Method for calculating discharge excitation amplitude in insulating oil by considering electron saturation speed

Abstract

The invention discloses an insulating oil discharge excitation amplitude calculation method and device considering electron saturation speed, a storage medium and computer equipment, and the method comprises the steps: applying impact voltage to two ends of a needle plate electrode in an arc fault simulation device of an oil-immersed current transformer, and calculating an ionization generation item corresponding to the arc fault simulation device, when an insulating oil layer breaks down due to an arc fault of the oil-immersed current transformer, a non-uniform field intensity is formed and abstracted into an insulating oil discharge process under a needle plate electrode; according to a plasma fluid dynamic model, calculating space electric field intensity and particle concentration distribution at any moment based on the ionization generation item; determining the electron saturation speed of the insulating oil according to the space electric field intensity and the particle concentration distribution; and obtaining discharge excitation amplitude data, and fitting a relational expression between the discharge excitation amplitude and the electronic saturation speed of the insulating oil based on the discharge excitation amplitude data and the electronic saturation speed of the insulating oil.

Description

Technical Field

[0001] The present application relates to the technical field of oil-immersed current transformers, and in particular to a method, device, storage medium and computer equipment for calculating the amplitude of discharge shock waves in insulating oil taking into account the electron saturation velocity. Background Art

[0002] In recent years, there have been many oil-immersed current transformer explosion accidents in Anhui Province, resulting in secondary damage such as sputtering. The fundamental reason is that the internal arc fault caused the insulation oil to break down, producing an oil-gas mixture that expanded rapidly under high temperature and high pressure conditions, which in turn caused the shell to be over-pressurized and ruptured. Due to the complex structure of the current transformer and the rapid development of the arc fault, it is not easy to capture the key characteristics of the arc fault, so it is currently unclear how the internal insulation oil changes under the arc fault.

[0003] The continuous development of arc discharge is the cause of the explosion. In this process, there is a strong electric field before the arc discharge occurs. During the arc development, the temperature and pressure inside the current transformer continue to rise until the explosion occurs. In the dynamic process of arc discharge before the current transformer explodes, there are multiple physical field coupling effects such as strong electric field, high temperature field and high pressure field, which constantly affect the overall operation of the current transformer. From a microscopic level, the arc in the insulating oil is a plasma that is electrically neutral as a whole due to the collision and coupling of a large number of charged particles. The energy generated by the collision of charged particles on the internal and external boundaries is displayed in the form of light. The more intense the reaction, the higher the brightness and the stronger the spectral signal.

[0004] Research on arc faults inside current transformers and construction of arc discharge plasma channel model in insulating oil are of guiding significance for revealing the evolution process from local discharge to arc formation before the explosion of current transformers, and lay a theoretical foundation for the pressure distribution analysis of transformer casings. Summary of the invention

[0005] In view of this, the embodiments of the present application provide a method, device, storage medium and computer equipment for calculating the discharge shock wave amplitude in insulating oil taking into account the electron saturation velocity, which can realize the modeling and analysis of the arc discharge plasma of insulating oil, and can not only reflect the development and motion characteristics of the arc plasma channel, but also quantitatively calculate the value of the electron saturation velocity that affects the development of the streamer, and then obtain the relationship between the shock wave amplitude and the electron saturation velocity through a large amount of liquid-electric effect experimental data. It can promote the theoreticalization and systematization of the arc discharge process in insulating oil, and has guiding significance for revealing the arc discharge mechanism in insulating oil.

[0006] According to one aspect of the present application, a method for calculating the discharge shock wave amplitude in insulating oil taking into account the electron saturation velocity is provided, the method comprising:

[0007] Apply impulse voltage to both ends of the needle plate electrode in the arc fault simulation device of the oil-immersed current transformer, and calculate the ionization generation item corresponding to the arc fault simulation device, wherein the uneven field strength formed when the insulating oil layer of the oil-immersed current transformer is broken down due to an arc fault is abstracted as the insulating oil discharge process under the needle plate electrode;

[0008] According to the plasma fluid dynamics model, the spatial electric field intensity and particle concentration distribution at any time are calculated based on the ionization generation term;

[0009] Determining the electronic saturation velocity of the insulating oil according to the spatial electric field strength and the particle concentration distribution;

[0010] The discharge shock wave amplitude data is acquired, and based on the discharge shock wave amplitude data and the insulating oil electron saturation velocity, a relationship between the discharge shock wave amplitude and the insulating oil electron saturation velocity is fitted.

[0011] Optionally, the device is also used for:

[0012] The ionization generation term is calculated using the field ionization theory equation, wherein the expression of the field ionization theory equation is:

[0013]

[0014] Among them, q is the electron charge, n0 is the number of ionizable molecules per unit volume, is the electric field strength, h is Planck's constant, a is the molecular distance, m * is the effective electron mass, Δ0 is the ionization energy of the insulating oil, and γ is the ionization coefficient.

[0015] Optionally, the ionization generation term includes a charge generation rate, and the particle concentration distribution includes a positive ion concentration distribution, a negative ion concentration distribution, and an electron concentration distribution; the expression of the plasma fluid dynamics model is:

[0016]

[0017]

[0018]

[0019]

[0020] Where t represents time, ε r represents the relative dielectric constant of insulating oil, ε0 represents the vacuum dielectric constant, q represents the amount of electrons, V represents the voltage value of the impulse voltage, and R ± Represents the recombination rate of positive and negative ions, R +e represents the recombination rate of positive ions and electrons, ρ +, - , e , respectively represent the concentration distribution of positive ions, negative ions, and electrons, μ + , μ - , μ e Respectively represent the mobility of positive ions, negative ions, and electrons, τ e is the electron-liquid molecule adsorption time, τ a is the electron attachment time constant, Represents the charge generation rate.

[0021] Optionally, the device is also used for:

[0022] The plasma channel conductivity is determined according to the particle concentration distribution, and the insulating oil electron saturation velocity is determined according to the insulating oil electron saturation velocity expression, wherein the insulating oil electron saturation velocity expression is:

[0023]

[0024] Among them, μ e_0 =1×10-4m2V-1s-1, reference electric field strength E0=0.1MV / cm, v1 is the fitting coefficient, σ is the plasma channel conductivity, ρ0 is the net space charge density, is a constant that depends on the electric field strength.

[0025] Optionally, Negatively correlated with the electric field strength.

[0026] Optionally, the relationship between the discharge shock wave amplitude and the electronic saturation velocity of the insulating oil is as follows:

[0027]

[0028]

[0029] Where I is the instantaneous current of the plasma arc channel, r is the streamer radius after the plasma arc breaks down, N A is Avogadro's constant, k is the streamer polarity coefficient of the insulating oil, L is the electrode distance, n + 、n - 、n e are the number of positive ions, negative ions and electrons respectively, and U(t) represents the change of impulse voltage over time.

[0030] Optionally, u(t)=U c (e -αt -e -βt ), where U c is the amplitude of the impulse voltage, α is the wavefront coefficient, and β is the wavetail coefficient.

[0031] According to another aspect of the present application, a device for calculating the discharge shock wave amplitude in insulating oil taking into account the electron saturation velocity is provided, the device being used for:

[0032] Apply impulse voltage to both ends of the needle plate electrode in the arc fault simulation device of the oil-immersed current transformer, and calculate the ionization generation item corresponding to the arc fault simulation device, wherein the uneven field strength formed when the insulating oil layer of the oil-immersed current transformer is broken down due to an arc fault is abstracted as the insulating oil discharge process under the needle plate electrode;

[0033] According to the plasma fluid dynamics model, the spatial electric field intensity and particle concentration distribution at any time are calculated based on the ionization generation term;

[0034] Determining the electronic saturation velocity of the insulating oil according to the spatial electric field strength and the particle concentration distribution;

[0035] The discharge shock wave amplitude data is acquired, and based on the discharge shock wave amplitude data and the insulating oil electron saturation velocity, a relationship between the discharge shock wave amplitude and the insulating oil electron saturation velocity is fitted.

[0036] Optionally, calculating an ionization generation item corresponding to the arc fault simulation device includes:

[0037] The ionization generation term is calculated using the field ionization theory equation, wherein the expression of the field ionization theory equation is:

[0038]

[0039] Among them, q is the electron charge, n0 is the number of ionizable molecules per unit volume, is the electric field strength, h is Planck's constant, a is the molecular distance, m * is the effective electron mass, Δ0 is the ionization energy of the insulating oil, and γ is the ionization coefficient.

[0040] Optionally, the ionization generation term includes a charge generation rate, and the particle concentration distribution includes a positive ion concentration distribution, a negative ion concentration distribution, and an electron concentration distribution; the expression of the plasma fluid dynamics model is:

[0041]

[0042]

[0043]

[0044]

[0045] Where t represents time, ε rrepresents the relative dielectric constant of insulating oil, ε0 represents the vacuum dielectric constant, q represents the amount of electrons, V represents the voltage value of the impulse voltage, and R ± Represents the recombination rate of positive and negative ions, R +e represents the recombination rate of positive ions and electrons, ρ + , - , e , respectively represent the concentration distribution of positive ions, negative ions, and electrons, μ + , μ - , μ e Respectively represent the mobility of positive ions, negative ions, and electrons, τ e is the electron-liquid molecule adsorption time, τ a is the electron attachment time constant, Represents the charge generation rate.

[0046] Optionally, determining the electronic saturation velocity of the insulating oil according to the spatial electric field strength and the particle concentration distribution includes:

[0047] The plasma channel conductivity is determined according to the particle concentration distribution, and the insulating oil electron saturation velocity is determined according to the insulating oil electron saturation velocity expression, wherein the insulating oil electron saturation velocity expression is:

[0048]

[0049] Among them, μ e_0 =1×10-4m2V-1s-1, reference electric field strength E0=0.1MV / cm, v1 is the fitting coefficient, σ is the plasma channel conductivity, ρ0 is the net space charge density, is a constant that depends on the electric field strength.

[0050] Optionally, Negatively correlated with the electric field strength.

[0051] Optionally, the relationship between the discharge shock wave amplitude and the electronic saturation velocity of the insulating oil is as follows:

[0052]

[0053]

[0054] Where I is the instantaneous current of the plasma arc channel, r is the streamer radius after the plasma arc breaks down, N A is Avogadro's constant, k is the streamer polarity coefficient of the insulating oil, L is the electrode distance, n + 、n-、n e are the number of positive ions, negative ions and electrons respectively, and U(t) represents the change of impulse voltage over time.

[0055] Optionally, u(t)=U c (e -αt -e -βt ), where U c is the amplitude of the impulse voltage, α is the wavefront coefficient, and β is the wavetail coefficient.

[0056] According to another aspect of the present application, a storage medium is provided, on which a computer program is stored, and when the program is executed by a processor, the method for calculating the discharge shock wave amplitude in insulating oil taking into account the electron saturation velocity is implemented.

[0057] According to another aspect of the present application, a computer device is provided, including a storage medium, a processor, and a computer program stored on the storage medium and executable on the processor, wherein when the processor executes the program, the method for calculating the discharge shock wave amplitude in insulating oil taking into account the electron saturation velocity is implemented.

[0058] By means of the above technical scheme, the present application provides a method, device, storage medium and computer equipment for calculating the discharge shock wave amplitude in insulating oil taking into account the electron saturation velocity, which can realize the modeling and analysis of the arc discharge plasma of insulating oil, and can not only reflect the development and motion characteristics of the arc plasma channel, but also quantitatively calculate the value of the electron saturation velocity that affects the development of the streamer, and then obtain the relationship between the shock wave amplitude and the electron saturation velocity through a large amount of experimental data of the liquid-electric effect. It can promote the theoreticalization and systematization of the arc discharge process in insulating oil, and has guiding significance for revealing the arc discharge mechanism in insulating oil.

[0059] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0061] Figure 1 A schematic flow chart of a method for calculating the amplitude of a discharge shock wave in insulating oil taking into account the electron saturation velocity provided in an embodiment of the present application is shown;

[0062] Figure 2 A flow chart of another method for calculating the discharge shock wave amplitude in insulating oil taking into account the electron saturation velocity provided in an embodiment of the present application is shown. DETAILED DESCRIPTION

[0063] The present application will be described in detail below with reference to the accompanying drawings and in combination with embodiments. It should be noted that the embodiments and features in the embodiments of the present application can be combined with each other without conflict.

[0064] In this embodiment, a method for calculating the discharge shock wave amplitude in insulating oil taking into account the electron saturation velocity is provided. Figure 1 As shown, the method includes:

[0065] S1, applying an impulse voltage to both ends of the needle plate electrode in the arc fault simulation device of the oil-immersed current transformer, and calculating the ionization generation item corresponding to the arc fault simulation device, wherein the uneven field strength formed when the insulating oil layer of the oil-immersed current transformer is broken down due to an arc fault is abstracted as the insulating oil discharge process under the needle plate electrode.

[0066] In the embodiment of the present application, in the arc fault simulation device of the oil-immersed current transformer, an impulse voltage is applied to both ends of the needle plate electrode. This step simulates the uneven field strength environment formed by the breakdown of the insulating oil layer when an arc fault occurs in the current transformer. Based on the field ionization theory equation of the insulating oil, the ionization generation term under this condition is calculated. Figure 2 The figure shows a schematic diagram of a needle plate electrode simulation model, where a high voltage electrode and a ground electrode are set in transformer oil, and an impulse voltage is applied to the high voltage electrode and the ground electrode. The calculation formula for the ionization generation term includes an impulse voltage equation and a field ionization theory equation. Optionally, in S1, the ionization generation term is calculated using the field ionization theory equation, wherein the expression of the field ionization theory equation is:

[0067]

[0068] Among them, q is the electron charge, n0 is the number of ionizable molecules per unit volume, is the electric field strength, h is Planck's constant, a is the molecular distance, m * is the effective electron mass, Δ0 is the ionization energy of the insulating oil, and γ is the ionization coefficient.

[0069] S2, according to the plasma fluid dynamics model, based on the ionization generation term, calculate the spatial electric field intensity and particle concentration distribution at any time.

[0070] In the embodiment of the present application, according to the plasma fluid dynamics model, the ionization generation term calculated in step S1 is used to further calculate the spatial electric field intensity and particle concentration distribution at any time. The model is based on a series of equations for iterative calculations, including the relative dielectric constant of the insulating oil, the vacuum dielectric constant, the electron charge, the voltage, the positive and negative ion recombination rate, the concentration of positive ions, negative ions, and electrons and their mobility, as well as parameters such as the electron-liquid molecule adsorption time and the charge generation rate. In S2, optionally, the ionization generation term includes the charge generation rate, and the particle concentration distribution includes the positive ion concentration distribution, the negative ion concentration distribution, and the electron concentration distribution; the expression of the plasma fluid dynamics model is:

[0071]

[0072]

[0073]

[0074]

[0075] Where t represents time, ε r represents the relative dielectric constant of insulating oil, ε0 represents the vacuum dielectric constant, q represents the amount of electrons, V represents the voltage value of the impulse voltage, and R ± Represents the recombination rate of positive and negative ions, R +e represents the recombination rate of positive ions and electrons, ρ + , - , e , respectively represent the concentration distribution of positive ions, negative ions, and electrons, μ + , μ - , μ e Respectively represent the mobility of positive ions, negative ions, and electrons, τ e is the electron-liquid molecule adsorption time, τ a is the electron attachment time constant, Represents the charge generation rate.

[0076] S3, determining the electron saturation velocity of the insulating oil according to the spatial electric field intensity and the particle concentration distribution.

[0077] In the embodiment of the present application, based on the spatial electric field strength and particle concentration distribution data calculated in step S2, an expression of the insulating oil electron saturation velocity is obtained by a data fitting method. The expression includes parameters such as the fitting coefficient, the plasma channel conductivity, the net space charge density, and a constant depending on the electric field. Optionally, the plasma channel conductivity is determined according to the particle concentration distribution, and the insulating oil electron saturation velocity is determined according to the insulating oil electron saturation velocity expression, wherein the insulating oil electron saturation velocity expression is:

[0078]

[0079] Among them, the electron mobility μ e_0 =1×10-4m2V-1s-1, reference electric field strength E0=0.1MV / cm, v1 is the fitting coefficient taken as 41km / s, σ is the plasma channel conductivity, ρ0 is the net space charge density, φ is a constant that depends on the electric field strength, and there is a negative correlation between φ and the electric field strength.

[0080] S4, acquiring discharge shock wave amplitude data, and fitting a relationship between the discharge shock wave amplitude and the insulating oil electron saturation velocity based on the discharge shock wave amplitude data and the insulating oil electron saturation velocity.

[0081] In the embodiment of the present application, by obtaining the experimental data of the discharge shock wave amplitude, combined with the insulating oil electron saturation velocity obtained in step S3, an empirical expression between the discharge shock wave amplitude and the insulating oil electron saturation velocity is established using a data fitting method. This expression includes parameters such as the instantaneous current of the plasma arc channel, the streamer radius after the plasma arc breakdown, the Avogadro constant, the streamer polarity coefficient of the insulating oil, and the electrode spacing. Optionally, the relationship between the discharge shock wave amplitude and the insulating oil electron saturation velocity is as follows:

[0082]

[0083]

[0084] Where I is the instantaneous current of the plasma arc channel, r is the streamer radius after the plasma arc breaks down, N A is Avogadro's constant, k is the streamer polarity coefficient of the insulating oil, which is 7.2, L is the electrode spacing, n + 、n - 、n e are the number of positive ions, negative ions and electrons respectively, U(t) represents the change of impulse voltage over time, u(t) = U c (e -αt -e -βt ), U c is the amplitude of the impulse voltage, α is the wavefront coefficient, and β is the wavetail coefficient.

[0085] Furthermore, the method may also include: S5, calculating the discharge shock wave amplitude of the oil-immersed current transformer based on the relationship.

[0086] Based on the relationship between the discharge shock wave amplitude and the insulating oil electron saturation velocity obtained in step S4, combined with the specific parameters of the oil-immersed current transformer (such as electrode spacing, insulating oil properties, etc.), the discharge shock wave amplitude of the oil-immersed current transformer is calculated. This step provides an important theoretical basis and calculation support for structural modification and performance improvement in actual engineering. Through the above steps, the present invention not only realizes the modeling and analysis of the insulating oil arc discharge process, but also quantitatively calculates the electron saturation velocity and the discharge shock wave amplitude, which is of great significance for revealing the arc discharge mechanism in insulating oil and guiding practical engineering applications.

[0087] By applying the technical solution of this embodiment, it is possible to model and analyze the arc discharge plasma of insulating oil, which can not only reflect the development and motion characteristics of the arc plasma channel, but also quantitatively calculate the value of the electron saturation velocity that affects the development of the streamer, and then obtain the relationship between the shock wave amplitude and the electron saturation velocity through a large amount of liquid-electric effect experimental data. It can promote the theoretical and systematized arc discharge process in insulating oil, and has guiding significance for revealing the arc discharge mechanism in insulating oil.

[0088] Further, as Figure 1 The specific implementation of the method, the embodiment of the present application provides a device for calculating the discharge shock wave amplitude in insulating oil taking into account the electron saturation velocity, the device comprising:

[0089] Apply impulse voltage to both ends of the needle plate electrode in the arc fault simulation device of the oil-immersed current transformer, and calculate the ionization generation item corresponding to the arc fault simulation device, wherein the uneven field strength formed when the insulating oil layer of the oil-immersed current transformer is broken down due to an arc fault is abstracted as the insulating oil discharge process under the needle plate electrode;

[0090] According to the plasma fluid dynamics model, the spatial electric field intensity and particle concentration distribution at any time are calculated based on the ionization generation term;

[0091] Determining the electronic saturation velocity of the insulating oil according to the spatial electric field strength and the particle concentration distribution;

[0092] The discharge shock wave amplitude data is acquired, and based on the discharge shock wave amplitude data and the insulating oil electron saturation velocity, a relationship between the discharge shock wave amplitude and the insulating oil electron saturation velocity is fitted.

[0093] Optionally, calculating an ionization generation item corresponding to the arc fault simulation device includes:

[0094] The ionization generation term is calculated using the field ionization theory equation, wherein the expression of the field ionization theory equation is:

[0095]

[0096] Among them, q is the electron charge, n0 is the number of ionizable molecules per unit volume, is the electric field strength, h is Planck's constant, a is the molecular distance, m * is the effective electron mass, Δ0 is the ionization energy of the insulating oil, and γ is the ionization coefficient.

[0097] Optionally, the ionization generation term includes a charge generation rate, and the particle concentration distribution includes a positive ion concentration distribution, a negative ion concentration distribution, and an electron concentration distribution; the expression of the plasma fluid dynamics model is:

[0098]

[0099]

[0100]

[0101]

[0102] Where t represents time, ε r represents the relative dielectric constant of insulating oil, ε0 represents the vacuum dielectric constant, q represents the amount of electrons, V represents the voltage value of the impulse voltage, and R ± Represents the recombination rate of positive and negative ions, R +e represents the recombination rate of positive ions and electrons, ρ + , - , e , respectively represent the concentration distribution of positive ions, negative ions, and electrons, μ + , μ - , μ e Respectively represent the mobility of positive ions, negative ions, and electrons, τ e is the electron-liquid molecule adsorption time, τ a is the electron attachment time constant, Represents the charge generation rate.

[0103] Optionally, determining the electronic saturation velocity of the insulating oil according to the spatial electric field strength and the particle concentration distribution includes:

[0104] The plasma channel conductivity is determined according to the particle concentration distribution, and the insulating oil electron saturation velocity is determined according to the insulating oil electron saturation velocity expression, wherein the insulating oil electron saturation velocity expression is:

[0105]

[0106] Among them, μ e_0=1×10-4m2V-1s-1, reference electric field strength E0=0.1MV / cm, v1 is the fitting coefficient, σ is the plasma channel conductivity, ρ0 is the net space charge density, is a constant that depends on the electric field strength.

[0107] Optionally, Negatively correlated with the electric field strength.

[0108] Optionally, the relationship between the discharge shock wave amplitude and the electronic saturation velocity of the insulating oil is as follows:

[0109]

[0110]

[0111] Where I is the instantaneous current of the plasma arc channel, r is the streamer radius after the plasma arc breaks down, N A is Avogadro's constant, k is the streamer polarity coefficient of the insulating oil, L is the electrode distance, n + 、n - 、n e are the number of positive ions, negative ions and electrons respectively, and U(t) represents the change of impulse voltage over time.

[0112] Optionally, u(t)=U c (e -αt -e -βt ), where U c is the amplitude of the impulse voltage, α is the wavefront coefficient, and β is the wavetail coefficient.

[0113] It should be noted that for other corresponding descriptions of the functional units involved in the device for calculating the discharge shock wave amplitude in insulating oil taking into account the electron saturation velocity provided in the embodiment of the present application, reference can be made to Figure 1 The corresponding description in the method will not be repeated here.

[0114] The embodiment of the present application also provides a computer device, which can be a personal computer, a server, a network device, etc. The computer device includes a bus, a processor, a memory and a communication interface, and can also include an input and output interface and a display device. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program and a database. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The database of the computer device is used to store location information. The network interface of the computer device is used to communicate with an external terminal through a network connection. When the computer program is executed by the processor, the steps in each method embodiment are implemented.

[0115] Those skilled in the art will appreciate that the structure of the above-mentioned computer device is only a partial structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components, or combine certain components, or have a different arrangement of components.

[0116] In one embodiment, a computer-readable storage medium is provided. The computer-readable storage medium may be non-volatile or volatile, and stores a computer program thereon. When the computer program is executed by a processor, the steps in the above-mentioned method embodiments are implemented.

[0117] In one embodiment, a computer program product is provided, including a computer program, which implements the steps in the above method embodiments when executed by a processor.

[0118] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, stored data, displayed data, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties.

[0119] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to the memory, database or other medium used in the embodiments provided in the present application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetoresistive random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. As an illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM). The database involved in each embodiment provided in this application may include at least one of a relational database and a non-relational database. Non-relational databases may include distributed databases based on blockchains, etc., but are not limited to this. The processor involved in each embodiment provided in this application may be a general-purpose processor, a graphics processor, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, etc., but are not limited to this.

[0120] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0121] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A method for calculating the discharge shock wave amplitude in insulating oil taking into account the electron saturation velocity, characterized in that: The method comprises: Apply impulse voltage to both ends of the needle plate electrode in the arc fault simulation device of the oil-immersed current transformer, and calculate the ionization generation item corresponding to the arc fault simulation device, wherein the uneven field strength formed when the insulating oil layer of the oil-immersed current transformer is broken down due to an arc fault is abstracted as the insulating oil discharge process under the needle plate electrode; According to the plasma fluid dynamics model, the spatial electric field intensity and particle concentration distribution at any time are calculated based on the ionization generation term; Determining the electronic saturation velocity of the insulating oil according to the spatial electric field strength and the particle concentration distribution; The discharge shock wave amplitude data is acquired, and based on the discharge shock wave amplitude data and the insulating oil electron saturation velocity, a relationship between the discharge shock wave amplitude and the insulating oil electron saturation velocity is fitted.

2. The method according to claim 1, characterized in that: Calculate the ionization generation items corresponding to the arc fault simulator, including: The ionization generation term is calculated using the field ionization theory equation, wherein the expression of the field ionization theory equation is: Among them, q is the electron charge, n0 is the number of ionizable molecules per unit volume, is the electric field strength, h is Planck's constant, a is the molecular distance, m * is the effective electron mass, Δ0 is the ionization energy of the insulating oil, and γ is the ionization coefficient.

3. The method according to claim 2, characterized in that The ionization generation term includes the charge generation rate, and the particle concentration distribution includes the positive ion concentration distribution, the negative ion concentration distribution and the electron concentration distribution; the expression of the plasma fluid dynamics model is: Where t represents time, ε r represents the relative dielectric constant of insulating oil, ε0 represents the vacuum dielectric constant, q represents the amount of electrons, V represents the voltage value of impulse voltage, and R ± Represents the recombination rate of positive and negative ions, R +e represents the recombination rate of positive ions and electrons, ρ + , - , e , respectively represent the concentration distribution of positive ions, negative ions, and electrons, μ + , μ - , μ e Respectively represent the mobility of positive ions, negative ions, and electrons, τ e is the electron-liquid molecule adsorption time, τ a is the electron attachment time constant, Represents the charge generation rate.

4. The method according to claim 3, characterized in that Determining the electronic saturation velocity of the insulating oil according to the spatial electric field strength and the particle concentration distribution includes: The plasma channel conductivity is determined according to the particle concentration distribution, and the insulating oil electron saturation velocity is determined according to the insulating oil electron saturation velocity expression, wherein the insulating oil electron saturation velocity expression is: Among them, μ e_0 =1×10 -4 m 2 V -1 s -1 , reference electric field strength E0 = 0.1 MV / cm, v1 is the fitting coefficient, σ is the plasma channel conductivity, ρ0 is the net space charge density, is a constant that depends on the electric field strength.

5. The method according to claim 4, characterized in that There is a negative correlation between φ and the electric field strength.

6. The method according to claim 4, characterized in that The relationship between the discharge shock wave amplitude and the electronic saturation velocity of the insulating oil is as follows: Where I is the instantaneous current of the plasma arc channel, r is the streamer radius after the plasma arc breaks down, N A is Avogadro's constant, k is the streamer polarity coefficient of the insulating oil, L is the electrode distance, n + 、n - 、n e are the number of positive ions, negative ions and electrons respectively, and U(t) represents the change of impulse voltage over time.

7. The method according to claim 6, characterized in that u(t)=U c (e -αt -e -βt ), where U c is the amplitude of the impulse voltage, α is the wavefront coefficient, and β is the wavetail coefficient.

8. A device for calculating the amplitude of discharge shock waves in insulating oil taking into account the electron saturation velocity, characterized in that: The device is used for: Apply impulse voltage to both ends of the needle plate electrode in the arc fault simulation device of the oil-immersed current transformer, and calculate the ionization generation item corresponding to the arc fault simulation device, wherein the uneven field strength formed when the insulating oil layer of the oil-immersed current transformer is broken down due to an arc fault is abstracted as the insulating oil discharge process under the needle plate electrode; According to the plasma fluid dynamics model, the spatial electric field intensity and particle concentration distribution at any time are calculated based on the ionization generation term; Determining the electronic saturation velocity of the insulating oil according to the spatial electric field strength and the particle concentration distribution; The discharge shock wave amplitude data is acquired, and based on the discharge shock wave amplitude data and the insulating oil electron saturation velocity, a relationship between the discharge shock wave amplitude and the insulating oil electron saturation velocity is fitted.

9. A storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the method according to any one of claims 1 to 7 is implemented.

10. A computer device comprising a storage medium, a processor, and a computer program stored in the storage medium and executable on the processor, characterized in that: When the processor executes the computer program, the method according to any one of claims 1 to 7 is implemented.

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