outer sheath, and X, Y, and Z represent the spatial X, Y, and Z dimensions, respectively.

[0100] By simplifying the Fourier heat diffusion equation and considering only the heat wave conduction along the Z-dimensional direction, we can obtain the analytical equation for the temperature distribution and change process when the sinusoidal heat flow is conducted in the outer sheath of the high-voltage cable:

[0101]

[0102] Where, T am is the ambient temperature, A is the temperature amplitude, ΔT is the temperature change of the high-voltage cable outer sheath under the excitation of the external heat source, τ is the excitation time range of the heat source, Λ is the heat diffusion length, α is the thermal diffusivity.

[0103] When Z = 0, T(0, t) is the surface temperature change of the high-voltage cable outer sheath. When a white powder defect exists in the high-voltage cable buffer layer, the temperature change at the white powder defect location is significantly different from that at the non-defective location. The defect location can be detected by measuring the amplitude change.

[0104] Since the actual measured thermal wave signal is composed of the incident thermal wave and the reflected thermal wave superimposed on the surface of the high-voltage cable outer sheath, assuming that the incident thermal wave amplitude is A1 and the reflected thermal wave amplitude is A2, the superimposed amplitude of the two on the surface of the high-voltage cable outer sheath is A. c and phase difference The relationship should satisfy the following formula:

[0105]

[0106] In one cycle of the external excitation source, the modulation phase is 90° different, and the incident thermal wave and reflected thermal wave signals are collected, and the following can be obtained:

[0107]

[0108]

[0109]

[0110]

[0111] By solving the above equations simultaneously, we can get the calculation formula for the reflected thermal wave amplitude as follows:

[0112]

[0113] According to the above description of the relevant principles of the infrared phase-locked method, when the infrared phase-locked method is used to calculate the reflected thermal wave amplitude of each unit point on the outer sheath of the target high-voltage cable, the reflected thermal wave amplitudes corresponding to phases of 0°, 90°, 180° and 270° can be extracted from the thermal wave amplitude curve diagram, and then the reflected thermal wave amplitude of each unit point on the outer sheath of the target high-voltage cable can be calculated according to the calculation formula of the reflected thermal wave amplitude.

[0114] In the above embodiment of the present invention, the infrared phase-locked method is used to calculate the reflected thermal wave amplitude of each unit point on the outer sheath of the target high-voltage cable. The method is objective and convenient.

[0115] In one achievable manner, determining the location of the ablation defect according to the degree of change and / or size of the reflected thermal wave amplitude includes:

[0116] The reflected thermal wave amplitude of each unit point on the outer sheath of the target high-voltage cable at the end of the external heat source excitation is used as the reflected thermal wave amplitude to be detected, the amplitude average of the reflected thermal wave amplitude to be detected is calculated, and the unit point corresponding to the reflected thermal wave amplitude to be detected being greater than the amplitude average is regarded as the ablation defect point;

[0117] And / or, calculate the degree of change in the reflected thermal wave amplitude of each unit point on the outer sheath of the target high-voltage cable during the excitation of the external heat source, calculate the average value of the change degree based on the degree of change in the reflected thermal wave amplitude, and take the unit point corresponding to the degree of change in the reflected thermal wave amplitude greater than the average value of the change degree as the ablation defect point.

[0118] It is understandable that by applying a sinusoidally modulated excitation heat source to the outer surface of the cable, thermal excitation of the cable can cause its surface temperature to rise. Since the temperature change of the excited object is related to its material properties, the phase and amplitude of its sine wave will vary depending on whether there are defects inside. There is a large amount of white powder at the location of the ablation defect, which significantly increases the contact resistance between the cable insulation shield and the aluminum sheath (normal cables are generally between 50 and 500Ω, and cables with ablation defects can reach more than 1kΩ), greatly reducing the thermal conductivity at the buffer layer ablation defect. In addition, since the buffer layer ablation defects are distributed in a point-like manner, the heat flux generated by the external excitation radiation energy inside the outer sheath is in an uneven diffusion state.

[0119] The above situation means that under the excitation of an external heat source at the same time, the temperature rise of the cable's ablation defect part will be higher than that of the non-defective position. The excitation source will amplify the temperature difference between the hot spot and the non-defective position. At this time, by comparing the degree of change and / or size of the reflected heat wave amplitude, the ablation defect position can be quickly determined, thereby greatly improving the efficiency and accuracy of the high-voltage cable buffer layer burn defect detection work.

[0120] In one possible implementation, the method further includes:

[0121] Determine the current maximum temperature of the outer sheath of the target high-voltage cable according to the current thermal infrared image;

[0122] Calculating the temperature difference between the maximum temperature and the ambient temperature of the target high-voltage cable;

[0123] When the temperature difference is greater than a preset temperature difference threshold, the external heat source is controlled to be turned off.

[0124] As a specific implementation, the preset temperature difference threshold is 50°C.

[0125] The heat flux intensity and heating time of the external heating radiation source should be appropriately selected for each cable to avoid excessive cable temperature rise and potential damage. The cable surface temperature is generally comparable to or slightly higher than the ambient temperature. Therefore, in the embodiments of the present invention, when using an external heat source for excitation, controlling the temperature difference of the high-voltage cable outer sheath not only prevents damage to the cable, but also allows for the rapid and effective identification of ablation defects.

[0126] A second embodiment of the present invention provides a high-voltage cable buffer layer ablation defect detection device based on heat source excitation.

[0127] See also Figure 2 , Figure 2 The diagram shows a structural connection block diagram of a high-voltage cable buffer layer ablation defect detection device based on heat source excitation provided by an embodiment of the present invention.

[0128] An embodiment of the present invention provides a high-voltage cable buffer layer ablation defect detection device based on heat source excitation, comprising:

[0129] A sending module 1 is used to send a heat source excitation instruction to a modulation signal instrument, so that the modulation signal instrument adjusts the heat flux intensity applied by the external heat source to the outer sheath of the target high-voltage cable according to the heat source excitation instruction according to a sine law;

[0130] Detection control module 2, used to control the infrared thermal imager to detect the heat wave generated by the outer sheath of the target high-voltage cable under the excitation of the external heat source, and obtain the thermal infrared image detected by the infrared thermal imager;

[0131] The analysis module 3 is used to analyze and process the thermal infrared image to obtain the reflected thermal wave amplitude of each unit point on the outer sheath of the target high-voltage cable, and determine the location of the ablation defect according to the degree of change and / or size of the reflected thermal wave amplitude.

[0132] In one achievable manner, the heat source excitation instruction includes the heating power, loading frequency, and heating time of the external heat source, and the expression for the change of the heat flux intensity is:

[0133]

[0134] Where I(t) represents the heat flux intensity at time t, P is the heating power of the external heat source, and f e is the loading frequency of the external heat source.

[0135] In one possible implementation, the analysis module 3 includes:

[0136] a first curve generating unit, configured to generate, based on the thermal infrared image, a temperature change curve of each unit point when the heat wave is transmitted through the outer sheath of the target high-voltage cable;

[0137] The second curve generating unit is used to perform fast Fourier transform on the temperature change curve of each unit point to obtain a corresponding thermal wave amplitude curve graph;

[0138] The calculation unit is used to calculate the reflected thermal wave amplitude of each unit point on the outer sheath of the target high-voltage cable using an infrared phase-locked method according to the thermal wave amplitude curve.

[0139] In one possible implementation, the analysis module 3 includes:

[0140] The first ablation defect judgment unit is configured to use the reflected thermal wave amplitude of each unit point on the outer sheath of the target high-voltage cable at the end of the external heat source excitation as the reflected thermal wave amplitude to be detected, calculate the amplitude average of the reflected thermal wave amplitude to be detected, and use the unit point corresponding to the reflected thermal wave amplitude to be detected being greater than the amplitude average as the ablation defect point;

[0141] And / or, a second ablation defect judgment unit is used to calculate the degree of change in the reflected thermal wave amplitude of each unit point on the outer sheath of the target high-voltage cable during the excitation of the external heat source, calculate the average value of the change degree based on the degree of change in the reflected thermal wave amplitude, and take the unit point corresponding to the degree of change in the reflected thermal wave amplitude greater than the average value of the change degree as the ablation defect point.

[0142] In one possible implementation, the device further includes:

[0143] a determination module, configured to determine a current maximum temperature of the outer sheath of the target high-voltage cable according to a current thermal infrared image;

[0144] A temperature difference calculation module, used to calculate the temperature difference between the maximum temperature and the ambient temperature of the target high-voltage cable;

[0145] The heat source control module is used to control the external heat source to be turned off when the temperature difference is greater than a preset temperature difference threshold.

[0146] A third embodiment of the present invention provides a high-voltage cable buffer layer ablation defect detection device based on heat source excitation.

[0147] The device includes an ablation defect detection device, a modulated signal meter, an external heat source and an infrared thermal imager;

[0148] The ablation defect detection device is used to send a heat source excitation instruction to the modulation signal instrument;

[0149] The modulation signal instrument is used to adjust the heat flux intensity applied by the external heat source to the outer sheath of the target high-voltage cable according to the heat source excitation instruction according to the sine law;

[0150] The ablation defect detection equipment is also used to control the infrared thermal imager to detect the heat waves generated by the target high-voltage cable outer sheath under the excitation of the external heat source, and obtain the thermal infrared image detected by the infrared thermal imager; analyze and process the thermal infrared image to obtain the reflected heat wave amplitude of each unit point on the target high-voltage cable outer sheath, and determine the ablation defect position according to the degree of change and / or size of the reflected heat wave amplitude.

[0151] As a specific implementation, the ablation defect detection device is a host computer.

[0152] In one possible implementation, the heat source excitation instruction includes the heating power and loading frequency of the external heat source, and the expression for the change of the heat flux intensity is:

[0153]

[0154] Where I(t) represents the heat flux intensity at time t, P is the heating power of the external heat source, and f e is the loading frequency of the external heat source.

[0155] In one achievable manner, the ablation defect detection device is specifically used to:

[0156] generating a temperature change curve of each unit point when the heat wave is transmitted through the outer sheath of the target high-voltage cable according to the thermal infrared image;

[0157] Perform fast Fourier transform on the temperature variation curve of each unit point to obtain the corresponding thermal wave amplitude curve;

[0158] According to the thermal wave amplitude curve, the reflected thermal wave amplitude of each unit point on the outer sheath of the target high-voltage cable is calculated using the infrared phase-locked method.

[0159] In one achievable manner, the ablation defect detection device is specifically used to:

[0160] The reflected thermal wave amplitude of each unit point on the outer sheath of the target high-voltage cable at the end of the external heat source excitation is used as the reflected thermal wave amplitude to be detected, the amplitude average of the reflected thermal wave amplitude to be detected is calculated, and the unit point corresponding to the reflected thermal wave amplitude to be detected being greater than the amplitude average is regarded as the ablation defect point;

[0161] And / or, calculate the degree of change in the reflected thermal wave amplitude of each unit point on the outer sheath of the target high-voltage cable during the excitation of the external heat source, calculate the average value of the change degree based on the degree of change in the reflected thermal wave amplitude, and take the unit point corresponding to the degree of change in the reflected thermal wave amplitude greater than the average value of the change degree as the ablation defect point.

[0162] In one achievable manner, the ablation defect detection device is further used for:

[0163] Determine the current maximum temperature of the outer sheath of the target high-voltage cable according to the current thermal infrared image;

[0164] Calculating the temperature difference between the maximum temperature and the ambient temperature of the target high-voltage cable;

[0165] When the temperature difference is greater than a preset temperature difference threshold, the external heat source is controlled to be turned off.

[0166] A fourth aspect of the present invention provides an electronic device comprising a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the program, the method for detecting ablation defects of a high-voltage cable buffer layer based on heat source excitation as described in any one of the above embodiments is implemented.

[0167] A fifth aspect of the present invention provides a non-transitory computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the method for detecting ablation defects of a high-voltage cable buffer layer based on heat source excitation as described in any of the above embodiments is implemented.

[0168] A sixth aspect of the present invention provides a computer program product, comprising a computer program, which, when executed by a processor, implements the high-voltage cable buffer layer ablation defect detection method based on heat source excitation as described in any of the above embodiments.

[0169] The above embodiment of the present invention amplifies the local temperature rise of the outer sheath corresponding to the ablation defect of the cable buffer layer through an external excitation source to form a clear contrast with the surrounding non-defective positions, which can effectively improve the accuracy and efficiency of ablation defect detection.

[0170] Those skilled in the art can clearly understand that, for the convenience and conciseness of description, the specific working processes of the above-described devices, equipment and modules can refer to the corresponding processes in the aforementioned method embodiments, and the specific beneficial effects of the above-described devices, equipment and modules can refer to the corresponding beneficial effects in the aforementioned method embodiments, which will not be repeated here.

[0171] In the several embodiments provided in this application, it should be understood that the disclosed devices, equipment and methods can be implemented in other ways. For example, the device embodiments described above are merely schematic. For example, the division of the modules is only a logical function division. In actual implementation, there may be other division methods, such as multiple modules or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or modules, which can be electrical, mechanical or other forms.

[0172] The modules described as separate components may or may not be physically separate, and the components shown as modules may or may not be physical modules, that is, they may be located in one place or distributed across multiple network modules. Some or all of the modules may be selected to achieve the purpose of the present embodiment according to actual needs.

[0173] In addition, the functional modules in various embodiments of the present invention may be integrated into a single processing module, or each module may exist physically separately, or two or more modules may be integrated into a single module. The aforementioned integrated modules may be implemented in the form of hardware or software functional modules.

[0174] If the integrated module is implemented in the form of a software functional module and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0175] As described above, the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that the technical solutions described in the above embodiments can still be modified, or some of the technical features thereof can be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for detecting ablation defects of a high-voltage cable buffer layer based on heat source excitation, characterized in that: include: Sending a heat source excitation instruction to the modulation signal instrument, so that the modulation signal instrument adjusts the heat flux intensity applied by the external heat source to the outer sheath of the target high-voltage cable according to the heat source excitation instruction according to the sine law; controlling an infrared thermal imager to detect heat waves generated by the outer sheath of the target high-voltage cable under the excitation of an external heat source, and obtaining a thermal infrared image detected by the infrared thermal imager; Analyzing and processing the thermal infrared image to obtain the reflected thermal wave amplitude of each unit point on the outer sheath of the target high-voltage cable, and determining the location of the ablation defect according to the degree of change and / or size of the reflected thermal wave amplitude; Determining the location of the ablation defect according to the degree of change and / or size of the reflected thermal wave amplitude includes: The reflected thermal wave amplitude of each unit point on the outer sheath of the target high-voltage cable at the end of the external heat source excitation is used as the reflected thermal wave amplitude to be detected, the amplitude average of the reflected thermal wave amplitude to be detected is calculated, and the unit point corresponding to the reflected thermal wave amplitude to be detected being greater than the amplitude average is regarded as the ablation defect point; And / or, calculate the degree of change in the reflected thermal wave amplitude of each unit point on the outer sheath of the target high-voltage cable during the excitation of the external heat source, calculate the average value of the change degree based on the degree of change in the reflected thermal wave amplitude, and take the unit point corresponding to the degree of change in the reflected thermal wave amplitude greater than the average value of the change degree as the ablation defect point.

2. The method for detecting ablation defects of a high-voltage cable buffer layer based on heat source excitation according to claim 1 is characterized in that: The heat source excitation instruction includes the heating power and loading frequency of the external heat source, and the change expression of the heat flux intensity is: ； Where, express The heat flux intensity, is the heating power of the external heat source, is the loading frequency of the external heat source.

3. The method for detecting ablation defects of a high-voltage cable buffer layer based on heat source excitation according to claim 1 is characterized in that: The analyzing and processing the thermal infrared image to obtain the reflected thermal wave amplitude of each unit point on the outer sheath of the target high-voltage cable includes: generating a temperature change curve of each unit point when the heat wave is transmitted through the outer sheath of the target high-voltage cable according to the thermal infrared image; Perform fast Fourier transform on the temperature variation curve of each unit point to obtain the corresponding thermal wave amplitude curve; According to the thermal wave amplitude curve, the reflected thermal wave amplitude of each unit point on the outer sheath of the target high-voltage cable is calculated using the infrared phase-locked method.

4. The method for detecting ablation defects of a high-voltage cable buffer layer based on heat source excitation according to claim 1 is characterized in that: The method further comprises: Determine the current maximum temperature of the outer sheath of the target high-voltage cable according to the current thermal infrared image; Calculating the temperature difference between the maximum temperature and the ambient temperature of the target high-voltage cable; When the temperature difference is greater than a preset temperature difference threshold, the external heat source is controlled to be turned off.

5. A high-voltage cable buffer layer ablation defect detection device based on heat source excitation, characterized in that: include: a sending module, configured to send a heat source excitation instruction to a modulation signal instrument, so that the modulation signal instrument adjusts the heat flux intensity applied by the external heat source to the outer sheath of the target high-voltage cable according to the heat source excitation instruction according to a sinusoidal law; a control module, configured to control an infrared thermal imager to detect heat waves generated by the outer sheath of the target high-voltage cable under the excitation of an external heat source, and to obtain a thermal infrared image detected by the infrared thermal imager; an analysis module, configured to analyze and process the thermal infrared image to obtain a reflected thermal wave amplitude at each unit point on the outer sheath of the target high-voltage cable, and determine a location of the ablation defect based on a change degree and / or size of the reflected thermal wave amplitude; The analysis module includes: The first ablation defect judgment unit is configured to use the reflected thermal wave amplitude of each unit point on the outer sheath of the target high-voltage cable at the end of the external heat source excitation as the reflected thermal wave amplitude to be detected, calculate the amplitude average of the reflected thermal wave amplitude to be detected, and use the unit point corresponding to the reflected thermal wave amplitude to be detected being greater than the amplitude average as the ablation defect point; And / or, a second ablation defect judgment unit is used to calculate the degree of change in the reflected thermal wave amplitude of each unit point on the outer sheath of the target high-voltage cable during the excitation of the external heat source, calculate the average value of the change degree based on the degree of change in the reflected thermal wave amplitude, and take the unit point corresponding to the degree of change in the reflected thermal wave amplitude greater than the average value of the change degree as the ablation defect point.

6. A high-voltage cable buffer layer ablation defect detection device based on heat source excitation, characterized in that: Includes ablation defect detection equipment, modulated signal meter, external heat source and infrared thermal imager; The ablation defect detection device is used to send a heat source excitation instruction to the modulation signal instrument; The modulation signal instrument is used to adjust the heat flux intensity applied by the external heat source to the outer sheath of the target high-voltage cable according to the heat source excitation instruction according to the sine law; The ablation defect detection device is further used to control the infrared thermal imager to detect the heat wave generated by the outer sheath of the target high-voltage cable under the excitation of the external heat source, and obtain the thermal infrared image detected by the infrared thermal imager; Analyzing and processing the thermal infrared image to obtain the reflected thermal wave amplitude of each unit point on the outer sheath of the target high-voltage cable, and determining the location of the ablation defect according to the degree of change and / or size of the reflected thermal wave amplitude; Determining the location of the ablation defect according to the degree of change and / or size of the reflected thermal wave amplitude includes: The reflected thermal wave amplitude of each unit point on the outer sheath of the target high-voltage cable at the end of the external heat source excitation is used as the reflected thermal wave amplitude to be detected, the amplitude average of the reflected thermal wave amplitude to be detected is calculated, and the unit point corresponding to the reflected thermal wave amplitude to be detected being greater than the amplitude average is regarded as the ablation defect point; And / or, calculate the degree of change in the reflected thermal wave amplitude of each unit point on the outer sheath of the target high-voltage cable during the excitation of the external heat source, calculate the average value of the change degree based on the degree of change in the reflected thermal wave amplitude, and take the unit point corresponding to the degree of change in the reflected thermal wave amplitude greater than the average value of the change degree as the ablation defect point.

7. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the program, the high-voltage cable buffer layer ablation defect detection method based on heat source excitation according to any one of claims 1 to 4 is implemented.

8. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the method for detecting ablation defects of a high-voltage cable buffer layer based on heat source excitation according to any one of claims 1 to 4 is implemented.

9. A computer program product comprising a computer program, characterized in that When the computer program is executed by a processor, the method for detecting ablation defects of a high-voltage cable buffer layer based on heat source excitation according to any one of claims 1 to 4 is implemented.

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