CN114167231A - Device and method for detecting internal conductivity defect of composite insulator - Google Patents
Device and method for detecting internal conductivity defect of composite insulator Download PDFInfo
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Abstract
The device comprises a pulse microwave generation module, an infrared thermal imager and a data processing unit, wherein the pulse microwave generation module is used for carrying out microwave heating on the composite insulator to realize heat generation of a conduction defect region, the infrared thermal imager is used for collecting an initial infrared thermal image of the composite insulator and an infrared thermal image sequence after microwave heating, the data processing unit is used for carrying out differential processing on the infrared thermal image sequence by taking the initial infrared thermal image as a reference thermal image to obtain a differential thermal image sequence, the differential thermal image sequence is processed to obtain amplitude characteristics and phase characteristics of thermal waves in a frequency domain, so that extraction of frequency domain characteristics of thermal wave signals is realized, the thermal image sequence of the composite insulator is reconstructed according to the frequency domain characteristics, and enhanced display of the conduction defect region in the composite insulator is realized. The method can realize rapid, accurate, non-contact and visual detection of the internal conductivity defect of the composite insulator.
Description
Technical Field
The invention relates to the technical field of power equipment detection, in particular to a device and a method for detecting internal conductivity defects of a composite insulator.
Background
In the process of composite insulator production and net hanging operation, due to the influence of multiple factors such as production process, operation environment and the like, the conductivity defects such as carbonization and the like may be generated at the interface of the silicon rubber and the epoxy of the composite insulator. Under the environment of high voltage and high humidity, the conductivity defect can be further developed, so that the severe consequences of composite insulator insulation breakdown, internal insulation failure and the like are caused, and the safe operation of the power transmission and transformation equipment is seriously influenced. At present, the existing composite insulator detection method has certain limitations in internal conductivity detection, is low in detection speed and poor in visualization degree, and is difficult to realize online detection, and the limitations provide challenges for prevention and detection of internal conductivity defects of the composite insulator.
The composite insulator is composed of a silicon rubber sheath and an epoxy resin core rod, and has the advantages of light weight, strong pollution flashover resistance, hydrophobicity mobility and the like, so that the composite insulator is widely applied to electric power systems in China. However, due to the special structure of the composite insulator, the long-term outdoor operation is easy to cause conductivity defects at the interface. Under the high-voltage environment of the operation of the suspended net, the further development of the internal conductivity defect may cause severe accidents such as insulation breakdown of the composite insulator, failure of the internal insulation and the like, and great threat is formed to the safe and stable operation of the power grid. Therefore, the defect of internal conductivity of the composite insulator can be timely and effectively found, and the problem to be solved urgently is solved.
For the detection of the internal conductivity defect of the composite insulator, various application practices of nondestructive detection methods are developed in engineering, such as an X-ray method, an ultrasonic detection method, an electric field measurement method and the like. However, these detection methods have certain limitations. For example, X-ray methods are sensitive to area-type defects, but have poor detection results in small-size volume-type defect detection. The ultrasonic detection method requires a coupling agent to be coated on the surface and depends very much on the experience of the detector. The electric field measurement method is point-to-point measurement, and large-area detection is difficult to realize.
The active thermal imaging detection technology is a novel nondestructive detection technology, a detected piece is heated by an external excitation source, the temperature change of a defect area is different from that of a normal area due to the difference of thermal physical parameters of the defect area and the normal area, and the difference is presented by a thermal image sequence acquired by an infrared thermal imager. Most of the traditional active thermal imaging technologies use photo-thermal excitation sources, and as conduction defects often occur at the interface, thermal waves generated by photo-thermal excitation are seriously attenuated at the interface, so that the defects at the interface are difficult to effectively present.
It is to be noted that the information disclosed in the above background section is only for understanding the background of the present application and thus may include information that does not constitute prior art known to a person of ordinary skill in the art.
Disclosure of Invention
The invention mainly aims to overcome the defects of the background technology and provides a device and a method for detecting the internal conductivity defect of a composite insulator, so that the internal conductivity defect of the composite insulator can be rapidly, accurately, contactlessly and visually detected.
In order to achieve the purpose, the invention adopts the following technical scheme:
the device for detecting the internal conduction defect of the composite insulator comprises a pulse microwave generation module, an infrared thermal imager and a data processing unit, wherein the pulse microwave generation module carries out microwave heating on the composite insulator to realize heat generation of a conduction defect region, the infrared thermal imager collects an initial infrared thermal image of the composite insulator and an infrared thermal image sequence after the microwave heating, the data processing unit takes the initial infrared thermal image as a reference thermal image to carry out differential processing on the infrared thermal image sequence to obtain a differential thermal image sequence, the differential thermal image sequence is processed to obtain an amplitude characteristic and a phase characteristic of a thermal wave in a frequency domain, extraction of a thermal wave signal frequency domain characteristic is realized, the thermal image sequence of the composite insulator is reconstructed according to the frequency domain characteristic, and enhanced display of the internal conduction defect region of the composite insulator is realized.
Further:
and extracting the frequency domain characteristics of the thermal wave signals through fast Fourier transform.
And selecting the frequency with the best detection effect to carry out heat map reconstruction.
And (3) taking the frequency domain signal of the region point at the conduction defect, taking the minimum phase point in the phase-frequency diagram of the region point as a characteristic quantity, and determining the depth of the conduction defect by using the frequency corresponding to the minimum phase point.
The pulse microwave generation module comprises a microwave signal generator, a signal amplifier and an antenna, wherein the microwave signal generator emits microwaves, the signal amplifier is used for improving the power of the microwaves, and the antenna adjusts the direction of the microwave signals to the detected composite insulator.
The combined control unit is connected with the pulse microwave generation module, the thermal infrared imager and the motion module and used for realizing linkage control of the pulse microwave generation module, the thermal infrared imager and the motion module, and the motion module is connected with the pulse microwave generation module and the thermal infrared imager and used for realizing azimuth control of the pulse microwave generation module and the thermal infrared imager and realizing multi-angle and multi-azimuth scanning type detection of the composite insulator.
The frequency of the microwave excitation was 2.4 GHz.
The data processing unit is also used for carrying out one or more of fitting, filtering and cutting on the acquired infrared heat map sequence.
A method for detecting the internal conductivity defect of a composite insulator by using the device comprises the following steps:
s1, microwave heating is carried out on the composite insulator through the pulse microwave generation module;
s2, acquiring an initial infrared thermal image of the composite insulator and an infrared thermal image sequence after microwave heating by using an infrared thermal imager;
s3, taking the initial infrared heat map as a reference heat map, carrying out differential processing on the infrared heat map sequence to obtain a differential heat map sequence, processing the differential heat map sequence to obtain amplitude characteristics and phase characteristics of thermal waves in a frequency domain, realizing extraction of frequency domain characteristics of thermal wave signals, reconstructing the heat map sequence of the composite insulator according to the frequency domain characteristics, and realizing enhanced display of a conduction defect region in the composite insulator; preferably, a frequency domain signal of an area point at the conduction defect is taken, a minimum phase point in a phase-frequency diagram of the area point is taken as a characteristic quantity, and the depth of the conduction defect is determined by using a frequency corresponding to the minimum phase point.
A computer-readable storage medium, storing a computer program which, when executed by a processor, implements step S3 of the method.
The invention has the following beneficial effects:
the invention provides a device and a method for detecting the internal conductivity defect of a composite insulator based on a pulse microwave thermal imaging technology. Compared with the existing detection scheme, the method utilizes the characteristic that microwave heating is positively correlated with the dielectric constant of a substance, and realizes large heat generation of the conduction defect area through microwave heating; secondly, acquiring a differential thermal image sequence on the surface of the composite insulator by using an infrared thermal imager, wherein a defect region has high heat generation and is displayed brighter in the thermal image, and the accurate visual positioning of the internal conductivity defect of the composite insulator can be realized by analyzing the thermal image sequence; moreover, based on the propagation characteristics of the heat wave after volume heating, the frequency domain feature extraction of the heat wave signal can be realized, and the heat map sequence of the composite insulator is reconstructed through the frequency domain feature, so that the defect detection effect is enhanced; finally, the method has the advantages of high detection speed, simplicity in operation, intuitionistic imaging and small external interference, can realize the detection of the deep conduction defect by combining the frequency domain characteristic reconstruction heat map, and effectively ensures the reliability, objectivity and effectiveness of the detection.
The method can realize the rapid and non-contact detection of the internal conductivity defect of the composite insulator and the visual defect presentation mode, has excellent detection effect and has the application prospect of defect online detection.
Drawings
Fig. 1 is a schematic structural diagram of a device for detecting a conductivity defect in a composite insulator according to an embodiment of the present invention.
Fig. 2 is a flowchart of a method for detecting a conductivity defect in a composite insulator according to an embodiment of the present invention.
Fig. 3 is a diagram illustrating the detection effect according to an embodiment of the present invention, wherein (a) is an original heat map, (b) is a magnitude-feature reconstructed heat map, and (c) is a phase-feature reconstructed heat map.
Reference numerals:
the device comprises a microwave signal generator 1, a signal amplifier 2, an antenna 3, a combined control unit 4, a motion module 5, a thermal infrared imager 6, a data processing unit 7, a pulse microwave generation module 8, a composite insulator 9 and a conduction defect area 10.
Detailed Description
The embodiments of the present invention will be described in detail below. It should be emphasized that the following description is merely exemplary in nature and is not intended to limit the scope of the invention or its application.
It will be understood that when an element is referred to as being "secured to" or "disposed on" another element, it can be directly on the other element or be indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or be indirectly connected to the other element. In addition, the connection may be for either a fixed or coupled or communicating function.
It is to be understood that the terms "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like are used in an orientation or positional relationship indicated in the drawings for convenience in describing the embodiments of the present invention and to simplify the description, and are not intended to indicate or imply that the referenced device or element must have a particular orientation, be constructed in a particular orientation, and be in any way limiting of the present invention.
Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the embodiments of the present invention, "a plurality" means two or more unless specifically limited otherwise.
Referring to fig. 1 and 2, an embodiment of the present invention provides a device for detecting a conductivity defect inside a composite insulator 9, including a pulse microwave generation module 8, an infrared thermal imager 6 and a data processing unit 7, where the pulse microwave generation module 8 performs microwave heating on the composite insulator 9 to realize heat generation of a conductivity defect region 10, the infrared thermal imager 6 acquires an initial infrared thermal image of the composite insulator 9 and an infrared thermal image sequence after the microwave heating, the data processing unit 7 performs differential processing on the infrared thermal image sequence by using the initial infrared thermal image as a reference thermal image to obtain a differential thermal image sequence, processes the differential thermal image sequence to obtain an amplitude characteristic and a phase characteristic of a thermal wave in a frequency domain, that is, extraction of a thermal wave signal characteristic is realized, and reconstructs the thermal image sequence of the composite insulator 9 according to the frequency domain characteristic extracted in the frequency domain, therefore, the conduction defect area 10 inside the composite insulator 9 is enhanced and displayed, and the conduction defect inside the composite insulator is accurately and visually positioned.
In a preferred embodiment, for the differential heat map sequence, the extraction of the frequency domain features of the thermal wave signal is realized by fast fourier transform.
In a preferred embodiment, the heat map reconstruction is performed by selecting the frequency with the best detection effect. The frequency with the best detection effect may be a frequency corresponding to a reconstructed image with the highest defect detection rate and the highest signal-to-noise ratio in the reconstructed amplitude map and the reconstructed phase map in the low frequency band.
In a preferred embodiment, a frequency domain signal of an area point at the conduction defect is taken, a minimum phase point in a phase-frequency diagram of the area point is taken as a characteristic quantity, and the depth of the conduction defect is determined by using a frequency corresponding to the minimum phase point.
Referring to fig. 1, in a preferred embodiment, the pulsed microwave generating module 8 includes a microwave signal generator 1, a signal amplifier 2 and an antenna 3, the microwave signal generator 1 emits microwaves, the signal amplifier 2 is used for increasing the power of the microwaves, and the antenna 3 adjusts the direction of the microwave signals to the composite insulator 9 to be detected.
Referring to fig. 1, in a preferred embodiment, the device further includes a joint control unit 4 and a motion module 5, the joint control unit 4 is connected to the pulse microwave generation module 8, the thermal infrared imager 6 and the motion module 5 to realize linkage control of the pulse microwave generation module 8, the thermal infrared imager 6 and the motion module 5, and the motion module 5 is connected to the pulse microwave generation module 8 and the thermal infrared imager 6 to realize azimuth control of the pulse microwave generation module 8 and the thermal infrared imager 6 to realize multi-angle and multi-azimuth scanning detection of the composite insulator 9.
In a preferred embodiment, the frequency of the microwave excitation is 2.4 GHz.
In some embodiments, the data processing unit 7 may further perform one or more of fitting, filtering, clipping, and the like on the acquired infrared heat map sequence.
Referring to fig. 1 and fig. 2, an embodiment of the present invention further provides a method for detecting a conductivity defect inside a composite insulator, where the method is used to detect a conductivity defect inside a composite insulator, and the method includes the following steps:
s1, microwave heating is carried out on the composite insulator 9 through the pulse microwave generation module 8;
s2, acquiring an initial infrared thermograph and an infrared thermograph sequence after microwave heating of the composite insulator 9 through the thermal infrared imager 6;
s3, taking the initial infrared heat map as a reference heat map, carrying out differential processing on the infrared heat map sequence to obtain a differential heat map sequence, processing the differential heat map sequence to obtain amplitude characteristics and phase characteristics of thermal waves in a frequency domain, realizing extraction of frequency domain characteristics of thermal wave signals, reconstructing the heat map sequence of the composite insulator 9 according to the frequency domain characteristics, and realizing enhanced display of a conduction defect area in the composite insulator 9; preferably, a frequency domain signal of an area point at the conduction defect is taken, a minimum phase point in a phase-frequency diagram of the area point is taken as a characteristic quantity, and the depth of the conduction defect is determined by using a frequency corresponding to the minimum phase point.
In some embodiments, the present invention further provides a computer-readable storage medium storing a computer program which, when executed by a processor, implements step S3 of the method.
The embodiment of the invention provides a device and a method for detecting the internal conductivity defect of a composite insulator based on a pulse microwave thermal imaging technology. Compared with the existing detection scheme, the embodiment of the invention utilizes the characteristic that microwave heating is positively correlated with the dielectric constant of a substance, and realizes large heat generation of the conduction defect area through microwave heating; secondly, acquiring a differential thermal image sequence on the surface of the composite insulator by using a thermal infrared imager 6, wherein a defect region has high heat generation and is displayed brighter in the thermal image, and the accurate visual positioning of the internal conductivity defect of the composite insulator can be realized by analyzing the thermal image sequence; moreover, based on the propagation characteristics of the heat wave after volume heating, the frequency domain characteristics of the heat wave signal can be extracted through fast Fourier transform, and the heat map sequence of the composite insulator is reconstructed through the frequency domain characteristics, so that the defect detection effect is enhanced; finally, the method has the advantages of high detection speed, simplicity in operation, intuitionistic imaging and small external interference, can realize the detection of the deep conduction defect by combining the frequency domain characteristic reconstruction heat map, and effectively ensures the reliability, objectivity and effectiveness of the detection.
Specific embodiments of the present invention and the principles of its implementation are described further below.
Different from the traditional infrared thermal wave technology which detects based on the difference of the heat conduction of the object, the pulse microwave thermal imaging technology adopted by the invention detects based on the different heating degrees of materials with different dielectric constants. As shown in the following formula (1).
In the above formula, f is the microwave frequency, ε0Is the dielectric constant, epsilon, in vacuum "rIs the relative dielectric constant of the material, E is the electric field strength in the material, and T is the pulsed microwave heating time.
According to the formula, the difference of the dielectric constants of the materials can cause the difference of the heat generation amount of microwave heating, the heat generation amount of the high dielectric constant (conduction defect area) is more, the heat generation amount of the low dielectric constant (normal area) is less, the thermal change process of the surface of the composite insulator is collected through the thermal infrared imager, and the area generating more heat is the conduction defect area.
Since the thermal wave can exhibit frequency sensitivity in the frequency domain, as shown in equation (2).
Where α is the material thermal conductivity and f is the thermal wave frequency. From the formula (2), the low-frequency thermal wave feature can reflect deep-layer structural information, and the high-frequency thermal wave feature can reflect shallow-layer structural information. And the heat map is reconstructed through the amplitude and phase characteristics of the frequency domain, so that the structural information of different depths can be reflected. And the heat map reconstruction is carried out by utilizing the amplitude characteristic and the phase characteristic of proper frequency, so that the defect can be displayed in an enhanced manner.
In order to obtain the position information of the defect, the frequency domain thermal wave signals of the area points are selected. According to the equation (3), the depth of the conductivity defect can be obtained from the frequency corresponding to the minimum phase point.
In the formula, a and b are constants and can be obtained from the material properties of the composite insulator to be tested.
Fig. 1 shows a device for detecting a conductivity defect in a composite insulator according to an embodiment of the present invention. The device comprises a microwave signal generator 1, a signal amplifier 2, an antenna 3, a combined control unit 4, a motion module 5, a thermal infrared imager 6, a data processing unit 7, a pulse microwave generation module 8, a composite insulator 9 and a conduction defect area 10.
As shown in FIG. 1, the device for detecting the internal conductivity defect of the composite insulator is an active thermal imaging detection system carrying pulse microwave excitation. And an excitation source carrying a pulse microwave generator is connected with the thermal infrared imager through a combined control unit, and scanning detection of the composite insulator is realized by combining a motion module. And the acquired data is processed to realize the defect enhancement display effect.
The system comprises 7 parts of a pulse microwave transmitting module 8, a combined control module 4, a motion module 5, a thermal infrared imager 6 and a data processing unit, wherein all the parts are mutually matched, so that the identification and detection of the internal conductivity defect of the composite insulator 9 are realized.
The pulse microwave generating module 8 comprises a microwave signal generator 1, a signal amplifier 2 and an antenna 3 and is used for generating short-time pulse microwave heating composite insulator internal conductivity defects. The frequency of microwave excitation is set to be 2.4GHz, the microwave excitation is sent out by a microwave signal generator, a signal amplifier is used for improving the power of microwaves, and an antenna adjusts the direction of the microwave signals to a detected sample to realize the heating function of the conductivity defects.
And the joint control unit 4 is used for realizing linkage control of the pulse microwave generation module, the motion module and the thermal infrared imager. After the pulse microwaves finish heating the detected composite insulator, synchronously triggering the thermal infrared imager to collect the thermal image sequence on the surface of the detected composite insulator, and simultaneously controlling the motion module to realize all-angle and multi-direction detection on the composite insulator.
And the motion module 5 is used for realizing the orientation control of the pulse microwave generation module and the thermal infrared imager, and can realize scanning detection on the composite insulator so as to realize the detection of the full-size composite insulator.
And the thermal infrared imager 6 is used for acquiring an infrared thermal image sequence of the composite insulator to be detected after thermal excitation loading. The acquisition spatial resolution of the thermal infrared imager should be equal to or higher than 640 x 512, the acquisition frequency should be up to more than 60Hz, and the minimum temperature difference should be up to 18 mK. The thermal infrared imager should have lenses with different focal lengths to meet the detection operation requirements at different distances.
And the data processing unit 7 is used for realizing acquisition, storage and post-processing of the infrared heat map sequence. And the data processing unit can perform various basic data processing such as fitting, filtering, cutting and the like on the acquired infrared heat map sequence. In order to enhance the display effect of the defects, the module is also embedded with a fast Fourier transform algorithm to extract the frequency domain characteristics of the heat map sequence. And (4) reconstructing the characteristic heat map by using the frequency domain characteristics so as to further realize the effect of enhancing the defect detection display.
The method for detecting the bonding defect inside the composite insulator, disclosed by the embodiment of the invention, has the flow shown in figure 2, and comprises the following steps:
And 2, setting relevant parameters of pulse microwave excitation and the thermal infrared imager, and adjusting the visual angle of the microwave transmitting antenna.
And step 3, synchronously triggering the microwave excitation and the thermal infrared imager, collecting the reference image by the thermal infrared imager, and heating the composite insulator.
And 4, finishing the pulse microwave heating, and acquiring a thermal image sequence by the thermal imager.
And 5, carrying out differential processing on the heat map sequence.
And 6, carrying out Fourier transform on the differential heat map sequence to obtain amplitude characteristics and phase characteristics.
And 7, selecting the frequency with the best detection effect to reconstruct the frequency domain characteristic heat map.
And 8, extracting the defect depth information by using the minimum phase signal.
In a specific embodiment, the following steps may be performed:
And 2, adjusting the frequency and power of a microwave generator, setting pulse microwave heating time and thermal infrared imager acquisition time, adjusting a power amplifier to system setting parameters, adjusting the antenna viewing angle, and ensuring that a microwave transmitting antenna is aligned to a detected composite insulator detection area.
And 3, synchronously triggering the pulse microwave excitation module and the thermal infrared imager, collecting an initial infrared chart of the detected composite insulator as a reference thermal chart, and heating the detected composite insulator, wherein at the moment, a large amount of heat is generated by the conductivity defect in the composite insulator.
And 4, after the pulse microwave excitation loading is finished, triggering the thermal infrared imager to acquire the infrared thermograph sequence on the surface of the composite insulator, and after the thermal infrared imager reaches the acquisition time, finishing the acquisition of the thermograph sequence.
And 5, carrying out differential processing on the acquired infrared heat map sequence and the reference heat map to obtain a differential infrared heat map sequence so as to eliminate background noise.
And 6, carrying out fast Fourier transform processing on the processed differential infrared heat map sequence to obtain the amplitude characteristic and the phase characteristic of the heat wave in the frequency domain.
And 7, according to the formula (2), the thermal wave characteristics of different frequencies can reflect the structural information of different depths. And selecting the frequency with the best detection effect to carry out heat map reconstruction by utilizing the amplitude and phase characteristics obtained in the last step to obtain the infrared heat map reconstructed by the frequency domain characteristics, thereby realizing the enhanced display of the conductivity defect.
And 8, selecting a frequency domain signal of a certain region point at the conduction defect position for analysis, selecting a minimum phase point in a phase-frequency graph of the region point as a characteristic quantity, and obtaining the depth position information of the conduction defect by using the corresponding frequency of the minimum phase point according to the formula (3).
Fig. 3 is a diagram illustrating the detection effect of an embodiment of the present invention, (a) being an original heat map, (b) being a magnitude signature reconstruction heat map, and (c) being a phase signature reconstruction heat map.
The innovation and the advantages of the invention at least lie in that:
(1) the invention provides a method and a system for detecting a conduction defect inside a composite insulator. In order to enhance the display effect of the defect and acquire the position information of the defect, Fourier transform is carried out on the processed differential infrared heat map sequence, and heat map reconstruction and depth quantification are carried out by utilizing frequency domain characteristics. The method can rapidly and intuitively display the conduction defect area in the composite insulator without contact, thereby realizing the detection and positioning of the conduction defect in the composite insulator.
(2) In the step 3, the conduction defect in the composite insulator is heated, so that a large amount of heat is generated in the conduction defect area, and the detection of the conduction defect is realized. The traditional infrared thermal wave method is to heat the whole test piece and detect the difference between the heat conduction of the defect area and the heat conduction of the normal area. Different from the traditional infrared thermal wave method, the method provided by the invention has the advantages that more heat is generated in the defect area, and a high-temperature heating area is generated, so that the detection of the conductivity defect of the composite insulator is realized.
(3) In the above step 5, step 6 and step 7, the heat map sequence is subjected to differential processing, so that the influence of background noise is obtained, the frequency domain features of the heat map sequence are extracted by fourier transform, and the heat map reconstruction is performed by using the frequency domain features at different frequencies, so that the enhanced display of the defect region is realized. Compared with a time domain analysis method, the method adopts a differential time domain sequence and utilizes the frequency domain characteristic of the thermal wave, can eliminate the influence of background noise, can realize the enhanced display of defects with different depths, and has higher robustness in detection.
(4) In the step 7, the depth quantitative measurement of the composite insulator conductivity defect is realized by utilizing the thermal wave frequency domain characteristics, so that the position information extraction of the defect is realized, and effective data can be provided for defect inversion and three-dimensional reconstruction.
The invention takes the heat map sequence collected by the infrared thermal wave technology as a reference object, and can realize the detection of the internal conductivity defect of the composite insulator.
The method can realize rapid, accurate, non-contact and visual detection of the conductivity defect in the composite insulator, has excellent detection effect on the tiny conductivity defect at the interface of the composite insulator, and further achieves the effect of rapidly, accurately and visually detecting the conductivity defect in the composite insulator.
The background of the present invention may contain background information related to the problem or environment of the present invention and does not necessarily describe the prior art. Accordingly, the inclusion in the background section is not an admission of prior art by the applicant.
The foregoing is a more detailed description of the invention in connection with specific/preferred embodiments and is not intended to limit the practice of the invention to those descriptions. It will be apparent to those skilled in the art that various substitutions and modifications can be made to the described embodiments without departing from the spirit of the invention, and these substitutions and modifications should be considered to fall within the scope of the invention. In the description herein, references to the description of the term "one embodiment," "some embodiments," "preferred embodiments," "an example," "a specific example," or "some examples" or the like are intended to mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Various embodiments or examples and features of various embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction. Although embodiments of the present invention and their advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the scope of the claims.
Claims (10)
1. A device for detecting the internal conductivity defect of a composite insulator is characterized by comprising a pulse microwave generation module, an infrared thermal imager and a data processing unit, the pulse microwave generation module carries out microwave heating on the composite insulator to realize heat generation in the conduction defect area, the infrared thermal imager collects an initial infrared thermal image of the composite insulator and an infrared thermal image sequence after microwave heating, the data processing unit takes the initial infrared heat map as a reference heat map to carry out differential processing on the infrared heat map sequence to obtain a differential heat map sequence, processing the differential heat map sequence to obtain amplitude characteristics and phase characteristics of the thermal wave in a frequency domain, realizing the extraction of the frequency domain characteristics of the thermal wave signal, and reconstructing a heat map sequence of the composite insulator according to the frequency domain characteristics to realize the enhanced display of the conduction defect region in the composite insulator.
2. The apparatus of claim 1, wherein the extraction of the frequency domain features of the thermal wave signal is achieved by a fast fourier transform.
3. The apparatus of claim 1 or 2, wherein the frequency with the best detection effect is selected for the heat map reconstruction.
4. The apparatus of any one of claims 1 to 3, wherein the depth of the conductivity defect is determined by taking the frequency domain signal of the region point at the conductivity defect, and taking the minimum phase point in the phase-frequency diagram of the region point as a feature quantity, and using the frequency corresponding to the minimum phase point.
5. The apparatus of any one of claims 1 to 4, wherein the pulsed microwave generating module comprises a microwave signal generator, a signal amplifier and an antenna, the microwave signal generator emits microwaves, the signal amplifier is used for increasing the power of the microwaves, and the antenna adjusts the direction of the microwave signal to the detected composite insulator.
6. The device according to any one of claims 1 to 5, further comprising a joint control unit and a motion module, wherein the joint control unit is connected with the pulse microwave generation module, the thermal infrared imager and the motion module for realizing linkage control of the pulse microwave generation module, the thermal infrared imager and the motion module, and the motion module is connected with the pulse microwave generation module and the thermal infrared imager for realizing azimuth control of the pulse microwave generation module and the thermal infrared imager so as to realize multi-angle and multi-azimuth scanning detection of the composite insulator.
7. The apparatus of any of claims 1 to 6, wherein the frequency of the microwave excitation is 2.4 GHz.
8. The apparatus of any one of claims 1 to 7, wherein the data processing unit further performs one or more of fitting, filtering, and cropping the sequence of acquired infrared heatmaps.
9. A method of detecting a conductivity defect in a composite insulator, wherein the method comprises the steps of:
s1, microwave heating is carried out on the composite insulator through the pulse microwave generation module;
s2, acquiring an initial infrared thermal image of the composite insulator and an infrared thermal image sequence after microwave heating by using an infrared thermal imager;
s3, taking the initial infrared heat map as a reference heat map, carrying out differential processing on the infrared heat map sequence to obtain a differential heat map sequence, processing the differential heat map sequence to obtain amplitude characteristics and phase characteristics of thermal waves in a frequency domain, realizing extraction of frequency domain characteristics of thermal wave signals, reconstructing the heat map sequence of the composite insulator according to the frequency domain characteristics, and realizing enhanced display of a conduction defect region in the composite insulator; preferably, a frequency domain signal of an area point at the conduction defect is taken, a minimum phase point in a phase-frequency diagram of the area point is taken as a characteristic quantity, and the depth of the conduction defect is determined by using a frequency corresponding to the minimum phase point.
10. A computer-readable storage medium, in which a computer program is stored which, when being executed by a processor, carries out step S3 of the method according to claim 9.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN118980562A (en) * | 2024-10-21 | 2024-11-19 | 内蒙古电力(集团)有限责任公司内蒙古超高压供电分公司 | A microwave detector and detection method for porcelain insulator production |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108693453A (en) * | 2018-05-18 | 2018-10-23 | 云南电网有限责任公司电力科学研究院 | A kind of active infrared thermal image detection device and method of composite insulator internal flaw |
| CN110827270A (en) * | 2019-11-12 | 2020-02-21 | 南方电网科学研究院有限责任公司 | Composite insulator defect diagnosis method and system |
| CN111090024A (en) * | 2019-11-14 | 2020-05-01 | 国网上海市电力公司 | GIS state assessment method and device based on external thermal and acoustic feature information |
| CN111208393A (en) * | 2018-11-22 | 2020-05-29 | 国网河南省电力公司平顶山供电公司 | Ground detection method for operation condition of line insulator |
| CN112162011A (en) * | 2020-09-16 | 2021-01-01 | 南方电网科学研究院有限责任公司 | Composite insulator defect detection method, device and storage medium |
| CN112649704A (en) * | 2020-12-15 | 2021-04-13 | 国网青海省电力公司 | Composite insulator defect detection equipment and method and unmanned aerial vehicle |
-
2021
- 2021-11-18 CN CN202111367883.6A patent/CN114167231B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108693453A (en) * | 2018-05-18 | 2018-10-23 | 云南电网有限责任公司电力科学研究院 | A kind of active infrared thermal image detection device and method of composite insulator internal flaw |
| CN111208393A (en) * | 2018-11-22 | 2020-05-29 | 国网河南省电力公司平顶山供电公司 | Ground detection method for operation condition of line insulator |
| CN110827270A (en) * | 2019-11-12 | 2020-02-21 | 南方电网科学研究院有限责任公司 | Composite insulator defect diagnosis method and system |
| CN111090024A (en) * | 2019-11-14 | 2020-05-01 | 国网上海市电力公司 | GIS state assessment method and device based on external thermal and acoustic feature information |
| CN112162011A (en) * | 2020-09-16 | 2021-01-01 | 南方电网科学研究院有限责任公司 | Composite insulator defect detection method, device and storage medium |
| CN112649704A (en) * | 2020-12-15 | 2021-04-13 | 国网青海省电力公司 | Composite insulator defect detection equipment and method and unmanned aerial vehicle |
Non-Patent Citations (1)
| Title |
|---|
| 刘文帅等: "基于频域热特征成像的复合绝缘子缺陷检测方法", 《中国电机工程》, pages 2498 - 2505 * |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN118980562A (en) * | 2024-10-21 | 2024-11-19 | 内蒙古电力(集团)有限责任公司内蒙古超高压供电分公司 | A microwave detector and detection method for porcelain insulator production |
| CN118980562B (en) * | 2024-10-21 | 2025-02-07 | 内蒙古电力(集团)有限责任公司内蒙古超高压供电分公司 | A microwave detector and detection method for porcelain insulator production |
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