An insulation paper aging state evaluation method, device, equipment, medium and product

Abstract

The application discloses an insulation paper aging state evaluation method, device, equipment, medium and product, relates to the technical field of insulation paper aging state evaluation, and the method comprises the following steps: obtaining an aging sample insulation paper; performing terahertz time-domain spectrum testing on the aging sample insulation paper to obtain a terahertz time-domain spectrum signal of the aging sample insulation paper; performing Fourier transform on the terahertz time-domain spectrum signal to obtain a terahertz frequency domain absorption spectrum of the aging sample insulation paper, and extracting an optical parameter of the aging sample insulation paper in a terahertz frequency band; based on the Pearson correlation absorption theory, an aging characteristic quantity characterized by an absorption spectrum similarity is proposed by using the optical parameter, and a similarity value between the aging sample insulation paper and a reference is calculated; and the aging condition of the to-be-tested insulation paper in an oil-paper insulation system is evaluated according to the similarity value. The application provides a new idea for accurate and nondestructive evaluation of the aging state of the insulation paper in the oil-paper insulation system.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of insulation paper aging state evaluation, in particular to an insulation paper aging state evaluation method and device based on terahertz absorption spectrum similarity. BACKGROUND

[0002] Accurate evaluation of the aging state of insulation paper / paperboard in an oil-paper insulation system is of great significance for long-term safe and stable operation of a transformer. Traditional average polymerization degree testing methods are lossy and have complicated steps and processes, and have the problem of low testing result accuracy. In nondestructive testing methods, the NIR technology cannot meet the engineering requirements of detection accuracy, and the peak fitting method based on the terahertz time-domain spectroscopy technology has the problems of poor practicability and universality in actual engineering application. SUMMARY

[0003] The application aims to provide an insulation paper aging state evaluation method, device, equipment, medium and product, and provides a new method for on-site nondestructive evaluation of insulation paper.

[0004] To achieve the above-mentioned purpose, the application provides the following solutions.

[0005] In a first aspect, the application provides an insulation paper aging state evaluation method, comprising:

[0006] Obtaining an aging sample insulation paper.

[0007] Performing terahertz time-domain spectroscopy testing on the aging sample insulation paper to obtain a terahertz time-domain spectroscopy signal of the aging sample insulation paper.

[0008] Performing Fourier transform on the terahertz time-domain spectroscopy signal to obtain a terahertz frequency-domain absorption spectrum of the aging sample insulation paper, and extracting optical parameters of the aging sample insulation paper in the terahertz frequency band; the optical parameters include a refractive index and an absorption coefficient.

[0009] Based on the Pearson correlation absorption theory, an aging characteristic quantity characterized by absorption spectrum similarity is proposed by using the optical parameters, and a similarity value between the aging sample insulation paper and a reference is calculated.

[0010] Evaluating the aging condition of a to-be-tested insulation paper in an oil-paper insulation system according to the similarity value.

[0011] In a second aspect, the application provides an insulation paper aging state evaluation device, comprising:

[0012] A sample acquisition module configured to acquire an aging sample insulation paper.

[0013] A test module is configured to perform a terahertz time-domain spectroscopy test on the aged sample insulation paper to obtain a terahertz time-domain spectroscopy signal of the aged sample insulation paper.

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

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

[0016] An evaluation module is configured to evaluate an aging condition of the to-be-tested insulation paper 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, and the processor executes the computer program to implement the insulation paper aging state evaluation method in any one of the above.

[0018] In a fourth aspect, the present application provides a computer readable storage medium, which stores a computer program, and the computer program is executed by a processor to implement the insulation paper aging state evaluation method in any one of the above.

[0019] In a fifth aspect, the present application provides a computer program product, comprising a computer program, and the computer program is executed by a processor to implement the insulation paper aging state evaluation method in any one of the above.

[0020] According to the specific embodiments provided in the present application, the following technical effects are disclosed:

[0021] The application provides an insulation paper aging state evaluation method, device, equipment, medium and product, and the method comprises the following steps: firstly, obtaining an aging sample insulation paper from an oil-paper insulation system to be evaluated; then, adopting a terahertz time domain spectrum technology to test the obtained aging sample insulation paper, so as to obtain a terahertz time domain spectrum signal; performing Fourier transform processing on the obtained terahertz time domain signal, and converting the terahertz time domain signal into a terahertz frequency domain absorption spectrum; meanwhile, extracting key optical parameters from the spectrum, and the parameters reflect the physical characteristics of the insulation paper in the terahertz frequency band; based on the Pearson correlation absorption theory, the extracted optical parameters are used to construct an aging characteristic quantity taking the absorption spectrum similarity as a feature; the characteristic quantity is used to quantitatively describe the aging degree of the insulation paper; the similarity value between the aging sample insulation paper and a preset reference is calculated; the similarity value is a key index for measuring the closeness between the aging state of the insulation paper and the standard state; finally, according to the calculated similarity value, the aging condition of the insulation paper to be measured in the oil-paper insulation system is comprehensively evaluated; the method provided by the application provides an accurate and non-destructive new idea for the evaluation of the aging state of the insulation paper in the oil-paper insulation system. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed in the embodiments will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor.

[0023] Figure 1 An application environment diagram of an insulation paper aging state evaluation method in an embodiment of the present application.

[0024] Figure 2 A flowchart of an insulation paper aging state evaluation method provided by an embodiment of the present application.

[0025] Figure 3 A schematic diagram of a terahertz test system provided by an embodiment of the present application.

[0026] Figure 4 A terahertz time domain spectrum signal diagram of a transmission type detection sample provided by an embodiment of the present application.

[0027] Figure 5 A terahertz time domain spectrum signal diagram of a reflection type detection sample provided by an embodiment of the present application.

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

[0029] Figure 7A reflected sample terahertz frequency domain spectrum signal diagram is provided for an embodiment of the present application.

[0030] Figure 8 A functional module schematic diagram of an insulation paper aging state evaluation device is provided for an embodiment of the present application.

[0031] Figure 9 A structural schematic diagram of a computer device is provided for an embodiment of the present application. DETAILED DESCRIPTION

[0032] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of protection of the present application.

[0033] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the present application will be further described in detail below with reference to the drawings and specific embodiments.

[0034] The insulation paper aging state evaluation method provided in the embodiments of the present application can be applied to, for example Figure 1The application environment shown. Among them, the terminal 102 communicates with the server 104 through the network. The data storage system can store the data required by the server 104 to process. The data storage system can be set up separately, or 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 aging sample insulation paper to be processed to the server 104. After receiving the terahertz time domain spectrum signal of the aging sample insulation paper to be processed, the server 104 performs Fourier transform on the terahertz time domain spectrum signal to obtain the terahertz frequency domain absorption spectrum of the aging sample insulation paper, and extracts the optical parameters of the aging sample insulation paper in the terahertz band. 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 aging sample insulation paper and the reference is calculated; the aging condition of the insulation paper to be measured in the oil-paper insulation system is evaluated according to the similarity value. The server 104 can feed back the similarity value between the aging sample insulation paper and the reference to the terminal 102. In addition, in some embodiments, the insulation paper aging state evaluation method can also be implemented by the server 104 or the terminal 102 alone, such as the terminal 102 can directly process the terahertz time domain spectrum signal of the aging sample insulation paper to be processed, or the server 104 can obtain the terahertz time domain spectrum signal of the aging sample insulation paper to be processed from the data storage system and process the terahertz time domain spectrum signal of the aging sample insulation paper to be processed.

[0035] Among them, the terminal 102 can be but not limited to various desktop computers, notebook computers, smart phones, tablet computers, Internet of Things devices and portable wearable devices. The Internet of Things device can be a smart speaker, a smart television, a smart air conditioner, a smart vehicle device, etc. The portable wearable device can be a smart watch, a smart bracelet, a head-mounted device, etc. The server 104 can be implemented by an independent server or a server cluster composed of multiple servers, and can also be a cloud server.

[0036] In an exemplary embodiment, as Figure 2 shown, an insulation paper aging state evaluation method is provided, which is executed by a computer device, specifically by a terminal or a server, etc. Computer device alone, or by a terminal and a server together, in the embodiment of the application, take the server 104 in Figure 1 as an example to illustrate, including the following steps 201 to 205. Among them:

[0037] Step 201: Obtain the aging sample insulation paper.

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

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

[0040] Step 204: Based on the Pearson correlation absorption theory, use the optical parameter to propose an aging characteristic quantity characterized by an absorption spectrum similarity, and calculate a similarity value between the aged sample insulation paper and the reference.

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

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

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

[0044] Specifically, the insulation paper with a set thickness is cut into rectangular samples of the same size; each of the rectangular samples and the transformer insulation oil are vacuum dried at a set temperature and a set pressure for 48 hours; for each of the vacuum-dried rectangular samples, the transformer insulation oil and the rectangular sample are mixed in a beaker at a mass ratio of 12:1, and vacuum drying impregnation is performed at 60℃ / 50Pa for 24 hours; the beaker containing the rectangular sample and the transformer insulation oil is placed in a 130℃ temperature aging oven for accelerated heat aging test, and samples are taken at 0 days, 2 days, 3 days, 7 days, 11 days, 17 days, 35 days and 58 days in turn to obtain several insulation paper samples with different aging degrees.

[0045] In this embodiment, when the aged sample insulation paper is prepared, the insulation paper with a thickness of 2mm is cut into rectangular samples of the same size, and the Karamay 25# transformer insulation oil is vacuum dried at 90℃ / 50Pa for 48 hours to remove water in the paper and the oil. Subsequently, the oil and the paper are mixed in a beaker at a mass ratio of 12:1, and vacuum drying impregnation is further performed at 60℃ / 50Pa for 24 hours. The sample is sealed (maintaining the oil-paper ratio of 12:1) and placed in a 130℃ temperature aging oven for accelerated heat aging test, and samples are taken at 0 days, 2 days, 3 days, 7 days, 11 days, 17 days, 35 days and 58 days in turn.

[0046] In some embodiments, when step 202 is performed, it can be specifically as follows:

[0047] Based on the terahertz testing system, the positions of the emission probe and the receiving probe in the terahertz testing system are adjusted to change the measurement method, and the terahertz time-domain spectra of the aged sample insulating paper measured by the transmission method and the reflection method are obtained respectively.

[0048] The terahertz testing system includes a terahertz spectrometer, a sample stage and a PC control end, and the entire terahertz testing system can generate and capture terahertz waves. Figure 3 The pulses from the femtosecond laser are split into pump light and probe light by a beam splitter. The probe light is transmitted to a terahertz receiver through a time delay device, and the pump light is transmitted to a terahertz emitter to generate a single-cycle terahertz radiation. The terahertz pulses are emitted to the sample through a photoconductive antenna. The pulse signals of the transmission method directly penetrate the sample, and the pulse signals of the perpendicular reflection method are partially reflected on the front surface and partially penetrate the sample to the metal bottom surface. Finally, the terahertz pulses carrying sample information are captured by the terahertz receiver, and the collected terahertz time-domain waveform signals are sent to the PC control end after being amplified by a lock-in amplifier.

[0049] During the test, nitrogen can be introduced to ensure the stability of the test environment, and a temperature and humidity device is introduced for monitoring to control the temperature of the environment at room temperature and the humidity below 6%. Different aging degrees of insulating paper samples are fixed on the sample stage in turn, the distance between the sample stage and the lens is adjusted to make the test spot diameter about 1mm, and the test spot 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 of each sample is about three minutes.

[0050] The prepared aged sample insulating paper is tested, the positions of the emission probe and the receiving probe are adjusted to change the measurement method, and the terahertz time-domain spectra of the insulating paper samples with different aging degrees measured by the transmission method and the perpendicular reflection method are finally obtained. The terahertz time-domain spectrum signals of the samples measured by the transmission method and the reflection method are shown in Figure 4 、 Figure 5 It can be seen that the terahertz signals produce different degrees of time delay and peak decay through insulating paper with different aging degrees, which is related to the fact that the long-chain cellulose is broken into small molecular substances during the aging process.

[0051] In some embodiments, when step 203 is performed, the following can be specifically performed:

[0052] Based on the terahertz time-domain spectrum of the aged sample insulating paper, the terahertz frequency-domain signal of the aged sample insulating 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 insulating paper into the terahertz frequency-domain spectrum is as follows:

[0053]

[0054] wherein E s (f) is the terahertz frequency domain spectrum of the aged sample insulation paper, f is frequency, E s (t) is the terahertz time domain spectrum 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 an imaginary unit.

[0055] Based on the reference terahertz time domain spectrum, the 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] wherein 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.

[0058] 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 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:

[0059]

[0060] wherein φ s (f) is the frequency domain phase of the terahertz frequency domain spectrum of the aged sample insulation paper; c is the speed of light in vacuum; d is the thickness of the aged sample insulation 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 represents the speed of light in vacuum; d represents the thickness of the aged sample insulation paper; f is frequency; n(f) represents 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 optical parameters of the reflection can be determined by using the self-reference based terahertz optical parameter extraction method. H is the ratio of the sample signal E s (f) to the reference signal E r (f), and the definition is as follows:

[0068]

[0069] where E s (f) and E r (f) are obtained by the same formula as the transmission method.

[0070] Based on the ratio H of the sample signal to the reference signal of the aged sample insulation paper, 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] where φ(H) is the frequency domain phase of the ratio of the sample signal to the reference signal of the aged sample insulation paper; c is the speed of light in 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 to the reference signal of the aged sample insulation paper 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] where θ1 is the incident angle of the terahertz signal to the plane of the paperboard, and θ2 is the refraction angle of the terahertz signal in the paperboard. 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 shown in Figure 6 , Figure 7 respectively.

[0076] The transmittance method has high signal-to-noise ratio, and the whole detection process is carried out in a closed environment, and the temperature and humidity of the environment is strictly controlled. Within the confidence interval, the terahertz absorption spectrum of 8 samples is similar, and obvious absorption peaks are observed near 1.0 THz and 1.5 THz. The absorption spectrum peak does not present a monotonous change rule with the aging degree, for example, the spectral peaks of the samples aged for 2 days and 3 days are slightly higher than those of other samples with more severe aging, and the spectral peak of the sample aged for 58 days is smaller than that of other samples.

[0077] The vertical reflection method has low signal-to-noise ratio, and in order to simulate the field test environment, the temperature and humidity of the environment is not strictly controlled during the experiment. Careful analysis of the spectrum can find that, unlike the transmittance spectrum of the transmittance method, this group of samples has a peak trend near 0.8 THz in the later aging stage, and the 0.8 THz characteristic peak is from the intermolecular rotational vibration. Even so, due to the complex influencing factors of the characteristic peak, its peak value does not present a monotonous change trend with aging. However, a more obvious feature is that as the aging degree deepens, the peak value characteristics here become more and more obvious, making the shape of the whole curve change significantly compared with the new sample.

[0078] In some embodiments, when step 204 is performed, the following can be specifically performed:

[0079] Compared with new paper, the spectrum of samples with different aging degrees will gradually change, including the shift of characteristic peaks, the change of peak intensity or steepness, etc. These changes are essentially caused by factors such as the loss of hydroxyl groups at different positions of cellulose molecules, the breakage of 1-4-β glycosidic bonds, the loss of intermolecular or intramolecular hydrogen bonds, etc. The response and mapping mechanism is very complex. For example, for a new sample, the transmittance test result is more obvious at 1.0 THz and 1.5 THz because of the higher signal-to-noise ratio and the wider confidence frequency interval, while the peak before 1 THz is weak and is basically submerged by other frequency waves; the vertical reflection method observes a relatively obvious characteristic peak near 0.6 THz in the initial aging stage, and the peak near 0.8 THz gradually appears as the aging degree deepens, and the peak intensity gradually increases. The spectrum of the sample at the end of aging changes significantly in shape compared with the unaged sample. If the change process is quantified, a new feature expressing the aging degree can be found.

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

[0081]

[0082] Wherein, cov is covariance, σ is standard deviation. Ini is the benchmark, representing the initial state of the paperboard in the effective frequency band Absorption coefficient, Sam represents the absorption coefficient of the sample at different aging stages in the effective frequency band. Ini,Sam The similarity of the sample is represented. According to the calculated absorption coefficient, the absorption coefficient of the 2mm new paperboard in the respective effective frequency band is selected as the benchmark, and the similarity between the paperboard at different aging degrees and the benchmark under different measurement methods of the two instruments is calculated respectively. This method does not involve a large amount of calculation, and is not affected by environmental interference.

[0083] Among them, in some embodiments, when step 205 is performed, it can be as follows:

[0084] The similarity values between the paperboard at different aging degrees and the benchmark under different measurement methods of the two instruments are shown in Table 1. It can be seen that the similarity of the two groups of data decreases significantly with the extension of the aging time, which better quantifies the degree of aging that causes the absorption spectrum to gradually deviate from its original state. For the test results of the transmission method, the absorption spectrum morphology presents a highly similar characteristic throughout the aging process, and the similarity after aging for 58 days is 0.995; while for the test results of the vertical reflection method, the similarity shows a more obvious decrease than the transmission method, and after aging for 58 days, the similarity is 0.949. Although the similarity characteristic parameter cannot establish a quantitative formula between similarity and DP value, the change law of similarity measured by different test methods has certain relevance with the change law of DP value, and both show a nonlinear decreasing trend.

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

[0086] Age time (days) Transmittance similarity value Perpendicular reflectance 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 application also provides an application scenario of the insulation paper aging state evaluation 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 is crucial for the long-term stable operation of the transformer. However, as the running time of the transformer increases, the insulation paper will gradually age, affecting its insulation performance, and even possibly causing a fault. Therefore, accurate evaluation of the aging state of the insulation paper is of great significance to ensure the safe operation of the transformer.

[0088] For example, in the transformer maintenance department of a certain power company, engineers found that a transformer that has been running for many years shows signs of declining insulation performance. In order to determine the root cause of the problem and take appropriate maintenance measures, they decide to assess the aging state of the insulation paper inside the transformer. First, the aging sample insulation paper is taken out from the transformer and tested using a terahertz time-domain spectrometer. Through the test, they obtain the terahertz time-domain spectrum signal of the aging sample insulation paper. Next, based on the computing device, the terahertz time-domain spectrum signal is Fourier transformed to obtain the terahertz frequency domain absorption spectrum of the aging sample insulation paper, and the optical parameters such as the refractive index and absorption coefficient of the aging sample insulation paper in the terahertz frequency band are successfully extracted. Then, based on the Pearson correlation absorption theory, the aging feature quantity characterized by the similarity of the absorption spectrum is proposed using these optical parameters, and the similarity value between the aging sample insulation paper and the reference (i.e. new insulation paper or insulation paper with known aging degree) is calculated. Finally, according to the size of the similarity value, the engineers assess the aging condition of the insulation paper to be tested in the transformer oil paper insulation system. If the assessment result shows 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 state assessment method can help engineers quickly and accurately assess the aging state of the insulation paper, and also provide an important reference for the maintenance and overhaul of the transformer.

[0089] Based on the same inventive concept, the embodiments of the present application also provide an insulation paper aging state assessment device for implementing the above-mentioned insulation paper aging state assessment method. The implementation scheme of the device for solving the problem is similar to the implementation scheme described in the above method, so the specific limitations in one or more insulation paper aging state assessment device embodiments provided below can refer to the limitations of the insulation paper aging state assessment method described above, which will not be repeated here.

[0090] In one exemplary embodiment, as shown in Figure 8 A video tag processing device is provided, comprising:

[0091] The sample acquisition module 801 is configured to acquire an aging sample insulation paper.

[0092] The test module 802 is configured to perform a terahertz time-domain spectrum test on the aging sample insulation paper to obtain a terahertz time-domain spectrum signal of the aging sample insulation paper.

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

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

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

[0096] In an exemplary embodiment, a computer device is provided, which can be a server or a terminal. An internal structure diagram of the computer device can be as shown in Figure 9 The computer device includes a processor, a memory, an input / output interface (I / O) and a communication interface. 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. The processor of the computer device is configured 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 operating system and the computer program in the non-volatile storage medium to run. The database of the computer device is configured to store the similarity value between the aging sample insulating paper and the reference and the aging condition evaluation result of the to-be-tested insulating paper. The input / output interface of the computer device is configured to exchange information between the processor and external devices. The communication interface of the computer device is configured to communicate with external terminals through network connection. The computer program is executed by the processor to implement an insulating paper aging state evaluation method.

[0097] Those skilled in the art can understand that Figure 9 the structure shown in the above

[0098] In an exemplary embodiment, a computer device is provided, which includes a memory and a processor. The memory stores a computer program, and the processor executes the computer program to implement the steps in the above method embodiments.

[0099] In an exemplary embodiment, a computer readable storage medium is provided, which stores a computer program. The computer program is executed by a processor to implement the steps in the above method embodiments.

[0100] In an example embodiment, a computer program product is provided, including a computer program which, when executed by a processor, implements the steps of any of the above method embodiments.

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

[0102] It can be understood by those skilled in the art that all or part of the processes in the above-mentioned embodiments can be completed by a computer program instructing related hardware, 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 above-mentioned embodiments. Any reference to memory, database or other medium used in the embodiments provided by the present application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (Read-Only Memory, ROM), magnetic tape, floppy disk, flash memory, optical storage, high-density embedded non-volatile memory, resistive memory (ReRAM), magnetoresistive random access memory (Magnetoresistive Random Access Memory, MRAM), ferroelectric memory (Ferroelectric Random Access Memory, FRAM), phase change memory (Phase Change Memory, PCM), graphene memory, etc. Volatile memory can include random access memory (Random Access Memory, RAM) or external cache memory, etc. As an illustration but not limitation, RAM can be in various forms, such as static random access memory (Static Random Access Memory, SRAM) or dynamic random access memory (Dynamic Random Access Memory, DRAM), etc.

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

[0104] The aging state evaluation method based on the terahertz non-destructive testing technology and the absorption spectrum similarity feature is not affected by the detection environment of the terahertz spectrum technology, and is suitable for analyzing terahertz spectrum signals obtained in various incident modes. By measuring the terahertz absorption spectrum of the sample insulating paper, the aging degree of the insulating paper can be evaluated, and a new idea is provided for accurate and non-destructive evaluation of the aging state of the insulating paper in the oil-paper insulation system of the on-site running transformer.

[0105] The database involved in each of the embodiments provided in the present application can include at least one of a relational database and a non-relational database. The non-relational database can include a distributed database based on a blockchain, and the like, without being limited thereto. The processor involved in each of the embodiments provided in the present application can be a general-purpose processor, a central processing unit, a graphics processing unit, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, and the like, without being limited thereto.

[0106] Any combination of the technical features of the above embodiments can be made. In order to make the description simple, all possible combinations of the technical features in the above embodiments are not described, however, as long as the combination of the technical features does not exist, it should be considered as the scope of the present application.

[0107] The principles and implementation modes of the present application are described by applying specific examples herein, and the above embodiments are only used to help understand the method of the present application and its core idea; meanwhile, for those skilled in the art, according to the idea of the present application, the specific implementation mode and application range will be changed. In conclusion, the content of the present application should not be understood as a limitation.

Claims

1. An insulation paper aging state evaluation method characterized by comprising: The insulation paper aging state evaluation method comprises the following steps: Obtain an aging sample insulation paper; Perform terahertz time-domain spectroscopy on the aging sample insulation paper to obtain a terahertz time-domain spectroscopy signal of the aging sample insulation paper; Perform Fourier transform on the terahertz time-domain spectroscopy signal to obtain a terahertz frequency domain absorption spectrum of the aging sample insulation paper, and extract optical parameters of the aging 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 absorption spectrum similarity, and a similarity value between the aging sample insulation paper and a reference is calculated; The aging condition of the insulation paper to be tested in the oil-paper insulation system is evaluated according to the similarity value. Perform terahertz time-domain spectroscopy on the aging sample insulation paper to obtain a terahertz time-domain spectroscopy signal of the aging sample insulation paper, specifically including: Based on the terahertz test system, the position of the transmitting probe and the receiving probe in the terahertz test system is adjusted to change the measurement method, and the terahertz time-domain spectroscopy of the aging sample insulation paper measured by the transmission method and the reflection method is obtained respectively; the terahertz test system is composed of a terahertz spectrometer, a sample stage and a PC control end; Based on the Pearson correlation absorption theory, the optical parameters are used to propose an aging characteristic quantity characterized by absorption spectrum similarity, and a similarity value between the aging sample insulation paper and a reference is calculated, specifically including: The similarity value between the aged sample insulation paper and the reference is calculated according to the formula The similarity value between the aged sample insulation paper and the reference is calculated according to the formula Wherein, cov is the covariance, σ is the standard deviation, Ini is the benchmark, representing the initial state of the paperboard in the effective frequency band Absorption coefficient, Sam represents the absorption coefficient of the sample at different aging stages in the effective frequency band, S Ini,Sam represents the similarity value between the aging sample insulation paper and the benchmark.

2. The method of claim 1, wherein Perform Fourier transform on the terahertz time-domain spectroscopy signal to obtain a terahertz frequency domain absorption spectrum of the aging sample insulation paper, and extract optical parameters of the aging sample insulation paper in the terahertz frequency band, specifically including: According to the formula The terahertz time domain spectrum signal is Fourier transformed to obtain a terahertz frequency domain signal; wherein, E s (f) is a terahertz frequency domain spectrum signal of the aged sample insulating paper, f is a frequency, E s (t) is a terahertz time domain spectrum signal of the aged sample insulating paper, A s (f) is a frequency domain amplitude of the terahertz frequency domain spectrum of the aged sample insulating paper; φ s (f) is a frequency domain phase of the terahertz frequency domain spectrum of the aged sample insulating paper; i represents an imaginary unit; According to the formula converting the reference terahertz time-domain spectrum into a reference terahertz frequency-domain spectrum; wherein A r (f) is a frequency-domain amplitude of the terahertz frequency-domain spectrum of the aged sample insulation paper; φ r (f) is a 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 aging sample insulation paper is determined based on the frequency domain phase of the terahertz frequency domain spectrum of the aging sample insulation paper and the frequency domain phase of the reference terahertz frequency domain spectrum; The extinction coefficient of the aging sample insulation paper is determined based on the frequency domain amplitude of the terahertz frequency domain spectrum of the aging sample insulation paper, the frequency domain amplitude of the reference terahertz frequency domain spectrum and the refractive index of the aging sample insulation paper; The absorption coefficient of the aging sample insulation paper is determined based on the extinction coefficient of the aging sample insulation paper; In the case of the reflection test method, the ratio H of the sample signal of the aged sample insulation paper to the reference signal is calculated according to the formula H = (Iref - Ia) / Iref Based on the ratio H of the sample signal of the aged sample insulation paper to the reference signal, according to the formula determining the refractive index of the aged sample insulation paper; Wherein, φ(H) is the frequency domain phase of the ratio of the sample signal of the aging sample insulation paper to the reference signal; c is the speed of light in vacuum; d is the thickness of the aging sample insulation paper; θ2 is the refraction angle of the terahertz signal in the paperboard; The absorption coefficient of the aging sample insulation paper is determined based on the ratio of the sample signal to the reference signal and the refractive index n(f).

3. The method of claim 1, wherein Before obtaining the aging sample insulation paper, it further comprises the following steps: Prepare the aging sample insulation paper; the aging sample insulation paper comprises a plurality of insulation paper samples with different aging degrees.

4. The method of claim 3, wherein Preparation of the aging sample insulation paper specifically includes: Cut the insulation paper with a set thickness into rectangular samples of the same size; Vacuum dry each rectangular sample and transformer insulation oil under the condition of a set temperature and a set pressure for 48 hours; For each vacuum-dried rectangular sample, mix the transformer insulation oil and the rectangular sample in a mass ratio of 12:1 in a beaker, and vacuum dry and impregnate under the condition of 60℃ / 50Pa for 24 hours; A beaker containing a rectangular sample and transformer insulation oil is placed in a 130℃ temperature aging oven for an accelerated heat aging experiment, and samples are taken at 0 days, 2 days, 3 days, 7 days, 11 days, 17 days, 35 days and 58 days in turn, to obtain several insulation paper samples with different aging degrees.

5. An insulation paper aging state evaluation device characterized by comprising: The insulation paper aging state evaluation device comprises: a sample acquisition module configured to acquire an aging sample insulation paper; a test module configured to perform a terahertz time-domain spectrum test on the aging sample insulation paper to obtain a terahertz time-domain spectrum signal of the aging sample insulation paper; the terahertz time-domain spectrum test on the aging sample insulation paper to obtain the terahertz time-domain spectrum signal of the aging sample insulation paper specifically comprises: based on a terahertz test system, the positions of a transmitting probe and a receiving probe in the terahertz test system are adjusted to change the measurement method, and terahertz time-domain spectra of the aging sample insulation paper measured by transmission and reflection are obtained respectively; the terahertz test system is composed of a terahertz spectrometer, a sample stage and a PC control end; an optical parameter extraction module configured to perform Fourier transform on the terahertz time-domain spectrum signal to obtain a terahertz frequency-domain absorption spectrum of the aging sample insulation paper, and extract optical parameters of the aging sample insulation paper in the terahertz frequency band; a similarity value calculation module configured to use the optical parameters to propose an aging characteristic quantity characterized by absorption spectrum similarity based on the Pearson correlation absorption theory, and calculate a similarity value between the aging sample insulation paper and a reference; the use of the optical parameters to propose an aging characteristic quantity characterized by absorption spectrum similarity based on the Pearson correlation absorption theory, and the calculation of a similarity value between the aging sample insulation paper and a reference specifically comprises: The similarity value between the aged sample insulation paper and the reference is calculated according to the formula The similarity value between the aged sample insulation paper and the reference is calculated according to the formula wherein cov is the covariance, σ is the standard deviation, Ini is the reference, representing the initial state of the paperboard in the effective frequency range, Sam represents the absorption coefficient of the sample at different aging stages in the effective frequency range, S Ini,Sam represents the similarity value between the aging sample insulation paper and the reference; an evaluation module configured to evaluate the aging condition of a to-be-tested insulation paper in an oil-paper insulation system according to the similarity value.

6. A computer device comprising: A memory, a processor and a computer program stored in the memory and executable on the processor, characterized in that the processor executes the computer program to implement the insulation paper aging state evaluation method of any one of claims 1-4.

7. A computer readable storage medium having stored thereon a computer program, characterized in that The computer program is executed by the processor to implement the insulation paper aging state evaluation method of any one of claims 1-4.

8. A computer program product comprising a computer program, characterized in that, The computer program is executed by the processor to implement the insulation paper aging state evaluation method of any one of claims 1-4.

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