Oil paper insulation temperature normalization method based on Dissado-Hill model

Abstract

The invention provides an oil paper insulation temperature normalization method based on a Dissado-Hill model, the Dissado-Hill model is utilized to analyze an FDS curve, an activation energy theory is analyzed through a double-barrier model, frequency temperature translation factors of different polarization processes and conductance processes in the Dissado-Hill model are provided, and finally all components are superposed at a standard temperature to restore the FDS curve at the standard temperature. A Dissado-Hill model parameter is solved by using an FDS spectral line so as to characterize the oil-paper insulating medium, and the Dissado-Hill model considers the interaction between dipoles in the dielectric medium and has practical physical significance; the components of different polarization processes and conductance processes in the FDS spectral line are restored through the obtained parameters of the Dissado-Hill model, the barrier height conditions of the different components are researched, the different components are restored to the standard temperature from the test temperature, and the FDS spectral line fitting goodness obtained through the final superposition method is higher.

Description

Technical Field

[0001] The invention relates to the technical fields of electrical equipment, electrical engineering, insulation condition diagnosis and evaluation of transformer oil-paper insulation, and in particular to a temperature normalization method of oil-paper insulation based on a Dissado-Hill model. Background Art

[0002] Transformer oil-paper insulation is the main protective insulation system in the transformer, which is composed of transformer oil and transformer paper. In the insulation condition diagnosis and evaluation of transformer oil-paper insulation, dielectric response technology has been widely used as an emerging non-destructive insulation condition diagnosis method in recent years. The equivalent model used to analyze the oil-paper insulation of power transformers is also the top priority in studying the relationship between the aging characteristic quantity of oil-paper insulation and its polarization characteristics. At present, the main equivalent models for oil-paper insulation of power transformers are Debye relaxation model, Cole-Cole relaxation model, Davidson-Cole relaxation model, Havriliak-Negami relaxation model and Dissado-Hill relaxation model. Among them, the Dissado-Hill model takes into account the interaction between the internal dipoles of the dielectric, so it has a clear physical meaning. If the specific parameters in the model are known, the mathematical model of transformer oil-paper insulation can be established to judge the insulation condition of oil-paper insulation.

[0003] Frequency-domain Dielectric Spectroscopy (FDS) is one of the most effective methods widely used in oil-paper insulation status evaluation. However, the frequency-domain dielectric spectrum will have different degrees of shape deviation at different temperatures. At this time, temperature normalization is required to restore the FDS spectrum lines at different temperatures to the standard temperature.

[0004] The prior art CN111693783A provides a "temperature correction method for oil-impregnated paper frequency domain dielectric spectrum based on segmented activation energy", and the technical solution implementation steps are as follows:

[0005] 1. Select the target curve: First, select the frequency domain dielectric spectrum curve at a certain temperature as the target curve. This is usually a curve at a standard temperature or reference temperature.

[0006] 2. Shift the frequency domain dielectric spectrum curve: For oil-paper insulation samples with low moisture content, the frequency domain dielectric spectrum curve at other temperatures can be directly shifted to the target curve, and the typical activation energy can be obtained through this process.

[0007] 3. Use segmented activation energy for correction: For oil-paper insulation samples with high moisture content, this method uses segmented activation energy. This means that unlike low moisture content samples that use constant activation energy for curve translation, high moisture content samples will take into account the changes in activation energy with temperature and moisture during translation. By fitting the segmented activation energy at high moisture content at different temperatures, the activation energy temperature curves at different high moisture contents are obtained.

[0008] This method mainly relies on the translation of the frequency domain dielectric spectrum and cannot fully capture the complex dielectric behavior of oil-paper insulation materials. In addition, the determination of the piecewise activation energy may require a large amount of experimental data and a complex fitting process, which increases the difficulty and cost of implementation. Although this method takes into account the case of high moisture content samples, in actual applications, high moisture content may lead to more complex dielectric behavior, and this method may not provide accurate correction in all cases. Summary of the invention

[0009] Considering that the implementation of the above existing solutions mainly relies on the concept of activation energy and the translation of the frequency domain dielectric spectrum, it does not take into account that the dielectric contains multiple types of polarization processes and conductivity processes, and different processes have different activation energies. The method of simply translating the segmented activation energy is too simplistic and has no physical meaning.

[0010] Different from the prior art, the oil-paper insulation temperature normalization method based on the Dissado-Hill model provided by the present invention is based on the Dissado-Hill relaxation model, which focuses more on describing the physical process of dielectric response. The frequency domain dielectric spectrum can be divided into different components by identifying model parameters, and the activation energy of each component can be calculated and normalized. The model adopted in this scheme has practical physical significance, and activation energy calculation by relaxation can more accurately restore the frequency domain dielectric curve at standard temperature.

[0011] Different from the prior art that corrects the temperature influence by simply shifting the frequency domain dielectric spectrum curve, the present invention solves the model parameters, restores the actual internal relaxation of the dielectric, calculates the activation energy in parts, and finally achieves temperature normalization, thereby more accurately reflecting the actual performance of the insulating material at different temperatures.

[0012] The present invention specifically adopts the following technical solutions:

[0013] A temperature normalization method for oil-paper insulation based on the Dissado-Hill model: The frequency-temperature shift factors of different polarization processes and conductivity processes in the Dissado-Hill model are used to superimpose all components at standard temperature to restore the FDS curve at standard temperature.

[0014] Furthermore, the frequency-temperature shift factor includes Dissado-Hill Loss Peak, Dissado-Hill QDC and frequency-temperature shift factors of the conductivity process.

[0015] Furthermore, the frequency-temperature shift factor is used to characterize the correction of the FDS spectral line component at temperature T to the standard temperature T s The frequency-temperature shift factors of Dissado-Hill Loss Peak, Dissado-Hill QDC and conductivity process are ɑ LP 、ɑ QDC 、ɑ G , calculated as follows:

[0016]

[0017] Where: k B is the Boltzmann constant, H LP , H QDC , H G They are the barrier heights of the relaxation peak dielectric response process, the low-frequency diffuse dielectric response process and the conductivity process, respectively.

[0018] Furthermore, the process of restoring the FDS curve at standard temperature by superimposing all components at standard temperature using the frequency-temperature shift factor includes: restoring each component to standard temperature using the frequency-temperature shift factor, and then restoring the FDS spectrum at standard temperature.

[0019] Furthermore, the method of restoring each component to the standard temperature by using the frequency-temperature frequency shift factor is specifically as follows:

[0020] According to the frequency temperature shift factor ɑ LP 、ɑ QDC 、ɑ G , the FDS spectra of the Dissado-Hill Loss Peak, Dissado-Hill QDC and each component of the conductivity process are translated, and the frequency characteristics before and after the translation satisfy the following formula:

[0021]

[0022] Furthermore, the reduction of the FDS spectrum at the standard temperature is specifically to normalize the temperature of the translated Dissado-Hill LossPeak, Dissado-Hill QDC and the components of the conductivity process to the standard temperature T s Then all components are superimposed to obtain the FDS spectrum at standard temperature after temperature normalization.

[0023] Furthermore, the frequency-temperature shift factor is obtained by analyzing the FDS curve using the Dissado-Hill model and by analyzing the activation energy theory using a double barrier model.

[0024] Furthermore, the use of the Dissado-Hill model to analyze the FDS curve specifically involves using the FDS spectrum to solve the Dissado-Hill model parameters to characterize the oil-paper insulation medium, and restoring the components of different polarization processes and conductivity processes in the FDS spectrum using the obtained Dissado-Hill model parameters.

[0025] A method for analyzing oil-paper insulation of a power transformer adopts the Dissado-Hill model to establish an equivalent mathematical model of transformer oil-paper insulation to analyze the relationship between oil-paper insulation aging characteristics and polarization characteristics, and adopts the above-mentioned oil-paper insulation temperature normalization method.

[0026] A power transformer oil-paper insulation analysis system comprises a memory, a processor and a computer program stored in the memory and executable on the processor. When the processor executes the program, the power transformer oil-paper insulation analysis method as described above is implemented.

[0027] Compared with the prior art, the present invention and its preferred embodiment use the Dissado-Hill model to analyze the FDS curve, and analyze the activation energy theory through the double barrier model, and propose the frequency-temperature shift factors of different polarization processes and conductivity processes in the Dissado-Hill model, and finally superimpose all components at standard temperature to restore the FDS curve at standard temperature.

[0028] Most of the existing technologies use the direct translation method to improve the deformation problem of the FDS curve at different temperatures, but this method will result in a low goodness of fit of the curve after translation, and there is no rigorous physical meaning interpretation. This is because the oil-paper insulation medium has complex polarization and conductivity phenomena in the AC electric field, and a single activation energy cannot simply represent the temperature characteristics of all processes. In addition, a few technologies extract the activation energy in frequency bands based on the extended Debye model to perform temperature normalization of the FDS curve, but the traditional model relies on the equivalent of capacitance and resistance to the oil-paper insulation dielectric, which has no actual physical meaning and is only mathematically equivalent. If the accuracy of temperature normalization is to be further improved, it is beyond its ability.

[0029] The scheme of the present invention utilizes FDS spectrum lines to solve Dissado-Hill model parameters to characterize the oil-paper insulation medium. The Dissado-Hill model takes into account the interaction between dipoles inside the dielectric and has practical physical significance. The components of different polarization processes and conductivity processes in the FDS spectrum lines are restored by the obtained Dissado-Hill model parameters, and the potential barrier heights of different components are studied. Different components are restored from the test temperature to the standard temperature respectively. Finally, the FDS spectrum lines obtained by the superposition method have a higher goodness of fit. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments:

[0031] Figure 1 Test connection diagram for FDS;

[0032] Figure 2 The real and imaginary parts of complex capacitance test curves are as follows: (a) complex capacitance real part test curve, (b) complex capacitance imaginary part test curve;

[0033] Figure 3 This is a schematic diagram of the repolarization rate of the Dissado-Hill Loss Peak model;

[0034] Figure 4 Schematic diagram of the repolarization rate of the Dissado-Hill QDC model;

[0035] Figure 5 Polarization process spectra and conductivity loss spectra at different temperatures: (a) Dissado-Hill LossPeak real spectrum, (b) Dissado-Hill Loss Peak imaginary spectrum, (c) Dissado-Hill QDC real spectrum, (d) Dissado-Hill QDC imaginary spectrum, (e) conductivity loss spectrum;

[0036] Figure 6 Schematic diagram of the double potential well model: (a) without external excitation electric field, (b) with external excitation electric field;

[0037] Figure 7 is a diagram showing the relationship between various characteristic parameters and temperature in an embodiment of the present invention;

[0038] Figure 8 The temperature normalization of the 55°C FDS spectrum line achieved by the solution of the present invention is shown in the following figure: (a) real part temperature normalization, (b) imaginary part temperature normalization. DETAILED DESCRIPTION

[0039] Hereinafter, the specific embodiments of the present application will be described in detail with reference to the accompanying drawings. According to these detailed descriptions, those skilled in the art can clearly understand the present application and can implement the present application. Without violating the principles of the present application, the features in the various embodiments can be combined to obtain new implementations, or certain features in certain embodiments can be replaced to obtain other preferred implementations.

[0040] In order to make the features and advantages of this patent more obvious and easy to understand, the following embodiments are specifically described in detail with the accompanying drawings as follows:

[0041] The construction process of the scheme of the present invention and the principles involved are described in detail below through an embodiment:

[0042] Step 1: Sample preparation

[0043] like Figure 1 As shown, an FDS test platform is built, and the broadband dielectric spectrum of oil-paper insulation is measured based on the platform. The test platform is shown in the figure below. The platform consists of a data acquisition computer, an FDS tester, a constant temperature box, and a three-electrode test device placed in the box. The method for preparing the sample belongs to the prior art, and those skilled in the art can also refer to other similar means.

[0044] Thus, the complex capacitance test spectra of the unaged oil-immersed paper samples at different test temperatures are obtained, such as Figure 2 Shown

[0045] Step 2: Data analysis and parameter identification

[0046] In order to enable those skilled in the art to better understand the scheme of the present invention, the following first introduces the principle of the Dissado-Hill model, and applies the equivalent model parameter identification method that integrates differential transformation to obtain conductance and improved particle swarm algorithm to construct the Dissado-Hill equivalent circuit model of oil-paper insulation at different test temperatures. This part of the content belongs to the prior art.

[0047] Table 1 Dissado-Hill model identification parameters

[0048]

[0049] The Dissado-Hill Loss Peak model is used to describe the relaxation peak dielectric response process generated by dipoles during dielectric relaxation. In the Dissado-Hill Loss Peak model, its repolarization rate can be expressed as:

[0050]

[0051] Where: p Expressed as characteristic frequency; m, n1 denoted as the parameter of the shape coefficient; Γ() is the gamma function; 2 F 1 (a, b; c; z) is the Gaussian hypergeometric function; χ LP (0) is expressed as the amplitude of the dielectric polarizability under a constant electric field. Its physical meaning refers to the degree to which the dielectric is polarized in response to the application of an external constant electric field. It can also represent the concentration of dipoles inside the dielectric under a constant electric field. The complex polarizability curve in the Dissado-Hill Loss Peak model is shown in Figure 3 shown.

[0052] The Dissado-Hill QDC model is used to describe the relaxation process in which the imaginary part of the repolarization rate does not contain the relaxation peak during dielectric relaxation, that is, the low-frequency dispersion process. The actual situation is that due to the weak coupling of some microscopic particles, the charge cannot be completely bound, causing the charge to jump on certain paths. In the Dissado-Hill Loss QDC model, the repolarization rate can be expressed as:

[0053]

[0054] Where: c Expressed as characteristic frequency; p, n 2 denoted as the parameter of the shape coefficient; Γ() is the gamma function; 2 F 1 (a, b; c; z) is the Gaussian hypergeometric function; χ QDC (0) is also expressed as the magnitude of the dielectric polarizability under a constant electric field, but its physical meaning is the same as that of the χ in the Dissado-Hill Loss Peak model. LP (0) is slightly different and refers to the concentration of positive and negative electron pairs generated by the polarization of the dielectric in response to the application of an external constant electric field. The repolarization rate curve in the Dissado-Hill Loss QDC model is shown in Figure 4 shown.

[0055] Step 3: Temperature characteristics analysis based on double barrier model

[0056] According to the parameter identification results, the relaxation polarization process spectrum and conductivity loss spectrum at different temperatures are plotted, such as Figure 5 shown.

[0057] Combination Figure 5 It can be seen from the Dissado-Hill model equation that as the temperature increases, the polarizability amplitude parameter (χ LP(0) , χ QDC(0) ) and charge motion characteristic parameters (m, n 1 ,p,n 2) does not show obvious temperature dependence, and the relaxation response characteristic frequency ω p ,ω c The value of conductivity G increases with temperature increase. According to the physical meaning of the model parameters, we can understand that the increase in temperature does not significantly change the concentration of the relaxation entity and its motion characteristics. However, its impact on the microscopic dielectric properties of oil-paper insulation is mainly reflected in accelerating the relaxation response and promoting the conductivity loss process. The mechanism of this effect can be explained as follows: as the temperature increases, the microscopic particles in the oil-paper insulation system gain more kinetic energy, thereby increasing their migration speed. This not only shortens the time required to establish the relaxation response, thereby accelerating the relaxation response speed, but also increases the jumping speed of the charge potential barrier, which increases the conductivity of the oil-paper composite insulation material.

[0058] Furthermore, by observing Figure 5 , we can find that since temperature only affects the relaxation response speed and the conductivity loss intensity, the effect of temperature on the microscopic dielectric properties of oil-paper insulation is reflected in the macroscopic spectrum characteristics: the relaxation peak response spectrum, the low-frequency dispersion response spectrum and the conductivity loss spectrum will shift toward the high frequency direction as the temperature increases. At the same time, we also need to note that due to the increase in temperature, the "amplitude" of movement of each microscopic dielectric process on the frequency axis is different, which leads to different dependence of the spectrum characteristics of different frequency bands in the wide band on temperature. Based on these observations, we can more deeply quantitatively analyze the temperature characteristics of the microscopic dielectric response of oil-paper insulation, and propose a new temperature normalization strategy based on this.

[0059] In addition, the double potential well model reveals that under the stimulation of an alternating electric field, the various relaxation response processes produced by dielectrics can actually be attributed to the jumping movement of charges between different potential energy wells. The "potential energy well" here refers to a structure that restricts the spatial movement of charges, and the charges in this structural area have relatively small potential energy. Figure 6 This is clearly demonstrated in the schematic diagram of the double potential well model shown in the figure, where point A and point B represent a pair of adjacent potential wells, and the charge in potential well A will jump to point B under certain conditions.

[0060] In the absence of an external excitation electric field, the charge jump motion can be described by referring to Figure 6 (a) is used to illustrate. In this case, the migration of charges between potential energy well A and potential energy well B requires overcoming the potential barrier H of the same height. Since the probability of directional movement of charges between different potential energy wells is closely related to the height of the potential barrier, the probability of charges migrating from potential energy well A to potential energy well B is equal to the probability of charges migrating from potential energy well B back to potential energy well A.

[0061] Under the condition of external excitation electric field, the charge jumps over the barrier as Figure 6 (b) is shown. The external electric field can change the force on the charge in the potential energy well by affecting the electric field distribution inside the potential energy well, thereby changing the potential energy of the charge. The relaxation time constant expression is:

[0062]

[0063] In the formula, A is the factor to be determined; P B→A represents the probability of moving from point A to point B; k B is the Boltzmann constant, T is the temperature of the environment; H is the potential barrier height. In addition, Dyre's related research pointed out that the relationship between the frequency domain response parameters of the conductivity process and the temperature and potential barrier height H has the same form as equation (3), which is as follows:

[0064]

[0065] Where: B is the factor to be determined. It can be seen from equations (3) and (4) that under given temperature conditions, the values ​​of the frequency domain characteristic parameters of the relaxation polarization process and the conductivity process directly depend on the potential barrier height H, so the potential barrier height H is the key parameter to characterize the temperature characteristics of the microscopic dielectric response.

[0066] Step 4: Extract the activation energy of each component and normalize it to temperature

[0067] Based on the analysis of the above steps, this embodiment considers the influence of temperature on Dissado-Hill Loss Peak, Dissado-Hill QDC and conductivity process is the characteristic frequency ω p ,ω c With the change of conductivity G, we choose ω p ,ω c , G as characteristic parameters, and obtain ln(ω p ), ln(ω c ), ln(G) and 1 / T, the results are as follows Figure 7 As shown. It can be seen that the logarithmic values ​​of each characteristic parameter are linearly related to 1 / T. According to the slope of the fitting line, combined with equation (3) and equation (4), the barrier height of each dielectric process is obtained, and the calculation results are shown in Table 2.

[0068] Table 2 Barrier heights of various microscopic dielectric processes

[0069]

[0070] It can be seen from the table that the temperature characteristics of Dissado-Hill Loss Peak, Dissado-Hill QDC and conductivity process are obviously different.

[0071] From the above analysis, it can be seen that the temperature characteristics of the polarization process and conductivity process of the oil-paper insulation medium are quite different. Therefore, the present invention proposes a temperature normalization method for oil-paper insulation based on the Dissado-Hill model. The specific application steps are as follows:

[0072] (1) Calculation of frequency-temperature shift factor

[0073] Define the frequency-temperature shift factor ɑ T , used to characterize the correction of the FDS spectral line components at temperature T to the standard temperature T s The frequency-temperature shift factors of Dissado-Hill Loss Peak, Dissado-Hill QDC and conductivity process are ɑ LP 、ɑ QDC 、ɑ G , which can be calculated as follows:

[0074]

[0075] Where: H LP , H QDC , H G They are the barrier heights of the relaxation peak dielectric response process, the low-frequency diffuse dielectric response process and the conductivity process. According to the barrier heights of each microscopic dielectric response process obtained in step 3, combined with formula (5), the corresponding temperature correction factor can be obtained.

[0076] (2) Use the frequency-temperature shift factor to restore each component to the standard temperature

[0077] According to the frequency-temperature translation factor obtained in step (1), the FDS spectrum line of each component is translated, and the frequency characteristics before and after the translation satisfy the following formula:

[0078]

[0079] (3) FDS spectrum at reduced standard temperature

[0080] Normalize all components in step (2) to the standard temperature T s By superimposing all components, the FDS spectrum at standard temperature after temperature normalization can be obtained.

[0081] Taking the FDS curve at 55℃ normalized to 35℃ as an example, the calculated frequency-temperature frequency shift factor values ​​are: LP :10.390、ɑ QDC :7.031、ɑ G : 7.584, according to formula (6), the frequency characteristics after translation are ω LP (T s ): 0.060, ωQDC (T s ): 3.866, G(T s ): 0.662. The final reduction curve is as follows Figure 8 shown.

[0082] The above is a preferred embodiment of the present invention. It should be pointed out that, for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications are also considered to be within the scope of protection of the present invention.

[0083] In addition, as described in the background technology of the present invention, the oil-paper insulation temperature normalization is to better realize the oil-paper insulation analysis of the power transformer. Therefore, the present invention also requests protection for a scheme of using the Dissado-Hill model to establish an equivalent mathematical model of transformer oil-paper insulation to analyze the relationship between the aging characteristic quantity and polarization characteristics of the oil-paper insulation, and using the oil-paper insulation temperature normalization method described in the above embodiment of the present invention.

[0084] Furthermore, considering that currently the calculation and processing of mathematical models related to transformer oil-paper insulation are mainly realized by computer systems in combination with computer programs, and the calculation process of the scheme of the present invention is also suitable for completion by compiled programs in computer systems, therefore, the present invention also requests protection for an oil-paper insulation analysis system for power transformers, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the oil-paper insulation analysis method for power transformers as described above when executing the program.

[0085] This patent is not limited to the above-mentioned optimal implementation mode. Anyone can derive other forms of a temperature normalization method for oil-paper insulation based on the Dissado-Hill model under the inspiration of this patent. All equal changes and modifications made according to the scope of the patent application of the present invention should be covered by this patent.

Claims

1. A method for normalizing oil-paper insulation temperature based on the Dissado-Hill model, characterized in that: The frequency-temperature shift factors of different polarization processes and conductivity processes in the Dissado-Hill model are used to superimpose all components at standard temperature to restore the FDS curve at standard temperature.

2. The oil-paper insulation temperature normalization method based on the Dissado-Hill model according to claim 1 is characterized by: The frequency-temperature shift factor includes the frequency-temperature shift factor of the Dissado-Hill Loss Peak, the Dissado-Hill QDC and the conductivity process.

3. The oil-paper insulation temperature normalization method based on the Dissado-Hill model according to claim 2 is characterized by: The frequency-temperature shift factor is used to characterize the correction of the FDS spectral line component at temperature T to the standard temperature T s The frequency-temperature shift factors of Dissado-Hill Loss Peak, Dissado-Hill QDC and conductivity process are ɑ LP 、ɑ QDC 、ɑ G , calculated as follows: Where: k B is the Boltzmann constant, H LP , H QDC , H G They are the barrier heights of the relaxation peak dielectric response process, the low-frequency diffuse dielectric response process and the conductivity process, respectively.

4. The oil-paper insulation temperature normalization method based on the Dissado-Hill model according to claim 1, characterized in that: The process of restoring the FDS curve at the standard temperature by superimposing all components at the standard temperature using the frequency-temperature shift factor includes: restoring each component to the standard temperature using the frequency-temperature shift factor, and then restoring the FDS spectrum at the standard temperature.

5. The oil-paper insulation temperature normalization method based on the Dissado-Hill model according to claim 4 is characterized in that: The method of restoring each component to the standard temperature by using the frequency-temperature frequency shift factor is specifically as follows: According to the frequency temperature shift factor ɑ LP 、ɑ QDC 、ɑ G , the FDS spectra of the Dissado-Hill Loss Peak, Dissado-Hill QDC and each component of the conductivity process are translated, and the frequency characteristics before and after the translation satisfy the following formula:

6. The oil-paper insulation temperature normalization method based on the Dissado-Hill model according to claim 4 is characterized by: The reduction of the FDS spectrum at the standard temperature is specifically to normalize the temperature of the shifted Dissado-Hill Loss Peak, Dissado-Hill QDC and the components of the conductivity process to the standard temperature T s Then all components are superimposed to obtain the FDS spectrum at standard temperature after temperature normalization.

7. The oil-paper insulation temperature normalization method based on the Dissado-Hill model according to claim 1 is characterized by: The frequency-temperature shift factor is obtained by analyzing the FDS curve using the Dissado-Hill model and analyzing the activation energy theory through a double barrier model.

8. The oil-paper insulation temperature normalization method based on the Dissado-Hill model according to claim 7 is characterized by: The use of the Dissado-Hill model to analyze the FDS curve specifically involves using the FDS spectrum to solve the Dissado-Hill model parameters to characterize the oil-paper insulation medium, and restoring the components of different polarization processes and conductivity processes in the FDS spectrum through the obtained Dissado-Hill model parameters.

9. A method for analyzing oil-paper insulation of power transformers, using the Dissado-Hill model to establish an equivalent mathematical model of transformer oil-paper insulation to analyze the relationship between oil-paper insulation aging characteristic quantities and polarization characteristics, characterized in that: The oil-paper insulation temperature normalization method according to claims 1-8 is adopted.

10. An oil-paper insulation analysis system for power transformers, characterized in that: The method comprises a memory, a processor and a computer program stored in the memory and executable on the processor, wherein the processor implements the oil-paper insulation analysis method for power transformers as claimed in claim 9 when executing the program.

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