Insulation structure electric field distribution calculation method, system, equipment and medium

Abstract

The invention belongs to the technical field of electric field distribution calculation, and discloses an insulation structure electric field distribution calculation method, system and device and a medium, and the method comprises the steps: carrying out the conductivity test of an oil paper insulation material based on a pre-constructed oil paper insulation material test platform, and obtaining the conductivity of the oil paper insulation material according to a test result; based on the ion migration injection process and the free ion degree concentration, the dependency relationship between the oil paper insulation material conductivity and the field intensity and the temperature is analyzed, and a field intensity and temperature dependency quantitative relationship model of the oil paper insulation conductivity is obtained; and the dependency quantitative relation model and the partial differential equation are fused to calculate the electric field distribution of the insulation structure under the oil paper conductivity electrothermal coupling characteristic. According to the method, the electric-heat-flow multi-field coupling relation in the valve side insulation structure is analyzed according to the analysis result to achieve electric field distribution calculation.

Description

Technical Field

[0001] The present invention relates to the technical field of electric field distribution calculation, and in particular to a method, system, device and medium for calculating electric field distribution of an insulating structure. Background Art

[0002] A transformer is a device that uses the principle of electromagnetic induction to change AC voltage. It is mainly used to change the voltage of an AC power source so that it can be applied to different electronic equipment or power transmission systems. Transformers are widely used in power systems, industrial automation, transportation and other fields. They are indispensable key equipment in power electronic equipment and systems. A converter transformer is a special transformer that is mainly used in high-voltage direct current (HVDC) transmission systems or back-to-back converter stations to achieve mutual conversion between AC and DC.

[0003] The insulation structure of a transformer is an important component to ensure its normal operation and prevent electrical failures. The insulation structure of a transformer is mainly divided into two categories: internal insulation and external insulation. The internal insulation is further divided into main insulation and longitudinal insulation. Since the valve-side winding of a converter transformer is subjected to AC and DC superimposed voltages, the electric field distribution in the insulation structure is more complicated than that of an AC transformer, causing its failure rate to remain high. The current mainstream insulation structure design method ignores the effects of electric fields, temperature, etc. on the conductivity of oil-paper materials, and is not suitable for the valve-side main insulation structure of a converter transformer containing a large amount of DC voltage.

[0004] Therefore, how to provide a method, system, equipment and medium for calculating the electric field distribution of an insulating structure is a problem that needs to be solved urgently. Summary of the invention

[0005] The embodiments of the present invention provide a method, system, device and medium for calculating the electric field distribution of an insulation structure, so as to solve the problem that the mainstream insulation structure design method in the prior art ignores the influence of electric field, temperature, etc. on the conductivity of oil-paper materials and is not suitable for the main insulation structure on the valve side of a converter transformer containing a large amount of DC voltage.

[0006] In order to have a basic understanding of some aspects of the disclosed embodiments, a brief summary is given below. This summary is not intended to be a general review, nor is it intended to identify key / important components or to delineate the scope of protection of these embodiments. Its only purpose is to present some concepts in a simple form as a preface to the detailed description that follows.

[0007] According to a first aspect of an embodiment of the present invention, a method for calculating electric field distribution of an insulating structure is provided.

[0008] In one embodiment, a method for calculating electric field distribution of an insulating structure includes:

[0009] Based on the pre-built oil-paper insulation material test platform, the conductivity of the oil-paper insulation material is tested, and the conductivity of the oil-paper insulation material is obtained according to the test results;

[0010] Based on the ion migration injection process and the free ion concentration, the dependence of the electrical conductivity of oil-paper insulation material on field intensity and temperature is analyzed, and the field intensity temperature dependence quantitative relationship model of the electrical conductivity of oil-paper insulation is obtained according to the dependence relationship;

[0011] The quantitative relationship model of the field intensity temperature dependence of the oil-paper insulation conductivity is integrated with the partial differential equation, and the electric field distribution of the insulation structure under the electrothermal coupling characteristics of the oil-paper conductivity is calculated based on the fusion results.

[0012] In one embodiment, based on a pre-built oil-paper insulation material test platform, the conductivity of the oil-paper insulation material is tested, and the conductivity of the oil-paper insulation material is obtained according to the test result, including:

[0013] The host computer, electrostatic machine and resistance tester are selected as the basis for the construction of the oil-paper insulation material test platform. The voltage excitation mode is set based on the DC step voltage excitation test method, and the electrostatic meter is used as the current signal acquisition device of the sample to be tested to obtain the oil-paper insulation material test platform.

[0014] Insulating oil and insulating paperboard are selected as test objects according to the set model information, and pre-treatment is performed on the insulating oil and insulating paperboard respectively, and the oil-paper insulating material is obtained based on the pre-treatment results;

[0015] The conductivity of insulating oil and insulating paperboard was tested respectively using the oil-paper insulation material test platform and the insulation conductivity test rules, and the insulation conductivity of the insulating oil and insulating paperboard was calculated based on the test results.

[0016] In one embodiment, based on the ion migration injection process and the free ion concentration, the dependence between the conductivity of the oil-paper insulation material and the field strength and temperature is analyzed, and the field strength temperature dependence quantitative relationship model of the oil-paper insulation conductivity is obtained according to the dependence, including:

[0017] The free ion migration process and ion injection process in the insulating oil are analyzed by Coulomb attraction, and the relationship between the conductivity of the insulating oil and the electric field strength is analyzed according to the migration and injection process. Based on the relationship results, the field strength dependence relationship of the conductivity of the insulating oil is generated;

[0018] The influence of field strength on the conductivity of insulating paper is analyzed based on the field strength dependence relation of the conductivity of insulating oil, and the field strength dependence relation of the conductivity of insulating paper is obtained according to the influence results;

[0019] The influence of different temperatures on the free ion concentration and ion traction rate of insulating oil and insulating paperboard is analyzed, and a quantitative relationship model of the field strength temperature dependence of the oil-paper insulation conductivity is obtained based on the influence relationship.

[0020] In one embodiment, the free ion migration process and the ion injection process in the insulating oil are analyzed by Coulomb attraction, and the relationship between the conductivity of the insulating oil and the electric field strength is analyzed according to the migration and injection process. The field strength dependence relationship of the conductivity of the insulating oil is generated based on the relationship result, including:

[0021] The attraction and association between free ions in the insulating oil is analyzed under the action of Coulomb attraction and molecular thermal motion, and the dissociation and complex equilibrium process in the insulating oil is analyzed based on the attraction and association, and the migration process of free ions in the insulating oil is obtained;

[0022] The current density of insulating oil is calculated based on the free ion escape rate constant, and the influence mechanism of free ions on the conductivity of insulating oil during injection and migration is determined according to the calculation results.

[0023] The relationship between the electrical conductivity of insulating oil and the electric field strength is analyzed based on the influencing mechanism, and the field strength dependence relationship of the electrical conductivity of insulating oil is generated according to the relationship results.

[0024] In one embodiment, the field intensity dependence of the electrical conductivity of the insulating oil is expressed as:

[0025]

[0026] Where σ(E) represents the field intensity dependence of the electrical conductivity of the insulating oil, E represents the electric field intensity, σ represents the electrical conductivity, and K + With K - They represent the mobility of positive and negative free ions, e0 represents the electron charge, and K D (E) represents the conductivity of the insulating oil when the dissociation and composite equilibrium is not broken, k R represents the dissociation coefficient, k m (E) represents the rate at which the ion mobility decreases with the concentration of free ions in the insulating oil, v0 represents the concentration of ion pairs in the insulating oil, represents the density of the interface charge, k es represents the interfacial ion escape rate constant.

[0027] In one embodiment, the field intensity temperature dependence quantitative relationship model of the oil-paper insulation conductivity is integrated with the partial differential equation, and the electric field distribution of the insulation structure under the electric-thermal coupling characteristics of the oil-paper conductivity is calculated based on the integrated result, including:

[0028] Based on the operating conditions of the converter transformer insulation structure, thermal-fluid coupling calculation is performed, and the steady-state temperature field distribution in the main insulation structure is obtained according to the calculation results;

[0029] Based on the partial differential equation and the quantitative relationship model of the field intensity temperature dependence of the oil-paper insulation conductivity, the DC electric field distribution solution equation is established to calculate the electric field distribution of the insulation structure under the electrothermal coupling characteristics of the oil-paper conductivity.

[0030] According to the distribution results, the conductivity of oil-paper insulation under the influence of field strength and temperature is analyzed to obtain the influence of electrothermal coupling on the electric field distribution. Based on the influence results, the main insulation structure of the valve side of the converter transformer is established.

[0031] In one embodiment, performing thermal-fluid coupling calculation based on the operating conditions of the converter transformer insulation structure and obtaining the steady-state temperature field distribution in the main insulation structure according to the calculation results includes:

[0032] Based on the operating conditions of the insulation structure of the converter transformer, the equivalent resistance of the grid-side and valve-side windings of the insulation structure is obtained, and the resistance loss and eddy current loss are obtained according to the equivalent resistance;

[0033] The loss coefficient between the eddy current loss and the winding DC loss is obtained based on the current density in the winding conductor. The loss coefficient is integrated with the energy conservation equation to implement thermal-fluid coupling calculation, and the steady-state temperature field distribution in the main insulation structure is obtained based on the calculation results.

[0034] In one embodiment, the loss coefficient is calculated as:

[0035]

[0036] In the formula, k W represents the loss factor, k represents a parameter related to resistivity, a represents the wire thickness, d represents the current density in the winding wire, and B mr It represents the maximum value of the leakage magnetic density in the main leakage flux channel, and f represents the frequency.

[0037] According to a second aspect of an embodiment of the present invention, a system for calculating electric field distribution of an insulating structure is provided.

[0038] In one embodiment, a system for calculating electric field distribution of an insulating structure includes:

[0039] An oil-paper insulation material conductivity calculation unit is used to perform a conductivity test on the oil-paper insulation material based on a pre-built oil-paper insulation material test platform, and obtain the conductivity of the oil-paper insulation material according to the test result;

[0040] A dependency quantitative relationship model acquisition unit is used to analyze the dependency relationship between the electrical conductivity of the oil-paper insulation material and the field intensity and temperature based on the ion migration injection process and the free ion concentration, and to obtain a field intensity temperature dependency quantitative relationship model of the electrical conductivity of the oil-paper insulation according to the dependency relationship;

[0041] The electric field distribution calculation unit of the insulation structure is used to integrate the quantitative relationship model of the field intensity temperature dependence of the oil-paper insulation conductivity with the partial differential equation, and calculate the electric field distribution of the insulation structure under the electrothermal coupling characteristics of the oil-paper conductivity based on the fusion result.

[0042] In one embodiment, the oil-paper insulation material conductivity calculation unit includes:

[0043] The oil-paper insulation material test platform construction module is used to select the host computer, electrostatic machine and resistance tester as the basis for the construction of the oil-paper insulation material test platform, set the voltage excitation mode based on the DC step voltage excitation test method, and use the electrostatic meter as the current signal acquisition device of the sample to be tested to obtain the oil-paper insulation material test platform;

[0044] The oil-paper insulation material acquisition module is used to select insulating oil and insulating paperboard as test objects according to the set model information, and perform pre-test processing on the insulating oil and insulating paperboard respectively, and obtain the oil-paper insulation material based on the pre-test processing results;

[0045] The insulation conductivity test module is used to perform conductivity tests on insulating oil and insulating paperboard respectively using the oil-paper insulation material test platform and the insulation conductivity test rules, and to obtain the insulation conductivity of the insulating oil and the insulating paperboard according to the test results.

[0046] In one embodiment, the dependency quantization relationship model acquisition unit includes:

[0047] The insulating oil dependency acquisition module is used to analyze the free ion migration process and ion injection process in the insulating oil through Coulomb attraction, and analyze the relationship between the insulating oil conductivity and the electric field strength according to the migration and injection process, and generate the field strength dependence relationship of the insulating oil conductivity based on the relationship results;

[0048] The insulation paperboard dependency acquisition module is used to analyze the influence of field strength on the conductivity of insulation paper based on the field strength dependency relationship of the conductivity of insulating oil, and obtain the field strength dependency relationship of the conductivity of insulation paper according to the influence result;

[0049] The quantitative relationship model acquisition module is used to analyze the influence of different temperatures on the free ion concentration and ion traction rate of insulating oil and insulating paperboard, and obtain the field intensity temperature dependence quantitative relationship model of oil-paper insulation conductivity based on the influence relationship.

[0050] In one embodiment, the insulating oil dependency acquisition module analyzes the free ion migration process and ion injection process in the insulating oil through Coulomb attraction, analyzes the relationship between the insulating oil conductivity and the electric field strength according to the migration and injection process, and generates the field strength dependence relationship of the insulating oil conductivity based on the relationship results. At the same time, the attractive association state between the free ions in the insulating oil is analyzed under the action of Coulomb attraction and molecular thermal motion, and the dissociation and complex equilibrium process in the insulating oil is analyzed based on the attractive association state to obtain the free ion migration process in the insulating oil; the insulating oil current density is calculated based on the free ion escape rate constant, and the influence mechanism of the free ions on the conductivity of the insulating oil during the injection process and the migration process is determined according to the calculation results; the relationship between the insulating oil conductivity and the electric field strength is analyzed based on the influence mechanism, and the field strength dependence relationship of the insulating oil conductivity is generated according to the relationship results.

[0051] In one embodiment, the field intensity dependence of the electrical conductivity of the insulating oil is expressed as:

[0052]

[0053] Where σ(E) represents the field intensity dependence of the electrical conductivity of the insulating oil, E represents the electric field intensity, σ represents the electrical conductivity, and K + With K - They represent the mobility of positive and negative free ions, e0 represents the electron charge, and K D (E) represents the conductivity of the insulating oil when the dissociation and composite equilibrium is not broken, k R represents the dissociation coefficient, k m (E) represents the rate at which the ion mobility decreases with the concentration of free ions in the insulating oil, v0 represents the concentration of ion pairs in the insulating oil, represents the density of the interface charge, k es represents the interfacial ion escape rate constant.

[0054] In one embodiment, the insulation structure electric field distribution calculation unit includes:

[0055] The steady-state temperature field distribution analysis module is used to perform thermal-fluid coupling calculation based on the operating conditions of the converter transformer insulation structure, and obtain the steady-state temperature field distribution in the main insulation structure according to the calculation results;

[0056] The electric field distribution calculation module is used to establish a DC electric field distribution solution equation based on the partial differential equation and the quantitative relationship model of the field intensity temperature dependence of the oil-paper insulation conductivity to calculate the electric field distribution of the insulation structure under the electrothermal coupling characteristics of the oil-paper conductivity;

[0057] The main insulation structure establishment module is used to analyze the oil-paper insulation conductivity under the influence of field strength and temperature according to the distribution results, obtain the influence of electrothermal coupling on the electric field distribution, and establish the main insulation structure on the valve side of the converter transformer based on the influence results.

[0058] According to a third aspect of an embodiment of the present invention, a computer device is provided.

[0059] In one embodiment, the computer device includes a memory and a processor, the memory stores a computer program, and the processor implements the steps of the above method when executing the computer program.

[0060] According to a fourth aspect of embodiments of the present invention, a computer-readable storage medium is provided.

[0061] In one embodiment, the computer-readable storage medium stores a computer program, and the computer program implements the steps of the above method when executed by a processor.

[0062] The technical solution provided by the embodiment of the present invention may have the following beneficial effects:

[0063] 1. The present invention supports adjusting the electric field strength and temperature by building an experimental platform, and performs conductivity tests on oil-paper samples under different electric fields and temperatures to obtain the conductivity data of oil and paper under different temperatures and electric fields in the experiment. The field strength and temperature dependence of conductivity are constructed in combination with the mechanism fitting curve, and the electric-thermal-fluid multi-field coupling relationship in the valve-side insulation structure is analyzed according to the analysis results, so as to improve the existing electric field calculation method of substituting a fixed conductivity, and obtain an electric field distribution calculation model that considers the electric-thermal coupling characteristics of oil-paper conductivity.

[0064] 2. The calculation method of the electric field distribution of the main insulation structure inside the converter transformer proposed in the present invention takes into account the field strength and temperature dependence of the oil-paper conductivity, compared with the commonly used constant conductivity method, thereby improving the accuracy of the calculation of the electric field strength inside the converter transformer.

[0065] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0067] Figure 1 is a flow chart of a method for calculating electric field distribution of an insulating structure according to an exemplary embodiment;

[0068] Figure 2is a principle block diagram of a system for calculating electric field distribution of an insulating structure according to an exemplary embodiment;

[0069] Figure 3 is a flowchart of a method for calculating electric field distribution of an insulating structure according to an exemplary embodiment;

[0070] Figure 4 It is an oil-paper insulation material conductivity testing platform shown according to an exemplary embodiment;

[0071] Figure 5 is a diagram showing the fitting results of the electric field and temperature dependence model of oil-paper insulation conductivity according to an exemplary embodiment;

[0072] Figure 6 is a flow chart of electric field distribution calculation considering the electric-thermal coupling effect of oil-paper conductivity according to an exemplary embodiment;

[0073] Figure 7 is a simulated cloud diagram of field intensity distribution under a DC applied voltage test according to an exemplary embodiment;

[0074] Figure 8 The figure is a schematic diagram showing the structure of a computer device according to an exemplary embodiment. DETAILED DESCRIPTION

[0075] The following description and accompanying drawings fully illustrate the specific embodiments of this article so that those skilled in the art can practice them. Parts and features of some embodiments may be included in or replace parts and features of other embodiments. The scope of the embodiments of this article includes the entire scope of the claims, as well as all available equivalents of the claims. Herein, the terms "first", "second", etc. are only used to distinguish one element from another, without requiring or implying any actual relationship or order between these elements. In fact, the first element can also be called the second element, and vice versa. Moreover, the terms "include", "comprise" or any other variant thereof are intended to cover non-exclusive inclusion, so that the structure, device or equipment including a series of elements includes not only those elements, but also other elements that are not explicitly listed, or also include elements inherent to such structure, device or equipment. In the absence of more restrictions, the elements defined by the sentence "including one..." do not exclude the existence of other identical elements in the structure, device or equipment including the elements. Each embodiment is described in a progressive manner herein, and each embodiment focuses on the differences from other embodiments, and the same and similar parts between the embodiments can be referred to each other.

[0076] The terms "longitudinal", "lateral", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc. in this document indicate the orientation or position relationship based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing this document and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In the description of this document, unless otherwise specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a mechanical connection or an electrical connection, it can also be the internal communication of two elements, it can be a direct connection, or it can be an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0077] As used herein, the term "plurality" means two or more than two, unless otherwise specified.

[0078] In this document, the character " / " indicates that the preceding and following objects are in an "or" relationship. For example, A / B means: A or B.

[0079] In this article, the term "and / or" is a description of the association relationship between objects, indicating that three relationships may exist. For example, A and / or B means: A or B, or, A and B.

[0080] It should be understood that, although the various steps in the flow chart are displayed in sequence according to the indication of the arrows, these steps are not necessarily executed in sequence according to the order indicated by the arrows. Unless there is a clear description in this article, the execution of these steps is not strictly limited in order, and these steps can be executed in other orders. Moreover, at least a portion of the steps in the figure may include multiple sub-steps or multiple stages, and these sub-steps or stages are not necessarily executed at the same time, but can be executed at different times, and the execution order of these sub-steps or stages is not necessarily to be carried out in sequence, but can be executed in turn or alternately with other steps or at least a portion of the sub-steps or stages of other steps.

[0081] Each module in the device or system of the present application can be implemented in whole or in part by software, hardware, or a combination thereof. The above modules can be embedded in or independent of a processor in a computer device in the form of hardware, or can be stored in a memory in a computer device in the form of software, so that the processor can call and execute operations corresponding to the above modules.

[0082] In the absence of conflict, the embodiments of the present invention and the features of the embodiments may be combined with each other.

[0083] Figure 1An embodiment of the method for calculating the electric field distribution of an insulating structure of the present invention is shown.

[0084] In this optional embodiment, the method for calculating the electric field distribution of the insulating structure includes:

[0085] Step S101, based on a pre-built oil-paper insulation material test platform, conduct an electrical conductivity test on the oil-paper insulation material, and obtain the electrical conductivity of the oil-paper insulation material according to the test result;

[0086] Step S103, based on the ion migration injection process and the free ion concentration, analyzing the dependence between the conductivity of the oil-paper insulation material and the field strength and temperature, and obtaining a quantitative relationship model of the field strength temperature dependence of the oil-paper insulation conductivity according to the dependence;

[0087] Step S105, integrating the quantitative relationship model of the field intensity temperature dependence of the oil-paper insulation conductivity with the partial differential equation, and calculating the electric field distribution of the insulation structure under the electric-thermal coupling characteristics of the oil-paper conductivity based on the fusion result.

[0088] In this optional embodiment, when conducting a conductivity test on the oil-paper insulation material based on a pre-constructed oil-paper insulation material test platform and obtaining the conductivity of the oil-paper insulation material according to the test results, a host computer, an electrostatic machine and a resistance tester can be selected as the basis for constructing the oil-paper insulation material test platform, a voltage excitation mode is set based on a DC step voltage excitation test method, and an electrostatic meter is used as a current signal acquisition device for the sample to be tested to obtain the oil-paper insulation material test platform; insulating oil and insulating cardboard are selected as test objects according to the set model information, and pre-test processing is performed on the insulating oil and the insulating cardboard respectively, and the oil-paper insulation material is obtained based on the pre-test processing results; the conductivity of the insulating oil and the insulating cardboard are tested respectively using the oil-paper insulation material test platform and the insulation conductivity test rules, and the insulation conductivity of the insulating oil and the insulating cardboard is obtained according to the test results.

[0089] In this optional embodiment, when analyzing the dependence between the electrical conductivity of the oil-paper insulation material and the field strength and temperature based on the ion migration injection process and the free ion concentration, and obtaining the field strength temperature dependence quantitative relationship model of the oil-paper insulation conductivity according to the dependence relationship, the free ion migration process and the ion injection process in the insulating oil can be analyzed by Coulomb attraction, and the relationship between the electrical conductivity of the insulating oil and the electric field strength can be analyzed according to the migration injection process, and the field strength dependence relationship of the insulating oil conductivity can be generated based on the relationship results; the influence of the field strength on the electrical conductivity of the insulating paper can be analyzed based on the field strength dependence relationship of the electrical conductivity of the insulating oil, and the field strength dependence relationship of the electrical conductivity of the insulating paper can be obtained according to the influence results; the influence of different temperatures on the free ion concentration and the ion pulling rate of the insulating oil and the insulating paperboard is analyzed, and the field strength temperature dependence quantitative relationship model of the electrical conductivity of the oil-paper insulation can be obtained based on the influence relationship.

[0090] In this optional embodiment, when analyzing the free ion migration process and ion injection process in the insulating oil through Coulomb attraction, and analyzing the relationship between the electrical conductivity of the insulating oil and the electric field strength based on the migration and injection process, and generating the field strength dependence relationship of the electrical conductivity of the insulating oil based on the relationship results, the attraction and association state between the free ions in the insulating oil can be analyzed under the action of Coulomb attraction and molecular thermal motion, and the dissociation and complex equilibrium process in the insulating oil can be analyzed based on the attraction and association state to obtain the free ion migration process in the insulating oil; the insulating oil current density is calculated based on the free ion escape rate constant, and the influence mechanism of the free ions on the electrical conductivity of the insulating oil during the injection process and the migration process is determined based on the calculation results; the relationship between the electrical conductivity of the insulating oil and the electric field strength is analyzed based on the influence mechanism, and the field strength dependence relationship of the electrical conductivity of the insulating oil is generated based on the relationship results.

[0091] In this optional embodiment, when the quantitative relationship model of the field strength temperature dependence of the oil-paper insulation conductivity is integrated with the partial differential equation, and the electric field distribution of the insulation structure under the electrothermal coupling characteristics of the oil-paper conductivity is calculated based on the fusion result, a thermal flow coupling calculation can be performed based on the operating conditions of the insulation structure of the converter transformer, and the steady-state temperature field distribution in the main insulation structure is obtained according to the calculation results; based on the partial differential equation and the quantitative relationship model of the field strength temperature dependence of the oil-paper insulation conductivity, a DC electric field distribution solution equation is established to calculate the electric field distribution of the insulation structure under the electrothermal coupling characteristics of the oil-paper conductivity; based on the distribution results, the oil-paper insulation conductivity under the influence of field strength and temperature is analyzed to obtain the influence of the electrothermal coupling on the electric field distribution, and the main insulation structure on the valve side of the converter transformer is established based on the influence results.

[0092] In this optional embodiment, when performing thermal-fluid coupling calculations based on the operating conditions of the converter transformer insulation structure and obtaining the steady-state temperature field distribution in the main insulation structure according to the calculation results, the equivalent resistance of the grid-side and valve-side windings of the insulation structure can be obtained based on the operating conditions of the converter transformer insulation structure, and the resistance loss and eddy current loss can be obtained based on the equivalent resistance; the loss coefficient between the eddy current loss and the winding DC loss is obtained based on the current density in the winding conductor, the loss coefficient is integrated with the energy conservation equation to implement thermal-fluid coupling calculations, and the steady-state temperature field distribution in the main insulation structure is obtained according to the calculation results.

[0093] Figure 2 An embodiment of an insulating structure electric field distribution calculation system of the present invention is shown.

[0094] In this optional embodiment, the insulation structure electric field distribution calculation system includes:

[0095] The oil-paper insulation material conductivity calculation unit 201 is used to perform a conductivity test on the oil-paper insulation material based on a pre-built oil-paper insulation material test platform, and obtain the conductivity of the oil-paper insulation material according to the test result;

[0096] The dependence quantitative relationship model acquisition unit 203 is used to analyze the dependence relationship between the conductivity of the oil-paper insulation material and the field intensity and temperature based on the ion migration injection process and the free ion concentration, and obtain the field intensity temperature dependence quantitative relationship model of the oil-paper insulation conductivity according to the dependence relationship;

[0097] The insulation structure electric field distribution calculation unit 205 is used to fuse the field intensity temperature dependence quantitative relationship model of the oil-paper insulation conductivity with the partial differential equation, and calculate the electric field distribution of the insulation structure under the electric-thermal coupling characteristics of the oil-paper conductivity based on the fusion result.

[0098] In this optional embodiment, the oil-paper insulation material conductivity calculation unit 201 includes an oil-paper insulation material test platform building module (not shown in the figure), an oil-paper insulation material acquisition module (not shown in the figure) and an insulation conductivity test module (not shown in the figure), wherein:

[0099] The oil-paper insulation material test platform construction module is used to select the host computer, electrostatic machine and resistance tester as the basis for the construction of the oil-paper insulation material test platform, set the voltage excitation mode based on the DC step voltage excitation test method, and use the electrostatic meter as the current signal acquisition device of the sample to be tested to obtain the oil-paper insulation material test platform;

[0100] The oil-paper insulation material acquisition module is used to select insulating oil and insulating paperboard as test objects according to the set model information, and perform pre-test processing on the insulating oil and insulating paperboard respectively, and obtain the oil-paper insulation material based on the pre-test processing results;

[0101] The insulation conductivity test module is used to perform conductivity tests on insulating oil and insulating paperboard respectively using the oil-paper insulation material test platform and the insulation conductivity test rules, and to obtain the insulation conductivity of the insulating oil and the insulating paperboard according to the test results.

[0102] In this optional embodiment, the dependency quantitative relationship model acquisition unit 203 includes an insulating oil dependency acquisition module (not shown in the figure), an insulating paperboard dependency acquisition module (not shown in the figure) and a quantitative relationship model acquisition module (not shown in the figure):

[0103] The insulating oil dependency acquisition module is used to analyze the free ion migration process and ion injection process in the insulating oil through Coulomb attraction, and analyze the relationship between the insulating oil conductivity and the electric field strength according to the migration and injection process, and generate the field strength dependence relationship of the insulating oil conductivity based on the relationship results;

[0104] The insulation paperboard dependency acquisition module is used to analyze the influence of field strength on the conductivity of insulation paper based on the field strength dependency relationship of the conductivity of insulating oil, and obtain the field strength dependency relationship of the conductivity of insulation paper according to the influence result;

[0105] The quantitative relationship model acquisition module is used to analyze the influence of different temperatures on the free ion concentration and ion traction rate of insulating oil and insulating paperboard, and obtain the field intensity temperature dependence quantitative relationship model of oil-paper insulation conductivity based on the influence relationship.

[0106] In this optional embodiment, the insulating oil dependence acquisition module analyzes the free ion migration process and ion injection process in the insulating oil through Coulomb attraction, and analyzes the relationship between the insulating oil conductivity and the electric field strength based on the migration and injection process, and generates the field strength dependence relationship of the insulating oil conductivity based on the relationship result. At the same time, the attractive association state between the free ions in the insulating oil is analyzed under the action of Coulomb attraction and molecular thermal motion, and the dissociation complex equilibrium process in the insulating oil is analyzed based on the attractive association state to obtain the free ion migration process in the insulating oil; the insulating oil current density is calculated based on the free ion escape rate constant, and the influence mechanism of the free ions on the conductivity of the insulating oil during the injection process and the migration process is determined according to the calculation results; the relationship between the insulating oil conductivity and the electric field strength is analyzed based on the influence mechanism, and the field strength dependence relationship of the insulating oil conductivity is generated according to the relationship result.

[0107] In this optional embodiment, the insulation structure electric field distribution calculation unit 205 includes a steady-state temperature field distribution analysis module (not shown in the figure), an electric field distribution calculation module (not shown in the figure) and a main insulation structure establishment module (not shown in the figure), wherein:

[0108] The steady-state temperature field distribution analysis module is used to perform thermal-fluid coupling calculation based on the operating conditions of the converter transformer insulation structure, and obtain the steady-state temperature field distribution in the main insulation structure according to the calculation results;

[0109] The electric field distribution calculation module is used to establish a DC electric field distribution solution equation based on the partial differential equation and the quantitative relationship model of the field intensity temperature dependence of the oil-paper insulation conductivity to calculate the electric field distribution of the insulation structure under the electrothermal coupling characteristics of the oil-paper conductivity;

[0110] The main insulation structure establishment module is used to analyze the oil-paper insulation conductivity under the influence of field strength and temperature according to the distribution results, obtain the influence of electrothermal coupling on the electric field distribution, and establish the main insulation structure on the valve side of the converter transformer based on the influence results.

[0111] In this embodiment, a method for calculating the electric field distribution of the main insulation structure of the converter transformer under DC conditions is proposed for the converter transformer, which takes into account the field strength and temperature dependence of the oil and paper conductivity. The main steps are divided into three steps. The overall process is as follows: Figure 1 and Figure 3 shown.

[0112] (1) Construction of conductivity test platform for oil and paper insulation materials: The test platform supports the adjustment of electric field strength and temperature, and conducts conductivity tests on oil-paper samples under different electric fields and temperatures.

[0113] (2) Analysis of the field strength and temperature dependence of the conductivity of oil and paper: The conductivity data of oil and paper under different temperatures and electric fields in the experiment were obtained, and the field strength and temperature dependence of the conductivity were constructed by combining the mechanism fitting curve.

[0114] (3) Electric field distribution calculation model considering the electrothermal coupling characteristics of oil and paper: The electric-thermal-fluid multi-field coupling relationship in the valve-side insulation structure is analyzed, and the existing electric field calculation method with a fixed conductivity is improved to obtain an electric field distribution calculation model considering the electrothermal coupling characteristics of oil-paper conductivity.

[0115] The specific implementation steps are as follows:

[0116] Step 1: Build the conductivity test platform for oil-paper insulation materials;

[0117] Build a test platform for testing the conductivity of oil-paper insulation materials under different electric field strengths and temperatures. The test method for the conductivity of oil-paper insulation materials refers to the national standard GB / T1410-2006 "Test method for volume resistivity and surface resistivity of solid insulating materials" and GB / T21216-2007 "Test method for measuring conductivity and capacitance of insulating liquids to determine dielectric loss factor";

[0118] Test platform:

[0119] The conductivity test of the material adopts the DC step voltage excitation test method. The test module is as follows: Figure 4 As shown, the DC power supply converts the 220V AC voltage into a DC voltage for testing different voltage levels through a rectifier circuit and a boost circuit, and applies voltage excitation to the sample to be tested through a DC voltage source. The current signal acquisition device of the sample adopts an electrometer Keithley 6517B with a sampling frequency of 10Hz and a current sampling resolution of up to 1×10-15A. The electrode used in the conductivity test is a flat three-electrode structure. The resistance tester communicates with the computer through the GPIB interface, and the collected sample current signal is processed in the upper computer, and finally the conductivity of the sample is calculated. The conductivity test circuit contains a sample short-circuit loop for the discharge process after DC charging.

[0120] Sample preparation:

[0121] KI-50X insulating oil and Weidmann T4 insulating paperboard were selected as test objects, and experimental pretreatment was carried out on the oil-paper insulating materials: the insulating paper samples were cut to 160×160 mm in length and width and 2 mm in thickness; the insulating paper samples were placed in a stainless steel can, placed in a vacuum impregnation equipment, and degassed and dried at a temperature of 90°C / 90Pa for 48 hours.

[0122] Prepare insulating oil samples, put them into a vacuum impregnation equipment at 90℃ / 90Pa for degassing and drying for 48 hours. After the insulating paper and insulating oil are dried respectively, they are immersed in oil in a drying oven at a preset temperature. The temperature of the drying oven is set to 40℃, and at a temperature of 40℃, add degassed and dried insulating oil into a stainless steel tank with an oil-paper ratio of 20:1. Then add an appropriate amount of copper bars to simulate the internal conditions of the transformer, and place the stainless steel tank containing the oil-paper insulation sample in a vacuum drying oil immersion tank. Also maintain an environment of 90℃ / 90Pa, immerse for 48 hours and then cool to room temperature. Take out the oil-paper sample at room temperature and transfer it to a sealed container for storage. Finally, prepare the oil-paper insulation sample to be tested.

[0123] Test method:

[0124] The test method for the conductivity of oil and paper insulation can refer to GB / T 1410-2006 "Test method for volume resistivity and surface resistivity of solid insulating materials" and the calculation formula to calculate the conductivity of the sample, specifically:

[0125]

[0126] Wherein, σ represents conductivity, unit S / m, J(t) represents current density, E represents electric field strength, unit kV / m; i(t) represents response current, unit A, U represents applied voltage, unit V, d represents the distance between upper and lower electrode plates, unit m, and Y represents the effective area of ​​the test electrode, unit m 2 .

[0127] Step 2: Analysis of field strength and temperature dependence of oil-paper conductivity;

[0128] (I) The influence of field strength on the conductivity of oil-paper insulation:

[0129] 1. The influence of field strength on the conductivity of insulating oil;

[0130] According to the experimental data and the influence of free ion concentration and ion mobility, a quantitative relationship model of the field strength and temperature dependence of oil-paper insulation conductivity was finally obtained.

[0131] Conductivity model considering ion migration process for insulating oil:

[0132] The interaction between free ions is affected by the ionic atmosphere. Under the combined effect of Coulomb attraction and molecular thermal motion, free ions can attract each other and associate to form ion pairs, while ion pairs can also dissociate to form free ions. This reversible change is called the dissociation-recombination equilibrium process, which is expressed as:

[0133]

[0134] In the formula, A + B - With A + , B - represent ion pairs and free ions, respectively, k R With k D They are the dissociation coefficient and the complex coefficient, which represent the rates of the dissociation and complex processes. The expression of the complex coefficient in the solution is:

[0135]

[0136] In the formula, K + With K - are the mobility of positive and negative free ions, e0 is the electron charge, ε0ε r It is generally believed that in the solution, k R Not affected by external electric fields.

[0137] The relationship between the conductivity of the insulating oil and the electric field strength after the balance is broken is:

[0138]

[0139] In the formula, k D (E) represents the conductivity of the solution when an external voltage is applied and the dissociation-combination equilibrium is not broken, k m (E) represents the influence factor of the migration process on the free ion concentration, which is used to express the rate at which the ion mobility reduces the free ion concentration in the solution, and v0 represents the ion pair concentration in the solution.

[0140] Considering the conductivity model of the ion injection process, the current density in the oil generated by the ion injection process can be expressed as:

[0141]

[0142] In the formula, represents the density of the interface charge; k es represents the interfacial ion escape rate constant, j i Represents the current density.

[0143] Taking into account the influence mechanism of the dissociation-combination equilibrium process, free ion migration process and ion plate injection process in the insulating oil on the conductivity of the insulating oil, the field strength dependence of the conductivity of the insulating oil can be fully described as follows:

[0144]

[0145] 2. The influence of field strength on the conductivity of insulating paper;

[0146] Referring to the field strength dependence relationship of the conductivity of insulating oil in the dissociation-compound equilibrium state, the field strength dependence relationship model of the conductivity of insulating paper is obtained, as follows:

[0147]

[0148] In the formula, σ P Indicates the conductivity of insulating paper, unit S / m, K + With K - are the mobility of positive and negative free ions, respectively, in m 2 / Vs,k p (E) shows the relationship between the dissociation rate of ion pairs in insulating paper and the electric field strength.

[0149] (ii) The influence of field strength and temperature on the conductivity of oil-paper insulation;

[0150] According to existing research results, the electrical conductivity of insulating oil and insulating paper both show an exponential increase with increasing temperature.

[0151] Existing research results show that the mobility of free ions in oil-paper insulation materials follows the Arrhenius equation with respect to temperature:

[0152]

[0153] In the formula, K ± Indicates the ion mobility of insulating oil and insulating paper, K ±0 It indicates the pre-exponential factor, which can refer to the initial ion mobility of insulating oil and insulating paper materials, in m 2 / Vs;E a It represents the reaction activation energy in the process of ion migration, the unit is eV, k represents the convergence rate of free ions in oil-paper insulation, and T represents temperature.

[0154] The increase in temperature not only increases the mobility of free ions, but also increases the dissociation coefficient of ion pairs, thereby increasing the concentration of free ions. The free ion concentration of oil-paper insulation materials at different temperatures is specifically:

[0155] n0=(v0·k p (E)fD (T)) 1 / 2 ;

[0156] f D (T) = P1·exp(-u a / k B T);

[0157] Where n0 represents the free particle concentration of oil-paper insulation material, f D (T) is the influence factor of temperature on the dissociation rate, which represents the dissociation rate of ion pairs at different temperatures, u a It represents the energy required for free ions in the material to overcome Coulomb attraction, in units of eV. P1 is the pre-exponential factor in the expression of free ion concentration in insulating oil or insulating paper, k B It represents the association equilibrium constant of the solution.

[0158] In summary, the relationship between the influence of temperature on the free ion concentration and ion mobility is substituted into the relationship between the conductivity of oil-paper insulation and the electric field strength, and finally the quantitative relationship model of the field strength and temperature dependence of the conductivity of oil-paper insulation is obtained:

[0159] Insulating oil:

[0160]

[0161] Insulation paper:

[0162]

[0163] Among them, the fitting parameters are shown in Table 1 and Table 2, and the fitting images are shown in Figure 5 As shown:

[0164] Table 1 Fitting parameters of the field intensity-temperature dependence model of insulating oil conductivity

[0165]

[0166] Table 2 Fitting parameters of the field intensity-temperature dependence model of the electrical conductivity of insulating paper

[0167]

[0168] Step 3: Calculation model of electric field distribution considering the electric-thermal coupling characteristics of oil-paper;

[0169] Based on the operating conditions of the converter transformer insulation structure, this embodiment selects three physical fields, namely, electric field, temperature and oil flow rate field, as calculation objects to form a simplified multi-physical field coupling relationship inside the converter transformer.

[0170] (1) Thermal-fluid coupling calculation of temperature field distribution;

[0171] The heat source in the temperature distribution calculation mainly considers the load loss from the winding, which mainly includes: DC resistance loss and eddy current loss in the winding:

[0172] P L =P R +P W ;

[0173]

[0174] Where P R Represents the resistance loss, P W represents eddy current loss, I 1N Indicates the rated current of the grid-side winding, I 2N It indicates the rated current of the valve side winding, in A. R1 and R2 indicate the equivalent resistance of the grid side and valve side winding, in Ω respectively.

[0175] The coefficient of eddy current loss in the winding to the DC loss of the winding can be estimated by the following formula:

[0176]

[0177] Where a represents the wire thickness, in mm, and d represents the current density in the winding wire, in A / mm 2 , B mr It represents the maximum value of the leakage magnetic density in the main leakage flux channel, with the unit of T. k is a parameter related to resistivity, and f represents frequency.

[0178] The specific form of the energy conservation equation for temperature distribution in steady state can be expressed as follows:

[0179]

[0180] Where U represents the fluid velocity in m / s, ρ represents the fluid density in kg / m3, S T Indicates the heat generation rate per unit volume, in W / m 3 , c p represents the specific heat capacity at constant pressure, and λ represents the thermal conductivity.

[0181] (2) Calculation of electric field distribution under electro-thermal coupling;

[0182] Based on the basic equation of the differential form of the electrostatic field, using the Laplace equation and boundary conditions, a two-dimensional DC electric field distribution solution equation is established:

[0183]

[0184] Wherein, σ(E,T) is the conductivity field strength and temperature dependence of oil-paper insulation, which is mainly obtained through experiments and fitting. G is the entire solution domain. Γ1 is the known high potential boundary (usually set to the valve side, grid side winding, etc. in the transformer); Γ2 is the zero potential boundary (usually the transformer tank wall, iron core and iron yoke, etc.); n is the normal direction of the boundary; Γ in is the boundary between the two media. The electric field analysis and calculation problem in the above formula can be reduced to the potential function is a boundary value problem of the quantity to be solved, To find the sign of the partial derivative, (x, y) is the horizontal and total coordinates in the two-dimensional field.

[0185] (3) Electric field calculation process considering the electrical-thermal coupling characteristics of conductivity;

[0186] There is a significant nonlinear relationship between the electrical conductivity of oil-paper insulation materials and the electric field strength and temperature. The electric field and temperature in the main insulation structure affect the electrical conductivity of oil-paper insulation, and changes in the material conductivity will affect the electric field distribution in the insulation structure. In order to consider the influence of unevenly distributed temperature on the electric field distribution in the electric field distribution calculation process, a thermal-fluid coupling calculation is first carried out to obtain the steady-state temperature distribution in the main insulation structure. The partial differential equation solved for the electric field is combined with the oil-paper nonlinear conductivity equation using the Newton-Raphson iteration method, and the oil-paper conductivity that changes dynamically under the influence of field strength and temperature is substituted into the electric field calculation process. In the electric-thermal coupling calculation process, only the unidirectional coupling of temperature on the material conductivity is considered, and the influence of the change in material conductivity on the temperature distribution is not considered. The electric field distribution calculation process considering the nonlinear electrical and thermal coupling characteristics of oil-paper conductivity is as follows: Figure 6 shown.

[0187] At the same time, in order to analyze the influence of electro-thermal coupling on the electric field distribution, the main insulation structure on the valve side is established, and then the electric field distribution calculation is carried out without considering the electro-thermal coupling characteristics of oil-paper conductivity, and the difference in electric field distribution between the two is compared, such as Figure 7 As shown, after considering the electrical and thermal coupling effects, under the DC external voltage withstand test conditions, the maximum electric field strength in the insulating oil increases significantly, with a change ratio of up to 133.2%, and the maximum electric field strength in the insulating paper decreases slightly, with a decrease ratio of about 1.7%.

[0188] In one embodiment, a computer device is provided. The computer device may be a server, and its internal structure diagram may be as follows: Figure 8As shown. The computer device includes a processor, a memory and a network interface connected through a system bus. 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 static information and dynamic information data. 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 the above method embodiment are implemented.

[0189] Those skilled in the art will understand that Figure 8 The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present invention, and does not constitute a limitation on the computer device to which the solution of the present invention is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine certain components, or have a different arrangement of components.

[0190] In addition, the present invention also provides a computer device, including a memory and a processor, wherein a computer program is stored in the memory, and the processor implements the steps in the above method embodiment when executing the computer program.

[0191] In addition, the present invention further provides a computer-readable storage medium on which a computer program is stored. When the computer program is executed by a processor, the steps in the above method embodiment are implemented.

[0192] 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 memory, storage, database or other media used in the embodiments provided by the present invention 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 or optical memory, etc. Volatile memory can include random access memory (RAM) or external cache memory. 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).

[0193] The present invention is not limited to the structures which have been described above and shown in the drawings, and various modifications and changes may be made without departing from the scope thereof. The scope of the present invention is limited only by the appended claims.

Claims

1. A method for calculating the electric field distribution of an insulating structure, characterized in that: The calculation method includes: Based on the pre-built oil-paper insulation material test platform, the conductivity of the oil-paper insulation material is tested, and the conductivity of the oil-paper insulation material is obtained according to the test results; Based on the ion migration injection process and the free ion concentration, the dependence of the electrical conductivity of oil-paper insulation material on field intensity and temperature is analyzed, and the field intensity temperature dependence quantitative relationship model of the electrical conductivity of oil-paper insulation is obtained according to the dependence relationship; The quantitative relationship model of the field intensity temperature dependence of the oil-paper insulation conductivity is integrated with the partial differential equation, and the electric field distribution of the insulation structure under the electrothermal coupling characteristics of the oil-paper conductivity is calculated based on the fusion results.

2. The method for calculating the electric field distribution of an insulating structure according to claim 1, characterized in that: The method of performing a conductivity test on the oil-paper insulation material based on the pre-built oil-paper insulation material test platform and obtaining the conductivity of the oil-paper insulation material according to the test result includes: The host computer, electrostatic machine and resistance tester are selected as the basis for the construction of the oil-paper insulation material test platform. The voltage excitation mode is set based on the DC step voltage excitation test method, and the electrostatic meter is used as the current signal acquisition device of the sample to be tested to obtain the oil-paper insulation material test platform. Insulating oil and insulating paperboard are selected as test objects according to the set model information, and pre-treatment is performed on the insulating oil and insulating paperboard respectively, and the oil-paper insulating material is obtained based on the pre-treatment results; The conductivity of insulating oil and insulating paperboard was tested respectively using the oil-paper insulation material test platform and the insulation conductivity test rules, and the insulation conductivity of the insulating oil and insulating paperboard was calculated based on the test results.

3. The method for calculating the electric field distribution of an insulating structure according to claim 2, characterized in that: The dependence relationship between the conductivity of the oil-paper insulation material and the field strength and temperature is analyzed based on the ion migration injection process and the free ion concentration, and the field strength temperature dependence quantitative relationship model of the oil-paper insulation conductivity is obtained according to the dependence relationship, including: The free ion migration process and ion injection process in the insulating oil are analyzed by Coulomb attraction, and the relationship between the conductivity of the insulating oil and the electric field strength is analyzed according to the migration and injection process. Based on the relationship results, the field strength dependence relationship of the conductivity of the insulating oil is generated; The influence of field strength on the conductivity of insulating paper is analyzed based on the field strength dependence relation of the conductivity of insulating oil, and the field strength dependence relation of the conductivity of insulating paper is obtained according to the influence results; The influence of different temperatures on the free ion concentration and ion traction rate of insulating oil and insulating paperboard is analyzed, and a quantitative relationship model of the field strength temperature dependence of the oil-paper insulation conductivity is obtained based on the influence relationship.

4. The method for calculating the electric field distribution of an insulating structure according to claim 3, characterized in that: The free ion migration process and ion injection process in the insulating oil are analyzed by Coulomb attraction, and the relationship between the conductivity of the insulating oil and the electric field strength is analyzed according to the migration and injection process. The field strength dependence relationship of the conductivity of the insulating oil is generated based on the relationship result, including: The attraction and association between free ions in the insulating oil is analyzed under the action of Coulomb attraction and molecular thermal motion, and the dissociation and complex equilibrium process in the insulating oil is analyzed based on the attraction and association, and the migration process of free ions in the insulating oil is obtained; The current density of insulating oil is calculated based on the free ion escape rate constant, and the influence mechanism of free ions on the conductivity of insulating oil during injection and migration is determined according to the calculation results. The relationship between the electrical conductivity of insulating oil and the electric field strength is analyzed based on the influencing mechanism, and the field strength dependence relationship of the electrical conductivity of insulating oil is generated according to the relationship results.

5. The method for calculating the electric field distribution of an insulating structure according to claim 4, characterized in that: The field intensity dependence of the insulating oil conductivity is expressed as: Where σ(E) represents the field intensity dependence of the electrical conductivity of the insulating oil, E represents the electric field intensity, σ represents the electrical conductivity, and K + With K - They represent the mobility of positive and negative free ions, e0 represents the electron charge, and K D (E) represents the conductivity of the insulating oil when the dissociation and composite equilibrium is not broken, k R represents the dissociation coefficient, k m (E) represents the rate at which the ion mobility decreases with the concentration of free ions in the insulating oil, v0 represents the concentration of ion pairs in the insulating oil, represents the density of the interface charge, k es represents the interfacial ion escape rate constant.

6. The method for calculating the electric field distribution of an insulating structure according to claim 5, characterized in that: The method of fusing the quantitative relationship model of the field intensity temperature dependence of the oil-paper insulation conductivity with the partial differential equation and calculating the electric field distribution of the insulation structure under the electric-thermal coupling characteristics of the oil-paper conductivity based on the fusion result includes: Based on the operating conditions of the converter transformer insulation structure, thermal-fluid coupling calculation is performed, and the steady-state temperature field distribution in the main insulation structure is obtained according to the calculation results; Based on the partial differential equation and the quantitative relationship model of the field intensity temperature dependence of the oil-paper insulation conductivity, the DC electric field distribution solution equation is established to calculate the electric field distribution of the insulation structure under the electrothermal coupling characteristics of the oil-paper conductivity. According to the distribution results, the conductivity of oil-paper insulation under the influence of field strength and temperature is analyzed to obtain the influence of electrothermal coupling on the electric field distribution. Based on the influence results, the main insulation structure of the valve side of the converter transformer is established.

7. The method for calculating the electric field distribution of an insulating structure according to claim 6, characterized in that: The thermal-fluid coupling calculation is performed based on the operating conditions of the converter transformer insulation structure, and the steady-state temperature field distribution in the main insulation structure is obtained according to the calculation results, including: Based on the operating conditions of the insulation structure of the converter transformer, the equivalent resistance of the grid-side and valve-side windings of the insulation structure is obtained, and the resistance loss and eddy current loss are obtained according to the equivalent resistance; The loss coefficient between the eddy current loss and the winding DC loss is obtained based on the current density in the winding conductor. The loss coefficient is integrated with the energy conservation equation to implement thermal-fluid coupling calculation, and the steady-state temperature field distribution in the main insulation structure is obtained based on the calculation results.

8. The method for calculating the electric field distribution of an insulating structure according to claim 7, characterized in that: The calculation formula of the loss coefficient is: In the formula, k W represents the loss factor, k represents a parameter related to resistivity, a represents the wire thickness, d represents the current density in the winding wire, and B mr It represents the maximum value of the leakage magnetic density in the main leakage flux channel, and f represents the frequency.

9. An insulation structure electric field distribution calculation system, characterized in that: The distributed computing system comprises: An oil-paper insulation material conductivity calculation unit is used to perform a conductivity test on the oil-paper insulation material based on a pre-built oil-paper insulation material test platform, and obtain the conductivity of the oil-paper insulation material according to the test result; A dependency quantitative relationship model acquisition unit is used to analyze the dependency relationship between the electrical conductivity of the oil-paper insulation material and the field intensity and temperature based on the ion migration injection process and the free ion concentration, and to obtain a field intensity temperature dependency quantitative relationship model of the electrical conductivity of the oil-paper insulation according to the dependency relationship; The electric field distribution calculation unit of the insulation structure is used to integrate the quantitative relationship model of the field intensity temperature dependence of the oil-paper insulation conductivity with the partial differential equation, and calculate the electric field distribution of the insulation structure under the electrothermal coupling characteristics of the oil-paper conductivity based on the fusion result.

10. The insulation structure electric field distribution calculation system according to claim 9, characterized in that: The oil-paper insulation material conductivity calculation unit comprises: The oil-paper insulation material test platform construction module is used to select the host computer, electrostatic machine and resistance tester as the basis for the construction of the oil-paper insulation material test platform, set the voltage excitation mode based on the DC step voltage excitation test method, and use the electrostatic meter as the current signal acquisition device of the sample to be tested to obtain the oil-paper insulation material test platform; The oil-paper insulation material acquisition module is used to select insulating oil and insulating paperboard as test objects according to the set model information, and perform pre-test processing on the insulating oil and insulating paperboard respectively, and obtain the oil-paper insulation material based on the pre-test processing results; The insulation conductivity test module is used to perform conductivity tests on insulating oil and insulating paperboard respectively using the oil-paper insulation material test platform and the insulation conductivity test rules, and to obtain the insulation conductivity of the insulating oil and the insulating paperboard according to the test results.

11. The electric field distribution calculation system for an insulating structure according to claim 10, characterized in that: The dependency quantization relationship model acquisition unit includes: The insulating oil dependency acquisition module is used to analyze the free ion migration process and ion injection process in the insulating oil through Coulomb attraction, and analyze the relationship between the insulating oil conductivity and the electric field strength according to the migration and injection process, and generate the field strength dependence relationship of the insulating oil conductivity based on the relationship results; The insulation paperboard dependency acquisition module is used to analyze the influence of field strength on the conductivity of insulation paper based on the field strength dependency relationship of the conductivity of insulating oil, and obtain the field strength dependency relationship of the conductivity of insulation paper according to the influence result; The quantitative relationship model acquisition module is used to analyze the influence of different temperatures on the free ion concentration and ion traction rate of insulating oil and insulating paperboard, and obtain the field intensity temperature dependence quantitative relationship model of oil-paper insulation conductivity based on the influence relationship.

12. The insulation structure electric field distribution calculation system according to claim 11, characterized in that: The insulating oil dependency acquisition module analyzes the free ion migration process and ion injection process in the insulating oil through Coulomb attraction, analyzes the relationship between the insulating oil conductivity and the electric field strength according to the migration and injection process, and generates the field strength dependence relationship of the insulating oil conductivity based on the relationship result. Under the action of Coulomb attraction and molecular thermal motion, the attraction and association state between the free ions in the insulating oil is analyzed, and the dissociation and complex equilibrium process in the insulating oil is analyzed based on the attraction and association state to obtain the free ion migration process in the insulating oil; the insulating oil current density is calculated based on the free ion escape rate constant, and the influence mechanism of the free ions on the conductivity of the insulating oil during the injection process and the migration process is judged according to the calculation result; the relationship between the insulating oil conductivity and the electric field strength is analyzed based on the influence mechanism, and the field strength dependence relationship of the insulating oil conductivity is generated according to the relationship result.

13. The insulation structure electric field distribution calculation system according to claim 12, characterized in that: The field intensity dependence of the insulating oil conductivity is expressed as: Where σ(E) represents the field intensity dependence of the electrical conductivity of the insulating oil, E represents the electric field intensity, σ represents the electrical conductivity, and K + With K - They represent the mobility of positive and negative free ions, e0 represents the electron charge, and K D (E) represents the conductivity of the insulating oil when the dissociation and composite equilibrium is not broken, k R represents the dissociation coefficient, k m (E) represents the rate at which the ion mobility decreases with the concentration of free ions in the insulating oil, v0 represents the concentration of ion pairs in the insulating oil, represents the density of the interface charge, k es represents the interfacial ion escape rate constant.

14. The insulation structure electric field distribution calculation system according to claim 13, characterized in that: The insulating structure electric field distribution calculation unit comprises: The steady-state temperature field distribution analysis module is used to perform thermal-fluid coupling calculation based on the operating conditions of the converter transformer insulation structure, and obtain the steady-state temperature field distribution in the main insulation structure according to the calculation results; The electric field distribution calculation module is used to establish a DC electric field distribution solution equation based on the partial differential equation and the quantitative relationship model of the field intensity temperature dependence of the oil-paper insulation conductivity to calculate the electric field distribution of the insulation structure under the electrothermal coupling characteristics of the oil-paper conductivity; The main insulation structure establishment module is used to analyze the oil-paper insulation conductivity under the influence of field strength and temperature according to the distribution results, obtain the influence of electrothermal coupling on the electric field distribution, and establish the main insulation structure on the valve side of the converter transformer based on the influence results.

15. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 8 are implemented.

16. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 8 are implemented.

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