CN108693453A - A kind of active infrared thermal image detection device and method of composite insulator internal flaw - Google Patents

Abstract

The invention discloses an active infrared thermal image detection device and method for internal defects of a composite insulator, comprising a modulating light radiation thermal excitation loading device, an infrared thermal image acquisition device, and a control and data processing and analysis device. Control the modulating light radiation thermal excitation loading device to apply controllable thermal excitation to the composite insulator, so that the composite insulator surface forms dynamic temperature field data; control the infrared thermal image acquisition device to collect dynamic temperature field data; use the control and data processing analysis device to analyze the dynamic temperature Identify and analyze the field data to obtain the specific situation of the internal defects of the composite insulator. Therefore, the active infrared thermal imaging detection device and method for internal defects of composite insulators provided by the present invention can solve the problems of low sensitivity, complicated and time-consuming, destructive and high detection conditions of existing detection methods for composite insulator defects.

Description

An active infrared thermal imaging detection device and method for internal defects of composite insulators

technical field

The invention relates to the field of electric equipment detection, in particular to an active infrared thermal image detection device and method for internal defects of a composite insulator.

Background technique

Since the application of composite insulators in my country in the 1970s, it has been more and more widely used due to its advantages of small size, light weight, high mechanical strength, strong anti-fouling flashover ability, excellent hydrophobicity and hydrophobic migration. . However, when the composite insulator has defects such as debonding of the sheath and the mandrel, pores or faults inside the sheath due to manufacturing processes, field operation aging, etc., the composite insulator will experience interface breakdown, flashover, silicone rubber aging, and mechanical strength reduction. , brittle mandrel and other problems, these hidden defects will pose a great threat to the safe operation of the power grid. The structure of the composite insulator is special, and there is an interface between the two layers of insulating materials inside the insulator. In the production process or long-term operation, it is difficult to ensure that the insulation performance of the internal interface is completely excellent. Under the action of water vapor, electric field, and leakage current, internal defects grow from scratch and further expand, gradually leading to pores, air gaps or internal discharges. Defects such as ablation channels, further development of defects may even cause serious consequences such as insulator breakdown or broken strings.

In order to reduce the occurrence of accidents, the use of non-destructive testing methods is an effective method. In the production process of composite insulators, the use of non-destructive testing methods can assist in improving the production quality of insulators. In the process of actual operation, non-destructive testing methods are regularly used to monitor and detect the operation of the insulators, so as to detect potential failures as early as possible, and avoid threatening the safety of the power grid due to insulator failures.

At present, most of the non-destructive testing methods for composite insulators are the continuation of the traditional methods for testing ceramic or glass insulators. These testing methods have their own scope of application, but there is no good method for detecting internal defects of composite insulators. Moreover, due to the particularity of the material properties and structure of composite materials, many non-destructive testing methods for ceramic or glass insulators are not suitable for composite insulators. In particular, composite insulators are different from ceramic or glass insulators. , there are hidden defects such as internal interface defects, and interface defects are a very important cause of failure for composite insulators. Therefore, it is urgent to improve and perfect the existing non-destructive testing methods, or to propose new testing methods to ensure the safety of composite insulators. At present, there are many detection methods for composite insulator defects, such as electric field distribution detection method, infrared detection method, steep wave test method, improved water diffusion test method, etc. However, these methods are either low in sensitivity, complex, time-consuming, destructive, or require high detection conditions. Before the composite insulator is put into operation, there is no standard detection method for whether there are internal defects in the composite insulator.

Contents of the invention

The invention provides an active infrared thermal imaging detection device and method for internal defects of composite insulators, to solve the problems of low sensitivity, complexity, time-consuming, destructiveness and high requirements for detection conditions in existing detection methods for composite insulator defects.

In the first aspect, the present invention provides an active infrared thermal image detection device for internal defects of a composite insulator, including a modulating optical radiation thermal excitation loading device, an infrared thermal image acquisition device, and a control and data processing and analysis device;

The modulating optical radiation thermal excitation loading device and the infrared thermal image acquisition device are respectively connected to the control and data processing and analysis device;

The modulating optical radiation thermal excitation loading device is composed of an optical radiation modulation circuit, a power supply and two modulating light sources; the optical radiation modulation circuit is connected with the control and data processing and analysis device, the power supply and two The adjustable light source is connected;

The infrared thermal image acquisition device includes a high-precision infrared thermal imager and a data acquisition card; the high-precision infrared thermal imager is connected to the data acquisition card, and the data acquisition card is connected to the control and data processing and analysis device ;

The control and data processing and analysis device includes a thermal excitation loading control module, an infrared thermal image data acquisition control module, an infrared thermal image sequence processing analysis and defect identification module, a data transmission module and a data management and maintenance module;

The thermal excitation loading control module is connected to the optical radiation modulation circuit; the infrared thermal imaging data acquisition control module is connected to the data acquisition card;

The thermal excitation loading control module and the infrared thermal image data acquisition control module are respectively connected to the infrared thermal image sequence processing analysis and defect identification module; the infrared thermal image sequence processing analysis and defect identification module is connected to the data transmission The modules are connected; the data transmission module is connected with the data management and maintenance module.

Optionally, the infrared heat map sequence processing analysis and defect identification module includes sequentially connected composite insulator infrared heat map sequence data fitting and reconstruction submodule, composite insulator infrared heat map sequence enhancement processing submodule, composite insulator infrared heat map Sequence information separation sub-module, composite insulator infrared heat map defect feature extraction and quantitative identification sub-module and composite insulator defect comparison judgment and fault assessment sub-module;

The composite insulator infrared thermal image sequence data fitting and reconstruction sub-module is respectively connected with the thermal excitation loading control module and the infrared thermal image data acquisition control module;

The composite insulator infrared heat map sequence data fitting and reconstruction submodule, the composite insulator infrared heat map sequence enhancement processing submodule, the composite insulator infrared heat map sequence information separation submodule, and the composite insulator infrared heat map defect feature extraction and quantitative identifier The module and the composite insulator defect comparison judgment and fault evaluation sub-module are respectively connected with the data transmission module.

Optionally, the data management and maintenance module includes a rights management module, a data storage module, a data query and export module, and a data maintenance module;

The data storage module is connected to the data transmission module;

The data storage module is respectively connected to the data query export module and the data maintenance module; the data query export module and the data maintenance module are respectively connected to the authority management module.

Optionally, the modulable light radiation thermal excitation loading device further includes a shading cover, the shading cover is surrounded by a reflector and transparent glass, the adjustable light source is located in the shading cover, and the modulating light source illuminates face towards the clear glass.

Optionally, the power of the adjustable light source is 800W.

Optionally, the high-precision infrared thermal imager is a cooled long-wave quantum well infrared photodetector.

In the second aspect, the present invention also provides an active infrared thermal image detection method for internal defects of composite insulators, including:

Create a background database;

Controlling the modulating optical radiation thermal excitation loading device to apply controllable thermal excitation to the composite insulator, so that the surface of the composite insulator forms dynamic temperature field data; the controllable thermal excitation includes the duration, power and modulation frequency of the thermal excitation;

Adjusting the field of view and focal length of the infrared thermal image acquisition device, setting the image acquisition duration and acquisition frequency of the infrared thermal image acquisition device, and controlling the infrared thermal image acquisition device to collect the dynamic temperature field data;

According to the dynamic temperature field data, data fitting, compression and reconstruction are performed on the dynamic temperature field data to obtain a composite insulator infrared heat map sequence;

According to the infrared heat map sequence of the composite insulator, a specific frequency target response signal of the composite insulator infrared heat map sequence is obtained through data post-processing;

According to the specific frequency target response signal of the composite insulator infrared heat map sequence, the amplitude diagram and phase diagram of the composite insulator target response signal are obtained;

storing the dynamic temperature field data, the composite insulator infrared heat map sequence, the composite insulator infrared heat map sequence specific frequency target response signal, and the amplitude map and phase map of the composite insulator target response signal into the background database;

According to the amplitude diagram and phase diagram of the target response signal of the composite insulator, internal defects of the composite insulator are identified and analyzed.

Optionally, also include:

Manage users' access rights to data in the background database, control external interfaces; provide data storage, query and export functions in the background database; modify, add or delete data in the background database.

Optionally, according to the following steps, the amplitude map and phase map of the target response signal of the composite insulator are obtained according to the specific frequency target response signal of the composite insulator infrared heat map sequence:

Obtain the amplitude and phase of the target response signal of the composite insulator according to the specific frequency target response signal of the composite insulator infrared heat map sequence;

According to the corresponding relationship between the amplitude and phase of the target response signal of the composite insulator and the modulation frequency of the controllable thermal excitation, an amplitude diagram and a phase diagram of the target response signal of the composite insulator are obtained.

Optionally, according to the amplitude diagram and phase diagram of the target response signal of the composite insulator, identify and analyze the internal defects of the composite insulator according to the following steps:

According to the amplitude map and phase map of the target response signal of the composite insulator, compare it with the data in the background database, separate and store the abnormal area information;

Extracting the abnormal area information, identifying and storing the internal defect area shape and defect area characteristics of the composite insulator according to the abnormal area information; the defect area characteristics include defect size, depth and thermal conductivity;

According to the shape and characteristics of the internal defect area of the composite insulator, and comparing with the data in the background database, the internal defect type and the cause of formation of the composite insulator are analyzed and stored.

It can be seen from the above technical solutions that the embodiment of the present invention provides an active infrared thermal image detection device and method for internal defects of a composite insulator, including a modulating optical radiation thermal excitation loading device, an infrared thermal image acquisition device, and a control and data processing and analysis device . Control the modulating light radiation thermal excitation loading device to apply controllable thermal excitation to the composite insulator, so that the composite insulator surface forms dynamic temperature field data; control the infrared thermal image acquisition device to collect dynamic temperature field data; use the control and data processing analysis device to analyze the dynamic temperature Identify and analyze the field data to obtain the specific situation of the internal defects of the composite insulator. Therefore, the active infrared thermal imaging detection device and method for internal defects of composite insulators provided by the present invention can solve the problems of low sensitivity, complicated and time-consuming, destructive and high detection conditions of existing detection methods for composite insulator defects.

Description of drawings

In order to illustrate the technical solution of the present invention more clearly, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, for those of ordinary skill in the art, on the premise of not paying creative labor, Additional drawings can also be derived from these drawings.

Fig. 1 is a schematic structural diagram of an active infrared thermal image detection device for internal defects of a composite insulator provided by an embodiment of the present invention;

Fig. 2 is a structural block diagram of a control and data processing and analyzing device provided by an embodiment of the present invention;

3 is a structural block diagram of the relationship between the infrared heat map sequence processing analysis and the defect identification module and the data transmission module provided by the embodiment of the present invention;

Fig. 4 is a structural block diagram of the relationship between the data transmission module and the data management and maintenance module provided by the embodiment of the present invention;

Fig. 5 is a schematic flowchart of an active infrared thermal image detection method for internal defects of a composite insulator provided by an embodiment of the present invention;

6 is a schematic flowchart of a method for obtaining an amplitude map and a phase map of a target response signal of a composite insulator provided by an embodiment of the present invention;

Fig. 7 is a schematic flowchart of a method for identifying and analyzing internal defects of a composite insulator provided by an embodiment of the present invention.

Detailed ways

Referring to Figures 1 and 2, Figure 1 is a schematic structural diagram of an active infrared thermal image detection device for internal defects in composite insulators, and Figure 2 is a structural block diagram of a control and data processing and analysis device provided by an embodiment of the present invention.

An active infrared thermal image detection device for internal defects of a composite insulator provided by an embodiment of the present invention includes a modulating optical radiation thermal excitation loading device, an infrared thermal image acquisition device, and a control and data processing and analysis device 1;

The modulating optical radiation thermal excitation loading device and the infrared thermal image acquisition device are respectively connected to the control and data processing and analysis device 1;

The modulating optical radiation thermal excitation loading device is composed of an optical radiation modulating circuit 5, a power supply 6 and two modulating light sources 4; the optical radiation modulating circuit 5 adjusts the optical radiation power and frequency to realize the adjustable heating of the surface of the detected object. The power supply is battery or 220V mains.

The optical radiation modulation circuit 5 is respectively connected with the control and data processing and analysis device 1 and the power supply 6, and the optical radiation modulation circuit 5 is respectively connected with two modulating light sources 4; the modulating optical radiation thermal excitation loading device also includes a hood, a hood Surrounded by a reflector and transparent glass, the modulatable light source 4 is located in the shading cover, and the illuminated surface of the modulatable light source 4 faces the transparent glass.

The main function of installing the reflector behind the adjustable light source 4 includes two aspects: one is the effect of concentrating light, collecting more light energy and preventing diffusion; A large-area planar thermal wave source can be well formed on the surface of the object to be detected, which can not only heat the object to be detected efficiently, but also protect human eyes from being directly irradiated by strong light. The transparent glass installed in front of the modulating light source 4 is transparent to visible light and opaque to infrared rays in the working band of the infrared thermal imaging camera, thereby eliminating the interference of the thermal excitation device on the data acquisition process of the infrared thermal imaging camera.

The infrared thermal image acquisition device includes a high-precision infrared thermal imager 3 and a data acquisition card 2; it is used to receive the infrared signal sent by the tested test piece, record the temperature change of the test piece surface before and after excitation, and provide the information to the control and data analysis. The system outputs dynamic temperature information. A high-precision infrared thermal imager should use a cooled long-wave quantum well infrared photodetector. The cooling-type long-wave quantum well infrared photodetector has high thermal sensitivity, wide dynamic range, and high-speed data acquisition functions. The original infrared heat map sequence is output in real time to the control and data processing and analysis device 1 through the data acquisition card 2 .

The high-precision thermal imaging camera 3 is connected to the data acquisition card 2, and the data acquisition card 2 is connected to the control and data processing and analysis device 1;

The control and data processing and analysis device 1 includes a thermal excitation loading control module 11, an infrared thermal image data acquisition control module 12, an infrared thermal image sequence processing analysis and defect identification module 10, a data transmission module 18, and a data management and maintenance module 19; thermal excitation loading The control module 11 can adjust and control to trigger the modulating optical radiation thermal excitation loading device to apply controllable thermal excitation to the composite insulator, and can adjust the duration, power, modulation frequency, etc. of the controllable thermal excitation.

The infrared thermal image data acquisition control module 12 can control the infrared thermal image acquisition device to collect the surface dynamic temperature field data formed by the composite insulator under external heating excitation conditions, and can adjust the acquisition time and acquisition frequency of the infrared thermal image acquisition system , The data acquisition results of the dynamic temperature field are transmitted and stored in the form of infrared heat map sequences.

The infrared thermal image sequence processing analysis and defect identification module can process and analyze the collected temperature data to realize defect identification, and has the function of performing related image processing operations on the original infrared thermal image sequence.

The thermal excitation loading control module 11 is connected to the optical radiation modulation circuit 5; the infrared thermal image data acquisition control module 12 is connected to the data acquisition card 2;

The thermal excitation loading control module 11 and the infrared thermal image data acquisition control module 12 are respectively connected with the infrared thermal image sequence processing analysis and defect identification module 10; the infrared thermal image sequence processing analysis and defect identification module 10 is connected with the data transmission module 18; the data transmission The module 18 is connected with the data management and maintenance module 19 .

Referring to FIG. 5 , FIG. 5 is a schematic flowchart of an active infrared thermal imaging detection method for internal defects of a composite insulator provided by an embodiment of the present invention.

The specific working process of active infrared thermal imaging detection of internal defects of composite insulators is as follows:

S110, establishing a background database;

It is used to store the detection data of the active infrared thermal image and the calculation data obtained according to the detection data when the composite insulator has no defects, as well as the intermediate data generated during the active infrared thermal image detection process of the internal defects of the composite insulator.

S120, controlling the modulating optical radiation thermal excitation loading device to apply controllable thermal excitation to the composite insulator to form dynamic temperature field data on the surface of the composite insulator; the controllable thermal excitation includes the duration, power and modulation frequency of the thermal excitation;

The thermal excitation loading control module 11 controls the modulating optical radiation thermal excitation loading device to apply controllable thermal excitation to the composite insulator, and the periodic heat wave propagates to the interior through the surface of the composite insulator. Internal defects such as interfacial debonding will spread heat unevenly, and will have a periodic effect on the temperature distribution on the surface of the composite insulator.

S130, adjusting the field of view and focal length of the infrared thermal image acquisition device, setting the image acquisition duration and acquisition frequency of the infrared thermal image acquisition device, and controlling the infrared thermal image acquisition device to collect the dynamic temperature field data;

The infrared thermal image data acquisition control module 12 adjusts the field of view and focal length of the infrared thermal image acquisition device, so that a clear infrared image of the detected area of the composite insulator appears on the computer display, and the image acquisition time and acquisition frequency of the infrared thermal image acquisition device are set. , start infrared image acquisition before triggering thermal excitation, and transmit the dynamic temperature distribution information before and after the detected area on the surface of the composite insulator is excited to the next processing procedure.

Active infrared thermal imaging detection technology has the characteristics of fast detection speed, high detection accuracy, non-contact measurement, intuitive results, wide application range, and convenient qualitative and quantitative analysis. It is very suitable for the factory quality control of composite insulators and defect detection during operation.

The original infrared heat map sequence output by the active infrared thermal imaging detection technology reflects the change information of the surface temperature field distribution of the detected object after being subjected to active thermal excitation. Features such as depth will be reflected as different temperature change features in the original infrared heat map sequence. Therefore, it is necessary to use appropriate means to analyze the obtained change temperature field information on the basis of a full understanding of the thermal wave theory and the failure mechanism of composite insulators. Excavation and analysis, in order to obtain accurate identification results of composite insulator defects. However, a unified processing and analysis method for the original infrared heat map sequence of composite insulator defects has not yet been formed. It requires inspectors to have relevant professional technical reserves, and the management of a large number of dynamic heat map data obtained is not standardized enough to comprehensively and deeply dig out. defect information. On the other hand, the working environment of composite insulators is complex, image background interference, on-site infrared noise, heating of composite insulators and other factors are more affected. In actual inspection, image noise needs to be processed to quickly and intelligently eliminate interference. The original infrared image of the insulator is obtained for processing and analysis.

To sum up, when using the active infrared thermal imaging detection technology to detect the internal defects of composite insulators, the original data is huge, the background interference is more, and the process of extracting the characteristic information of the original data is relatively complicated, which affects the active infrared thermal imaging detection technology in Popularization and application in the detection of internal defects of composite insulators. The infrared heat map sequence processing analysis and defect identification module can help solve this problem.

Referring to FIG. 3, FIG. 3 is a structural block diagram of the relationship between the infrared thermal image sequence processing analysis and defect identification module and the data transmission module provided by the embodiment of the present invention.

The infrared heat map sequence processing analysis and defect identification module 10 includes a sequentially connected composite insulator infrared heat map sequence data fitting and reconstruction submodule 13, a composite insulator infrared heat map sequence enhancement processing submodule 14, a composite insulator infrared heat map sequence information analysis Ion module 15, composite insulator infrared heat map defect feature extraction and quantitative identification sub-module 16 and composite insulator defect comparison judgment and fault assessment sub-module 17;

The composite insulator infrared thermal image sequence data fitting and reconstruction sub-module 13 is connected to the thermal excitation loading control module 11 and the infrared thermal image data acquisition control module 12 respectively.

The composite insulator infrared thermal image sequence data fitting and reconstruction sub-module 13 can receive data from the thermal excitation loading control module 11 and the infrared thermal image data acquisition control module 12, and process the data.

S140. According to the dynamic temperature field data, perform data fitting, compression and reconstruction on the dynamic temperature field data, and obtain a composite insulator infrared heat map sequence;

In the detection process, the infrared thermal image acquisition device collects the surface temperature change information of the composite insulator before and after thermal excitation at high frequency, and will obtain a relatively large amount of experimental data, and the amount of stored data increases linearly with the increase of the acquisition frequency and duration. The amount of data that needs to be processed in the follow-up is also greatly increased. In order to reduce the temporal noise between frames, reduce the influence of uneven heating, compress the storage space, and improve the detection speed, the composite insulator infrared heat map sequence data fitting and reconstruction sub-module 13 performs data simulation on the collected original dynamic temperature information. Fitting, compression and reconstruction, according to the characteristics of the data and the requirements of goodness-of-fit, select an appropriate fitting algorithm to fit the dynamic temperature data. The fitting algorithms for dynamic temperature data included in the module include but are not limited to polynomial fitting, nonlinear Levenberg-Marquardt fitting, fitting based on genetic algorithm, fitting based on differential evolution algorithm, etc. The fitted dynamic temperature data only needs to store limited fitting parameters, and the amount of stored data does not increase with the increase of acquisition frequency and duration. The fitted dynamic temperature data can reconstruct the original infrared heat map sequence into an infrared heat map sequence, reducing temporal noise between frames, and the reconstructed image lays the foundation for subsequent operations.

First, the high-frequency noise of the signal is removed by mean filtering, and then the image data is fitted based on the theoretical formula of the temperature change of the composite insulator after excitation and the Levenberg-Marquardt algorithm. According to the theoretical analysis of heat transfer, the temperature-time relationship of a certain point on the surface of the composite insulator after excitation is:

Combining the constants and redefining the three parameters a, b, and c to be sought, the formula can be further simplified as:

The Levenberg‐Marquardt algorithm (LM algorithm for short) is a nonlinear optimization method between the Newton method and the gradient descent method, which can effectively deal with the nonlinear parameter fitting problem mentioned above. Consider the functional relationship x=f(p), where p∈R ^n×1 is a parameter vector, and x∈R ^m×1 is close to the real value observation vector. Due to measurement errors, there is no strict functional relationship, only estimated values Therefore, it is necessary to make the estimation error As small as possible, that is, to solve the following minimization problem:

Given an initial solution p _k , consider the first-order approximation f(p _k +δ _k )=f(p _k )+J _k ·δ _k of f(p) around point p _k , where J _k is the Jacobi matrix at The value of point p _k . Find the next iteration point p _k+1 = p _k + δ _k such that:

The essence of this minimization problem is to solve the overdetermined linear equation J _k δ _k =ε _k when J _k and ε _k are known. According to the method of least squares, the solution is:

The LM algorithm uses replace get:

In the LM algorithm, each iteration is to find a suitable damping factor λ _k , and λ _k I is the damping item. The initial infrared heat map sequence becomes an infrared heat map sequence after fitting, the time domain noise between frames is significantly reduced, the influence of uneven heating is reduced, the defect contrast is enhanced, the storage space is greatly compressed, and the detection accuracy and speed are improved. The subsequent qualitative and quantitative identification of defects laid the foundation. The composite insulator infrared heat map sequence is input to the composite insulator infrared heat map sequence enhancement processing sub-module 14 .

S150, according to the composite insulator infrared heat map sequence, obtain a specific frequency target response signal of the composite insulator infrared heat map sequence through data post-processing;

S160. Acquire an amplitude map and a phase map of the target response signal of the composite insulator according to the specific frequency target response signal of the composite insulator infrared heat map sequence.

The above functions are realized by the composite insulator infrared thermal image sequence enhancement processing sub-module 14 .

Referring to FIG. 6 , FIG. 6 is a schematic flowchart of a method for obtaining an amplitude map and a phase map of a target response signal of a composite insulator provided by an embodiment of the present invention. According to the following steps, according to the specific frequency target response signal of the composite insulator infrared heat map sequence, the amplitude map and phase map of the composite insulator target response signal are obtained:

S210. Obtain the amplitude and phase of the target response signal of the composite insulator according to the specific frequency target response signal of the composite insulator infrared heat map sequence;

S220. Obtain an amplitude diagram and a phase diagram of the composite insulator target response signal according to the corresponding relationship between the amplitude and phase of the composite insulator target response signal and the modulation frequency of the controllable thermal excitation.

The dynamic temperature field data usually contains interference signals such as DC signals and noise signals, and it is necessary to extract the response signal with the same frequency as the modulation frequency of the controllable thermal excitation, and then analyze the defect information. If the defect size is small or the depth is deep, the useful signal is likely to be submerged in the noise signal. At this time, it is necessary to suppress the noise signal through data post-processing, enhance the useful signal, and then separate the specific frequency target response of the composite insulator infrared heat map sequence Signal.

Here, the Fourier transform method is used to separate the specific frequency target response signal of the composite insulator infrared heat map sequence. During the defect detection process, each pixel point collected by the infrared thermal image acquisition device at the sampling frequency f _s (time interval Δt) corresponds to N discrete temperature time-domain signals T(t). The signal in the frequency domain is obtained by fast Fourier transform:

In the formula, n is the serial number of the discrete value, and Re(f) and Im(f) are the real part and imaginary part of the frequency domain signal respectively. The expressions for magnitude and phase are:

All pixels in the composite insulator infrared thermal image sequence are calculated, and the amplitude map and phase map of the thermal image are obtained respectively. Since the time domain signal is real-valued, N/2 frequency data can be obtained by using the time data of N heatmaps. The discrete frequencies are:

In the formula, N is the image frame number of the heat map sequence, Δt is the sampling time interval, n=0,1,2,...,N/2. The highest frequency is determined by the acquisition rate and the lowest frequency is determined by the duration of the experiment. In fact, because most of the energy is concentrated in the low frequencies, only the first few frequencies are more important. The high frequency part contains strong noise.

The specific frequency target response signal of the composite insulator infrared heat map sequence extracted from the infrared heat map sequence can calculate the amplitude and phase of the response signal at each point on the surface of the detected composite insulator under the modulation frequency excitation of the controllable thermal excitation, according to the composite insulator The corresponding relationship between the amplitude and phase of the target response signal and the modulation frequency of the controllable thermal excitation can be arranged in order to obtain the amplitude diagram and phase diagram of the target response signal of the composite insulator. The characteristic frequency amplitude map and phase map obtained after processing are transmitted to the composite insulator infrared heat map sequence information separation sub-module 15 .

S170, storing the dynamic temperature field data, the composite insulator infrared heat map sequence, the composite insulator infrared heat map sequence specific frequency target response signal, and the amplitude map and phase map of the composite insulator target response signal into the background database;

It should be noted that the above-mentioned data stored in the background database are intermediate data in the process of active infrared thermal imaging detection of internal defects of composite insulators. The heat map sequence enhancement processing sub-module 14, the composite insulator infrared heat map sequence information separation sub-module 15, the composite insulator infrared heat map defect feature extraction and quantitative identification sub-module 16, and the composite insulator defect comparison judgment and fault evaluation sub-module 17 are respectively connected with the data The transmission module 18 is connected, and the processed data is transmitted backward through the data transmission module 18, applied to the subsequent detection process, and sent to the module responsible for storage for storage.

S180. Identify and analyze internal defects of the composite insulator according to the amplitude diagram and phase diagram of the target response signal of the composite insulator.

Referring to FIG. 7 , FIG. 7 is a schematic flowchart of a method for identifying and analyzing internal defects of a composite insulator provided by an embodiment of the present invention. Identify and analyze the internal defects of the composite insulator according to the amplitude diagram and phase diagram of the target response signal of the composite insulator according to the following steps:

S310. According to the amplitude diagram and phase diagram of the target response signal of the composite insulator, compare it with the data in the background database, separate and store abnormal area information;

Composite insulator infrared heat map sequence information separation sub-module 15, conducts comparative search on the amplitude map and phase map of the composite insulator target response signal, and locks the pixels in the image that are different from the data in the background database and the differences in frequency response The change of the frequency response can be used to separate the suspected defect area that needs further discrimination and its characteristics that change with the frequency response. This process can also eliminate the noise points of the suspected defect on the image. The abnormal area information is transmitted to the defect feature extraction and quantitative identification sub-module 16 of the composite insulator infrared heat map.

S320, extracting the abnormal area information, identifying and storing the internal defect area shape and defect area characteristics of the composite insulator according to the abnormal area information; the defect area characteristics include defect size, depth and thermal conductivity;

The defect feature extraction and quantitative identification sub-module 16 of the composite insulator infrared heat map is used to extract the feature of the separated abnormal area information, identify the shape of the defect area and calculate the size, depth, thermal conductivity and other parameters of the defect. The internal defect area shape and defect area characteristics of the composite insulator are transmitted to the composite insulator defect comparison judgment and fault evaluation sub-module 17 .

S330, according to the internal defect area shape and defect area characteristics of the composite insulator, compare with the data in the background database, analyze and store the internal defect type and formation cause of the composite insulator.

The Composite Insulator Defect Comparison Judgment and Fault Evaluation Sub-module 17 is used to compare the internal defect area shape and defect area characteristics of the composite insulator with the data in the background database, analyze the defect type and its possible causes, and possible failure modes, etc. .

It should be noted that due to the composite insulator infrared heat map sequence data fitting and reconstruction sub-module 13, the composite insulator infrared heat map sequence enhancement processing sub-module 14, the composite insulator infrared heat map sequence information separation sub-module 15, and the composite insulator infrared heat map sequence The defect feature extraction and quantitative identification sub-module 16 and the composite insulator defect comparison determination and fault evaluation sub-module 17 are respectively connected to the data transmission module 18, and the processed data is transmitted backward through the data transmission module 18, and applied to the subsequent detection process, And it is sent to the module responsible for storage for storage.

The data transmission module 8 inputs the extracted composite insulator defect infrared thermal map sequence features, quantitatively calculated defect parameters, and judgment conclusions on defect characteristics and other information into the composite insulator active infrared thermal imaging feature database, and can serve as an interface to transfer the background database The specified data in is imported to composite insulator defect comparison judgment and fault evaluation sub-module 17 for data comparison.

Referring to FIG. 4, FIG. 4 is a structural block diagram of the relationship between the data transmission module and the data management and maintenance module provided by the embodiment of the present invention.

The data management and maintenance module 19 includes a rights management module 191, a data storage module 192, a data query derivation module 193 and a data maintenance module 194; the data storage module 192 is connected with the data transmission module 18;

The data storage module 192 is connected to the data query export module 193 and the data maintenance module 194 respectively; the data query export module 193 and the data maintenance module 194 are connected to the authority management module 191 respectively.

The function of the data management and maintenance module 19 is to manage the user's access authority to the data in the background database, and control the external interface; provide data storage, query and export functions in the background database; modify, add or delete data in the background database . specific:

The authority management module 191 manages the user's access authority to the background database, including two authentication methods of fingerprint authentication and password authentication, and controls the external interface.

The data storage module 192 is responsible for storing background database data. It is used to store the detection data of the active infrared thermal image and the calculation data obtained according to the detection data when the composite insulator has no defects, as well as the intermediate data generated during the active infrared thermal image detection process of the internal defects of the composite insulator.

Data query and export module 193, the user can query the dynamic temperature field data and corresponding fault information of the composite insulator in the database according to the insulator model, defect parameters, detection date, etc., and use the infrared heat map sequence, characteristic frequency amplitude map and phase map , temperature characteristic curve, characteristic parameter table and other forms to export data results.

The data maintenance module 194 modifies, adds or deletes the data in the background database.

In addition, it should be noted that all data related to storage in the present invention finally enters the data storage module 192, and all data together form a background database.

It can be seen from the above technical solutions that the embodiment of the present invention provides an active infrared thermal image detection device and method for internal defects of a composite insulator, including a modulating optical radiation thermal excitation loading device, an infrared thermal image acquisition device, and a control and data processing and analysis device 1. Control the modulatable optical radiation thermal excitation loading device to apply controllable thermal excitation to the composite insulator, so that the composite insulator surface forms a dynamic temperature field data control infrared thermal image acquisition device to collect dynamic temperature field data; use the control and data processing analysis device 1 to monitor the dynamic temperature Identify and analyze the field data to obtain the specific situation of the internal defects of the composite insulator. Therefore, the active infrared thermal imaging detection device and method for internal defects of composite insulators provided by the present invention can solve the problems of low sensitivity, complicated and time-consuming, destructive and high detection conditions of existing detection methods for composite insulator defects.

Other embodiments of the invention will be readily apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any modification, use or adaptation of the present invention, these modifications, uses or adaptations follow the general principles of the present invention and include common knowledge or conventional technical means in the technical field not disclosed in the present invention . The specification and examples are to be considered exemplary only, with the true scope and spirit of the invention indicated by the appended claims.

It should be understood that the present invention is not limited to the precise constructions which have been described above and shown in the accompanying drawings, and various modifications and changes may be made without departing from the scope thereof. The scope of the invention is limited only by the appended claims.

For the same and similar parts among the various embodiments in this specification, please refer to each other. In particular, for the method embodiment, since it is basically similar to the device embodiment, the description is relatively simple, and for relevant parts, refer to the description in the device embodiment.

Claims (10)

1. An active infrared thermal image detection device for internal defects of a composite insulator, characterized in that it includes a modulating optical radiation thermal excitation loading device, an infrared thermal image acquisition device, a control and data processing and analysis device; The modulating optical radiation thermal excitation loading device and the infrared thermal image acquisition device are respectively connected to the control and data processing and analysis device; The modulating optical radiation thermal excitation loading device is composed of an optical radiation modulation circuit, a power supply and two modulating light sources; the optical radiation modulation circuit is connected with the control and data processing and analysis device, the power supply and two The adjustable light source is connected; The infrared thermal image acquisition device includes a high-precision infrared thermal imager and a data acquisition card; the high-precision infrared thermal imager is connected to the data acquisition card, and the data acquisition card is connected to the control and data processing and analysis device ; The control and data processing and analysis device includes a thermal excitation loading control module, an infrared thermal image data acquisition control module, an infrared thermal image sequence processing analysis and defect identification module, a data transmission module and a data management and maintenance module; The thermal excitation loading control module is connected to the optical radiation modulation circuit; the infrared thermal imaging data acquisition control module is connected to the data acquisition card; The thermal excitation loading control module and the infrared thermal image data acquisition control module are respectively connected to the infrared thermal image sequence processing analysis and defect identification module; the infrared thermal image sequence processing analysis and defect identification module is connected to the data transmission The modules are connected; the data transmission module is connected with the data management and maintenance module. 2. The active infrared thermal imaging detection device for internal defects of composite insulators according to claim 1, wherein the infrared thermal image sequence processing analysis and defect identification module includes sequentially connected composite insulator infrared thermal image sequence data fitting and reconstruction sub-module, composite insulator infrared heat map sequence enhancement processing sub-module, composite insulator infrared heat map sequence information separation sub-module, composite insulator infrared heat map defect feature extraction and quantitative identification sub-module and composite insulator defect comparison judgment and fault evaluation sub-module module; The composite insulator infrared thermal image sequence data fitting and reconstruction sub-module is respectively connected with the thermal excitation loading control module and the infrared thermal image data acquisition control module; The composite insulator infrared heat map sequence data fitting and reconstruction submodule, the composite insulator infrared heat map sequence enhancement processing submodule, the composite insulator infrared heat map sequence information separation submodule, and the composite insulator infrared heat map defect feature extraction and quantitative identifier The module and the composite insulator defect comparison judgment and fault evaluation sub-module are respectively connected with the data transmission module. 3. The active infrared thermal image detection device for internal defects of a composite insulator according to claim 1, wherein the data management and maintenance module includes a rights management module, a data storage module, a data query and export module, and a data maintenance module; The data storage module is connected to the data transmission module; The data storage module is respectively connected to the data query export module and the data maintenance module; the data query export module and the data maintenance module are respectively connected to the authority management module. 4. The active infrared thermal imaging detection device for internal defects of composite insulators according to claim 1, characterized in that, the modulating optical radiation thermal excitation loading device also includes a light shield, and the light shield is composed of a reflector and a transparent glass Enclosed, the adjustable light source is located in the shading cover, and the illuminated surface of the adjustable light source faces the transparent glass. 5 . The active infrared thermal imaging detection device for internal defects of composite insulators according to claim 1 , wherein the power of the adjustable light source is 800W. 6 . The active infrared thermal image detection device for internal defects of composite insulators according to claim 1 , wherein the high-precision infrared thermal imager is a cooled long-wave quantum well infrared photodetector. 7. An active infrared thermal image detection method for internal defects of a composite insulator, characterized in that it comprises: Create a background database; Controlling the modulating optical radiation thermal excitation loading device to apply controllable thermal excitation to the composite insulator, so that the surface of the composite insulator forms dynamic temperature field data; the controllable thermal excitation includes the duration, power and modulation frequency of the thermal excitation; Adjusting the field of view and focal length of the infrared thermal image acquisition device, setting the image acquisition duration and acquisition frequency of the infrared thermal image acquisition device, and controlling the infrared thermal image acquisition device to collect the dynamic temperature field data; According to the dynamic temperature field data, data fitting, compression and reconstruction are performed on the dynamic temperature field data to obtain a composite insulator infrared heat map sequence; According to the infrared heat map sequence of the composite insulator, a specific frequency target response signal of the composite insulator infrared heat map sequence is obtained through data post-processing; According to the specific frequency target response signal of the composite insulator infrared heat map sequence, the amplitude diagram and phase diagram of the composite insulator target response signal are obtained; storing the dynamic temperature field data, the composite insulator infrared heat map sequence, the composite insulator infrared heat map sequence specific frequency target response signal, and the amplitude map and phase map of the composite insulator target response signal into the background database; According to the amplitude diagram and phase diagram of the target response signal of the composite insulator, internal defects of the composite insulator are identified and analyzed. 8. The active infrared thermal image detection method for internal defects of a composite insulator according to claim 7, further comprising: Manage users' access rights to data in the background database, control external interfaces; provide data storage, query and export functions in the background database; modify, add or delete data in the background database. 9. The active infrared thermal image detection method for internal defects of composite insulators according to claim 7, characterized in that, according to the following steps, according to the specific frequency target response signal of the composite insulator infrared heat map sequence, the composite insulator target response signal is obtained The magnitude and phase plots for : Obtain the amplitude and phase of the target response signal of the composite insulator according to the specific frequency target response signal of the composite insulator infrared heat map sequence; According to the corresponding relationship between the amplitude and phase of the target response signal of the composite insulator and the modulation frequency of the controllable thermal excitation, an amplitude diagram and a phase diagram of the target response signal of the composite insulator are obtained. 10. The active infrared thermal image detection method for internal defects of composite insulators according to claim 7, characterized in that the composite insulators are identified and analyzed according to the amplitude diagram and phase diagram of the target response signal of the composite insulator according to the following steps internal flaws: According to the amplitude map and phase map of the target response signal of the composite insulator, compare it with the data in the background database, separate and store the abnormal area information; Extracting the abnormal area information, identifying and storing the internal defect area shape and defect area characteristics of the composite insulator according to the abnormal area information; the defect area characteristics include defect size, depth and thermal conductivity; According to the shape and characteristics of the internal defect area of the composite insulator, and comparing with the data in the background database, the internal defect type and the cause of formation of the composite insulator are analyzed and stored.