Semi-conductive glaze parameter determination method special for vacuum arc-extinguishing chamber, semi-conductive glaze and insulating material surface potential test system

Abstract

The invention relates to a semi-conductive glaze parameter determination method special for a vacuum arc-extinguishing chamber, semi-conductive glaze and an insulating material surface potential test system. The method comprises multiple aspects of model simulation, material selection, glaze layer coating, glaze firing, experimental testing and optimization and improvement, and by adopting the method, charges at the three junctions can be effectively inhibited, so that the flashover voltage of the surface of the vacuum ceramic is improved.

Description

Technical Field

[0001] The present application relates to the technical field of vacuum interrupter chambers, and in particular to a method for determining parameters of a semi-conductive glaze specifically used in vacuum interrupter chambers, and a surface potential testing system for the semi-conductive glaze and insulating materials. Background Art

[0002] In the power sector, vacuum circuit breakers are highly favored for their superior insulation and arc-extinguishing performance across the vacuum gap, along with advantages such as simple structure and compact size. However, surface flashover severely restricts the performance of their insulation systems. When voltage is applied, surface flashover is prone to occur, and the flashover voltage is significantly lower than the vacuum gap and insulator breakdown voltage. This occurs when electrons are emitted from the insulator-electrode-vacuum interface, accumulating positive charge on the insulating material surface. This triggers a secondary electron emission avalanche, which in turn causes the desorbed gas layer to break down.

[0003] While existing surface coating treatment technologies can improve flashover characteristics, such as reducing secondary electron emission energy and dissipating field-induced junction charge, they also have significant drawbacks. Due to a mismatch between the properties of the coating and the insulating material, defects are easily formed during bonding and the coating is susceptible to detachment under environmental influences. Furthermore, the treatment process is complex and time-consuming, increasing costs.

[0004] Therefore, it is extremely important to develop a method that can effectively suppress the charge at the three junctions, increase the surface flashover voltage of vacuum ceramics, and has simple process and good compatibility. Summary of the Invention

[0005] Based on this, it is necessary to provide a method for determining the parameters of a semi-conductive glaze specifically for a vacuum interrupter, and a surface potential testing system for a semi-conductive glaze and insulating material in response to the above technical problems.

[0006] In a first aspect, the present application provides a method for determining parameters of a semi-conductive glaze specifically for a vacuum interrupter, the method comprising:

[0007] Based on computer equipment, a geometric simulation model of the vacuum interrupter is constructed according to the structural parameters and material parameters of the vacuum interrupter;

[0008] Iterate the following steps until the first flashover voltage of the workpiece to be tested is greater than or equal to the preset threshold, and use the corresponding semi-conductive glaze formula at the end of the iteration as the target formula:

[0009] Using computer equipment, a semi-conductive glaze layer structure with different electrical conductivities is set at three intersections of a geometric simulation model of a vacuum interrupter to form a model to be simulated;

[0010] Based on the finite element analysis software of computer equipment, multi-dimensional physical field simulation analysis is performed on the simulation model according to the actual working conditions of the vacuum interrupter;

[0011] Based on computer equipment and simulation analysis results, the conductivity range, firing temperature range and thermal expansion coefficient range of the semi-conductive glaze are determined;

[0012] Based on the medium and low temperature glass glaze formula, the semi-conductive glaze formula is determined based on the conductivity range, firing temperature range and thermal expansion coefficient range;

[0013] Printing a semi-conductive glaze slurry prepared based on a semi-conductive glaze formula onto the surface of the ceramic sheet by screen printing and drying the slurry;

[0014] The ceramic sheet coated with the semi-conductive glaze slurry is fired into a finished product using a neutral flame or a reducing flame, and then cooled naturally after heat preservation to obtain a workpiece to be tested;

[0015] Conduct surface flashover test on the workpiece to be tested to determine the first flashover voltage;

[0016] When the first flashover voltage is less than the preset threshold, the surface potential distribution of the workpiece to be tested is measured after the surface flashover test is completed;

[0017] Based on the surface potential distribution measurement results, the conductivity of the semiconductive glaze layer structure is adjusted.

[0018] In one embodiment, the process of the surface flashover test includes:

[0019] Based on the initial test voltage, gradually increase the test voltage applied to the workpiece to be tested, and perform a preset number of tests at each test voltage, recording the current and light intensity after each application of the test voltage until the number of light intensity peaks corresponding to the test voltage equals the preset number;

[0020] Gradually reduce the test voltage applied to the workpiece to be tested, and perform a preset number of tests at each test voltage, recording the current and light intensity after each application of the test voltage until the number of light intensity peaks corresponding to the test voltage reaches zero;

[0021] The test voltage at which the light intensity peak is first recorded is determined as the first flashover voltage.

[0022] In one embodiment, a geometric simulation model of the vacuum interrupter is constructed based on a computer device according to structural parameters and material parameters of the vacuum interrupter, including:

[0023] Inputting structural parameters and material parameters of the vacuum interrupter into a computer device, and constructing a geometric simulation model using two-dimensional axisymmetry based on the computer device;

[0024] Among them, the structural parameters include shielding cover, moving contact, static contact, conductive rod, insulating shell, and bellows; the material parameters include relative dielectric constant, electrical conductivity, thermal conductivity, and density.

[0025] In one embodiment, the process conditions of screen printing are:

[0026] The mesh number of the screen is 200, the printing pressure is 50-100N, and the thickness of the semi-conductive glaze is 0.2-0.4mm.

[0027] In one embodiment, the process conditions for drying are:

[0028] The drying temperature is 150-200℃ and the drying time is 1-2 hours.

[0029] In one embodiment, a ceramic sheet coated with a semi-conductive glaze slurry is fired into a finished product using a neutral flame or a reducing flame, and then cooled naturally after heat preservation. The process conditions for obtaining the workpiece to be tested are:

[0030] The temperature of the neutral flame or reducing flame is 750-1050℃, the kiln pressure for firing ceramic pieces is a positive pressure of 12-22Pa, the hot air flow range of the observation hole in the lower layer of the kiln bottom is 180-260mm, and the insulation time is 2-4 hours.

[0031] In a second aspect, the present application further provides a semiconductive glaze, which is prepared based on a target formula, and the target formula is determined based on the steps of the method for determining parameters of a semiconductive glaze specifically for a vacuum arc chamber in the above embodiment.

[0032] In one embodiment, the semiconductive glaze comprises feldspar powder, quartz powder, quartz, calcite, TiO2, Fe2O3, Cr2O3 and Sb2O3.

[0033] In a third aspect, the present application provides an insulating material surface potential testing system for testing a workpiece to be tested as in the above-mentioned embodiment, the system comprising: an organic glass cavity, a two-dimensional moving mechanism, a high-voltage discharge needle, an electrostatic probe, an electrometer, a data acquisition system, a computer device, and a high-voltage DC power supply;

[0034] The two-dimensional moving mechanism is arranged in the organic glass cavity, and the two-dimensional moving mechanism includes a base, a movable platform arranged on the base, and a first bracket and a second bracket arranged on both sides of the base;

[0035] The high-voltage discharge needle is mounted on the first bracket, and the electrostatic probe is mounted on the second bracket;

[0036] The high-voltage DC power supply is connected to the high-voltage discharge needle and the discharge electrode on the movable platform respectively. The discharge electrode on the movable platform is used to place the workpiece to be tested;

[0037] The electrostatic probe is connected to the electrometer, the data acquisition system and the computer device in sequence, and the computer device is also connected to the movable platform.

[0038] In one embodiment, the computer device is used to control the movable platform to move to the detection area of the electrostatic probe after the high-voltage DC power supply applies the target voltage to the workpiece to be tested through the high-voltage discharge needle and the discharge electrode for a preset time, and control the movable platform to move in a Z shape within the detection area of the electrostatic probe according to a preset moving step length to measure the surface potential distribution of the workpiece to be tested.

[0039] The above-mentioned method for determining parameters of semi-conductive glaze specifically for vacuum interrupter, and the surface potential testing system of semi-conductive glaze and insulating material have at least the following beneficial effects:

[0040] Through model simulation, material selection, glaze coating, glaze firing, experimental testing, optimization and improvement, the parameters of the semi-conductive glaze specifically used for vacuum interrupter are determined to be more accurate, effective and compatible, so that the semi-conductive glaze prepared based on this method can significantly improve the electric field distribution of the vacuum interrupter, effectively suppress the charge at the three junctions, and thus increase the surface flashover voltage of the vacuum ceramic. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the technical solutions in the embodiments of the present application or related technologies, the following briefly introduces the drawings required for use in the embodiments of the present application or related technical descriptions. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying any creative work.

[0042] Figure 1 1 is a flow chart of a method for determining parameters of a semi-conductive glaze specifically for a vacuum interrupter in one embodiment;

[0043] Figure 2 FIG. 1 is a geometric simulation model diagram of a vacuum interrupter in one embodiment;

[0044] Figure 3 A schematic flow chart of a process of a surface flashover experiment in one embodiment;

[0045] Figure 4 A schematic diagram of a surface flashover test method and surface flashover characteristic parameters in one embodiment;

[0046] Figure 5 Schematic diagram of a system for testing the surface potential of an insulating material in one embodiment;

[0047] Figure 6 A two-dimensional surface charge distribution diagram drawn by charge inversion calculation in one embodiment;

[0048] Figure 7A schematic diagram of the position of the semi-conductive glaze coating on the upper side of the ceramic shell at the static end of a high-voltage vacuum interrupter geometric model and the glaze layer structure in one embodiment;

[0049] Figure 8 This is a schematic diagram of the electric field simulation results at the three intersections slightly above the static end porcelain shell of a simulation model before coating with semi-conductive glaze in one embodiment;

[0050] Figure 9 This is a schematic diagram of the electric field simulation results at the three intersections slightly above the static end porcelain shell of the simulation model after coating with semi-conductive glaze in one embodiment;

[0051] Figure 10 A schematic diagram of the position of the semi-conductive glaze coating and the glaze layer structure on the lower side of the static end porcelain shell of a geometric model of a high-voltage vacuum interrupter in one embodiment;

[0052] Figure 11 A schematic diagram of the electric field simulation results at the three intersections at the lower part of the static end porcelain shell of a simulation model before coating with semi-conductive glaze in one embodiment;

[0053] Figure 12 A schematic diagram of the electric field simulation results at the three intersections at the lower part of the static end porcelain shell of the simulation model after coating with semi-conductive glaze in one embodiment;

[0054] Figure 13 A schematic diagram of the position of the semi-conductive glaze coating on the upper side of the moving end porcelain shell of a geometric model of a high-voltage vacuum interrupter in one embodiment and the glaze layer structure;

[0055] Figure 14 Schematic diagram of the electric field simulation results at the three intersections of the upper part of the ceramic shell of the dynamic end of the simulation model before coating with semi-conductive glaze in one embodiment;

[0056] Figure 15 A schematic diagram of the electric field simulation results at the three intersections at the upper part of the dynamic end ceramic shell of the simulation model after coating with semi-conductive glaze in one embodiment;

[0057] Figure 16 A schematic diagram of the position of the semi-conductive glaze coating and the glaze layer structure on the lower side of the moving end porcelain shell of a geometric model of a high-voltage vacuum interrupter in one embodiment;

[0058] Figure 17 A schematic diagram of the electric field simulation results at the three intersections of the lower portion of the moving end porcelain shell of a simulation model before coating with semi-conductive glaze in one embodiment;

[0059] Figure 18 This is a schematic diagram of the electric field simulation results at the three intersections at the lower part of the dynamic end ceramic shell of the simulation model after coating with semi-conductive glaze in one embodiment. DETAILED DESCRIPTION

[0060] In order to make the purpose, technical solutions and advantages of this application more clear, the following further describes this application in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0061] In an exemplary embodiment, Figure 1 As shown, the present application provides a method for determining parameters of a semi-conductive glaze specifically for a vacuum interrupter, the method comprising:

[0062] S101, based on computer equipment, construct a geometric simulation model of the vacuum interrupter according to the structural parameters and material parameters of the vacuum interrupter.

[0063] For example, the structural parameters of the vacuum interrupter and the material parameters of the components of the vacuum interrupter are collected, and the structural parameters and material parameters are input into computer-aided design software to construct a vacuum interrupter. Figure 2 The geometric simulation model of the vacuum interrupter is shown.

[0064] S102, iteratively executing the following steps S103 to S111 until the first flashover voltage of the workpiece to be tested is greater than or equal to a preset threshold, and taking the corresponding semi-conductive glaze formula at the end of the iteration as the target formula:

[0065] S103, using computer equipment, setting semi-conductive glaze structures with different electrical conductivities at three intersections of the geometric simulation model of the vacuum interrupter to form a model to be simulated.

[0066] For example, according to the research requirements, the three intersections in the geometric simulation model of the vacuum interrupter are selected as the area where the semi-conductive glaze layer is set. Different conductivity values are determined, for example, in the range of 10⁻²-10⁻ 6 Select multiple different conductivity values within the S / m range. For each selected conductivity, design a corresponding semi-conductive glaze layer structure, such as a triangular structure or a rounded structure that fills the gaps at the three intersections. These structures are then placed at the three intersections of the geometric simulation model to form different models to be simulated.

[0067] S104, based on the finite element analysis software of the computer equipment, perform multi-dimensional physical field simulation analysis on the simulation model according to the actual working conditions of the vacuum interrupter.

[0068] For example, suitable finite element analysis software, such as ANSYS, is selected. Simulation analysis parameters, including initial values and boundary conditions for the electrostatic field, current field, and solid heat transfer field, are set based on the actual operating conditions of the vacuum interrupter. For example, the iteration method is set to direct iteration, the steady-state solver to MUMPS or GRMES, the nonlinear method to automatic Newton, and the maximum number of iterations and residual factor are set based on actual conditions (e.g., a maximum number of iterations of 25 or 100, and a residual factor of 1000). Multi-physics simulation analysis of electricity, heat, and force is performed on each model to simulate the performance of the semi-conductive glaze under different operating conditions.

[0069] S105 , determining the conductivity range, firing temperature range, and thermal expansion coefficient range of the semi-conductive glaze based on computer equipment and simulation analysis results.

[0070] For example, the electric field, thermal field, and force field data in the simulation analysis results are analyzed to observe the electric field distribution of the semi-conductive glaze layers with different conductivities at the three intersections. Based on actual needs, the conductivity range of the semi-conductive glaze that can effectively improve the electric field distribution and suppress the charge is determined, which can be 10⁻²-10⁻ 6 S / m. Based on the results of thermal field analysis, the appropriate firing temperature range for semi-conductive glaze during firing is determined to be 750-1050°C. Through a comprehensive analysis of the force field and material properties, the thermal expansion coefficient range of the semi-conductive glaze is determined to ensure its compatibility with vacuum ceramics, metals, and other materials.

[0071] S106, based on the medium and low temperature glass glaze formula, determine the semi-conductive glaze formula based on the conductivity range, firing temperature range and thermal expansion coefficient range.

[0072] For example, using the formula for medium- and low-temperature glass glaze as a basic framework, combined with the established conductivity range, firing temperature range, and thermal expansion coefficient range, the proportions of the various ingredients in the formula are adjusted through experiments and theoretical calculations. For example, a semi-conductive glaze might contain feldspar powder, quartz powder, Kuancheng clay, calcite, TiO2, Fe2O3, Cr2O3, Sb2O3, and other components, with the specific mass percentages of each component determined.

[0073] S107, printing the semi-conductive glaze slurry prepared based on the semi-conductive glaze formula onto the surface of the ceramic sheet by screen printing, and drying the slurry.

[0074] For example, the materials are accurately prepared according to the specified semi-conductive glaze formula and wet-ball milled at a specific material: ball: water ratio (e.g., 1:1.5:0.5 or 1.5:2:1) for approximately 25-30 hours. The milled glaze is then passed through a 320-mesh sieve, with the residue controlled within the range of 0.02-0.05, before being adjusted to a semi-conductive glaze slurry with a concentration of 50-70 degrees Baume. Using a 200-mesh screen and applying a printing pressure of 50-100N, the semi-conductive glaze slurry is evenly printed onto the surface of a ceramic sheet using a scraper, maintaining a thickness of 0.2-0.4 mm. The printed ceramic sheet is then placed in a drying machine, for example, at a temperature of 150-200°C for 1-2 hours.

[0075] S108, using a neutral flame or a reducing flame to sinter the ceramic sheet coated with the semi-conductive glaze slurry into a finished product, and then cooling it naturally after heat preservation to obtain a workpiece to be tested.

[0076] Illustratively, the ceramic sheet coated with the semiconductive glaze slurry is placed in a firing device and fired using a neutral flame or a reducing flame.

[0077] S109, performing a surface flashover test on the workpiece to be tested to determine the first flashover voltage.

[0078] For example, a surface flashover test device is built, and a voltage source, a current measuring device, a light intensity measuring device, etc. are connected. A surface flashover test is performed on the workpiece to be tested to determine the first flashover voltage.

[0079] S110 , when the first flashover voltage is less than a preset threshold, measuring the surface potential distribution of the workpiece to be tested after the surface flashover test is completed.

[0080] The preset threshold serves as a key reference value for determining whether the semi-conductive glaze formulation meets the optimization objective. In this embodiment, the optimization objective is to increase the initial flashover voltage after applying the semi-conductive glaze by 10% compared to the initial value, and the preset threshold is determined based on this objective. Specifically, the initial value refers to the initial flashover voltage of the vacuum interrupter when the semi-conductive glaze is not applied. This serves as a benchmark for measuring the effectiveness of the improvement. It reflects the voltage level at which surface flashover occurs in the vacuum interrupter in its original state. This data, obtained through experimental measurements or existing technical data, forms the basis for subsequent calculation of the preset threshold. During the iterative determination of the semi-conductive glaze formulation, the initial flashover voltage obtained from each surface flashover experiment on the test workpiece is compared with the preset threshold. If the initial flashover voltage is greater than or equal to the preset threshold, the current semi-conductive glaze formulation meets the optimization objective of increasing the initial flashover voltage by 10% and the formulation can be used as the target formulation. If the initial flashover voltage is less than the preset threshold, the conductivity of the semi-conductive glaze layer structure is adjusted based on the surface potential distribution measurement results, and iterative optimization continues until the preset threshold requirement is met.

[0081] For example, when the initial flashover voltage is less than a preset threshold, a surface potential test system for insulating materials is prepared. The system primarily consists of a plexiglass chamber, a two-dimensional motion mechanism, a high-voltage discharge needle, an electrostatic probe and electrometer, a data acquisition system, a motion control system, and a high-voltage DC power supply. After the surface flashover experiment, the workpiece to be tested is placed in the test system, and the system's movement step length is set to 1 mm. Driven by the two-dimensional motion mechanism, a Z-shaped scanning method is used to measure the corresponding surface potentials of distributed points within the central area of the sample surface.

[0082] S111, adjusting the conductivity of the semi-conductive glaze layer structure based on the surface potential distribution measurement result.

[0083] For example, the surface potential distribution measurement results are analyzed to observe the surface charge distribution and determine the effectiveness of the semi-conductive glaze layer in suppressing charge. Based on the analysis results, the conductivity of the semi-conductive glaze layer structure is adjusted in the next iteration. If the charge suppression effect is poor, the conductivity value is appropriately increased or decreased, and step S104 and subsequent steps are repeated until the first flashover voltage is greater than or equal to the preset threshold, thereby determining the final target semi-conductive glaze formulation.

[0084] The above-mentioned method for determining the parameters of the semi-conductive glaze specifically used for the vacuum interrupter is more accurate, effective and compatible through model simulation, material selection, glaze coating, glaze firing, experimental testing, optimization and improvement, so that the semi-conductive glaze prepared based on this method can significantly improve the electric field distribution of the vacuum interrupter, effectively suppress the charge at the three junctions, and thus increase the surface flashover voltage of the vacuum ceramic.

[0085] In an exemplary embodiment, Figure 3 As shown in Figure 2, the process of surface flashover test includes:

[0086] S301, based on the initial test voltage, gradually increase the test voltage applied to the workpiece to be tested, and perform a preset number of tests at each test voltage, recording the current and light intensity after each application of the test voltage until the number of light intensity peaks corresponding to the test voltage is equal to the preset number.

[0087] Among them, the light intensity peak is a key indicator in the surface flashover experiment, which intuitively reflects the occurrence and change of the surface flashover phenomenon. In the surface flashover experiment of the vacuum arc chamber, when the applied voltage reaches a certain level and triggers surface flashover, it will be accompanied by the generation of light. The light intensity peak refers to the peak point in the light intensity variation curve over time during this process. At the moment of surface flashover, due to physical processes such as gas ionization and electron transition, strong light radiation will be released, resulting in a sharp increase in light intensity and the formation of a peak. By monitoring the light intensity peak, it can be determined whether surface flashover occurs. During the experimental process of the embodiment, the number of light intensity peaks and the corresponding voltage values under different test voltages are recorded to determine the first flashover voltage. If the light intensity peak appears for the first time under a certain test voltage, then this voltage is the first flashover voltage.

[0088] For example, a surface flashover experimental device is built, and a voltage source, current measuring device, light intensity measuring device, etc. are connected. Figure 4 As shown, a starting voltage value is selected as the initial test voltage, such as 20kV. This voltage is lower than the expected first flashover voltage to ensure that the occurrence process of the flashover phenomenon can be fully observed. Taking into account the experimental accuracy and efficiency, determine the preset number of tests at each test voltage, such as 10 times. This number must ensure that the current and light intensity data can be fully obtained at this voltage to accurately reflect the flashover situation. Starting from the initial test voltage, increase the test voltage step by step according to a certain voltage change amplitude, such as increasing by 2kV each time. At each test voltage, perform a preset number of tests (such as 10 times). During each test, use high-precision current measuring instruments and light intensity detection equipment to record the current value and light intensity data after the test voltage is applied. Continue this process until a certain test voltage (such as Figure 4 The voltage U CO ) reaches the preset number of light intensity peaks, which indicates that the surface flashover phenomenon has occurred stably under this voltage.

[0089] S302, gradually reducing the test voltage applied to the workpiece to be tested, and performing a preset number of tests at each test voltage, recording the current and light intensity after each application of the test voltage, until the number of light intensity peaks corresponding to the test voltage is zero.

[0090] For example, Figure 4 As shown, after the voltage boost test is completed and the voltage point is reached where the number of light intensity peaks is equal to the preset number, the test voltage applied to the workpiece to be tested is gradually reduced. Similarly, the voltage is reduced according to a certain voltage change amplitude, such as reducing it by 2kV each time. At each test voltage after the voltage reduction, the preset number of tests (such as 10 times) is still carried out, and the current and light intensity data after each application of the test voltage are synchronously recorded. As the voltage gradually decreases, the change in the number of light intensity peaks is observed. The voltage reduction test is continued until a certain test voltage (such as voltage Uho ) reaches zero. This means that surface flashover no longer occurs at this voltage, and the voltage reduction test phase ends. The current and light intensity data collected at this point provide comprehensive information for studying the flashover characteristics of the test object at different voltages.

[0091] S303: Determine the test voltage at which the light intensity peak is first recorded as the first flashover voltage.

[0092] For example, the light intensity data recorded during the entire step-up and step-down test process are sorted and analyzed. Starting from the initial test voltage, the light intensity data recorded for each test is checked in sequence, and the test voltage corresponding to the test where the light intensity peak first appears is found (e.g. Figure 4 The voltage U fb The test voltage at which the light intensity peak is first recorded is determined as the first flashover voltage. Subsequent material optimization and process improvements can use this first flashover voltage as a reference.

[0093] In this example, the experiment began with an initial voltage lower than the expected value, gradually increasing the voltage. Current and light intensity were measured and recorded multiple times. Light intensity peaks were used to accurately determine the occurrence of flashover and determine the first flashover voltage (Ufb), thereby measuring the insulation performance of the vacuum interrupter. Furthermore, a complete step-up and step-down process was performed, and data from each stage was collected to construct a flashover characteristic dataset. This data, along with the first flashover voltage, provides a key reference for subsequent material optimization and process improvements, helping to increase the surface flashover voltage of vacuum ceramics, enhance the performance of power equipment, and promote the development of vacuum interrupter technology.

[0094] In an exemplary embodiment, a geometric simulation model of the vacuum interrupter is constructed based on a computer device according to structural parameters and material parameters of the vacuum interrupter, including:

[0095] Inputting structural parameters and material parameters of the vacuum interrupter into a computer device, and constructing a geometric simulation model using two-dimensional axisymmetry based on the computer device;

[0096] Among them, the structural parameters include shielding cover, moving contact, static contact, conductive rod, insulating shell, and bellows; the material parameters include relative dielectric constant, electrical conductivity, thermal conductivity, and density.

[0097] For example, the structural parameters of the vacuum interrupter are collected, such as the size and shape of the shield, moving contact, static contact, conductive rod, insulating shell, bellows, etc. The material parameters of each component of the vacuum interrupter are obtained, including relative dielectric constant, conductivity, thermal conductivity, density, etc. Using a two-dimensional axisymmetric method and computer-aided design software, the above structural parameters and material parameters are input to construct a vacuum interrupter. Figure 2 The geometric simulation model of the vacuum interrupter is shown.

[0098] In this embodiment, by comprehensively collecting the structural parameters of each component of the vacuum interrupter, including information such as size and shape, and accurately obtaining material parameters such as relative dielectric constant and conductivity, a detailed and accurate data foundation is provided for the simulation. The model is constructed using a two-dimensional axisymmetric method and computer-aided design software. This not only simplifies the modeling process of complex structures, but also effectively simulates the physical properties of the vacuum interrupter under actual operating conditions. The construction of this model facilitates preliminary evaluation and analysis of the performance of the vacuum interrupter before experiments, identifies potential problems in advance, optimizes design solutions, reduces the number of actual experiments, reduces R&D costs, improves R&D efficiency, and promotes the development of vacuum interrupt technology and the performance improvement of power equipment.

[0099] In an exemplary embodiment, the process conditions of screen printing are: screen mesh number is 200, printing pressure is 50-100N, and the thickness of the semi-conductive glaze is 0.2-0.4mm.

[0100] In this embodiment, a 200-mesh screen is used. During printing, the semi-conductive glaze slurry is ensured to be sufficiently transferred through the mesh openings onto the alumina ceramic surface to form a uniform glaze layer, while also ensuring that the mesh openings are not too large, resulting in uneven glaze accumulation or leakage, thus ensuring the smoothness and consistency of the glaze layer. A printing pressure of 50-100N, within this range, allows the scraper to smoothly and evenly squeeze the glaze slurry through the screen onto the ceramic surface without damaging the screen or making the glaze layer thickness difficult to control due to excessive pressure. Furthermore, it ensures that the glaze slurry adheres tightly to the ceramic surface, enhancing its bonding strength. Controlling the thickness of the semi-conductive glaze to 0.2-0.4mm ensures that the semi-conductive glaze can improve the electric field distribution and suppress charge at the three junctions, while also avoiding excessive thickness, which results in material waste and increased firing difficulty and cost, or excessive thinness, which fails to achieve the expected performance improvement. These process conditions work together to ensure the quality and performance of the semi-conductive glaze layer, which is beneficial for improving the surface flashover voltage of vacuum ceramics and enhancing the insulation performance of vacuum interrupters, thereby improving the reliability and stability of power equipment.

[0101] In an exemplary embodiment, the drying process conditions are: a drying temperature of 150-200° C., and a drying time of 1-2 hours.

[0102] In this embodiment, by setting a drying temperature range of 150-200°C, the moisture in the semi-conductive glaze slurry evaporates quickly and evenly, ensuring that the glaze layer is appropriately dry, avoiding moisture residue due to too low a temperature, affecting the subsequent firing effect, such as the appearance of bubbles, cracks and other defects; at the same time, it also prevents the glaze from reacting or deforming prematurely due to excessively high temperatures, thereby ensuring the integrity and stability of the glaze layer. The drying time of 1-2 hours ensures that the moisture is fully evaporated, and does not cause energy waste and reduced production efficiency due to excessively long drying times. Appropriate drying conditions allow the semi-conductive glaze slurry coated on the surface of the workpiece to solidify better, enhance adhesion to the workpiece surface, and provide a good foundation for subsequent firing, ultimately helping to improve the performance of the semi-conductive glaze in improving electric field distribution, suppressing charges at the three junctions, and increasing the surface flashover voltage of vacuum ceramics.

[0103] In an exemplary embodiment, a ceramic sheet coated with a semi-conductive glaze slurry is fired into a finished product using a neutral flame or a reducing flame, and then cooled naturally after heat preservation. The process conditions for the workpiece to be tested are as follows: the temperature of the neutral flame or the reducing flame is 750-1050°C, the kiln pressure for firing the ceramic sheet is a positive pressure of 12-22Pa, the range of the hot air flow from the observation hole in the lower layer of the kiln bottom is 180-260mm, and the heat preservation time is 2-4 hours.

[0104] For example, the firing atmosphere is controlled at a kiln pressure of 12-22 Pa, with the hot air flow range from the lower observation hole being 180-260 mm. Firing is performed at a temperature of 750-1050°C, with a holding temperature of 2-4 hours. After the holding temperature is reached, the workpiece is cooled naturally to obtain the test piece. If metal sealing is required, two firing methods are available: first sealing the alumina ceramic to the metal and then coating it with a semi-conductive glaze and firing, with a firing temperature range of 750-900°C; or first coating it with a semi-conductive glaze and then sealing it to the metal, with a firing temperature range of 900-1050°C.

[0105] In this embodiment, the temperature range of 750-1050°C meets the firing requirements of the semi-conductive glaze, which can make its internal components fully react and crystallize to form a stable structure, ensuring that the semi-conductive glaze has good conductivity and physical properties. The positive kiln pressure of 12-22Pa and the hot air flow range of the lower observation hole of 180-260mm ensure that the atmosphere in the kiln is uniform and stable, so that the ceramic pieces are heated evenly, avoiding glaze defects caused by local overheating or overcooling, and improving product quality stability. The 2-4 hours of insulation time promotes the element diffusion and interface bonding between the glaze and the ceramic matrix, enhances the adhesion between the semi-conductive glaze and the ceramic piece, and makes the semi-conductive glaze not easy to fall off during subsequent use. The natural cooling method can make the glaze layer shrink slowly and evenly, reduce internal stress concentration, and prevent the glaze layer from cracking.

[0106] In an exemplary embodiment, the present application further provides a semiconductive glaze, which is prepared based on a target formula, and the target formula is determined based on the steps of the method for determining parameters of the semiconductive glaze specifically for the vacuum interrupter in the above embodiment.

[0107] In an exemplary embodiment, the semiconductive glaze includes feldspar powder, quartz powder, quartz, calcite, TiO2, Fe2O3, Cr2O3, and Sb2O3.

[0108] In an exemplary embodiment, Figure 5 As shown, the present application provides an insulating material surface potential testing system for testing a workpiece to be tested as in the above-mentioned embodiment, the system comprising: an organic glass cavity 2, a two-dimensional moving mechanism 4, a high-voltage discharge needle 6, an electrostatic probe 8, an electrometer 10, a data acquisition system 12, a computer device 14 and a high-voltage DC power supply 16; wherein, the two-dimensional moving mechanism 4 is arranged in the organic glass cavity 2, the two-dimensional moving mechanism 4 comprises a base 42, a movable platform 44 arranged on the base 42, and a first bracket 46 and a second bracket 48 arranged on both sides of the base 42; the high-voltage discharge needle 6 is installed on the first bracket 46, and the electrostatic probe 8 is installed on the second bracket 48; the high-voltage DC power supply 16 is respectively connected to the high-voltage discharge needle 6 and the discharge electrode 442 on the movable platform 44, and the discharge electrode 442 on the movable platform 44 is used to place the workpiece to be tested; the electrostatic probe 8 is connected in sequence via the electrometer 10, the data acquisition system 12 and the computer device 14, and the computer device 14 is also connected to the movable platform 44.

[0109] For example, the insulating material surface potential testing system based on the above structure can complete the surface charge distribution test of the workpiece to be tested through the control of the high-voltage DC power supply 16 and the computer device 14.

[0110] In an exemplary embodiment, the computer device 14 is used to control the movable platform 44 to move to the detection area of the electrostatic probe 8 after the high-voltage DC power supply applies the target voltage to the workpiece to be tested through the high-voltage discharge needle 6 and the discharge electrode 442 for a preset time, and control the movable platform 44 to move along a Z shape within the detection area of the electrostatic probe 8 according to a preset moving step length to measure the surface potential distribution of the workpiece to be tested.

[0111] For example, Figure 5As shown, when measuring the surface potential, a high voltage is applied to the workpiece to be tested through a high-voltage DC power supply 16, a high-voltage discharge needle 6, and a discharge electrode 442 for a preset time (e.g., 1 minute). The high-voltage DC power supply 16 is turned off, and based on the control of the computer device 14, the movable platform 44 is driven to move the workpiece to be tested to the detection area below the electrostatic probe 8. Then, the movable platform 44 is driven to control the movable platform 44 to move along a Z-shape within the detection area of the electrostatic probe 8 according to a preset moving step length to measure the surface potential distribution of the workpiece to be tested. Data collection is completed by the electrometer 10 and the data acquisition system 12, and the data is transmitted to the computer device 14. Based on the acquired data, the computer device 14 draws a corresponding two-dimensional surface charge distribution diagram (e.g., Figure 6 The surface potential distribution of the workpiece under test (shown in Figure 2) is measured. By comparing and analyzing the surface charge distribution characteristics of the workpiece before and after the test, the charge suppression effect of the semiconductive glaze applied to the workpiece and its effect on increasing the surface flashover voltage of the vacuum ceramic can be determined. This provides a reference for adjusting the conductivity of the semiconductive glaze layer in the simulation model, and for simultaneously adjusting the firing temperature range and thermal expansion coefficient. Specifically, if the two-dimensional surface charge distribution indicates a concentrated charge distribution, the conductivity can be appropriately increased to improve the charge dissipation rate. Increasing the conductivity requires increasing the firing temperature to increase the material's conductivity. This is because increasing the firing temperature allows for more complete sintering of the glaze particles, resulting in greater material density. Increased density improves the continuity of the conductive pathways, facilitates charge migration, and leads to increased conductivity. Furthermore, increasing the density of the glaze reduces porosity, making the overall structure more compact and enhancing interactions between molecules or atoms, which in turn reduces the thermal expansion coefficient.

[0112] In this embodiment, computer device 14 precisely controls the surface potential measurement process, acquiring two-dimensional surface charge distribution data for the workpiece under test, thereby evaluating the performance of the semiconductive glaze. Based on the evaluation results, the conductivity, firing temperature, and thermal expansion coefficient of the semiconductive glaze are adjusted to optimize its performance, increase the surface flashover voltage of the vacuum ceramic, enhance the insulation and stability of power equipment, and promote the development of power technology.

[0113] In order to describe the technical solution of the present application in more detail, some more specific embodiments are provided below:

[0114] In a specific embodiment, in order to suppress the charge at the three junctions above the static end porcelain shell of a high-voltage vacuum interrupter and improve the surface flashover voltage, this embodiment mainly determines the parameters of the semi-conductive glaze specifically used for the vacuum interrupter through multiple aspects such as model simulation, material selection, glaze coating, glaze firing, experimental testing, and optimization and improvement. The specific implementation method is as follows:

[0115] Model simulation includes the following steps: geometric model establishment, material addition, parameter setting and meshing. The geometric model is constructed based on the structural parameters of the vacuum interrupter, including the shielding cover, moving contact, static contact, conductive rod, insulating shell, bellows, etc. The geometric simulation model is constructed using two-dimensional axisymmetry, such as Figure 2 The material addition is specifically to add the material parameters of the vacuum interrupter including relative dielectric constant, electrical conductivity, thermal conductivity, density, etc. to the model. Preferably, as shown in FIG. Figure 7 As shown, a semi-conductive glaze material is added to the three intersections A1 at the upper position of the static end porcelain shell of the vacuum interrupter, and the glaze layer adopts a triangular structure that fills the gaps at the three intersections, as shown in FIG. Figure 7 The red part in the middle. Parameter settings include those of the electrostatic field, current field and solid heat transfer field, and the initial values and boundary conditions need to be set respectively. The iterative method is preferably direct iteration, the steady-state solver is preferably MUMPS, the nonlinear method is preferably automatic Newton, the maximum number of iterations is preferably 25, and the residual factor is preferably 1000. Meshing specifically involves meshing the geometric model of the vacuum interrupter. The mesh cannot be too coarse, which can easily lead to model deformation and affect the calculation accuracy. At the same time, the mesh should not be too fine, which will result in a large number of meshes, increase the amount of calculation, make the calculation complicated, and occupy too much computer memory, causing the software to crash. This embodiment uses a component and region-based approach to perform optimal meshing based on the computer's allowed memory. The change in the electric field modulus in the simulation results can be used to determine the material conductivity that has the greatest degree of electric field reduction at the three junctions. Combined with theoretical analysis, the reduction in the electric field slows down the charge accumulation rate, thereby suppressing the flashover formation process. Therefore, the charge suppression and surface flashover voltage enhancement effects can be indirectly reflected through the electric field modulus. The electric field modes of the two different three-junctions of the model before and after coating with semi-conductive glaze are compared. The electric field mode of the three-junction A1 at the upper position of the static end porcelain shell of the simulation model before coating with semi-conductive glaze is as follows: Figure 8 As shown in the figure, the electric field model of the three junctions A1 at the upper position of the static end porcelain shell of the simulation model after coating with semi-conductive glaze is as follows: Figure 9 As shown in the figure, the electric field norm at the three junctions A1 is significantly reduced after the semi-conductive glaze is applied. Therefore, the conductivity range, firing temperature range, and thermal expansion coefficient range corresponding to the semi-conductive glaze in the simulation model are used as the basis for formula screening.

[0116] Material selection includes the following steps: for example, based on the formula of medium and low temperature glass glaze, the components of the semi-conductive glaze and the mass proportions of each component screened out based on the above-determined conductivity range, firing temperature range and thermal expansion coefficient range are as follows: 22 parts of feldspar powder, 22 parts of quartz powder, 3 parts of calcite, 9 parts of Kuancheng soil, 3 parts of TiO2, 15 parts of Fe2O3, 1.5 parts of Cr2O3, and 1.5 parts of Sb2O3.

[0117] Glaze application and glaze firing include the following steps:

[0118] (a) preparing the semi-conductive glaze according to the above components and weight proportions of each component;

[0119] (b) Wet ball milling for about 25 hours according to the material: ball: water ratio of 1:1.5:0.5;

[0120] (c) The ball-milled glaze is passed through a 320-mesh sieve with the sieve residue controlled within the range of 0.02-0.05, and then adjusted to a semi-conductive glaze slurry of 50-70 degrees Baume for later use;

[0121] (d) A scraper is used to evenly squeeze the semi-conductive glaze slurry through the holes in the screen onto the alumina ceramic surface. During the printing process, because the screen has a certain degree of elasticity and the screen and printing plate are not in contact, the scraper, under pressure, always has a single contact line with the screen and the printing plate, improving printing precision. The mesh size used for screen printing is 200, the printing pressure is 50-100N, and the thickness of the semi-conductive glaze is 0.2-0.4mm.

[0122] (e) Place the sample in a vacuum bonding furnace, using Ar as the protective gas, heating at a temperature range of 750–900°C, applying a pressure of 5 MPa, and pressing for 1.5 hours.

[0123] (f) Drying the sample at a temperature of 150-200°C for 1-2 hours;

[0124] (g) The finished product is fired in an atmosphere of 750-1050°C using a neutral flame or a reducing flame. The kiln pressure for firing the semi-conductive glaze is a positive pressure of 12-22 Pa. The range of the hot air flow through the lower observation hole is 180-260 mm. The heat preservation time is 2-4 hours. Natural cooling is used to obtain the workpiece to be tested.

[0125] The experimental test includes the following steps: Figure 4As shown, the initial charging voltage is 20kV, with a variation of 2kV. Ten impacts are performed at each voltage level, and the peak values of voltage, current, and light intensity, as well as the number of flashovers, are recorded. The average value of the peak voltage is used as the valid data. When the applied voltage gradually increases to a certain voltage level, an accidental flashover occurs, namely the first breakdown voltage Ufb. As the voltage level continues to increase to a certain level, surface flashover will occur each time the voltage is applied. The average voltage value at this voltage level is recorded as the complete flashover voltage Uco (conditioned voltage) on the surface of the specimen. After reaching complete flashover, the applied voltage is gradually reduced, with the variation still being 2kV. During the voltage reduction process, it usually drops to a certain voltage level below the complete flashover voltage Uco, and no further flashover will occur. The voltage level at this time is defined as the residual withstand voltage Uho (hold-off voltage) of the specimen. At this point, the surface flashover experiment is completed. If the first flashover voltage Ufb measured during the surface flashover experiment is less than the preset threshold, a surface potential test system for insulating materials is used, such as Figure 5 As shown, the surface potential distribution of the workpiece under test is measured before and after the experiment. The specific testing process can be referred to the description of the above embodiment and will not be repeated here. The corresponding two-dimensional surface charge distribution map is drawn through charge inversion calculation. The surface charge distribution characteristics of the sample before and after the experiment are compared and analyzed. The conductivity of the semi-conductive glaze layer structure in the simulation model is adjusted accordingly until the measured first flashover voltage of the workpiece under test is greater than or equal to the preset threshold.

[0126] In another specific embodiment, in order to suppress the charge at the three junctions below the static end porcelain shell of a high-voltage vacuum interrupter and increase the surface flashover voltage, this embodiment mainly determines the parameters of the semi-conductive glaze specifically used for the vacuum interrupter through model simulation, material selection, glaze coating, glaze firing, experimental testing, optimization and improvement. The specific implementation method is as follows:

[0127] Model simulation includes the following steps: geometric model establishment, material addition, parameter setting and meshing. The geometric model is constructed based on the structural parameters of the vacuum interrupter, including the shielding cover, moving contact, static contact, conductive rod, insulating shell, bellows, etc. The geometric simulation model is constructed using two-dimensional axisymmetry. Material addition specifically involves adding the material parameters of the vacuum interrupter, including relative dielectric constant, conductivity, thermal conductivity, density, etc., to the model. Preferably, Figure 10 As shown, a semi-conductive glaze material is added to the three intersections A2 at the lower position of the static end porcelain shell of the vacuum interrupter, and the glaze layer adopts a triangular structure that fills the gaps at the three intersections, as shown in FIG. Figure 10The red part in the middle. Parameter settings include those of the electrostatic field, current field and solid heat transfer field, and the initial values and boundary conditions need to be set respectively. The iterative method is preferably direct iteration, the steady-state solver is preferably GRMES, the nonlinear method is preferably automatic Newton, the maximum number of iterations is preferably 100, and the residual factor is preferably 1000. Meshing is specifically to mesh the geometric model of the vacuum interrupter. The mesh cannot be too coarse, which can easily lead to model deformation and affect the calculation accuracy. At the same time, the mesh should not be too fine, which will result in a large number of meshes, increase the amount of calculation, make the calculation complicated, and occupy too much computer memory, resulting in software crashes. This embodiment uses the method of dividing components and regions for optimal meshing according to the computer's allowed memory. The change in the electric field modulus in the simulation results can be used to determine the material conductivity that has the greatest degree of electric field reduction at the three junctions. Combined with theoretical analysis, the reduction in the electric field slows down the charge accumulation rate, thereby suppressing the flashover formation process. Therefore, the charge suppression and surface flashover voltage enhancement effects can be indirectly reflected through the electric field modulus. The electric field norms of the two different three-junction A2 of the model before and after coating with semi-conductive glaze are compared. The electric field norm of the three-junction A2 of the lower position of the static end porcelain shell of the simulation model before coating with semi-conductive glaze is as follows: Figure 11 As shown in the figure, the electric field model of the three junctions A2 at the upper position of the static end porcelain shell of the simulation model after coating with semi-conductive glaze is as follows: Figure 12 As shown in the figure, the electric field norm at the three junctions is significantly reduced after the semi-conductive glaze is applied. Therefore, the conductivity range, firing temperature range, and thermal expansion coefficient range corresponding to the semi-conductive glaze in the simulation model are used as the basis for formula screening.

[0128] Material selection includes the following steps: for example, based on the formula of medium and low temperature glass glaze, the components and the mass proportions of each component screened based on the above-determined conductivity range, firing temperature range and thermal expansion coefficient range are as follows: 32 parts of feldspar powder, 32 parts of quartz powder, 8 parts of calcite, 16 parts of Kuancheng soil, 8 parts of TiO2, 22 parts of Fe2O3, 35 parts of Cr2O, and 35 parts of Sb2O.

[0129] Glaze application and glaze firing include the following steps:

[0130] (a) preparing the semi-conductive glaze according to the above components and weight proportions of each component;

[0131] (b) Wet ball milling for about 30 hours according to the material: ball: water ratio of 1.5:2:1;

[0132] (c) The ball-milled glaze is passed through a 320-mesh sieve with the sieve residue controlled within the range of 0.02-0.05, and then adjusted to a semi-conductive glaze slurry of 50-70 degrees Baume for later use;

[0133] (d) A scraper is used to evenly squeeze the semi-conductive glaze slurry through the holes in the screen onto the alumina ceramic surface. During the printing process, because the screen has a certain degree of elasticity and the screen and printing plate are not in contact, the scraper, under pressure, always has a single contact line with the screen and the printing plate, improving printing precision. The mesh size used for screen printing is 200, the printing pressure is 50-100N, and the thickness of the semi-conductive glaze is 0.2-0.4mm.

[0134] (e) Place the sample in a vacuum bonding furnace, using Ar as the protective gas, heating at a temperature range of 750–900°C, applying a pressure of 5 MPa, and pressing for 1.5 hours.

[0135] (f) Drying the sample at a temperature of 150-200°C for 1-2 hours;

[0136] (g) The finished product is fired in an atmosphere of 750-1050°C using a neutral flame or a reducing flame. The kiln pressure for firing the semi-conductive glaze is a positive pressure of 12-22 Pa. The range of the hot air flow through the lower observation hole is 180-260 mm. The heat preservation time is 2-4 hours. Natural cooling is used to obtain the workpiece to be tested.

[0137] The surface flashover test process in the experimental test and the surface charge distribution of the workpiece to be tested can be combined Figure 5 And refer to the description in the above embodiments, which will not be repeated here.

[0138] In another specific embodiment, in order to suppress the charge at the three junctions above the moving end porcelain shell of a high-voltage vacuum interrupter and increase the surface flashover voltage, this embodiment mainly determines the parameters of the semi-conductive glaze specifically used for the vacuum interrupter through model simulation, material selection, glaze coating, glaze firing, experimental testing, optimization and improvement. The specific implementation method is as follows:

[0139] Model simulation includes the following steps: geometric model establishment, material addition, parameter setting and meshing. The geometric model is constructed based on the structural parameters of the vacuum interrupter, including the shielding cover, moving contact, static contact, conductive rod, insulating shell, bellows, etc. The geometric simulation model is constructed using two-dimensional axisymmetry. Material addition specifically involves adding the material parameters of the vacuum interrupter, including relative dielectric constant, conductivity, thermal conductivity, density, etc., to the model. Preferably, Figure 13 As shown in FIG, a semi-conductive glaze material is added to the three intersections A3 on the upper side of the porcelain shell of the moving end of the vacuum interrupter, and the glaze layer adopts a rounded corner structure, as shown in FIG. Figure 13The red part in the middle. Parameter settings include those of the electrostatic field, current field and solid heat transfer field, and the initial values and boundary conditions need to be set respectively. The iterative method is preferably direct iteration, the steady-state solver is preferably MUMPS, the nonlinear method is preferably automatic Newton, the maximum number of iterations is preferably 25, and the residual factor is preferably 1000. Meshing specifically involves meshing the geometric model of the vacuum interrupter. The mesh cannot be too coarse, which can easily lead to model deformation and affect the calculation accuracy. At the same time, the mesh should not be too fine, which will result in a large number of meshes, increase the amount of calculation, make the calculation complicated, and occupy too much computer memory, causing the software to crash. This embodiment uses a component and region-based approach to perform optimal meshing based on the computer's allowed memory. The change in the electric field modulus in the simulation results can be used to determine the material conductivity that has the greatest degree of electric field reduction at the three junctions. Combined with theoretical analysis, the reduction in the electric field slows down the charge accumulation rate, thereby suppressing the flashover formation process. Therefore, the charge suppression and surface flashover voltage enhancement effects can be indirectly reflected through the electric field modulus. The electric field modes of the two different three-junctions of the model before and after coating with semi-conductive glaze are compared. The electric field mode of the three-junction A3 at the upper position of the dynamic end porcelain shell of the simulation model before coating with semi-conductive glaze is as follows: Figure 14 As shown in the figure, the electric field model of the three junctions A3 at the upper position of the dynamic end ceramic shell of the simulation model after coating with semi-conductive glaze is as follows: Figure 15 As shown in the figure, the electric field norm at the three junctions A3 is significantly reduced after the semi-conductive glaze is applied. Therefore, the conductivity range, firing temperature range, and thermal expansion coefficient range corresponding to the semi-conductive glaze in the simulation model are used as the basis for formula screening.

[0140] Material selection includes the following steps: for example, based on the formula of medium and low temperature glass glaze, the components and the mass proportions of each component screened based on the above-determined conductivity range, firing temperature range and thermal expansion coefficient range are as follows: 27 parts of feldspar powder, 26 parts of quartz powder, 3 parts of calcite, 12 parts of Kuancheng soil, 6 parts of TiO2, 18 parts of Fe2O3, 3 parts of Cr2O3, and 33 parts of Sb2O3.

[0141] Glaze application and glaze firing include the following steps:

[0142] (a) preparing the semi-conductive glaze according to the above components and weight proportions of each component;

[0143] (b) Wet ball milling for about 28 hours according to the material: ball: water ratio of 1.5:1.5:0.5;

[0144] (c) The ball-milled glaze is passed through a 320-mesh sieve with the sieve residue controlled within the range of 0.02-0.05, and then adjusted to a semi-conductive glaze slurry of 50-70 degrees Baume for later use;

[0145] (d) A scraper is used to evenly squeeze the semi-conductive glaze slurry through the holes in the screen onto the alumina ceramic surface. During the printing process, because the screen has a certain degree of elasticity and the screen and printing plate are not in contact, the scraper, under pressure, always has a single contact line with the screen and the printing plate, improving printing precision. The mesh size used for screen printing is 200, the printing pressure is 50-100N, and the thickness of the semi-conductive glaze is 0.2-0.4mm.

[0146] (e) Place the sample in a vacuum bonding furnace, using Ar as the protective gas, heating at a temperature range of 750–900°C, applying a pressure of 5 MPa, and pressing for 1.5 hours.

[0147] (f) Drying the sample at a temperature of 150-200°C for 1-2 hours;

[0148] (g) The finished product is fired in an atmosphere of 750-1050°C using a neutral flame or a reducing flame. The kiln pressure for firing the semi-conductive glaze is a positive pressure of 12-22 Pa. The range of the hot air flow through the lower observation hole is 180-260 mm. The heat preservation time is 2-4 hours. Natural cooling is used to obtain the workpiece to be tested.

[0149] The surface flashover test process in the experimental test and the surface charge distribution of the workpiece to be tested can be combined Figure 5 And refer to the description in the above embodiments, which will not be repeated here.

[0150] In another specific embodiment, in order to suppress the charge and increase the flashover voltage at the three junctions located below the moving end porcelain shell of a high-voltage vacuum interrupter, this embodiment mainly determines the parameters of the semi-conductive glaze specifically used for the vacuum interrupter through model simulation, material selection, glaze coating, glaze firing, experimental testing, optimization and improvement. The specific implementation method is as follows:

[0151] Model simulation includes the following steps: geometric model establishment, material addition, parameter setting and meshing. The geometric model is constructed based on the structural parameters of the vacuum interrupter, including the shielding cover, moving contact, static contact, conductive rod, insulating shell, bellows, etc. The geometric simulation model is constructed using two-dimensional axisymmetry. Material addition specifically involves adding the material parameters of the vacuum interrupter, including relative dielectric constant, conductivity, thermal conductivity, density, etc., to the model. Preferably, Figure 16 As shown in FIG, a semi-conductive glaze material is added to the three intersections A4 at the lower position of the porcelain shell of the moving end of the vacuum interrupter, and the glaze layer adopts a rounded corner structure, as shown in FIG. Figure 16The red part in the middle. Parameter settings include those of the electrostatic field, current field and solid heat transfer field, and the initial values and boundary conditions need to be set respectively. The iterative method is preferably direct iteration, the steady-state solver is preferably GRMES, the nonlinear method is preferably automatic Newton, the maximum number of iterations is preferably 100, and the residual factor is preferably 1000. Meshing is specifically to mesh the geometric model of the vacuum interrupter. The mesh cannot be too coarse, which can easily lead to model deformation and affect the calculation accuracy. At the same time, the mesh should not be too fine, which will result in a large number of meshes, increase the amount of calculation, make the calculation complicated, and occupy too much computer memory, resulting in software crashes. This embodiment uses the method of dividing components and regions for optimal meshing according to the computer's allowed memory. The change in the electric field modulus in the simulation results can be used to determine the material conductivity that has the greatest degree of electric field reduction at the three junctions. Combined with theoretical analysis, the reduction in the electric field slows down the charge accumulation rate, thereby suppressing the flashover formation process. Therefore, the charge suppression and surface flashover voltage enhancement effects can be indirectly reflected through the electric field modulus. The electric field modes of the two different three-junctions of the model before and after coating with semi-conductive glaze are compared. The electric field mode of the three-junction A4 at the upper position of the dynamic end porcelain shell of the simulation model before coating with semi-conductive glaze is as follows: Figure 17 As shown in the figure, the electric field model of the three junctions A4 at the upper position of the dynamic end ceramic shell of the simulation model after coating with semi-conductive glaze is as follows: Figure 18 As shown in the figure, the electric field norm at the three junctions is significantly reduced after the semi-conductive glaze is applied. Therefore, the conductivity range, firing temperature range, and thermal expansion coefficient range corresponding to the semi-conductive glaze in the simulation model are used as the basis for formula screening.

[0152] Material selection includes the following steps: for example, based on the formula of medium and low temperature glass glaze, the components of the semi-conductive glaze and the mass proportions of each component screened out based on the above-determined conductivity range, firing temperature range and thermal expansion coefficient range are as follows: 24 parts of feldspar powder, 25 parts of quartz powder, 2 parts of calcite, 11 parts of Kuancheng soil, 24 parts of TiO, 16 parts of Fe2O3, 32 parts of Cr2O, and 32 parts of Sb2O.

[0153] Glaze application and glaze firing include the following steps:

[0154] (h) preparing the semi-conductive glaze according to the above components and weight proportions of each component;

[0155] (i) Wet ball milling for about 27 hours according to the material: ball: water ratio of 1:1.5:0.5;

[0156] (j) The ball-milled glaze is passed through a 320-mesh sieve, with the sieve residue controlled within the range of 0.02-0.05, and then adjusted to a semi-conductive glaze slurry of 50-70 degrees Baume for later use;

[0157] (k) A scraper is used to evenly squeeze the semi-conductive glaze slurry through the holes in the screen onto the alumina ceramic surface. During the printing process, because the screen has a certain degree of elasticity and the screen and printing plate are not in contact, the scraper, under pressure, always has a single line of contact with the screen and the printing plate, improving printing precision. The mesh size used for screen printing is 200, the printing pressure is 50-100N, and the thickness of the semi-conductive glaze is 0.2-0.4mm.

[0158] (l) Place the sample in a vacuum bonding furnace, use Ar as the protective gas, heat at 750-900°C, apply a pressure of 5 MPa, and press for 1.5 hours.

[0159] (m) Dry the sample at a temperature of 150-200°C for 1-2 hours;

[0160] (n) The finished product is fired in an atmosphere of 750-1050°C using a neutral flame or a reducing flame. The kiln pressure for firing the semi-conductive glaze is a positive pressure of 12-22 Pa. The range of the hot air flow through the lower observation hole is 180-260 mm. The holding time is 2-4 hours. Natural cooling is used to obtain the workpiece to be tested.

[0161] The surface flashover test process in the experimental test and the surface charge distribution of the workpiece to be tested can be combined Figure 5 And refer to the description in the above embodiments, which will not be repeated here.

[0162] Those skilled in the art will understand that all or part of the processes in the above-mentioned embodiments can be implemented by instructing the relevant hardware through a computer program. 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. In particular, any reference to memory, database, or other media used in the embodiments provided in this application can include at least one of non-volatile memory 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), magnetic 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. By way of illustration and not limitation, RAM can take various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM). The databases involved in the various embodiments provided herein may include at least one of a relational database and a non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the various embodiments provided herein may be, but are not limited to, general-purpose processors, central processing units (CPUs), graphics processing units (GPUs), digital signal processors (DSPs), programmable logic devices (PLDs), quantum computing-based data processing logic devices, artificial intelligence (AI) processors, and the like.

[0163] The technical features of the above embodiments can be combined arbitrarily. In order 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 application.

[0164] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, and these modifications and improvements fall within the scope of protection of the present application. Therefore, the scope of protection of the present application shall be determined by the appended claims.

Claims

1. A method for determining parameters of a semi-conductive glaze specifically for a vacuum interrupter, characterized in that: The method comprises: Based on computer equipment, a geometric simulation model of the vacuum interrupter is constructed according to the structural parameters and material parameters of the vacuum interrupter; Iterate the following steps until the first flashover voltage of the workpiece to be tested is greater than or equal to the preset threshold, and use the corresponding semi-conductive glaze formula at the end of the iteration as the target formula: Based on the computer device, a semi-conductive glaze layer structure with different electrical conductivities is arranged at three intersections of the geometric simulation model of the vacuum interrupter to form a model to be simulated; Based on the finite element analysis software of the computer device, a multi-dimensional physical field simulation analysis is performed on the model to be simulated according to the actual working conditions of the vacuum interrupter; Determining, based on the computer device and according to the simulation analysis results, the conductivity range, firing temperature range, and thermal expansion coefficient range of the semi-conductive glaze; Based on the medium and low temperature glass glaze formula, the semi-conductive glaze formula is determined based on the conductivity range, the firing temperature range and the thermal expansion coefficient range; Printing a semiconductive glaze slurry prepared based on the semiconductive glaze formula onto the surface of the ceramic sheet by screen printing and drying the slurry; The ceramic sheet coated with the semi-conductive glaze slurry is fired into a finished product using a neutral flame or a reducing flame, and then cooled naturally after heat preservation to obtain a workpiece to be tested; Performing a surface flashover test on the workpiece to be tested to determine the first flashover voltage; When the first flashover voltage is less than the preset threshold, measuring the surface potential distribution of the workpiece to be tested after the surface flashover experiment is completed; Based on the surface potential distribution measurement results, the conductivity of the semiconductive glaze layer structure is adjusted.

2. The method for determining parameters of a semi-conductive glaze specifically for a vacuum interrupter according to claim 1, characterized in that: The process of the surface flashover test includes: Based on the initial test voltage, gradually increase the test voltage applied to the workpiece to be tested, and perform a preset number of tests at each test voltage, recording the current and light intensity after each application of the test voltage until the number of light intensity peaks corresponding to the test voltage equals the preset number; Gradually reducing the test voltage applied to the workpiece to be tested, and performing the preset number of tests at each test voltage, recording the current and light intensity after each application of the test voltage, until the number of light intensity peaks corresponding to the test voltage is zero; The test voltage at which the light intensity peak is first recorded is determined as the first flashover voltage.

3. The method for determining parameters of a semi-conductive glaze specifically for a vacuum interrupter according to claim 1, characterized in that: The method of constructing a geometric simulation model of the vacuum interrupter based on computer equipment according to the structural parameters and material parameters of the vacuum interrupter includes: Inputting structural parameters and material parameters of the vacuum interrupter into the computer device, and constructing the geometric simulation model based on the computer device using two-dimensional axisymmetry; The structural parameters include the shielding cover, the moving contact, the static contact, the conductive rod, the insulating shell, and the bellows; and the material parameters include the relative dielectric constant, the electrical conductivity, the thermal conductivity, and the density.

4. The method for determining parameters of a semi-conductive glaze specifically for a vacuum interrupter according to claim 1, characterized in that: The process conditions of the screen printing are: The mesh number of the screen is 200, the printing pressure is 50-100N, and the thickness of the semi-conductive glaze is 0.2-0.4mm.

5. The method for determining parameters of a semi-conductive glaze specifically for a vacuum interrupter according to claim 1, characterized in that: The process conditions of the drying are: The drying temperature is 150-200℃ and the drying time is 1-2 hours.

6. The method for determining parameters of a semi-conductive glaze specifically for a vacuum interrupter according to claim 1, characterized in that: The ceramic sheet coated with the semi-conductive glaze slurry is fired into a finished product using a neutral flame or a reducing flame, and then cooled naturally after heat preservation to obtain the workpiece to be tested. The process conditions are: The temperature of the neutral flame or reducing flame is 750-1050° C., the kiln pressure for firing the ceramic piece is a positive pressure of 12-22 Pa, the range of the hot air flow from the observation hole at the bottom of the kiln is 180-260 mm, and the holding time is 2-4 hours.

7. A semi-conductive glaze, characterized in that: The semi-conductive glaze is prepared based on a target formula, and the target formula is determined based on the steps of the method for determining parameters of a semi-conductive glaze specifically for a vacuum interrupter according to any one of claims 1 to 6.

8. The semiconductive glaze according to claim 7, characterized in that The semi-conductive glaze comprises feldspar powder, quartz powder, kaolin, calcite, TiO2, Fe2O3, Cr2O3 and Sb2O3.

9. A surface potential testing system for insulating materials, characterized in that: For testing a workpiece to be tested as claimed in any one of claims 1 to 6, the system comprising: an organic glass cavity, a two-dimensional moving mechanism, a high-voltage discharge needle, an electrostatic probe, an electrometer, a data acquisition system, a computer device and a high-voltage DC power supply; The two-dimensional moving mechanism is arranged in the organic glass cavity, and the two-dimensional moving mechanism includes a base, a movable platform arranged on the base, and a first bracket and a second bracket arranged on both sides of the base; The high-voltage discharge needle is mounted on the first bracket, and the electrostatic probe is mounted on the second bracket; The high-voltage DC power supply is connected to the high-voltage discharge needle and the discharge electrode on the movable platform respectively, and the discharge electrode on the movable platform is used to place the workpiece to be tested; The electrostatic probe is connected to the electrometer, the data acquisition system and the computer device in sequence, and the computer device is also connected to the movable platform.

10. The insulating material surface potential testing system according to claim 9, characterized in that: The computer device is used to control the movable platform to move to the detection area of the electrostatic probe after the high-voltage DC power supply applies the target voltage to the workpiece to be tested through the high-voltage discharge needle and the discharge electrode for a preset time, and control the movable platform to move in a Z-shape within the detection area of the electrostatic probe according to a preset moving step length, so as to measure the surface potential distribution of the workpiece to be tested.

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