Calculation method of static pressure generated by arc discharge in transformer oil tank

Abstract

Disclosed is a method for calculating the static pressure generated by arc discharge in a transformer oil tank. In the method, the expansion coefficient c of the transformer oil tank is obtained; the time-varying arc power P(t) and energy W(t) of the arc discharge in the transformer oil tank are calculated; the arc discharge product temperature T of the arc discharge in the transformer oil tank is obtained; the gas space V0 existing in the transformer oil tank is measured, and the solubility k of the characteristic gas generated by the arc in the oil is calculated. h , calculate the amount of dissolved gas in oil V g ; Calculate the static pressure p generated by arc discharge in the transformer oil tank according to the static pressure calculation formula.

Description

Technical Field

[0001] The invention relates to the technical field of transformer detection, in particular to a method for calculating static pressure generated by arc discharge in a transformer oil tank. Background Art

[0002] When a short circuit occurs within a transformer tank, it triggers an arc discharge, causing the transformer oil to decompose and generate gas. This increases the tank's internal pressure, leading to further tank rupture and even explosion and fire. Tank pressure is divided into dynamic and static pressures. Existing research indicates that the primary cause of tank damage is the accumulation of gas generated by the arc, resulting in increased static pressure. Therefore, calculating static pressure is essential for explosion-proof transformer tank designs. Existing methods for calculating static pressure within tanks exhibit significant inaccuracies, failing to account for factors such as the presence of gas spaces within the tank and the dissolution of gas generated by the discharge in the oil.

[0003] The information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known to a person of ordinary skill in the art. Summary of the Invention

[0004] In response to the shortcomings or defects of the above-mentioned existing technologies, a method for calculating the static pressure generated by arc discharge in a transformer oil tank is provided. The static pressure of arc discharge in the transformer oil tank is effectively and accurately calculated, which can reduce the cost of discharge experiments and provide support for the explosion-proof design of the transformer oil tank.

[0005] The purpose of the present invention is achieved through the following technical solutions.

[0006] A method for calculating the static pressure generated by arc discharge in a transformer tank includes:

[0007] Obtain the expansion coefficient c of the transformer tank;

[0008] The time-varying power P(t) of the arc discharge in the transformer oil tank is calculated and the energy W(t) is obtained by integration. Based on the relationship between arc energy and gas production, that is, the discharge gas production is proportional to the arc energy, the arc discharge gas production V in the transformer oil is obtained. g ;

[0009] Obtaining the arc discharge product temperature T of the arc discharge in the transformer tank;

[0010] Measure the gas space V0 in the transformer tank and the solubility k of the characteristic gas generated by the arc in the oil h , calculate the amount of dissolved gas in oil V g ;

[0011] According to the static pressure calculation formula, the static pressure p generated by arc discharge in the transformer tank is calculated. p: static pressure of liquid and gas in transformer tank, unit is bar, c: expansion coefficient of tank, unit is L / bar, V g : discharge gas production, which is the volume under normal pressure, unit is L, T: arc discharge product temperature, T0: ambient temperature, V0: gas space in the transformer tank before discharge, unit is L, k h : Henry's constant, which characterizes the volume of gas generated by discharge dissolved in unit volume of oil at atmospheric pressure, with the unit being L.

[0012] In the method for calculating the static pressure generated by arc discharge in the transformer oil tank, the expansion coefficient c of the transformer oil tank is obtained by an explicit dynamics method or a strain measurement method. The explicit dynamics method is used to calculate the stress, strain or deformation when pressure exists in the transformer oil tank to obtain the expansion coefficient c of the transformer oil tank, and the explicit dynamics calculation results are verified by strain measurement and displacement measurement of the deformation.

[0013] In the method for calculating the static pressure generated by arc discharge in the transformer oil tank, the time-varying arc power P(t) and energy W(t) are calculated by measuring the actual data of the arc voltage u(t) and current i(t) through arc measurement, or according to the short-circuit arc voltage estimation method. In the arc measurement experiment, the arc discharge current and voltage are measured by a current sensor and a voltage sensor, or the arc voltage is deduced through recorded data, or the arc voltage is estimated based on transformer disassembly analysis combined with an arc voltage estimation method. Subsequently, the waveform of the arc power and energy varying with time is calculated based on the arc voltage and current.

[0014] In the method for calculating the static pressure generated by arc discharge in the transformer oil tank, the Rogowski coil measures the arc discharge current, and the high-voltage differential probe measures the arc discharge voltage.

[0015] In the method for calculating the static pressure generated by arc discharge in the transformer oil tank, the arc voltage is estimated using the Ayrton model, the Cassie arc voltage model or the Mayr arc voltage model.

[0016] In the method for calculating the static pressure generated by arc discharge in the transformer oil tank, the arc discharge product temperature T is measured based on a transient high temperature measurement experiment or is deduced by an ideal gas state equation.

[0017] In the method for calculating the static pressure generated by arc discharge in the transformer oil tank, gas is injected into the oil tank through an in-tank gas injection experiment, and the gas space V0 is calculated by counting the gas injection amount and its corresponding static pressure in the oil tank. An airbag diaphragm is set at the gas injection port to prevent the injected gas from affecting the gas content in the oil.

[0018] In the method for calculating the static pressure generated by arc discharge in the transformer tank, the amount of dissolved gas in the oil V g The relationship between it and the corresponding static pressure p in the fuel tank is linear.

[0019] In the method for calculating the static pressure generated by arc discharge in the transformer tank, the amount of dissolved gas in the oil V g The linear relationship between the static pressure p in the corresponding fuel tank is: V0′=V0+k h , V′0 is the equivalent reserved gas volume including dissolved gas.

[0020] In the method for calculating the static pressure generated by arc discharge in the transformer tank, the static pressure indicates that the pressure is evenly distributed in the tank. The static pressure has a time-varying characteristic that changes over time. The trend of the static pressure in the tank changing with gas production and equivalent reserved gas volume V′0 is plotted and displayed in a three-dimensional contour map.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] This method considers factors such as the presence of gas spaces within the tank and the dissolution of gas generated by discharge in the oil. It analyzes and calculates the static pressure variation trends under the influence of various factors, as well as the variation patterns of the static pressure gradient under these factors. This gradient reflects the relationship between the strength of these factors on the static pressure. This method can more effectively and accurately calculate the static pressure of arc discharges within transformer tanks, reducing discharge experiment costs and providing support for explosion-proof transformer tank design.

[0023] The above description is only an overview of the technical solution of the present invention. In order to make the technical means of the present invention clearer and easier to understand, so that those skilled in the art can implement it according to the contents of the description, and in order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are illustrated below. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Various other advantages and benefits of the present invention will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiments below. The accompanying drawings are intended only to illustrate preferred embodiments and are not to be construed as limiting the present invention. It should be understood that the drawings described below are merely examples of the present invention, and that those skilled in the art will be able to derive other drawings from these drawings without inventive effort. Throughout the drawings, identical reference numerals are used to denote identical components.

[0025] In the attached figure:

[0026] Figure 1This is a flow chart of a method for calculating the static pressure generated by arc discharge in a transformer tank;

[0027] Figure 2 is the simulation and experimental measurement result of the tank strain;

[0028] Figure 3 It is the power and energy waveform calculated based on the arc voltage and current in the experiment;

[0029] Figure 4 It is the experimental measurement result of the existence of gas space in the tank;

[0030] FIG5( a ) is a comparison of the calculation results of the calculation method proposed by the present invention and the existing method after the discharge product temperature has cooled to room temperature;

[0031] FIG5( b ) is a comparison of the calculation results of the calculation method proposed by the present invention and the existing method when considering the temperature change of the discharge products during the arcing process;

[0032] Figure 6 It is a three-dimensional contour map of the static pressure change trend under the influence of various factors;

[0033] Figure 7 It is a graph of static pressure gradient changes under the influence of multiple factors.

[0034] The present invention will be further explained below with reference to the accompanying drawings and embodiments. DETAILED DESCRIPTION

[0035] Specific embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although specific embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.

[0036] It should be noted that certain words are used in the specification and claims to refer to specific components. Those skilled in the art should understand that technicians may use different nouns to refer to the same component. This specification and claims do not use the difference in nouns as a way to distinguish components, but use the difference in the functions of the components as the criterion for distinction. As mentioned throughout the specification and claims, "including" or "comprising" is an open term, so it should be interpreted as "including but not limited to". The subsequent description of the specification is a preferred embodiment of the present invention, but the description is based on the general principles of the specification and is not intended to limit the scope of the invention. The scope of protection of the present invention shall be as defined in the attached claims.

[0037] To facilitate understanding of the embodiments of the present invention, several specific embodiments will be further explained below with reference to the accompanying drawings. However, the accompanying drawings do not limit the embodiments of the present invention.

[0038] For better understanding, Figures 1 to 7 As shown, a method for calculating the static pressure generated by arc discharge in a transformer tank includes:

[0039] Obtain the expansion coefficient c of the transformer tank;

[0040] The time-varying power P(t) of the arc discharge in the transformer oil tank is calculated and the energy W(t) is obtained by integration. Based on the relationship between arc energy and gas production, that is, the discharge gas production is proportional to the arc energy, the arc discharge gas production V in the transformer oil is obtained. g ;

[0041] Obtaining the arc discharge product temperature T of the arc discharge in the transformer tank;

[0042] Measure the gas space V0 in the transformer tank and the solubility k of the characteristic gas generated by the arc in the oil h , calculate the amount of dissolved gas in oil V g ;

[0043] According to the static pressure calculation formula, the static pressure p generated by arc discharge in the transformer tank is calculated. p: static pressure of liquid and gas in transformer tank, unit is bar, c: expansion coefficient of tank, unit is L / bar, V g : discharge gas production, which is the volume under normal pressure, unit is L, T: arc discharge product temperature, T0: ambient temperature, V0: gas space in the transformer tank before discharge, unit is L, k h : Henry's constant, which characterizes the volume of gas generated by discharge dissolved in unit volume of oil at atmospheric pressure, with the unit being L.

[0044] In a preferred embodiment of the method for calculating the static pressure generated by arc discharge in the transformer tank, the expansion coefficient c of the transformer tank is obtained by an explicit dynamics method or a strain measurement method, wherein the explicit dynamics method is used to calculate the stress, strain or deformation when pressure exists in the transformer tank to obtain the expansion coefficient c of the transformer tank, and the explicit dynamics calculation results are verified by strain measurement and displacement measurement of the deformation.

[0045] In a preferred embodiment of the method for calculating the static pressure generated by arc discharge in the transformer oil tank, the arc voltage u(t) and current i(t) are measured by arc measurement, or the arc time-varying power P(t) is calculated based on the short-circuit arc voltage estimation method and the energy W(t) is obtained by integration. In the arc measurement experiment, the arc discharge current and voltage are measured by current sensors and voltage sensors, or the arc voltage is deduced through recorded data, or the arc voltage is estimated based on transformer disassembly analysis combined with the arc voltage estimation method, and then the arc power and energy waveforms varying with time are calculated based on the arc voltage and current. Based on the relationship between arc energy and gas production, that is, the discharge gas production is proportional to the arc energy, the arc discharge gas production V in the transformer oil is obtained. g .

[0046] In a preferred embodiment of the method for calculating the static pressure generated by arc discharge in the transformer oil tank, the Rogowski coil measures the arc discharge current, and the high-voltage differential probe measures the arc discharge voltage.

[0047] In a preferred embodiment of the method for calculating the static pressure generated by arc discharge in the transformer oil tank, the arc voltage is estimated using an Ayrton model, a Cassie arc voltage model, or a Mayr arc voltage model.

[0048] In a preferred embodiment of the method for calculating the static pressure generated by arc discharge in the transformer tank, the arc discharge product temperature T is measured based on a transient high temperature measurement experiment or is deduced by an ideal gas state equation.

[0049] In a preferred embodiment of the method for calculating the static pressure generated by arc discharge in the transformer oil tank, gas is injected into the oil tank through an in-tank gas injection experiment, and the gas space V0 is calculated by counting the injected gas volume and its corresponding static pressure in the oil tank. An airbag diaphragm is provided at the gas injection port to prevent the injected gas from affecting the gas content in the oil.

[0050] In the preferred embodiment of the method for calculating the static pressure generated by arc discharge in the transformer tank, the amount of dissolved gas in the oil V g The relationship between it and the corresponding static pressure p in the fuel tank is linear.

[0051] In the preferred embodiment of the method for calculating the static pressure generated by arc discharge in the transformer tank, the amount of dissolved gas in the oil V g The linear relationship between the static pressure p in the corresponding fuel tank is: V′0=V0+k h , V′0 is the equivalent reserved gas volume including dissolved gas.

[0052] In a preferred embodiment of the method for calculating the static pressure generated by arc discharge in the transformer tank, the static pressure indicates that the pressure is evenly distributed in the tank, and the static pressure has a time-varying characteristic that changes over time. The trend of the static pressure in the tank changing with the gas production and the equivalent reserved gas volume V′0 is plotted and displayed in a three-dimensional contour map.

[0053] In one embodiment, a method for calculating the static pressure generated by arc discharge in a transformer tank includes:

[0054] Obtain the expansion coefficient c of the oil tank by explicit dynamics method or strain measurement method;

[0055] The arc time-varying power is calculated by the measured data of arc voltage and current, or by the estimation method of short-circuit arc voltage, and the energy W(t) is obtained by integration. Based on the relationship between arc energy and gas production, that is, the discharge gas production is proportional to the arc energy, the arc discharge gas production V in transformer oil is obtained. g ;

[0056] The arc discharge product temperature T is derived from the ideal gas state equation or measured experimentally based on transient high temperature measurement technology.

[0057] Through the gas injection experiment in the oil tank, the gas space inside the oil tank is measured, and the amount of dissolved gas in the oil is calculated based on the solubility of the characteristic gas generated by the arc in the oil.

[0058] Substituting the above parameters into the static pressure calculation formula proposed in the present invention, the temporal variation pattern of the static pressure generated by arc discharge in the transformer tank is calculated.

[0059] In a preferred embodiment of the method, it is necessary to obtain the expansion coefficient c of the fuel tank in the calculation object. This parameter is used to quantitatively characterize the flexibility of the fuel tank. Methods for obtaining this coefficient c include, but are not limited to, using explicit dynamics methods to calculate parameters such as stress, strain, and deformation under pressure within the fuel tank, and verifying the explicit dynamics calculation results through strain measurement and displacement measurement of the deformation.

[0060] In a preferred embodiment of the method, during experimental measurements, the arc discharge current and voltage can be measured using current and voltage sensors. However, in the event of an arc fault during actual transformer operation, the arc voltage cannot be accurately determined. In this case, the arc voltage must be deduced from recorded waveform data or estimated using transformer disassembly analysis and arc voltage estimation methods. The arc voltage and current are then used to calculate the arc power and energy waveforms over time.

[0061] In a preferred embodiment of the method, a small amount of gas may be stored in the transformer tank, or a pressure protection measure of a buffer airbag is expected to be present. The gas space in the transformer tank needs to be considered, and when performing static pressure calculations, the accurate value of the gas space V0 needs to be obtained.

[0062] In a preferred embodiment of the method, V'0 can be calculated by injecting gas into the oil tank and calculating the injected gas volume and the corresponding static pressure within the tank. To prevent the injected gas from affecting the gas content in the oil, a gas sac diaphragm can be installed at the injection port to prevent gas from dissolving in the oil. In this case, V'0 is obtained.

[0063] In a preferred embodiment of the method, the volume of dissolved gas per unit pressure in the transformer tank is calculated based on the characteristic gas composition and content generated by arc discharge in the tank and the solubility of the characteristic gas in the oil. h .

[0064] In a preferred embodiment of the method, based on the aforementioned parameters, the corresponding static pressure waveform within the transformer tank is calculated according to the arc energy waveform. It is worth noting that static pressure does not mean constant pressure, but rather indicates that the pressure is evenly distributed within the tank. Static pressure also changes over time, exhibiting time-varying characteristics.

[0065] In a preferred embodiment of the method, in order to more intuitively demonstrate the differences in the degree of influence of various factors on the static pressure in the fuel tank, the changing trend of the static pressure in the fuel tank with the gas production and the equivalent reserved gas volume is calculated and plotted, and displayed in a three-dimensional contour map.

[0066] In a preferred embodiment of the method, in order to further obtain the strong and weak relationship between the influence of different factors on the static pressure in the fuel tank, a gradient analysis method is used to analyze the strong and weak coupling mechanism of the static pressure in the fuel tank.

[0067] In this embodiment, the explicit dynamic finite element calculation method is first used to establish a three-dimensional model of the experimental oil tank, apply pressure to the inner wall, calculate the change in internal volume under different pressures, and set two sampling points at the side wall flange and the top to analyze its stress changes. Strain gauges and strain meters are used to carry out strain measurement experiments. Gas is filled into the oil tank to subject its inner wall to pressure and generate strain. Strain gauges are pasted at the corresponding positions of the two sampling points in the simulation, and the strain value of the oil tank is measured and compared with the simulation value. The accuracy of the simulation results is verified. The experimental and simulation comparison results are shown in the figure. Figure 2 The fuel tank expansion coefficient is defined as the change in tank volume per unit pressure. The fuel tank expansion coefficient is approximately 0.0042 L / bar.

[0068] In this embodiment, the arc discharge current is measured using a Rogowski coil, and the arc discharge voltage is measured using a high-voltage differential probe. The arc power and energy waveforms are calculated according to the following formula.

[0069] P(t)=u(t)i(t)(1)

[0070] W(t)=∫P(t)dt(2)

[0071] Where: u(t) is the arc voltage, i(t) is the arc current, P(t) is the arc power, and W(t) is the arc energy

[0072] When arc voltage estimation is required, the Ayrton model (as shown below), Cassie arc voltage model, or Mayr arc voltage model can generally be used to estimate the arc voltage, and further obtain the arc power and energy waveform.

[0073]

[0074] Among them, l is the arc length, a, b, c, d are model parameters

[0075] In this embodiment, when the oil tank is almost full of oil, there are still a few micro air gaps in the oil tank. In order to calculate the volume of gas in the micro air gaps, gas is injected into the oil tank and the gas injection volume V is calculated. g The gas space in the tank can be calculated using the following formula: and the corresponding static pressure p in the tank. Since no airbag diaphragm is used in this experiment, the injected gas will partially dissolve in the oil. Therefore, the equivalent reserved gas volume V′0 obtained by fitting is the equivalent reserved gas volume including the dissolved gas. Figure 4 The slope of the fitted line is V′0=0.275L

[0076]

[0077] In this embodiment, the gas composition and content of the arc gas is approximately 70% H2, 15% CH4, 10% C2H2, and 5% other. Based on the solubility of the above characteristic gases in oil, it is calculated that the amount of dissolved gas in the transformer oil in the tank at normal pressure is approximately 200 mL.

[0078] In this embodiment, the calculation formula for the static pressure in the fuel tank is as follows:

[0079]

[0080] Where, p: static pressure of liquid and gas in the tank, unit bar = 100kPa = 1atm. c: expansion coefficient of the tank, unit L / bar. V g: discharge gas production (volume at normal pressure), unit is L. T: average temperature of arc discharge products. T0: ambient temperature, usually room temperature. V0: reserved gas volume at normal pressure in the experimental chamber before discharge, or gas bag volume, unit is L. k h : Henry's constant, which characterizes the volume of gas generated by discharge dissolved in unit volume of oil at atmospheric pressure, with the unit being L.

[0081] In the above formula, V0, which represents the reserved gas volume, and k, which represents the amount of dissolved gas in the discharge h In mathematical form, it has a symmetrical position, that is, the effect of gas dissolved in oil and the gas space reserved in the oil tank on the static pressure of discharge is equivalent. In order to simplify the study, V0′=V0+k h , which is called the equivalent reserved gas volume in the fuel tank.

[0082] Substituting the above parameters into the static pressure calculation formula proposed by the present invention, the temporal variation of the static pressure generated by arc discharge within the transformer tank was calculated. The results are compared with those of existing calculation methods, as shown in Figures 5(a) and 5(b). The calculation results proposed by the present invention significantly outperform existing methods.

[0083] In this embodiment, in order to more intuitively demonstrate the differences in the degree of influence of the three factors of fuel tank expansion coefficient, gas production, and equivalent reserved gas volume on the static pressure in the fuel tank, under different fuel tank expansion coefficient conditions, the changing trend of the static pressure in the fuel tank with gas production and equivalent reserved gas volume is calculated and plotted, and displayed in a three-dimensional contour map.

[0084] In this embodiment, in order to further obtain the strength relationship of the influence of the three factors of fuel tank expansion coefficient, gas production, and equivalent reserved gas volume on the static pressure in the fuel tank, the gradient analysis method is used to solve the gradient of the static pressure calculation expression. The gradient of the static pressure is solved under different independent variable ranges, and the strength and weakness coupling mechanism of the above three factors on the static pressure in the fuel tank is characterized.

[0085] The basic principles of the present application have been described above in conjunction with specific embodiments. However, it should be noted that the advantages, strengths, and effects mentioned in this application are merely illustrative and not restrictive, and it should not be assumed that these advantages, strengths, and effects are required of each embodiment of this application. In addition, the specific details disclosed above are merely illustrative and facilitating understanding, and are not restrictive. The above details do not limit this application to necessarily being implemented using the above specific details.

[0086] The above description has been provided for the purpose of illustration and description. Furthermore, this description is not intended to limit the embodiments of the present application to the forms disclosed herein. Although a number of example aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, alterations, additions, and sub-combinations thereof.

Claims

1. A method for calculating the static pressure generated by arc discharge in a transformer tank, characterized in that: It includes, Obtain the expansion coefficient c of the transformer tank; The time-varying power P(t) of the arc discharge in the transformer oil tank is calculated and the energy W(t) is obtained by integration. Based on the relationship between arc energy and gas production, that is, the discharge gas production is proportional to the arc energy, the arc discharge gas production V in the transformer oil is obtained. g ; Obtaining the arc discharge product temperature T of the arc discharge in the transformer tank; Measure the gas space V0 in the transformer tank and the solubility k of the characteristic gas generated by the arc in the oil h , calculate the amount of dissolved gas in oil V g ; According to the static pressure calculation formula, the static pressure p generated by arc discharge in the transformer tank is calculated. p: static pressure of liquid and gas in transformer tank, unit is bar, c: expansion coefficient of tank, unit is L / bar, V g : discharge gas production, which is the volume under normal pressure, unit is L, T: arc discharge product temperature, T0: ambient temperature, V0: gas space in the transformer tank before discharge, unit is L, k h : Henry's constant, which characterizes the volume of gas generated by discharge dissolved in unit volume of oil at atmospheric pressure, with the unit being L.

2. The method for calculating the static pressure generated by arc discharge in a transformer oil tank according to claim 1, characterized in that: Preferably, the expansion coefficient c of the transformer tank is obtained by an explicit dynamics method or a strain measurement method, wherein the explicit dynamics method is used to calculate the stress, strain or deformation when pressure exists in the transformer tank to obtain the expansion coefficient c of the transformer tank, and the explicit dynamics calculation results are verified by strain measurement and displacement measurement of the deformation.

3. The method for calculating the static pressure generated by arc discharge in a transformer oil tank according to claim 1, characterized in that: The arc voltage u(t) and current i(t) are measured by arc measurement, or the arc time-varying power P(t) is calculated based on the short-circuit arc voltage estimation method and the energy W(t) is obtained by integration. In the arc measurement experiment, the arc discharge current and voltage are measured by current sensors and voltage sensors, or the arc voltage is deduced through recorded data, or the arc voltage is estimated based on transformer disassembly analysis combined with the arc voltage estimation method. The arc power and energy waveforms that vary with time are then calculated based on the arc voltage and current. Based on the relationship between arc energy and gas production, that is, the discharge gas production is proportional to the arc energy, the arc discharge gas production V in the transformer oil is obtained. g .

4. The method for calculating the static pressure generated by arc discharge in a transformer oil tank according to claim 3, characterized in that: The arc discharge current was measured by a Rogowski coil, and the arc discharge voltage was measured by a high-voltage differential probe.

5. The method for calculating the static pressure generated by arc discharge in a transformer oil tank according to claim 3, characterized in that: The arc voltage is estimated using the Ayrton model, the Cassie arc voltage model, or the Mayr arc voltage model.

6. The method for calculating the static pressure generated by arc discharge in a transformer oil tank according to claim 1, characterized in that: The arc discharge product temperature T is measured based on transient high temperature measurement experiments or is deduced by the ideal gas state equation.

7. The method for calculating the static pressure generated by arc discharge in a transformer oil tank according to claim 1, characterized in that: Gas is injected into the oil tank through the gas injection experiment, and the gas space V0 is calculated by counting the gas injection volume and its corresponding static pressure in the oil tank. An airbag diaphragm is set at the gas injection port to prevent the injected gas from affecting the gas content in the oil.

8. The method for calculating the static pressure generated by arc discharge in a transformer oil tank according to claim 1, characterized in that: The amount of gas dissolved in oil V g The relationship between it and the corresponding static pressure p in the fuel tank is linear.

9. The method for calculating the static pressure generated by arc discharge in a transformer oil tank according to claim 1, characterized in that: The amount of gas dissolved in oil V g The linear relationship between the static pressure p in the corresponding fuel tank is: V0′=V0+k h , V′0 is the equivalent reserved gas volume including dissolved gas.

10. The method for calculating the static pressure generated by arc discharge in a transformer oil tank according to claim 9, characterized in that: Static pressure indicates that the pressure is evenly distributed in the tank. Static pressure has a time-varying characteristic that changes over time. The trend of static pressure in the tank versus gas production and equivalent reserved gas volume V′0 is plotted and displayed in a three-dimensional contour map.

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