A method and system for predicting the dissolution time of air bubbles in oil-paper insulation.

Abstract

This invention discloses a method and system for predicting the dissolution time of bubbles in oil-paper insulation, belonging to the field of electrical equipment insulation technology. The method includes: calculating the amount of various gases dissolved per unit volume of oil after the gas dissolution in oil reaches equilibrium; using 47℃ as a reference temperature, extrapolating this data to other temperatures and solubilities using the Arrhenius relation, and calculating the diffusion coefficients of various gases in oil at each temperature; calculating the diffusion coefficients of various gases in paper at each temperature; establishing a prediction model for the dissolution time of bubbles in oil-paper insulation, and calculating the dissolution time. This invention considers three factors—gas solubility in oil, diffusion coefficient in oil, and diffusion coefficient in paper—that vary with temperature and gas type, and calculates the dissolution time of a single stationary bubble in oil-paper insulation. This effectively reduces the risk of bubbles during transformer operation and can be widely applied to oil-paper insulation systems with the same kinetic description.

Description

Technical Field

[0001] This invention relates to the field of electrical equipment insulation technology, and more specifically, to a method and system for predicting the dissolution time of air bubbles in oil-paper insulation. Background Technology

[0002] Oil-paper insulation is the main insulation structure of oil-immersed power transformers. Under the combined effects of internal latent faults or the influence of electric fields, moisture, temperature, and material degradation, long-term operation of power transformers can lead to the formation of bubbles within the oil-paper insulation structure. Generally, the longer a transformer operates, the higher the accumulated gas and moisture concentrations within its insulation, which increases the risk of bubble formation and reduces the insulation strength of the transformer's insulation system. Previous studies, focusing on the physical phenomenon of bubble dissolution in liquid nitrogen or pure oil, often only considered the dissolution and dissipation of bubbles in a single liquid medium. Furthermore, due to the extremely low solubility of water in oil, previous studies often directly ignored the dissolution of water vapor bubbles in oil. However, as cellulose paper / paperboard insulation plays an increasingly important role in oil-immersed power transformers (oil-to-paper mass ratio 10:1), and given that cellulose paper / paperboard has a moisture absorption capacity tens of thousands of times greater than insulating oil, current research needs to shift from focusing on a single liquid medium to an oil-paper mixed medium, and special attention must be paid to the dissolution of water vapor bubbles in contact with cellulose paper / paperboard. In summary, this study helps us understand the dissipation mechanism of air bubbles in oil-paper insulation, and provides a reference for transformer overload operation and fault diagnosis. Summary of the Invention

[0003] To address the aforementioned problems, the present invention aims to provide a method for predicting the dissolution time of bubbles in oil-paper insulation. Based on a kinetic model of bubble dissolution, this method considers three factors that vary with temperature and gas type: the solubility of gas in oil, the diffusion coefficient in oil, and the diffusion coefficient in paper. It can be widely applied to oil-paper insulation systems with the same kinetic description, and is of great significance for studying the temperature limit of transformers. It also provides an important methodological basis for reducing the risk of bubbles during transformer operation.

[0004] To achieve the above technical objective, this application provides a method for predicting the dissolution time of air bubbles in oil-paper insulation, comprising the following steps:

[0005] The amount of gas dissolved per unit volume of transformer oil after the dissolution of gases in the oil reaches equilibrium is obtained. The gases include C2H6, C2H4, CO2, C2H2, CH4, CO, H2, moisture, and air.

[0006] Using 47℃ as the reference temperature, the Arrhenius relation was used to obtain the first diffusion coefficient of gas in transformer oil and the second diffusion coefficient of gas in insulating paper at different temperatures.

[0007] Based on the amount of gas dissolved per unit volume of oil, the first diffusion coefficient, and the second diffusion coefficient, a predictive model for the dissolution time of bubbles in oil-paper insulation is constructed. The dissolution time of bubbles in oil-paper insulation is predicted according to the contact area ratio between the bubble boundary layer and the oil and paper, as well as the concentration of dissolved gas in the oil at time t.

[0008] Preferably, in the process of obtaining the amount of gas dissolved per unit volume of oil, the amount of gas dissolved per unit volume of oil is expressed as:

[0009]

[0010] In the formula, M l ρ is the molar mass of the liquid; T is the temperature; l Density of insulating oil: 22.4 × 10⁻⁶ 4 The molar volume of the gas at 273 K and 101.3 kPa is 5.95 × 10⁻⁶. -4 And 1.21 are the corrected ρ l The empirical constant for a specific T; B is the Bunsen coefficient, representing the volume of dissolved gas per unit volume of oil under standard conditions.

[0011] Preferably, in the process of obtaining the Bunsen coefficients, the Bunsen coefficients are expressed as:

[0012]

[0013] In the formula, P and P s These represent gas pressure and liquid saturated vapor pressure, respectively; k i This is the Ostwald constant under standard conditions, which is dimensionless and depends on the type of gas.

[0014] Preferably, in the process of obtaining the first diffusion coefficient, the first diffusion coefficient is expressed as:

[0015]

[0016] In the formula, D b_O At temperature T b =Base diffusion coefficient in oil, C(T) and C measured at 47℃ b The saturated solubility at temperature T and the temperature T are respectively. b The reference solubility at that time, α is a dimensionless constant equal to -3.6 × 10⁻⁶. -6 β is a constant equal to 3464K.

[0017] Preferably, in the process of obtaining the second diffusion coefficient, the second diffusion coefficient is expressed as:

[0018]

[0019] In the formula, D b_P At temperature T b = The reference diffusion coefficient in paper measured at 47℃.

[0020] Preferably, during the construction of the prediction model, the prediction model is represented as follows:

[0021]

[0022] In the formula, δ1 and δ2 are the percentages of the contact area between the bubble boundary layer and the oil and paper, respectively, and C t Let t be the concentration of dissolved gases in the oil at time t.

[0023] The present invention also provides a system for predicting the dissolution time of air bubbles in oil-paper insulation, comprising:

[0024] The data acquisition module is used to obtain the types of gases dissolved in transformer oil, as well as the amount of gas dissolved per unit volume of oil after the dissolution of gases in transformer oil reaches equilibrium. The gases include C2H6, C2H4, CO2, C2H2, CH4, CO, H2, moisture, and air.

[0025] The data processing module is used to obtain the first diffusion coefficient of gas in transformer oil and the second diffusion coefficient of gas in insulating paper at different temperatures, using 47℃ as the reference temperature and the Arrhenius relation.

[0026] The prediction module is used to construct a prediction model for the dissolution time of bubbles in oil-paper insulation based on the amount of gas dissolved per unit volume of oil, the first diffusion coefficient, and the second diffusion coefficient. It predicts the dissolution time of bubbles in oil-paper insulation based on the contact area ratio between the bubble boundary layer and the oil and paper, as well as the concentration of dissolved gas in the oil at time t.

[0027] Preferably, the amount of gas dissolved per unit volume of oil acquired by the data acquisition module is expressed as:

[0028]

[0029] In the formula, M l ρ is the molar mass of the liquid; T is the temperature; l Density of insulating oil: 22.4 × 10⁻⁶ 4 The molar volume of the gas at 273 K and 101.3 kPa is 5.95 × 10⁻⁶. -4 And 1.21 are the corrected ρ l The empirical constant for a specific T; B is the Bunsen coefficient, representing the volume of dissolved gas per unit volume of oil under standard conditions;

[0030] The Bunsen coefficient is expressed as:

[0031]

[0032] In the formula, P and P s These represent gas pressure and liquid saturated vapor pressure, respectively; k i This is the Ostwald constant under standard conditions, which is dimensionless and depends on the type of gas.

[0033] Preferably, the first diffusion coefficient obtained by the data processing module is expressed as:

[0034]

[0035] In the formula, D b_O At temperature T b =Base diffusion coefficient in oil, C(T) and C measured at 47℃ b The saturated solubility at temperature T and the temperature T are respectively. b The reference solubility at that time, α is a dimensionless constant equal to -3.6 × 10⁻⁶. -6 β is a constant equal to 3464K;

[0036] The second diffusion coefficient is expressed as:

[0037]

[0038] In the formula, D b_P At temperature T b = The reference diffusion coefficient in paper measured at 47℃.

[0039] Preferably, the prediction module predicts the bubble dissolution time using a prediction model, which is expressed as follows:

[0040]

[0041] In the formula, δ1 and δ2 are the percentages of the contact area between the bubble boundary layer and the oil and paper, respectively, and C t Let t be the concentration of dissolved gases in the oil at time t.

[0042] The present invention discloses the following technical effects:

[0043] The present invention provides a method for predicting the bubble dissolution time in oil-paper insulation, which can be widely applied to oil-paper insulation systems with the same kinetic description, and has the following advantages:

[0044] This invention applies the standard method of ASTM D2779 for estimating the solubility of gases in petroleum liquids to the calculation of gas solubility in transformer oil, and provides a set of calculation equations for the solubility of various gases in oil, making the model closer to the actual physical process.

[0045] This invention applies the diffusion law of water in oil to a bubble dissolution model, and uses 47℃ as the base temperature to extrapolate this data to other temperatures and other solubilities using the Arrhenius relation. It incorporates the influence of water diffusion in oil and provides methods for calculating the diffusion coefficients of various gases in oil at different temperatures, thus making the model more complete.

[0046] This invention is the first to consider the influence of the diffusion coefficient in cellulose paper / paperboard in an oil-paper insulation bubble dissolution model, and provides a method for calculating the diffusion coefficients of various gases in paper as a function of temperature. Compared with the model in technical solution two, which only considers the diffusion coefficient in oil, technical solution three, by adding the diffusion coefficient in paper, makes the model more complete and closer to the actual physical process.

[0047] This invention constructs a relatively comprehensive bubble dissolution model in oil-paper insulation. Based on the different physical processes of bubble dissolution in oil-paper insulation, it considers the influence of the solubility of various gases in oil, the diffusion coefficient in oil, and the diffusion coefficient in paper on bubble dissolution, and predicts the bubble dissolution time, providing technical support for the application of transformer condition assessment and diagnosis.

[0048] The present invention has a simple calculation process and fast calculation speed. Once the model parameters are determined, the bubble dissolution time can be calculated quickly. Attached Figure Description

[0049] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0050] Figure 1 This is a schematic diagram of the physical process of bubble dissolution in the oil paper insulation described in the invention;

[0051] Figure 2 It refers to the solubility of various gases in the insulating oil described in the invention at different temperatures;

[0052] Figure 3 It is the curve of the diffusion coefficient of nine types of gases in oil as a function of temperature as described in the invention;

[0053] Figure 4 It is a curve showing the change of the diffusion coefficient of nine types of gases in the paper described in the invention with temperature;

[0054] Figure 5 This is a flowchart for calculating the bubble dissolution time in the oil-paper insulation described in the invention;

[0055] Figure 6 The dissolution time of a 360-micrometer radius bubble at different temperatures as described in the invention;

[0056] Figure 7 This is a schematic diagram illustrating the implementation steps of the method described in the invention. Detailed Implementation

[0057] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely represents selected embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0058] like Figure 1-7 As shown, the present invention provides a method for predicting the dissolution time of air bubbles in oil-paper insulation, comprising the following steps:

[0059] S1, After the gases have dissolved in the oil to reach equilibrium, calculate the amount of each type of gas dissolved per unit volume of oil.

[0060] S2, using 47℃ as the reference temperature, extrapolates this data to other temperatures and other solubilities using the Arrhenius relation, and calculates the diffusion coefficients of various gases in oil at each temperature;

[0061] S3, using 47℃ as the reference temperature, extrapolate the data to other temperatures using the Arrhenius relation, and calculate the diffusion coefficient of various gases in paper at each temperature;

[0062] S4. Establish a prediction model for the dissolution time of air bubbles in oil-paper insulation and calculate the dissolution time;

[0063] In step S1, the amount of various gases dissolved per unit volume of oil is calculated, and the specific analysis is as follows:

[0064] ASTM D2779 is a standard method for estimating the solubility of gases in petroleum liquids. This method is also applicable to calculating the solubility of gases in transformer oil. Under certain temperature and pressure conditions, after a gas reaches equilibrium in oil, the amount of gas C(T) dissolved per unit volume of oil can be expressed as:

[0065]

[0066] In the formula, M l (g / mol) is the molar mass of the liquid; T (°C) is the temperature; ρ l (kg / L) represents the density of the insulating oil, taken as 0.885 kg / L; 22.4 × 10 4 The molar volume of the gas at 273 K and 101.3 kPa is 5.95 × 10⁻⁶. -4 And 1.21 are the corrected ρ l The empirical constant up to a specific T; B is the Bunsen coefficient, representing the volume of dissolved gas per unit volume of oil under standard conditions, which can be described as:

[0067]

[0068] In the formula, P(MPa) and P s (MPa) represents the gas pressure and the saturated vapor pressure of the liquid, respectively; k i Ostwald constant under standard conditions is dimensionless and depends on the type of gas. IEC and IEEE standards publish the Ostwald constant for mineral oils. The solubility of various gases in oil depends on the Ostwald constant.

[0069] S2, using 47℃ as the base temperature, extrapolated this data to other temperatures and solubilities using the Arrhenius relation, and calculated the diffusion coefficients of various gases in oil at each temperature. The average diffusion coefficients of various gases in oil and cellulose paper (×10) -12 m 2 / s) is shown in Table 1:

[0070] Table 1

[0071]

[0072] The diffusion coefficients in the table and 47℃ are used as the reference diffusion coefficients D. b and reference temperature T b The Arrhenius relation was used to extrapolate this data to other temperatures and solubilities. The diffusion coefficients of various gases in oil at each temperature were calculated.

[0073]

[0074] In the formula, T (°C) is the temperature, and D... b_O At temperature T b = Baseline diffusion coefficient in oil measured at 47℃. C(T) and C b These represent the saturated solubility at temperature T and the baseline solubility at temperature Tb, respectively. α is a dimensionless constant equal to -3.6 × 10⁻⁶. -6 β is a constant equal to 3464K.

[0075] S3. Based on the average diffusion coefficient table of various gases in the oil-paper system from step S2, and still using 47℃ as the reference temperature, extrapolate the data to other temperatures using the Arrhenius relation, and calculate the diffusion coefficient of various gases in the paper at each temperature:

[0076]

[0077] In the formula, D b_P At temperature T b =The baseline diffusion coefficient in paper measured at 47℃. This invention is the first to consider the influence of the diffusion coefficient in paper in the bubble dissolution model of oil-paper insulation, and provides a method for calculating the diffusion coefficient of various gases in paper as a function of temperature. Compared with the model in step 2 that only considers the diffusion coefficient in oil, the addition of the diffusion coefficient in paper in step 3 makes the model more complete and closer to the actual physical process.

[0078] S4. Establish a prediction model for the dissolution time of air bubbles in oil-paper insulation, and calculate the dissolution time of a single stationary air bubble in oil-paper insulation:

[0079]

[0080] In the formula, δ1 and δ2 represent the contact area ratios between the bubble boundary layer and the oil / paper, respectively. δ1 + δ2 = 1, and these values ​​can be assigned based on the form in which the bubbles exist in the oil-cellulose medium. t0 is the initial time, and C... t R(t0) represents the concentration of dissolved gas in the oil at time t, and R(t0) represents the bubble radius at the initial time.

[0081] In one specific embodiment, such as Figure 1 As shown, bubbles in the oil-cellulose medium will shrink and dissolve due to the undersaturation of dissolved gas components within the medium. Gas inside the bubble diffuses along the bubble boundary layer into the oil and cellulose paperboard, respectively. The physical reason for this phenomenon is that the gas concentration in the oil medium surrounding the bubble or the cellulose medium in contact with the bubble is much lower than the gas concentration inside the bubble. Therefore, the bubble-oil boundary layer and the bubble-cellulose boundary layer are particularly important because they determine the interfacial area for mass transfer between the phases. Simultaneously, the diffusion coefficient D of the gas in the oil and cellulose media... O (T), D PThe diffusion rate is also determined by the diffusion coefficient (T) and the solubility (C(T)) in the oil. These three physical quantities are mainly related to the type of gas inside the bubble and the temperature (T). Generally, as temperature increases, molecular kinetic energy increases, leading to faster gas molecule movement and an increased diffusion coefficient in both oil and paper. This makes it easier for gas molecules to escape from the bubble, resulting in lower internal pressure, smaller volume, and eventual disappearance of the bubble.

[0082] like Figure 2 As shown, the solubility of a certain gas in insulating oil under equilibrium conditions can be calculated using equations (1) and (2) under different pressures and temperatures. Furthermore, for better comparison, the solubility of water in mineral oil was also included in this paper.

[0083] like Figure 3 As shown, the diffusion coefficients in Table S2 and 47℃ are used as the reference diffusion coefficients D. b_O and reference temperature T b The Arrhenius relation was used to extrapolate the data to other temperatures and solubilities, and the diffusion coefficients of nine gases (C2H6, C2H4, CO2, C2H2, CH4, CO, H2, water and air) in oil were calculated at 0-160℃.

[0084] like Figure 4 As shown, the adsorption of solid materials inside the transformer also reduces dissolved gases in the oil. This is because atoms and molecules on the surface of the solid material can adsorb external molecules. The adsorption capacity depends on the chemical composition and surface structure of the adsorbed substance. The diffusion coefficients in Table S2 and 47℃ are used as the baseline diffusion coefficients D. b_P and reference temperature T b The Arrhenius relation was used to extrapolate the data to other temperatures, and the diffusion coefficients of nine gases, namely C2H6, C2H4, CO2, C2H2, CH4, CO, H2, moisture and air, in paper were calculated at 0-160℃.

[0085] like Figure 5 As shown, by comprehensively considering three factors—gas solubility in oil, diffusion coefficient in oil, and diffusion coefficient in paper—that vary with temperature and gas type, a numerical simulation process for predicting bubble dissolution in oil-paper insulation can be obtained. Thus, a flowchart for calculating bubble dissolution time in oil-paper insulation is derived.

[0086] like Figure 6 As shown, the bubbles of nine gases—C2H6, C2H4, CO2, C2H2, CH4, CO, H2, moisture, and air—were analyzed. The dissolution time of the bubbles can be determined by... Figure 5 Numerical simulations were performed using the flowchart in the figure to obtain the dissolution time of various types of bubbles in oil-paper insulation at 20-140℃.

[0087] This invention provides a method for calculating the bubble dissolution time in oil-paper insulation. For the first time, it considers the influence of the diffusion coefficient in the paper within the bubble dissolution model for oil-paper insulation and presents methods for calculating the diffusion coefficients of various gases in the paper as temperature changes. Based on a kinetic model of bubble dissolution, this invention takes into account three factors—gas solubility in oil, diffusion coefficient in oil, and diffusion coefficient in paper—that vary with temperature and gas type. It can be widely applied to oil-paper insulation systems with the same kinetic description, and is of great significance for studying the temperature limits of transformers, providing an important methodological foundation for reducing the risk of bubble formation during transformer operation.

[0088] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0089] In the description of this invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0090] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A method for predicting the dissolution time of air bubbles in oil-paper insulation, characterized in that, Includes the following steps: The amount of gas dissolved per unit volume of transformer oil after the dissolution of gases in the oil reaches equilibrium is obtained, wherein the gases include C2H6, C2H4, CO2, C2H2, CH4, CO, H2, moisture and air; Using 47℃ as the reference temperature, the Arrhenius relation was used to obtain the first diffusion coefficient of the gas in the transformer oil and the second diffusion coefficient of the gas in the insulating paper at different temperatures. Based on the amount of gas dissolved per unit volume of oil, the first diffusion coefficient, and the second diffusion coefficient, a prediction model for the dissolution time of bubbles in oil-paper insulation is constructed. The dissolution time of bubbles in oil-paper insulation is predicted according to the contact area ratio between the bubble boundary layer and oil and paper, and the concentration of dissolved gas in oil at time t. In the process of constructing the prediction model, the prediction model is represented as follows: In the formula, δ1 and δ2 are the percentages of the contact area between the bubble boundary layer and the oil and paper, respectively, and C t Let t be the concentration of dissolved gases in the oil at time t; In the process of obtaining the amount of gas dissolved per unit volume of oil, the amount of gas dissolved per unit volume of oil is expressed as: In the formula, M l ρ is the molar mass of the liquid; T is the temperature; l Density of insulating oil: 22.4 × 10⁻⁶ 4 The molar volume of the gas at 273 K and 101.3 kPa is 5.95 × 10⁻⁶. -4 And 1.21 are the corrected ρ l The empirical constant for a specific T; B is the Bunsen coefficient, representing the volume of dissolved gas per unit volume of oil under standard conditions; In obtaining the Bunsen coefficients, the Bunsen coefficients are represented as follows: In the formula, P and P s These represent gas pressure and liquid saturated vapor pressure, respectively; k i This is the Ostwald constant under standard conditions, which is dimensionless and depends on the type of gas. In obtaining the first diffusion coefficient, the first diffusion coefficient is expressed as: In the formula, D b_O At temperature T b The reference diffusion coefficient in oil, C(T) and C, were measured at 47℃. b The saturated solubility at temperature T and the temperature T are respectively. b The reference solubility at that time, α is a dimensionless constant equal to -3.6 × 10⁻⁶. -6 β is a constant equal to 3464K; In obtaining the second diffusion coefficient, the second diffusion coefficient is expressed as: In the formula, D b_P At temperature T b =The baseline diffusion coefficient in paper measured at 47℃.

2. A prediction system for the bubble dissolution time in oil-paper insulation, used in the prediction system of the method for predicting the bubble dissolution time in oil-paper insulation as described in claim 1, characterized in that, include: The data acquisition module is used to acquire the types of gases dissolved in transformer oil, and the amount of gas dissolved per unit volume of oil after the dissolution of the gases in the transformer oil reaches equilibrium. The gases include C2H6, C2H4, CO2, C2H2, CH4, CO, H2, moisture, and air. The data processing module is used to obtain the first diffusion coefficient of the gas in the transformer oil and the second diffusion coefficient of the gas in the insulating paper at different temperatures, using 47°C as the reference temperature and the Arrhenius relation. The prediction module is used to construct a prediction model for the dissolution time of bubbles in oil-paper insulation based on the amount of gas dissolved in the unit volume of oil, the first diffusion coefficient and the second diffusion coefficient. The model predicts the dissolution time of bubbles in oil-paper insulation based on the contact area ratio between the bubble boundary layer and the oil and paper and the concentration of dissolved gas in the oil at time t.

3. The prediction system for bubble dissolution time in oil-paper insulation according to claim 2, characterized in that: The amount of gas dissolved per unit volume of oil, as obtained by the data acquisition module, is expressed as follows: In the formula, M l ρ is the molar mass of the liquid; T is the temperature; l Density of insulating oil: 22.4 × 10⁻⁶ 4 These are the molar volumes of the gas at 273 K and 101.3 kPa; 5.95×10 -4 And 1.21 are the corrected ρ l The empirical constant for a specific T; B is the Bunsen coefficient, representing the volume of dissolved gas per unit volume of oil under standard conditions; The Bunsen coefficient is expressed as follows: In the formula, P and P s These represent gas pressure and liquid saturated vapor pressure, respectively; k i This is the Ostwald constant under standard conditions, which is dimensionless and depends on the type of gas.

4. The prediction system for bubble dissolution time in oil-paper insulation according to claim 3, characterized in that: The first diffusion coefficient obtained by the data processing module is expressed as: In the formula, D b_O At temperature T b The reference diffusion coefficient in oil, C(T) and C, were measured at 47℃. b The saturated solubility at temperature T and the temperature T are respectively. b The reference solubility at that time, α is a dimensionless constant equal to -3.6 × 10⁻⁶. -6 β is a constant equal to 3464K; The second diffusion coefficient is expressed as: In the formula, D b_P At temperature T b =The baseline diffusion coefficient in paper measured at 47℃.

5. The prediction system for bubble dissolution time in oil-paper insulation according to claim 4, characterized in that: The prediction module predicts the bubble dissolution time using a prediction model, which is expressed as follows: In the formula, δ1 and δ2 are the percentages of the contact area between the bubble boundary layer and the oil and paper, respectively, and C t Let t be the concentration of dissolved gases in the oil at time t.

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