Method and device for improving alternating current / direct current withstand voltage test electric field of tank-type circuit breaker and storage medium

Abstract

The invention provides a tank-type circuit breaker AC / DC voltage withstand test electric field improvement method and device and a storage medium, and the device comprises an epoxy resin composite insulator embedded with an aluminum alloy spherical shell, and the spherical shell achieves the equipotential connection with the wire outlet end of a circuit breaker sleeve through conical surface cooperation. And the curvature radius is optimally designed to transfer an electric field peak value to an equatorial region. The spherical shell is coated with a semi-conductive silicone rubber layer with resistivity distributed in a gradient manner, and the outer insulator forms a multi-stage umbrella skirt structure. During installation, dimensional tolerance self-adaptive compensation is achieved through a cam locking mechanism of the floating flange, and the belleville spring set provides axial sealing pre-tightening force. The method comprises four core processes of composite structure coaxial installation, gradient electric field regulation and control, dynamic sealing locking and electric heating state verification. According to the scheme, an electrode structure is reconstructed to suppress point discharge, space charge accumulation is blocked through dielectric layer resistivity gradient distribution, the creepage distance along the surface is prolonged through the multi-stage umbrella skirts, and the technical defect that the safety distance is shortened by a traditional grading ring is overcome.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of power detection, in particular to a tank circuit breaker AC-DC withstand voltage test electric field improvement method and device and a storage medium. BACKGROUND

[0002] When a tank circuit breaker is subjected to AC-DC withstand voltage test, the two sides of the bushing outgoing line are electrified due to the closing of the circuit breaker to ground, the safety distance of the adjacent bus is close to the critical value, and there is a risk of discharge causing the bus to be powered off. The traditional solution uses an aluminum equalizing ring to improve the electrode shape, but the size of the metal equalizing ring is too large to reduce the air insulation distance, and the conductor property cannot increase the substantial insulation isolation. Some circuit breakers in Pu'er station and other converter stations are not equipped with equalizing rings, and strong corona loss is generated during the withstand voltage test. The existing technology has double defects of the metal equalizing ring: firstly, the geometric size and the insulation distance are in a contradictory relationship, and increasing the equalizing ring improves the electric field distribution but compresses the safety margin; secondly, the metal material cannot block the discharge channel, especially under the condition of AC-DC superposition, the space charge accumulation aggravates the risk of surface flashover. These defects cause the compact layout scene in the converter station to be unable to safely carry out high voltage test, and an innovative solution is urgently needed. SUMMARY

[0003] The application provides a tank circuit breaker AC-DC withstand voltage test electric field improvement method and device and a storage medium to solve the contradiction between the geometric size and the insulation distance of the traditional metal equalizing ring in improving the electric field distribution in the prior art.

[0004] The application aims to provide a tank circuit breaker AC-DC withstand voltage test electric field improvement method, which comprises the following steps: composite structure installation, coaxially sleeving an insulating assembly with an embedded metal conductive spherical shell on the outgoing line end of the circuit breaker bushing, realizing equipotential connection through the taper surface cooperation, wherein the curvature radius of the metal spherical shell is configured according to the electric field distribution characteristics, and a multistage umbrella skirt configuration is formed on the outer edge of the insulator; gradient electric field regulation, coating a semiconductive medium layer with continuously changing resistivity on the outer surface of the metal spherical shell, the medium layer forms a transition zone with increasing volume resistivity from inside to outside, which is used for establishing a nonlinear resistance voltage division network during DC voltage withstand and smoothing the dielectric constant jump of the metal and insulator interface during AC voltage withstand; dynamic sealing locking, driving the radial contraction of the circumferential cam locking block of the floating flange to generate an axial pre-tightening force of the disc spring set, compensating the size tolerance of the bushing terminal, and triggering the mechanical limiting mechanism to fixedly connect the interface when the locking torque reaches the preset threshold; electric heat state verification, applying a detection voltage after the device is installed, measuring the loop resistance of the metal spherical shell and the circuit breaker conductor, synchronously monitoring the temperature distribution field of the umbrella skirt surface, and entering the withstand voltage test mode after confirming that there is no local overheating area.

[0005] In one of the schemes, further comprising the steps of measuring the geometric parameters such as the diameter, length, end shape, etc. of the bushing outgoing line, and the computer-aided design software generates a three-dimensional model according to the geometric parameters, and the three-dimensional model contains the composite structure design of the aluminum spherical shell and the insulating material.

[0006] In one of the schemes, further comprising the steps of setting the voltage parameters of the AC-DC withstand voltage test, and analyzing the electric field intensity distribution between the bushing outgoing line and the operating busbar after the installation of the device, and the optimization process includes adjusting the curvature radius of the aluminum spherical shell and the thickness of the insulating material.

[0007] In one of the schemes, further comprising the steps of using a metal cutting process to prepare the aluminum spherical shell, using a mold forming process to prepare the insulating material shell, and assembling and connecting the aluminum spherical shell and the insulating material shell to form a composite device.

[0008] In a second aspect, the application also provides a tank circuit breaker AC-DC withstand voltage test electric field improvement device, which comprises a main structure customized according to the shape and size of the circuit breaker bushing outgoing line, an aluminum spherical shell inside the main structure for improving the tip electric field, and an insulating material such as epoxy resin outside the main structure for isolating the discharge channel, and the aluminum spherical shell and the insulating material form a composite structure to improve the air breakdown voltage.

[0009] In one of the schemes, the connection mode of the aluminum spherical shell and the circuit breaker bushing outgoing line is detachable fixed connection, and the insulating material is covered on the outside of the aluminum spherical shell through pouring or wrapping process to form a tightly fitted composite layer structure.

[0010] In one of the schemes, the outside surface of the insulating material is provided with a shed structure for enhancing the surface insulation performance, and the shape and distribution of the shed structure are designed according to the electric field distribution characteristics of the bushing outgoing line.

[0011] In one of the schemes, the inside of the aluminum spherical shell is provided with a support framework for fixed installation, and the support framework is adapted to the end structure of the circuit breaker bushing outgoing line to ensure the coaxiality and stability of the device after installation.

[0012] In a third aspect, the application also provides a computer readable storage medium, and the storage medium stores a computer program, and the computer program is executed by a processor to realize the steps of the tank circuit breaker AC-DC withstand voltage test electric field improvement method as claimed in any one of the schemes, including size measurement, model design, simulation analysis, optimization control, etc.

[0013] In one of the schemes, the computer program includes an instruction module for driving the computer-aided design software to generate a three-dimensional model, and a calculation module for calling an electric field simulation algorithm to analyze the electric field distribution of the device, and a data interaction interface is established between the instruction module and the calculation module.

[0014] Advantages

[0015] The application provides a tank circuit breaker AC / DC withstand voltage test electric field improvement method, device and storage medium. The device converts the original rod-plate electrode into a quasi-spherical-plate system through metal spherical shell curvature optimization, so that the maximum field strength reduction amplitude is improved, and the air breakdown voltage margin is significantly improved. The semiconductive transition layer establishes a nonlinear resistance voltage division network under a DC working condition, and eliminates the field strength distortion of an insulation interface; under an AC working condition, the dielectric constant transition characteristic smoothes the potential jump gradient. The multi-stage umbrella skirt structure is aerodynamically optimized to suppress transverse wind vortex, the surface super-hydrophobic modification blocks the formation of a continuous water film, and the ZnO microcrystal band at the umbrella skirt root realizes self-suppression of surface flashover. The floating flange mechanism amplifies the locking force through a cam wedge angle, and the design of the difference in thermal expansion coefficients causes the contact resistance to change negatively with temperature rise, and the disc spring set absorbs the deformation stress under a 150 DEG C temperature difference. Field verification shows that the device reduces the critical safety distance by 1.2 meters, the 630kV AC withstand voltage test corona inception voltage is increased by 42%, the ±750kV DC leakage current is reduced by 75%, and there is no leakage at the sealing interface after-40 DEG C to 70 DEG C circulation. BRIEF DESCRIPTION OF DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description only show some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor on the basis of the drawings shown.

[0017] Figure 1 The tank circuit breaker AC / DC withstand voltage test electric field improvement method provided by the embodiment of the present application has the working flowchart shown in the figure.

[0018] Figure 2 The tank circuit breaker AC / DC withstand voltage test electric field improvement device provided by the embodiment of the present application has the structure schematic diagram shown in the figure.

[0019] 1, central control module; 2, instruction module; 3, calculation module; 4, output module DETAILED DESCRIPTION

[0020] With reference to the accompanying drawings, the technical solutions in the embodiments of the present application will be described clearly and completely. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all the other embodiments obtained by a person of ordinary skill in the art without creative effort are within the protection scope of the present application.

[0021] It should be noted that if the embodiments of the present application involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement condition, etc. between components in a certain posture, and if the certain posture changes, the directional indications also change accordingly.

[0022] In addition, if the embodiments of the present application involve descriptions of “first”, “second”, etc., the descriptions of “first”, “second”, etc. are only for description purposes, and cannot be understood as indicating or implying the relative importance of the indicated technical features or implicitly indicating the number of the indicated technical features. Therefore, the features limited by “first” and “second” can explicitly or implicitly include at least one of the features. In addition, “and / or” or “and / or” appearing throughout the text means that the three parallel schemes are included, for example, “A and / or B” includes A scheme, or B scheme, or A and B simultaneously satisfy the scheme. In addition, the technical solutions of each embodiment can be combined with each other, but it must be based on the realization of a person of ordinary skill in the art, and when the combination of technical solutions contradicts each other or cannot be realized, it should be considered that the combination of technical solutions does not exist and is not within the protection scope of the present application.

[0023] During the AC and DC withstand voltage test of the tank circuit breaker, when the circuit breaker is in the closed state and withstands voltage to the ground, the voltage is applied from one side of the bushing, and the other side of the bushing will be in a charged state. At this time, the safety distance between the bushing and the operating bus is often close to the critical value, which is easy to cause discharge to the bus, and further causes the serious consequences of bus power failure. In addition, the tank circuit breaker of the converter station such as Pu'er station is not configured with a grading ring, and when the AC and DC withstand voltage test is carried out, strong corona loss will be generated, which not only has an adverse effect on the smooth progress of the AC and DC withstand voltage test, but also increases the energy loss and the risk of equipment operation.

[0024] In the prior art, the electrode shape is usually improved by adding an aluminum voltage grading ring during tank circuit breaker voltage withstand test, so as to reduce corona loss and improve breakdown voltage. However, this scheme has obvious defects: on the one hand, the aluminum voltage grading ring is large in size, which can improve the electrode, but reduces the air insulation distance, and may increase the discharge risk; on the other hand, the aluminum voltage grading ring as a metal conductor cannot increase the insulation isolation in the air, and cannot effectively block the discharge channel of the circuit breaker to the operating bus.

[0025] Based on the above technical problems, the present embodiment proposes a tank circuit breaker AC / DC voltage withstand test electric field improvement method, device and storage medium, the core design idea of which is to combine metal materials and insulating materials, to realize effective improvement of the electric field and isolation of the discharge channel through customized structure design, so as to greatly improve the air breakdown voltage, reduce the corona discharge loss, ensure the smooth development of the AC / DC voltage withstand test, and improve the safety of the bus operation.

[0026] The present application provides a tank circuit breaker AC / DC voltage withstand test electric field improvement method, comprising the following steps:

[0027] S110, composite structure installation, the insulating assembly with the embedded metal conductive spherical shell is coaxially sleeved on the circuit breaker bushing outgoing line end, and the equipotential connection is realized through the taper surface cooperation, wherein the curvature radius of the metal spherical shell is configured according to the electric field distribution characteristics, and the outer edge of the insulator forms a multi-stage umbrella skirt configuration;

[0028] S120, gradient electric field regulation, a semiconductive medium layer with continuously changing resistivity is coated on the outer surface of the metal spherical shell, the medium layer forms a transition zone with increasing volume resistivity from inside to outside, which is used to establish a nonlinear resistance voltage division network during DC voltage withstand, and smooth the dielectric constant jump of the metal and insulator interface during AC voltage withstand;

[0029] S130, dynamic sealing locking, the radial contraction of the circumferential cam locking block of the floating flange makes the disc spring set generate an axial pre-tightening force, and the size tolerance of the bushing terminal is compensated, and when the locking torque reaches the preset threshold, the mechanical limiting mechanism is triggered to fixedly connect the interface;

[0030] S140, electric heating state verification, after the device is installed, a detection voltage is applied, the loop resistance of the metal spherical shell and the circuit breaker conductor is measured, and the temperature distribution field of the umbrella skirt surface is synchronously monitored, and after confirming that there is no local overheating area, the voltage withstand test mode is entered.

[0031] In one of the schemes, the following steps are further included: the diameter, length, end shape and other geometric parameters of the bushing outgoing line are measured, the computer-aided design software generates a three-dimensional model according to the geometric parameters, and the three-dimensional model includes the composite structure design of the aluminum spherical shell and the insulating material.

[0032] In one of the schemes, further comprising the step of: setting the voltage parameters of AC-DC withstand voltage test, analyzing the electric field intensity distribution between the bushing outgoing line and the operating bus after the installation of the device, and the optimization process includes adjusting the curvature radius of the aluminum spherical shell and the thickness of the insulating material.

[0033] In one of the schemes, further comprising the steps of: preparing the aluminum spherical shell by a metal cutting process, preparing the insulating material shell by a mold forming process, and assembling and connecting the aluminum spherical shell and the insulating material shell to form the composite device.

[0034] In this embodiment, the mechanical centering process during the installation stage of the composite structure needs to be accurately controlled: first, a laser interferometer is used to scan the end face of the bushing to generate a three-dimensional point cloud, and the optimal assembly path is calculated; during installation, the pose of the insulating assembly is adjusted by a piezoelectric ceramic micro-displacement mechanism to eliminate the axis offset caused by gravity deformation. The cooperation between the inner conical surface of the metal spherical shell and the terminal of the bushing needs to meet the self-sealing condition that the contact stress increases with the increase of temperature, and the contact resistance negative feedback regulation under high temperature working condition is realized by using the difference of the thermal expansion coefficients of the materials.

[0035] The gradient electric field regulation depends on the constitutive properties of the dielectric layer: the functional filler in the semi-conductive layer has a concentration gradient distribution along the radial direction, and under an alternating current electric field, an equivalent dielectric constant (ε'∝f -0.5 ) varying with frequency is formed, which enables the device to maintain electric field uniformity in the frequency band from power frequency to harmonic frequency; under a direct current electric field, the depth of the carrier trap level formed by the filler increases from the inner layer to the outer layer, blocking the space charge migration path. The regulation process collects the harmonic components of the leakage current in real time, and optimizes the gradient of the dielectric layer formula through feedback control.

[0036] The mechanical mechanism of dynamic sealing locking includes three stages: in the initial contact stage, the cam wedge angle produces mechanical gain to amplify the locking force; in the critical locking stage, the disc spring enters the nonlinear deformation zone to store elastic potential energy; in the final retention stage, the pin and the positioning hole form an interference fit to suppress vibration and loosening. Throughout the process, the strain gauge monitoring method is used to monitor the prestress decay rate of the flange bolts, and when the decay slope exceeds the threshold, the locking torque is automatically compensated.

[0037] The electric heating state verification establishes a multi-physical field coupling criterion: the temperature field spatial frequency components are extracted from the Fourier transform of the infrared thermal image data, and the abnormal hot spots correspond to the sudden change of the high frequency component amplitude; the four-terminal method is used for dynamic measurement of loop resistance to eliminate lead errors, and combined with the piezoresistive effect model (ΔR / R0∝P -n ) of contact pressure to identify virtual connection faults. The reset process for verification failure includes self-repairing operations such as cam phase re-adjustment and plasma cleaning of the contact surface.

[0038] The embodiment also provides a tank-type circuit breaker AC / DC withstand voltage test electric field improvement device, which comprises a main body structure customized according to the shape and size of the circuit breaker bushing outgoing line, an aluminum spherical shell for improving the electric field at the tip is arranged inside the main body structure, an insulating material such as epoxy resin for isolating the discharge channel is wrapped outside the main body structure, and the aluminum spherical shell and the insulating material form a composite structure to improve the air breakdown voltage.

[0039] In one of the schemes, the aluminum spherical shell is connected to the circuit breaker bushing outgoing line in a detachable fixed connection mode, and the insulating material is covered on the outside of the aluminum spherical shell through a pouring or wrapping process to form a closely fitted composite layer structure.

[0040] In one of the schemes, the outside surface of the insulating material is provided with a petticoat structure for enhancing the surface insulation performance, and the shape and distribution of the petticoat structure are designed according to the electric field distribution characteristics of the bushing outgoing line.

[0041] In one of the schemes, the inside of the aluminum spherical shell is provided with a support framework for fixed installation, the support framework is matched with the end structure of the circuit breaker bushing outgoing line to ensure the coaxiality and stability of the device after installation. The electric field improvement device adopts a composite structure design, and the overall shape is customized according to the shape and size of the circuit breaker bushing outgoing line to ensure that the device can closely fit the bushing outgoing line to achieve the best electric field improvement effect. The main body structure of the device is composed of an internal electric field improvement layer and an external insulating isolation layer, and the two are combined together through a specific process to form a complete functional body.

[0042] The core component of the internal electric field improvement layer is an aluminum spherical shell, which is made of high-purity aluminum alloy material and has good electrical conductivity and mechanical strength. The design of the aluminum spherical shell fully considers the electric field distribution characteristics of the end part of the circuit breaker bushing outgoing line. The shape of the aluminum spherical shell is not a standard perfect sphere, but is optimized according to the cross-sectional shape and electric field concentration area of the bushing outgoing line. For example, the radius of curvature of the spherical shell at the tip of the bushing outgoing line is specially designed to smooth the electric field distribution and avoid electric field concentration. The inside of the aluminum spherical shell is provided with a support framework structure, which is matched with the end structure of the circuit breaker bushing outgoing line. The support framework is made of light-weight high-strength metal material, and its structure design not only ensures the reliable support of the aluminum spherical shell to ensure the coaxiality and stability of the device after installation, but also avoids adversely affecting the electric field distribution. A special fixing interface is arranged at the connecting position of the support framework and the bushing outgoing line, and the interface adopts a detachable fixed connection design to facilitate the installation and disassembly of the device.

[0043] The outer insulation isolation layer is made of epoxy resin and other insulating materials, which has excellent electrical insulation performance and mechanical protection performance. The insulating material is covered on the outside of the aluminum spherical shell through pouring or wrapping process, forming a tightly fitted composite layer structure. During pouring or wrapping, process parameters need to be strictly controlled to ensure that there is no gap or bubble between the insulating material and the aluminum spherical shell, so as to avoid affecting the insulation performance and the overall strength of the device. The outer surface of the insulating material is provided with a skirt structure, and the shape and distribution of the skirt structure are specially designed according to the electric field distribution characteristics of the bushing outlet. The number, height and spacing of the skirt are determined through electric field simulation and actual test, and the main function of the skirt is to increase the surface discharge distance of the insulating material, further improve the surface insulation performance of the device, and prevent surface discharge phenomenon under high voltage.

[0044] Based on the measured bushing outlet size data, SolidWorks computer-aided design software is used to design the three-dimensional model of the electric field improvement device. In the design process, first of all, according to the shape and size of the bushing outlet, the overall shape and basic size of the device are determined. Then, the detailed structure design of the internal aluminum spherical shell and the outer insulation isolation layer is carried out.

[0045] For the design of the aluminum spherical shell, the curvature radius and thickness of the shell need to be adjusted according to the requirements of electric field improvement. In the tip part of the bushing outlet, the curvature radius of the shell is appropriately increased to smooth the electric field distribution; in other parts, the overall strength and electric field improvement effect of the shell are optimized according to the actual situation. The design of the outer insulation isolation layer needs to consider the requirements of insulation performance and mechanical strength. According to the characteristics of the insulating material, the thickness of the insulating layer is determined, and the surface discharge distance is increased by designing the skirt structure. The shape and distribution of the skirt are optimized through multiple design iterations and electric field simulation to achieve the best insulation effect. In the three-dimensional model design process, the installation convenience and fixing method of the device also need to be considered. Special installation interface and fixing structure are designed to ensure that the device can be firmly installed on the bushing outlet and will not be loose or displaced during operation.

[0046] Through COMSOL simulation, the electric field intensity distribution cloud diagram between the bushing outlet and the operating bus after the device is installed can be obtained. Analyze the electric field distribution, focus on the areas with concentrated electric field and high field strength. According to the simulation results, the shape, size and material combination of the device are optimized.

[0047] The optimization process includes adjusting the radius of curvature of the aluminum spherical shell, the thickness of the insulating material, the parameters of the umbrella skirt structure, etc. For example, when it is found that the electric field intensity of a certain part is too high, the field intensity can be reduced by increasing the radius of curvature of the aluminum spherical shell or increasing the thickness of the insulating material. Through multiple simulation and optimization iterations, determine which shape, size, and material composition scheme is best for improving the electric field and increasing the breakdown voltage, and ultimately obtain the optimized device design scheme.

[0048] Before installing the device, the circuit breaker bushing outgoing line needs to be cleaned and inspected to ensure that its surface is free of oil, dust and other impurities, and there are no obvious damage and defects. At the same time, prepare the required installation tools and equipment, such as wrenches, hoisting equipment, etc. Transport the processed electric field improvement device to the site, and take effective protective measures during transportation to avoid damage to the device. After arriving at the site, use hoisting equipment to accurately hoist the device to the installation position near the bushing outgoing line. Connect and fix the device to the circuit breaker bushing outgoing line through a special installation interface. During installation, use level and dial indicator to ensure that the installation coaxiality and perpendicularity of the device meet the requirements, to ensure the electric field improvement effect and operation stability of the device. After installation is completed, check all connection parts of the device comprehensively to ensure that the connection is firm and reliable, and there is no looseness. At the same time, check the sealing performance between the device and the bushing outgoing line to ensure that there is no gap and leakage point.

[0049] Before performing the voltage test, a detailed test plan needs to be developed, specifying the voltage parameters, test steps, and safety precautions. At the same time, prepare the required test equipment and monitoring instruments, such as AC / DC high-voltage power supply, voltage transformer, current transformer, corona loss monitor, etc.

[0050] According to the test plan, conduct AC / DC voltage withstand test on the tank-type circuit breaker installed with the electric field improvement device. During the test, gradually increase the voltage until the specified voltage value is reached and maintained for a certain period of time. During the voltage application process, closely observe the operation state of the circuit breaker and the device, such as whether there is discharge phenomenon, abnormal sound, etc.

[0051] Use the corona loss monitor to monitor the corona loss in real time during the test. The monitoring content includes corona current, corona power and other parameters. By analyzing the changes of these parameters, evaluate the corona loss reduction effect of the electric field improvement device. During the test, record the test voltage, current, corona loss and other data in detail, as well as the operation state of the device. After the test is completed, analyze and process the recorded data, compare the corona loss and breakdown voltage improvement effect before and after installing the device, and verify whether the actual performance of the device meets the design requirements.

[0052] When the tank circuit breaker is subjected to AC / DC voltage withstand test, the voltage is applied to the circuit breaker through the bushing outgoing line, at this time, a strong electric field is formed at the end of the bushing outgoing line and the surrounding area. Since the traditional aluminum grading ring can only smooth the electric field by improving the electrode shape, it cannot provide effective insulation isolation, therefore, when the electric field intensity is high, air breakdown and corona discharge phenomena are prone to occur. The internal aluminum spherical shell of the device can redistribute the electric field at the end of the bushing outgoing line as a good conductor. The curved shape of the aluminum spherical shell makes the electric field lines uniformly distributed on its surface, avoiding the concentration of electric field at the sharp end. By reasonably designing the curvature radius and size of the spherical shell, the electric field intensity at the end of the bushing outgoing line can be reduced to a safe range, thereby improving the air breakdown voltage and reducing the occurrence of corona discharge.

[0053] The external insulating material such as epoxy resin forms an effective insulation isolation layer, which can block the discharge channel between the circuit breaker bushing outgoing line and the operating bus. When the voltage is applied to the bushing outgoing line, the insulation isolation layer can withstand a certain voltage gradient to prevent the discharge phenomenon from developing directly from the bushing outgoing line to the operating bus. In addition, the umbrella skirt structure outside the insulating material further improves the surface insulation performance of the device by increasing the surface discharge distance. The special shape of the umbrella skirt makes the surface discharge path longer, increasing the energy required for discharge, thereby reducing the possibility of surface discharge. This insulation isolation mechanism, combined with the internal electric field improvement layer, forms a complete electric field improvement and insulation protection system, which can greatly improve the air breakdown voltage and ensure the smooth progress of the AC / DC voltage withstand test.

[0054] In one of the schemes, the size measurement includes the diameter, length, end shape and other geometric parameters of the bushing outgoing line, and the computer-aided design software generates a three-dimensional model according to the geometric parameters, which contains the composite structure design of the aluminum spherical shell and the insulating material.

[0055] In one of the schemes, in the electric field distribution simulation step, the voltage parameters of the AC / DC voltage withstand test are set to analyze the electric field intensity distribution between the bushing outgoing line and the operating bus after the device is installed, and the optimization process includes adjusting the curvature radius of the aluminum spherical shell and the thickness of the insulating material.

[0056] In one of the schemes, the processing and production step includes preparing the aluminum spherical shell by using metal cutting process, preparing the insulating material shell by using molding process, and assembling and connecting the aluminum spherical shell and the insulating material shell to form the composite device.

[0057] In this embodiment, the composite structure installation stage needs to accurately control the mechanical centering process: first, a laser interferometer is used to scan the end face of the sleeve to generate a three-dimensional point cloud, and the optimal assembly path is calculated; during installation, the pose of the insulating assembly is adjusted by a piezoelectric ceramic micro-displacement mechanism to eliminate the axis offset caused by gravity deformation. The cooperation between the inner conical surface of the metal sphere and the terminal of the sleeve needs to meet the self-sealing condition-the contact stress increases with the increase of temperature, and the contact resistance is adjusted by the negative feedback under high temperature working condition by using the difference of the thermal expansion coefficient of the material.

[0058] The gradient electric field regulation depends on the constitutive properties of the dielectric layer: the functional filler in the semi-conductive layer has a concentration gradient distribution along the radial direction, and under an alternating current electric field, an equivalent dielectric constant that changes with frequency is formed, which enables the device to maintain electric field uniformity in the power frequency to harmonic frequency band; under a direct current electric field, the carrier trap level formed by the filler increases from the inner layer to the outer layer, blocking the space charge migration path. The regulation process collects the harmonic components of the leakage current in real time, and optimizes the gradient of the dielectric layer formula through feedback control.

[0059] The mechanical mechanism of dynamic sealing locking includes three stages: in the initial contact stage, the cam wedge angle produces mechanical gain to amplify the locking force; in the critical locking stage, the disc spring enters the nonlinear deformation zone to store elastic potential energy; in the final retention stage, the pin and the positioning hole form an interference fit to suppress vibration and loosening. Throughout the process, the strain gauge monitoring method is used to monitor the prestress decay rate of the flange bolts, and when the decay slope exceeds the threshold, the locking torque is automatically compensated.

[0060] The electric heating state verification establishes a multi-physical field coupling criterion: the temperature field spatial frequency components are extracted from the Fourier transform of the infrared thermal image data, and the abnormal hot spots correspond to the sudden change of the high frequency component amplitude; the four-terminal method is used for dynamic measurement of loop resistance to eliminate lead errors, and the piezoresistive effect model of contact pressure is used to identify virtual connection faults. The reset process for verification failure includes cam phase readjustment, plasma cleaning of the contact surface and other self-repairing operations.

[0061] Reference Figure 2 In a third aspect, the application further provides a computer readable storage medium, wherein the storage medium stores a computer program, and the computer program is executed by a processor to implement the steps of the tank circuit breaker AC-DC withstand voltage test electric field improvement method, including size measurement, model design, simulation analysis and optimization control, etc.

[0062] In one of the schemes, the computer program includes an instruction module for driving a computer-aided design software to generate a three-dimensional model of the device, and a calculation module for calling an electric field simulation algorithm to analyze the electric field distribution of the device, and a data interaction interface is established between the instruction module and the calculation module.

[0063] Storage media - any various types of memory devices or storage devices. The term "storage media" is intended to include an installation medium, e.g., a CD-ROM, floppy disks, or tape apparatus; computer system memory or random access memory such as DRAM, DDR RAM, SRAM, EDO RAM, Rambus RAM, etc.; non-volatile memory such as flash, magnetic media (e.g., hard disks or optical storage); registers or other similar types of memory elements, etc. The memory medium can also include other types of storage medium or combinations thereof. In addition, the memory medium can be located in a first computer system in which the programs are executed, or be located in a second different computer system which connects to the first computer system over a network such as the Internet. The second computer system can provide program instructions to the first computer system for execution. The term "memory medium" can include two or more memory mediums that reside in different locations, e.g., in different computer systems that are connected over a network. The memory medium can store program instructions (e.g., as an installed program) that can be executed by one or more processors.

[0064] Of course, the storage medium provided by the embodiments of the present application includes computer executable instructions, and the computer executable instructions are not limited to the tank circuit breaker AC-DC withstand voltage test electric field improvement method as above, but can also perform the related operations in the tank circuit breaker AC-DC withstand voltage test electric field improvement method provided by any of the embodiments of the present application.

[0065] The device changes the electric field distribution by the curvature of the metal conductive spherical shell. In the traditional rod-plate electrode system formed by the outlet end of the bushing, the electric field intensity at the conductor tip shows geometric progression growth, which easily leads to corona discharge and air breakdown. The metal spherical shell is coaxially covered outside the conductor in this scheme, which converts the electrode structure into a quasi-spherical-plate system. According to the principle of electrostatics, the uniform electric field distribution in the equatorial region of the sphere greatly weakens the field strength peak value of the original tip. This geometric optimization essentially reduces the ionization starting voltage and significantly improves the insulation margin of the gas medium. The ceramic layer generated by micro-arc oxidation on the surface of the spherical shell realizes atomic-level smoothness, eliminating the field distortion caused by micro protrusions, and its dielectric constant gradient transition characteristics more effectively suppress the initial and development of partial discharge. The innovative design of the gradient dielectric layer realizes the intelligent adaptation of electric field regulation. The concentration of functional fillers in the semi-conductive transition layer changes continuously along the radial direction, forming a natural transition from conductive state to insulating state. Under DC voltage working conditions, this structure establishes a nonlinear resistance voltage division network, and its volt-ampere characteristic shows a positive temperature coefficient effect: when the local current density increases, the material resistivity automatically rises to limit the current growth and block the avalanche accumulation of space charges; under AC working conditions, the gradient dielectric constant makes the capacitive coupling strength of the metal and insulator interface smoothly transition, avoiding the electric field jump at the discontinuous medium. This adaptive characteristic is particularly suitable for complex conditions such as harmonic pollution environment in converter stations, and its equivalent dielectric constant changes with frequency (ε∝f -k ) can automatically compensate for the electric field distortion caused by high-frequency components. The multi-stage umbrella skirt structure realizes environmental robustness through aerodynamic optimization. The specific ratio design of umbrella inclination and umbrella extension distance suppresses vortex generation under crosswind conditions and avoids the deposition of flying dust in the umbrella skirt groove to form a continuous pollution layer. The umbrella skirt surface is modified by fluorosilicone to construct a micro-nano composite structure, forming a super-hydrophobic interface that can block water film connection even in high-humidity environments. The ring-shaped functional material belt at the root of the umbrella skirt constitutes a self-response protection mechanism: when the surface field strength exceeds the critical threshold, the functional material undergoes a crystal phase transition to form an equipotential surface, actively suppressing the development of streamer along the surface.

[0066] This structure-material synergistic design greatly improves the pressure stability under severe weather conditions, especially in rain, fog, and ice melting conditions. The floating flange mechanism solves the engineering adaptation problem through a mechanical compensation mechanism. The cam locking system uses the mechanical gain principle of the wedge-shaped slope to generate several times the radial compression force of traditional bolts under limited operating torque. The nonlinear deformation characteristics of the disc spring group provide dual advantages: constant contact pressure during the initial compression stage to compensate for manufacturing tolerances; and additional compression under high temperature conditions, resulting in a negative temperature coefficient characteristic of the contact resistance. This self-reinforced sealing design maintains a stable interface resistance in a wide temperature range of -40°C to 150°C, completely eliminating the risk of connection degradation caused by thermal cycling. The phase lock pin in the anti-loose mechanism and the vibration damping structure form a mechanical interlock, effectively resisting structural relaxation caused by equipment operation vibration. The full life cycle management system ensures long-term operation through multiple protection mechanisms. The crack propagation indicator slot at the root of the umbrella skirt provides visual failure warning, and when the crack depth reaches the critical size, the warning color mark is exposed. The buffer gap between the spherical shell and the insulator absorbs the material thermal expansion difference, avoiding cracking caused by thermal stress accumulation. The built-in fault current limiting structure establishes a secondary conduction channel under overvoltage conditions, protecting the main insulation from arc ablation. The device life model is based on material accelerated aging experiments, and when the hydrophobicity decreases to the threshold or the cumulative amount of ultraviolet radiation exceeds the standard, a maintenance signal is triggered.

[0067] This technical solution fundamentally breaks through the physical limitations of traditional grading rings: the metal spherical shell improves the electric field distribution while its external insulation layer substantially expands the discharge channel blocking capability; the gradient dielectric layer has both electric field homogenization and space charge suppression functions; the adaptive sealing mechanism solves the installation reliability problem in a compact space. The entire system provides an intrinsically safe pressure test guarantee for space-limited scenarios such as converter stations and urban substations, solving the long-standing technical bottleneck in the power industry.

[0068] The above only describes the preferred embodiments of the present application, and does not limit the patent scope of the present application. Any equivalent structural transformation based on the inventive concept of the present application, or direct / indirect application in other related technical fields is included in the patent protection scope of the present application.

Claims

1. A method for improving the electric field during AC / DC withstand voltage tests of a tank-type circuit breaker, characterized in that, Includes the following steps: The composite structure installation involves coaxially mounting the insulating component with an embedded metal conductive spherical shell onto the outlet end of the circuit breaker bushing. Equipotential bonding is achieved through conical surface mating. The radius of curvature of the metal spherical shell is configured according to the electric field distribution characteristics, and the outer edge of the insulating body forms a multi-level umbrella skirt configuration. Gradient electric field modulation involves coating the outer surface of a metal spherical shell with a semiconductive dielectric layer whose resistivity changes continuously. This dielectric layer forms a transition region with increasing volume resistivity from the inside to the outside, which is used to establish a nonlinear resistive voltage divider network during DC withstand voltage and to smooth the abrupt change in dielectric constant at the metal-insulator interface during AC withstand voltage. Dynamic sealing and locking drive the circumferential cam locking block of the floating flange to retract radially, causing the disc spring assembly to generate axial preload, compensating for the dimensional tolerance of the sleeve terminal. When the locking torque reaches the preset threshold, the mechanical limit mechanism is triggered to fix the connection interface. Electrothermal condition verification involves applying a probe voltage after the device is installed, measuring the loop resistance between the metal spherical shell and the circuit breaker conductor, and simultaneously monitoring the temperature distribution field on the umbrella skirt surface. Once it is confirmed that there are no local overheating areas, the device enters the withstand voltage test mode.

2. The method for improving the electric field during AC / DC withstand voltage tests of tank-type circuit breakers according to claim 1, characterized in that, The method also includes the following steps: measuring geometric parameters, including the diameter, length, and end shape of the bushing outlet wire, and the computer-aided design software generating a three-dimensional model based on the geometric parameters. The three-dimensional model includes a composite structure design of an aluminum spherical shell and insulating materials.

3. The method for improving the electric field during AC / DC withstand voltage tests of tank-type circuit breakers according to claim 1, characterized in that, The process also includes the following steps: by setting the voltage parameters for the AC / DC withstand voltage test, analyzing the electric field strength distribution between the bushing outlet and the operating bus after the device is installed, and the optimization process includes adjusting the radius of curvature of the aluminum spherical shell and the thickness of the insulating material.

4. The method for improving the electric field during AC / DC withstand voltage tests of tank-type circuit breakers according to claim 1, characterized in that, The process also includes the steps of: preparing an aluminum spherical shell using a metal cutting process, preparing an insulating material shell using a molding process, and assembling and connecting the aluminum spherical shell and the insulating material shell to form a composite device.

5. A device for improving the electric field during AC / DC withstand voltage tests of a tank-type circuit breaker, based on the method for improving the electric field during AC / DC withstand voltage tests of a tank-type circuit breaker as described in claims 1-4, characterized in that... It includes a main structure customized according to the shape and size of the bushing outlet of the circuit breaker. The main structure has an aluminum spherical shell inside to improve the electric field at the tip, and is wrapped with an insulating material to isolate the discharge channel. The aluminum spherical shell and the insulating material form a composite structure to improve the air breakdown voltage.

6. The electric field improvement device according to claim 5, characterized in that, The aluminum spherical shell is connected to the circuit breaker bushing outlet in a detachable fixed connection. The insulating material is applied to the outside of the aluminum spherical shell by casting or wrapping to form a composite layer structure.

7. The electric field improvement device according to claim 5, characterized in that, The outer surface of the insulating material is provided with a skirt structure to enhance the surface insulation performance. The shape and distribution of the skirt structure are designed according to the electric field distribution characteristics of the bushing outlet.

8. The electric field improvement device according to claim 5, characterized in that, The aluminum spherical shell is equipped with a support frame for fixed installation, and the support frame is adapted to the end structure of the circuit breaker bushing outlet.

9. A computer-readable storage medium, characterized in that, The storage medium stores a computer program, which, when executed by a processor, implements the steps of the method for improving the electric field of the AC / DC withstand voltage test of the tank-type circuit breaker as described in any one of claims 1 to 4, including operations such as dimensional measurement, model design, simulation analysis, and optimization control.

10. The computer-readable storage medium according to claim 9, characterized in that, The computer program includes an instruction module for driving computer-aided design software to generate a three-dimensional model of the device, and a calculation module for calling an electric field simulation algorithm to analyze the electric field distribution of the device. A data interaction interface is established between the instruction module and the calculation module.

Images