Insulation paper aging state evaluation method, device, equipment, medium and product

Abstract

The invention discloses an insulation paper aging state evaluation method and device, equipment, a medium and a product, and relates to the technical field of insulation paper aging state evaluation. Carrying out terahertz time-domain spectroscopy test on the aged insulation paper sample to obtain a terahertz time-domain spectroscopy signal of the aged insulation paper sample; fourier transform is carried out on the terahertz time-domain spectral signal to obtain a terahertz frequency-domain absorption spectrum of the aged insulation paper sample, and optical parameters of the aged insulation paper sample in a terahertz frequency band are extracted; based on the Pearson's related absorption theory, using optical parameters to propose an aging characteristic quantity with absorption spectrum similarity as a characteristic, and calculating a similarity value between the aging sample insulation paper and a reference; and evaluating the aging condition of the to-be-tested insulation paper in the oil paper insulation system according to the similarity value. According to the invention, a new idea is provided for accurate and lossless evaluation of the aging state of the insulation paper in the oil paper insulation system.

Description

Technical Field

[0001] The present application relates to the technical field of insulation paper aging status assessment, and in particular to an insulation paper aging status assessment method, device, equipment, medium and product characterized by terahertz absorption spectrum similarity. Background Art

[0002] Accurate assessment of the aging state of insulating paper / paperboard in oil-paper insulation systems is of great significance for the long-term safe and stable operation of transformers. The traditional viscosity-average polymerization degree test method is lossy, cumbersome and complex, and the test results are not accurate. Among non-destructive testing methods, NIR technology cannot meet the engineering requirements of detection accuracy, and the peak fitting method based on terahertz time-domain spectroscopy technology has poor practicality and universality in actual engineering applications. Summary of the invention

[0003] The purpose of this application is to provide a method, device, equipment, medium and product for evaluating the aging state of insulating paper, which provides a new method for on-site non-destructive evaluation of insulating paper.

[0004] To achieve the above objectives, this application provides the following solutions:

[0005] In a first aspect, the present application provides a method for evaluating the aging state of insulating paper, comprising:

[0006] Obtain aged sample insulation paper.

[0007] A terahertz time-domain spectrum test is performed on the aged sample insulation paper to obtain a terahertz time-domain spectrum signal of the aged sample insulation paper.

[0008] The terahertz time-domain spectrum signal is Fourier transformed to obtain the terahertz frequency-domain absorption spectrum of the aged sample insulation paper, and the optical parameters of the aged sample insulation paper in the terahertz frequency band are extracted; the optical parameters include the refractive index and the absorption coefficient.

[0009] Based on the Pearson correlation absorption theory, the optical parameters are used to propose an aging characteristic quantity characterized by the similarity of the absorption spectrum, and the similarity value between the aged sample insulation paper and the benchmark is calculated.

[0010] The aging condition of the insulating paper to be tested in the oil-paper insulation system is evaluated according to the similarity value.

[0011] In a second aspect, the present application provides an insulating paper aging state assessment device, comprising:

[0012] The sample acquisition module is used to obtain aged sample insulation paper.

[0013] The testing module is used to perform a terahertz time-domain spectrum test on the aged sample insulation paper to obtain a terahertz time-domain spectrum signal of the aged sample insulation paper.

[0014] The optical parameter extraction module is used to perform Fourier transform on the terahertz time-domain spectrum signal to obtain the terahertz frequency-domain absorption spectrum of the aged sample insulation paper and extract the optical parameters of the aged sample insulation paper in the terahertz frequency band.

[0015] The similarity value calculation module is used to propose an aging characteristic quantity characterized by absorption spectrum similarity based on the Pearson correlation absorption theory and the optical parameters, and calculate the similarity value between the aged sample insulation paper and the benchmark.

[0016] The evaluation module is used to evaluate the aging condition of the insulation paper to be tested in the oil-paper insulation system according to the similarity value.

[0017] In a third aspect, the present application provides a computer device, comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement any one of the above-described methods for evaluating the aging state of insulating paper.

[0018] In a fourth aspect, the present application provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements any one of the above-mentioned methods for evaluating the aging state of insulating paper.

[0019] In a fifth aspect, the present application provides a computer program product, including a computer program, which, when executed by a processor, implements any one of the above-mentioned methods for evaluating the aging state of insulating paper.

[0020] According to the specific embodiments provided in this application, this application discloses the following technical effects:

[0021] The present application provides an insulating paper aging state evaluation method, device, equipment, medium and product, the method comprising: first, obtaining aged sample insulating paper from an oil-paper insulation system to be evaluated; then, testing the obtained aged sample insulating paper using terahertz time-domain spectroscopy technology to obtain its terahertz time-domain spectral signal; performing Fourier transform processing on the obtained terahertz time-domain signal to convert it into a terahertz frequency-domain absorption spectrum; at the same time, extracting key optical parameters from the spectrum, which reflect the physical properties of the insulating paper in the terahertz frequency band; based on the Pearson correlation absorption theory, using the above-extracted optical parameters, constructing an aging feature quantity characterized by absorption spectrum similarity; this feature quantity is used to quantitatively describe the degree of aging of the insulating paper; calculating the similarity value between the aged sample insulating paper and a preset benchmark; the similarity value is a key indicator for measuring the degree of proximity between the aging state of the insulating paper and the standard state; finally, based on the calculated similarity value, performing a comprehensive evaluation of the aging condition of the insulating paper to be tested in the oil-paper insulation system; the method proposed in the present application provides an accurate and non-destructive new idea for evaluating the aging state of insulating paper in the oil-paper insulation system. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1 This is an application environment diagram of an insulation paper aging status assessment method in one embodiment of the present application.

[0024] Figure 2 A schematic flow chart of a method for evaluating the aging state of insulating paper provided in one embodiment of the present application.

[0025] Figure 3 A schematic diagram of a terahertz testing system provided in one embodiment of the present application.

[0026] Figure 4 A terahertz time-domain spectrum signal diagram of a transmission detection sample provided in one embodiment of the present application.

[0027] Figure 5 A terahertz time-domain spectrum signal diagram of a reflective detection sample provided in one embodiment of the present application.

[0028] Figure 6 A terahertz frequency domain spectrum signal diagram of a transmission detection sample provided in one embodiment of the present application.

[0029] Figure 7A terahertz frequency domain spectrum signal diagram of a reflective detection sample provided in one embodiment of the present application.

[0030] Figure 8 A schematic diagram of functional modules of an insulating paper aging status assessment device provided in one embodiment of the present application.

[0031] Fig. 9 A schematic diagram of the structure of a computer device provided in one embodiment of the present application. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0033] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0034] The insulation paper aging state evaluation method provided in the embodiment of the present application can be applied to Figure 1In the application environment shown. Among them, the terminal 102 communicates with the server 104 through the network. The data storage system can store the data that the server 104 needs to process. The data storage system can be set up separately, integrated on the server 104, or placed on the cloud or other servers. The terminal 102 can send the terahertz time-domain spectrum signal of the aged sample insulation paper to be processed to the server 104. After the server 104 receives the terahertz time-domain spectrum signal of the aged sample insulation paper to be processed, the server 104 performs Fourier transform on the terahertz time-domain spectrum signal of the aged sample insulation paper to be processed, and obtains the terahertz frequency domain absorption spectrum of the aged sample insulation paper, and extracts the optical parameters of the aged sample insulation paper in the terahertz frequency band; based on the Pearson correlation absorption theory, the optical parameters are used to propose an aging feature quantity characterized by the similarity of the absorption spectrum, and the similarity value between the aged sample insulation paper and the benchmark is calculated; according to the similarity value, the aging condition of the insulation paper to be tested in the oil-paper insulation system is evaluated. The server 104 can feed back the obtained similarity value between the aged sample insulation paper and the benchmark to the terminal 102. In addition, in some embodiments, the insulation paper aging state assessment method can also be implemented by the server 104 or the terminal 102 alone, such as the terminal 102 can directly perform signal processing on the terahertz time domain spectrum signal of the aged sample insulation paper to be processed, or the server 104 can obtain the terahertz time domain spectrum signal of the aged sample insulation paper to be processed from the data storage system, and perform signal processing on the terahertz time domain spectrum signal of the aged sample insulation paper to be processed.

[0035] The terminal 102 may be, but is not limited to, various desktop computers, laptop computers, smart phones, tablet computers, IoT devices, and portable wearable devices. The IoT devices may be smart speakers, smart TVs, smart air conditioners, smart vehicle-mounted devices, etc. The portable wearable devices may be smart watches, smart bracelets, head-mounted devices, etc. The server 104 may be implemented as an independent server or a server cluster consisting of multiple servers, or may be a cloud server.

[0036] In an exemplary embodiment, Figure 2 As shown, a method for evaluating the aging state of insulating paper is provided. The method is executed by a computer device, and can be executed by a computer device such as a terminal or a server alone, or by a terminal and a server together. In the embodiment of the present application, the method is applied to Figure 1 The server 104 in the example is used as an example to illustrate, including the following steps 201 to 205. Among them:

[0037] Step 201: Obtain aged sample insulation paper.

[0038] Step 202: Perform a terahertz time-domain spectrum test on the aged insulating paper sample to obtain a terahertz time-domain spectrum signal of the aged insulating paper sample.

[0039] Step 203: Perform Fourier transform on the terahertz time-domain spectrum signal to obtain the terahertz frequency-domain absorption spectrum of the aged sample insulation paper, and extract the optical parameters of the aged sample insulation paper in the terahertz frequency band; the optical parameters include the refractive index and the absorption coefficient.

[0040] Step 204: Based on the Pearson correlation absorption theory, the optical parameters are used to propose an aging characteristic quantity characterized by the similarity of the absorption spectrum, and the similarity value between the aged sample insulation paper and the reference is calculated.

[0041] Step 205: Evaluate the aging condition of the insulation paper to be tested in the oil-paper insulation system according to the similarity value.

[0042] In some embodiments, before executing step 201, the method further includes:

[0043] Prepare aged sample insulation paper; the aged sample insulation paper includes several insulation paper samples with different aging degrees.

[0044] Specifically, insulating paper of a set thickness is cut into rectangular samples of the same size; each of the rectangular samples and transformer insulating oil are vacuum dried for 48 hours under set temperature and set pressure conditions; for each rectangular sample after vacuum drying, the transformer insulating oil and the rectangular sample are mixed in a mass ratio of 12:1 and placed in a beaker, and vacuum dried and immersed for 24 hours under 60°C / 50Pa conditions; the beaker containing the rectangular sample and the transformer insulating oil is placed in a 130°C temperature aging box for accelerated thermal aging experiments, and samples are taken at 0 days, 2 days, 3 days, 7 days, 11 days, 17 days, 35 days and 58 days in sequence to obtain several insulating paper samples with different aging degrees.

[0045] In this embodiment, when preparing the aged sample insulating paper, first cut the 2mm thick insulating paper into rectangular samples of the same size, and vacuum dry them with Karamay 25# transformer insulating oil at 90℃ / 50Pa for 48h to remove moisture from the paper and oil. Subsequently, the oil and paper were mixed in a beaker at a mass ratio of 12:1, and further vacuum dried and immersed at 60℃ / 50Pa for 24h. The sample was sealed (keeping the oil-paper ratio of 12:1) and placed in a 130℃ temperature aging box for accelerated thermal aging experiments, and samples were taken at 0 days, 2 days, 3 days, 7 days, 11 days, 17 days, 35 days and 58 days respectively.

[0046] In some embodiments, when executing step 202, the specific steps may be as follows:

[0047] Based on the terahertz test system, the measurement method is changed by adjusting the positions of the transmitting probe and the receiving probe in the terahertz test system, and the terahertz time domain spectra of the aged sample insulation paper measured by transmission and reflection are obtained respectively.

[0048] Among them, terahertz test systems such as Figure 3 As shown in the figure, the main body includes three parts: terahertz spectrometer, sample stage and PC control terminal. The whole terahertz test system can generate and capture terahertz waves. The pulse from the femtosecond laser is divided into pump light and detection light by the beam splitter. The detection light is transmitted to the terahertz receiver through the time delay device, and the pump light is transmitted to the terahertz transmitter to generate a single cycle of terahertz radiation. The terahertz pulse is directed to the sample through the photoconductive antenna. The pulse signal of the transmission method will directly penetrate the sample, while the pulse signal of the vertical reflection method will have part of the pulse reflected on the front surface and the other part of the pulse pass through the sample to the bottom surface of the metal. Finally, the terahertz pulse carrying the sample information is captured by the terahertz receiver, and the collected terahertz time domain waveform signal is sent to the PC control terminal after passing through the lock-in amplifier.

[0049] During the test, nitrogen can be introduced to ensure the stability of the test environment, and a thermo-humidifier is placed for monitoring to control the temperature of the environment to room temperature and the humidity to below 6%. Insulation paper samples with different aging degrees are fixed on the sample stage in turn, and the distance between the sample stage and the lens is adjusted so that the test spot diameter is about 1mm, and passes through the center of the test sample. The number of tests for each sample is set to 256 to remove noise, and the terahertz spectrum test is started. The test time for each sample is about three minutes.

[0050] The prepared aged sample insulation paper was tested, and the measurement method was changed by adjusting the position of the transmitting probe and the receiving probe, and finally the terahertz time-domain spectra of the insulation paper samples with different degrees of aging were obtained by transmission and vertical reflection. The terahertz time-domain spectra signals of the samples measured by transmission / reflection are as follows: Figure 4 , Figure 5 As shown in the figure, it can be seen that the terahertz signal produced different degrees of time delay and peak attenuation when passing through the insulating paper with different aging degrees, which is related to the breakage of the long chain of cellulose during the aging process, which makes the high molecular polymer reorganized into small molecular substances.

[0051] In some embodiments, when executing step 203, the specific steps may be as follows:

[0052] Based on the terahertz time domain spectrum of the aged sample insulation paper, the terahertz frequency domain signal of the aged sample insulation paper is obtained, and the frequency domain phase of the terahertz frequency domain spectrum is determined. The calculation formula for converting the terahertz time domain spectrum of the aged sample insulation paper into the terahertz frequency domain spectrum is as follows:

[0053]

[0054] Among them, E s (f) is the terahertz frequency domain spectrum signal of the aged sample insulation paper, f is the frequency, E s (t) is the terahertz time domain spectrum signal of the aged sample insulation paper, A s (f) is the frequency domain amplitude of the terahertz frequency domain spectrum of the aged sample insulation paper; φ s (f) is the frequency domain phase of the terahertz frequency domain spectrum of the aged sample insulating paper; i represents the imaginary unit.

[0055] Based on the reference terahertz time domain spectrum, a reference terahertz frequency domain spectrum is determined, and the frequency domain phase of the reference terahertz frequency domain spectrum is determined; wherein the calculation formula for converting the reference terahertz time domain spectrum into the reference terahertz frequency domain spectrum is as follows:

[0056]

[0057] Among them A r (f) is the frequency domain amplitude of the terahertz frequency domain spectrum of the aged sample insulation paper; φ r (f) is the frequency domain phase of the terahertz frequency domain spectrum of the aged sample insulating paper.

[0058] The transmission method determines the refractive index of the aged sample insulation paper based on the frequency domain phase of the terahertz frequency domain spectrum of the aged sample insulation paper and the frequency domain phase of the reference terahertz frequency domain spectrum. The calculation formula of the refractive index of the aged sample insulation paper is as follows:

[0059]

[0060] Among them, φ s (f) is the frequency domain phase of the terahertz frequency domain spectrum of the aged sample insulating paper; c is the speed of light in vacuum; d is the thickness of the aged sample insulating paper.

[0061] Based on the frequency domain amplitude of the terahertz frequency domain spectrum of the aged sample insulation paper, the frequency domain amplitude of the reference terahertz frequency domain spectrum and the refractive index of the aged sample insulation paper, the extinction coefficient of the aged sample insulation paper is determined. The expression of the extinction coefficient of the aged sample insulation paper is:

[0062]

[0063] Wherein, k(f) is the extinction coefficient of the aged sample insulation paper; c is the speed of light in vacuum; d is the thickness of the aged sample insulation paper; f is the frequency; n(f) is the refractive index of the aged sample insulation paper; A s (f) is the frequency domain amplitude of the terahertz frequency domain spectrum of the aged sample insulation paper; A s (f) is the frequency domain amplitude of the reference terahertz frequency domain spectrum.

[0064] Based on the extinction coefficient of the aged sample insulation paper, the absorption coefficient of the aged sample insulation paper is determined. The expression of the absorption coefficient of the aged sample insulation paper is:

[0065]

[0066] where d is the thickness of the aged sample insulation paper, c is the speed of light in vacuum, φ s (f) is the phase of the sample signal, φ r (f) is the phase of the reference signal, A s (f) is the amplitude of the sample signal, A r (f) is the amplitude of the reference signal.

[0067] For the reflection test method, the reflected optical parameters can be determined using the terahertz optical parameter extraction method based on self-reference. H is the sample signal E s (f) and the reference signal E r (f) is defined as follows:

[0068]

[0069] Among them, E s (f) and E r The formula for obtaining (f) is the same as that of the transmission method.

[0070] Based on the ratio H of the sample signal of the aged sample insulation paper to the reference signal, the refractive index of the aged sample insulation paper is determined. The calculation formula of the refractive index of the aged sample insulation paper is as follows:

[0071]

[0072] Wherein, φ(H) is the frequency domain phase of the ratio of the sample signal of the aged sample insulation paper to the reference signal; c is the speed of light in a vacuum; d is the thickness of the aged sample insulation paper; θ2 is the refraction angle of the terahertz signal in the cardboard. Based on the ratio of the sample signal of the aged sample insulation paper to the reference signal and the refractive index n(f), the absorption coefficient of the aged sample insulation paper is determined. The calculation formula of the absorption coefficient of the aged sample insulation paper is as follows:

[0073]

[0074] Wherein, θ1 is the incident angle of the terahertz signal contacting the cardboard plane, and θ2 is the refraction angle of the terahertz signal in the cardboard. When the reflection is vertical reflection, θ1 and θ2 are both 0°.

[0075] Specifically, the frequency domain spectra obtained by the transmission method and the reflection method are as follows: Figure 6 , Figure 7 shown.

[0076] The transmission method has a high signal-to-noise ratio, and the entire detection process is carried out in a closed environment, strictly controlling the temperature and humidity of the environment. Within the confidence interval, the terahertz absorption spectra of the eight samples have a high degree of similarity, and obvious absorption peaks are observed near 1.0THz and 1.5THz. The absorption spectrum peak does not show a monotonous change with the degree of aging. For example, the spectrum peaks of samples aged for 2 and 3 days are slightly higher than those of other samples with more severe aging, while the spectrum peaks of samples aged for 58 days are smaller than those of other samples.

[0077] The vertical reflection method has a low signal-to-noise ratio, and in order to simulate the on-site test environment, the ambient temperature and humidity are not strictly controlled during the experiment. A careful analysis of the spectrum shows that, unlike the transmission method spectrum of the transmission method, this group of samples has a peak trend near 0.8 THz in the later stage of aging, and the 0.8 THz characteristic peak comes from the rotational vibration between molecules. Even so, due to the complex influencing factors of this characteristic peak, its peak value does not show a monotonous change trend with aging. But a more obvious feature is that as the degree of aging deepens, the peak characteristics here become more and more obvious, causing the shape of the entire curve to change significantly compared to the new sample.

[0078] In some embodiments, when executing step 204, the specific steps may be as follows:

[0079] Compared with new paper, the spectra of samples with different degrees of aging will gradually change, including the shift of characteristic peaks, changes in peak intensity or steepness, etc. These changes are essentially caused by factors such as the shedding of hydroxyl groups at different positions of cellulose molecules, the breaking of 1-4-β glycosidic bonds, and the loss of hydrogen bonds between or within molecules. The response and mapping mechanisms are very complex. For example, for new samples, the transmission method test results are more obvious at 1.0THz and 1.5THz due to the higher signal-to-noise ratio and wider credible frequency range, while the peak intensity before 1THz is weak and is basically submerged by waves of other frequencies; while the vertical reflection method observes relatively obvious characteristic peaks near 0.6THz in the initial stage of aging. As the degree of aging deepens, the peak near 0.8THz gradually appears, and the peak intensity gradually increases. The spectrum of the sample at the end of aging has undergone very significant changes in morphology compared to the unaged sample. If this change process is quantified, it will be possible to find new features that express the degree of aging.

[0080] Therefore, the characteristic parameter of self-similarity is proposed to describe the aging degree of cardboard. The correlation coefficient between the cardboard at each aging stage and the initial state cardboard can be calculated using the following formula:

[0081]

[0082] Where cov is the covariance and σ is the standard deviation. Ini is the reference, representing the absorption coefficient of the initial state paperboard in the effective frequency band, and Sam represents the absorption coefficient of the samples in different aging stages in the effective frequency band. Ini,Sam Represents sample similarity. Based on the calculated absorption coefficient, the absorption coefficient of 2mm new paperboard in each effective frequency band is selected as the benchmark, and the similarity between the paperboard of each aging degree and the benchmark under different measurement methods of the two instruments is calculated respectively. This method does not involve a lot of calculations and is not affected by the environment.

[0083] In some embodiments, when executing step 205, the specific steps may be as follows:

[0084] Under different measurement methods of the two instruments, the similarity values ​​between the cardboards of different aging degrees and the benchmark are shown in Table 1 below. It can be seen that the similarity of the two sets of data shows a more significant downward trend with the extension of aging time, which better quantifies the degree to which the absorption spectrum gradually deviates from its original state due to aging. For the test results of the transmission method, the absorption spectrum morphology shows highly similar characteristics throughout the aging process, and the similarity after 58 days of aging is 0.995; while for the test results of the vertical reflection method, the similarity shows a more obvious decline than the transmission method, reaching 0.949 after 58 days of aging. Although the characteristic parameter of similarity cannot establish a quantitative formula for similarity and DP value, the similarity change law measured by different test methods has a certain correlation with the DP change law, and both show a nonlinear reduction trend.

[0085] Table 1 Similarity values ​​of different measurement methods of the two instruments

[0086] Aging time (days) Transmission method similarity value Vertical reflection method similarity value 0 1 1 2 0.99796 0.9841 3 0.99819 0.9634 7 0.99761 0.9599 11 0.99673 0.9637 17 0.99518 0.9756 35 0.99402 0.9518 58 0.99375 0.9490

[0087] The present application also provides an application scenario, which applies the above-mentioned insulation paper aging status assessment method. Specifically: In the power industry, the transformer is one of the key equipment for power transmission and distribution, and the oil-paper insulation system used inside it is essential for the long-term stable operation of the transformer. However, as the transformer runs for a longer time, the insulation paper will gradually age, affecting its insulation performance and may even cause failures. Therefore, accurately assessing the aging status of the insulation paper is of great significance to ensuring the safe operation of the transformer.

[0088] For example, in the transformer maintenance department of a power company, engineers found that a transformer that had been in operation for many years showed signs of deterioration in insulation performance. In order to determine the root cause of the problem and take corresponding maintenance measures, they decided to evaluate the aging status of the insulation paper inside the transformer. First, the aged sample insulation paper was taken out of the transformer and tested using a terahertz time-domain spectrometer. Through the test, they obtained the terahertz time-domain spectrum signal of the aged sample insulation paper. Then, based on the computing device, the terahertz time-domain spectrum signal was Fourier transformed to obtain the terahertz frequency domain absorption spectrum of the aged sample insulation paper, and the optical parameters such as the refractive index and absorption coefficient of the aged sample insulation paper in the terahertz frequency band were successfully extracted. Then, based on the Pearson correlation absorption theory, these optical parameters were used to propose an aging feature quantity characterized by the similarity of the absorption spectrum, and the similarity value between the aged sample insulation paper and the benchmark (i.e., new insulation paper or insulation paper with a known degree of aging) was calculated. Finally, according to the size of the similarity value, the engineers evaluated the aging of the insulation paper to be tested in the transformer oil-paper insulation system. If the evaluation results show that the insulation paper in the transformer has been seriously aged, new insulation paper needs to be replaced to restore the insulation performance of the transformer. The insulation paper aging status evaluation method can help engineers quickly and accurately evaluate the aging status of insulation paper, and can also provide an important reference for the maintenance and overhaul of transformers.

[0089] Based on the same inventive concept, the embodiment of the present application also provides an insulating paper aging state assessment device for implementing the insulating paper aging state assessment method involved above. The implementation scheme for solving the problem provided by the device is similar to the implementation scheme recorded in the above method, so the specific limitations in one or more insulating paper aging state assessment device embodiments provided below can refer to the limitations of the insulating paper aging state assessment method above, and will not be repeated here.

[0090] In an exemplary embodiment, Figure 8 As shown, a video tag processing device is provided, comprising:

[0091] The sample acquisition module 801 is used to obtain aged sample insulation paper.

[0092] The testing module 802 is used to perform a terahertz time-domain spectrum test on the aged insulating paper sample to obtain a terahertz time-domain spectrum signal of the aged insulating paper sample.

[0093] The optical parameter extraction module 803 is used to perform Fourier transform on the terahertz time-domain spectrum signal to obtain the terahertz frequency-domain absorption spectrum of the aged sample insulation paper and extract the optical parameters of the aged sample insulation paper in the terahertz frequency band.

[0094] The similarity value calculation module 804 is used to propose an aging feature quantity characterized by absorption spectrum similarity based on the Pearson correlation absorption theory and the optical parameters, and calculate the similarity value between the aged sample insulation paper and the reference.

[0095] The evaluation module 805 is used to evaluate the aging condition of the insulation paper to be tested in the oil-paper insulation system according to the similarity value.

[0096] In an exemplary embodiment, a computer device is provided. The computer device may be a server or a terminal. The internal structure diagram thereof may be as follows: Fig. 9 As shown. The computer device includes a processor, a memory, an input / output interface (Input / Output, referred to as I / O) and a communication interface. Wherein, the processor, the memory and the input / output interface are connected through a system bus, and the communication interface is connected to the system bus through the input / output interface. Wherein, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program and a database. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The database of the computer device is used to store the similarity value between the aged sample insulating paper and the benchmark and the aging evaluation result of the insulating paper to be tested. The input / output interface of the computer device is used to exchange information between the processor and an external device. The communication interface of the computer device is used to communicate with an external terminal through a network connection. When the computer program is executed by the processor, a method for evaluating the aging state of insulating paper is implemented.

[0097] Those skilled in the art will understand that Fig. 9 The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine certain components, or have a different arrangement of components.

[0098] In an exemplary embodiment, a computer device is further provided, including a memory and a processor, wherein a computer program is stored in the memory, and the processor implements the steps in the above-mentioned method embodiments when executing the computer program.

[0099] In an exemplary embodiment, a computer-readable storage medium is provided, storing a computer program, and when the computer program is executed by a processor, the steps in the above method embodiments are implemented.

[0100] In an exemplary embodiment, a computer program product is provided, including a computer program, and when the computer program is executed by a processor, the steps in the above method embodiments are implemented.

[0101] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, stored data, displayed data, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of relevant data must comply with relevant regulations.

[0102] Those of ordinary skill in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to the memory, database or other medium used in the embodiments provided in the present application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM may be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM).

[0103] In summary, this application has the following technical effects:

[0104] This application is based on the terahertz nondestructive testing technology to evaluate the aging state characterized by the similarity of the absorption spectrum. This method is not affected by the detection environment of the terahertz spectroscopy technology and is suitable for analyzing terahertz spectral signals obtained by various incident modes. By measuring the terahertz absorption spectrum of the sample insulation paper, this method can be used to evaluate the degree of insulation paper aging, providing a new idea for the accurate nondestructive evaluation of the insulation paper aging state in the oil-paper insulation system of the field-operated transformer.

[0105] The database involved in each embodiment provided in this application may include at least one of a relational database and a non-relational database. The non-relational database may include a distributed database based on blockchain, etc., but is not limited thereto. The processor involved in each embodiment provided in this application may be a general-purpose processor, a central processing unit, a graphics processor, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, etc., but is not limited thereto.

[0106] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0107] This article uses specific examples to illustrate the principles and implementation methods of this application. The description of the above embodiments is only used to help understand the method and core ideas of this application. At the same time, for those skilled in the art, according to the ideas of this application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting this application.

Claims

1. A method for evaluating the aging state of insulating paper, characterized in that: The insulating paper aging status assessment method comprises: Obtain aged sample insulation paper; Performing a terahertz time-domain spectroscopy test on the aged sample insulating paper to obtain a terahertz time-domain spectroscopy signal of the aged sample insulating paper; Performing Fourier transform on the terahertz time-domain spectrum signal to obtain the terahertz frequency-domain absorption spectrum of the aged sample insulation paper, and extracting the optical parameters of the aged sample insulation paper in the terahertz frequency band; the optical parameters include refractive index and absorption coefficient; Based on the Pearson correlation absorption theory, the optical parameters are used to propose an aging characteristic quantity characterized by the similarity of the absorption spectrum, and the similarity value between the aged sample insulation paper and the benchmark is calculated; The aging condition of the insulating paper to be tested in the oil-paper insulation system is evaluated according to the similarity value.

2. The method for evaluating the aging state of insulating paper according to claim 1, characterized in that: Performing a terahertz time-domain spectroscopy test on the aged sample insulating paper to obtain a terahertz time-domain spectroscopy signal of the aged sample insulating paper specifically includes: Based on a terahertz testing system, the measurement method is changed by adjusting the positions of a transmitting probe and a receiving probe in the terahertz testing system, and the terahertz time domain spectra of the aged sample insulating paper measured by transmission and reflection are obtained respectively; the terahertz testing system is composed of a terahertz spectrometer, a sample stage and a PC control terminal.

3. The method for evaluating the aging state of insulating paper according to claim 1, characterized in that: The terahertz time-domain spectrum signal is Fourier transformed to obtain the terahertz frequency-domain absorption spectrum of the aged sample insulation paper, and the optical parameters of the aged sample insulation paper in the terahertz frequency band are extracted, specifically including: According to the formula Perform Fourier transform on the terahertz time-domain spectrum signal to obtain the terahertz frequency-domain signal; where E s (f) is the terahertz frequency domain spectrum signal of the aged sample insulation paper, f is the frequency, E s (t) is the terahertz time domain spectrum signal of the aged sample insulation paper, A s (f) is the frequency domain amplitude of the terahertz frequency domain spectrum of the aged sample insulation paper; φ s (f) is the frequency domain phase of the terahertz frequency domain spectrum of the aged sample insulation paper; i represents the imaginary unit; According to the formula The reference terahertz time domain spectrum is converted into the reference terahertz frequency domain spectrum; where A r (f) is the frequency domain amplitude of the terahertz frequency domain spectrum of the aged sample insulation paper; φ r (f) is the frequency domain phase of the terahertz frequency domain spectrum of the aged sample insulation paper; When the transmission method is used, the refractive index of the aged sample insulation paper is determined based on the frequency domain phase of the terahertz frequency domain spectrum of the aged sample insulation paper and the frequency domain phase of the reference terahertz frequency domain spectrum; Determine the extinction coefficient of the aged sample insulation paper based on the frequency domain amplitude of the terahertz frequency domain spectrum of the aged sample insulation paper, the frequency domain amplitude of the reference terahertz frequency domain spectrum, and the refractive index of the aged sample insulation paper; Based on the extinction coefficient of the aged sample insulation paper, the absorption coefficient of the aged sample insulation paper is determined; When using the reflex test method, according to the formula Calculate the ratio H of the sample signal of the aged sample insulation paper to the reference signal; Based on the ratio H of the sample signal of the aged sample insulation paper to the reference signal, according to the formula Determine the refractive index of aged sample insulation paper; Wherein, φ(H) is the frequency domain phase of the ratio of the sample signal of the aged sample insulation paper to the reference signal; c is the speed of light in a vacuum; d is the thickness of the aged sample insulation paper; θ2 is the refraction angle of the terahertz signal in the paperboard; Based on the ratio of the sample signal of the aged sample insulation paper to the reference signal and the refractive index n(f), the absorption coefficient of the aged sample insulation paper is determined.

4. The method for evaluating the aging state of insulating paper according to claim 1, characterized in that: Based on the Pearson correlation absorption theory, the optical parameters are used to propose an aging characteristic quantity characterized by the similarity of the absorption spectrum, and the similarity value between the aged sample insulation paper and the benchmark is calculated, specifically including: According to the formula Calculate the similarity value between the aged sample insulation paper and the benchmark; Among them, cov is the covariance, σ is the standard deviation, Ini is the reference, represents the absorption coefficient of the initial state cardboard in the effective frequency band, Sam represents the absorption coefficient of the samples in different aging stages in the effective frequency band, S Ini,Sam Represents the similarity value between the aged sample insulation paper and the benchmark.

5. The method for evaluating the aging state of insulating paper according to claim 1, characterized in that: Before obtaining the aged sample insulation paper, it also includes: Prepare aged sample insulation paper; the aged sample insulation paper includes several insulation paper samples with different aging degrees.

6. The method for evaluating the aging state of insulating paper according to claim 5, characterized in that: The aged sample insulating paper is prepared, specifically including: Cut the insulating paper of set thickness into rectangular samples of the same size; The rectangular samples and transformer insulating oil are vacuum dried for 48 hours at a set temperature and a set pressure; For each rectangular sample after vacuum drying, transformer insulating oil and rectangular sample were mixed in a mass ratio of 12:1 and placed in a beaker, and vacuum dried and immersed for 24 hours at 60°C / 50Pa; A beaker containing a rectangular sample and transformer insulating oil was placed in a 130°C temperature aging box for an accelerated thermal aging experiment, and samples were taken at 0 days, 2 days, 3 days, 7 days, 11 days, 17 days, 35 days and 58 days in sequence to obtain several insulating paper samples with different aging degrees.

7. An insulating paper aging status assessment device, characterized in that: The insulating paper aging state assessment device comprises: A sample acquisition module, used to obtain aged sample insulation paper; A testing module, used for performing a terahertz time-domain spectrum test on the aged sample insulation paper to obtain a terahertz time-domain spectrum signal of the aged sample insulation paper; An optical parameter extraction module is used to perform Fourier transform on the terahertz time-domain spectrum signal to obtain the terahertz frequency-domain absorption spectrum of the aged sample insulation paper, and to extract the optical parameters of the aged sample insulation paper in the terahertz frequency band; A similarity value calculation module is used to propose an aging characteristic quantity characterized by absorption spectrum similarity based on the Pearson correlation absorption theory and the optical parameters, and calculate the similarity value between the aged sample insulation paper and the benchmark; The evaluation module is used to evaluate the aging condition of the insulation paper to be tested in the oil-paper insulation system according to the similarity value.

8. A computer device comprising: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement a method for evaluating the aging state of insulating paper according to any one of claims 1 to 6.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, an insulating paper aging state assessment method according to any one of claims 1 to 6 is implemented.

10. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, an insulating paper aging state assessment method according to any one of claims 1 to 6 is implemented.

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