Long-time breakdown test method and system for cable insulation sample wafer

Abstract

The invention discloses a long-time breakdown test method and system for a cable insulation sample wafer, and the method comprises the steps: introducing an AC / DC power supply output end into a high-voltage isolation oven through a high-voltage bushing, and connecting the AC / DC power supply output end with a test multi-electrode; respectively dividing the plurality of test samples into a plurality of areas, increasing test voltage of the test multi-electrode based on a preset step length, respectively carrying out a breakdown test on the first areas of the plurality of test samples, and recording breakdown voltages of different test samples; processing the plurality of breakdown voltages of the different test samples, and determining first insulation breakdown voltages of the different test samples; carrying out a breakdown test on a plurality of areas except the first area of the plurality of test samples based on different proportions of the first insulation breakdown voltage by testing the plurality of electrodes, and recording the breakdown time when the breakdown voltage occurs in the plurality of areas of the plurality of test samples in different proportions; and processing the breakdown time, and determining insulation breakdown time of different proportions of the first insulation breakdown voltage based on parameters obtained after processing.

Description

Technical Field

[0001] The present invention relates to the technical field of power cable structure design, and more specifically, to a long-term breakdown test method and system for cable insulation specimens. Background Art

[0002] When power cables are used for a long time under harsh conditions such as high electric fields and high temperatures, the insulation performance of the insulation material will deteriorate, which will affect the cable life. The basic idea of accelerated life testing is to use the life characteristics under high stress to extrapolate the life characteristics under normal stress levels. The key lies in establishing the relationship between life characteristics and stress levels, and thus the purpose of extrapolating the life characteristics under normal stress levels can be achieved. This relationship between life characteristics and stress levels is the acceleration model, also known as the acceleration equation.

[0003] In the research of existing power cables, usually only the short-term breakdown performance of cable insulation specimens is studied, and there is little research on long-term breakdown analysis. This leads to a lack of effective parameters for design and verification in insulation design, and it is necessary to propose a technology that can reflect long-term breakdown of insulation and conduct test verification. Summary of the Invention

[0004] The technical solution of the present invention provides a long-term breakdown test method and system for cable insulation specimens to solve the problem of how to conduct long-term breakdown tests on cable insulation specimens.

[0005] To solve the above problems, the present invention provides a long-term breakdown test method for cable insulation specimens, and the method includes:

[0006] Introduce the output end of the AC / DC power supply into the high-voltage isolation oven through a high-voltage bushing and connect it to the test multi-electrode arranged in the high-voltage isolation oven;

[0007] Divide multiple test specimens into multiple regions respectively, and the test multi-electrode increases the test voltage based on a preset step size, and conducts breakdown tests on the first regions of multiple test specimens respectively, and records the breakdown voltages of different test specimens;

[0008] Process the multiple breakdown voltages of different test specimens, and determine the first insulation breakdown voltage of the different test specimens based on the parameters obtained after processing;

[0009] Through the test multi-electrode, conduct breakdown tests on multiple regions of multiple test specimens except the first region based on different proportions of the first insulation breakdown voltage, and record the breakdown times of the breakdown voltages when different proportions of the first insulation breakdown voltage occur in multiple regions of multiple test specimens;

[0010] Process the breakdown times of different proportions of the first insulation breakdown voltage, and determine the insulation breakdown times of different proportions of the first insulation breakdown voltage based on the parameters obtained after processing.

[0011] Preferably, the process of processing the multiple breakdown voltages of different test specimens and determining the first insulation breakdown voltage of the different test specimens based on the parameters obtained after processing includes:

[0012] Process the multiple breakdown voltages of different test specimens through the Weibull function to obtain the shape parameter, and determine the shape parameter as the first insulation breakdown voltage of the different test specimens.

[0013] Preferably, the first insulation breakdown voltage is the insulation breakdown voltage with a breakdown probability of 63.5%.

[0014] Preferably, the different proportions of the first insulation breakdown voltage are three values between 70% and 90%.

[0015] Based on another aspect of the present invention, the present invention provides a long-term breakdown test system for cable insulation specimens. The system includes: an AC-DC power supply, a high-voltage bushing, a high-voltage isolation oven, and a test multi-electrode; the output end of the AC-DC power supply is introduced into the high-voltage isolation oven through the high-voltage bushing and is connected to the test multi-electrode arranged in the high-voltage isolation oven;

[0016] The test multi-electrode is used to increase the test voltage based on a preset step size and perform breakdown tests on the first regions of multiple test specimens respectively; and is used to perform breakdown tests on multiple regions of multiple test specimens except the first region based on different proportions of the first insulation breakdown voltage;

[0017] The AC-DC power supply is used to record the breakdown voltages of different test specimens; process the multiple breakdown voltages of different test specimens, and determine the first insulation breakdown voltage of the different test specimens based on the parameters obtained after processing; record the breakdown times when the breakdown voltages occur in multiple regions of multiple test specimens for different proportions of the first insulation breakdown voltage; process the breakdown times of different proportions of the first insulation breakdown voltage, and determine the insulation breakdown times of different proportions of the first insulation breakdown voltage.

[0018] Preferably, the AC-DC power supply is an AC-DC integrated transformer, with a maximum AC voltage value of 50 kV to 70 kV and a maximum DC voltage value of 70 kV to 100 kV.

[0019] Preferably, the high-voltage bushing is arranged on both sides of the top of the high-voltage isolation oven through the openings at the top of the high-voltage isolation oven. The outer wall-piercing bushing of the high-voltage bushing is arranged outside the top of the high-voltage isolation oven, and the inner wall-piercing bushing of the high-voltage bushing is arranged inside the top of the high-voltage isolation oven.

[0020] Preferably, the lengths of the outer wall-piercing bushing and the inner wall-piercing bushing are from 0.4 m to 0.6 m, the nominal creepage distance is from 750 nm to 1000 nm, the power-frequency dry withstand voltage is from 50 kV to 75 kV, the power-frequency wet withstand voltage is from 50 kV to 75 kV, and the full-wave impulse withstand voltage is from 125 kV to 150 kV.

[0021] Preferably, the internal size of the high-voltage isolation oven is not less than 1 m × 1 m × 1 m, the maximum temperature is not less than 100 °C, and the temperature control accuracy is not less than 0.5 °C.

[0022] Preferably, the test multi-electrode includes two rows, and 4 spherical electrodes are arranged in each row;

[0023] The spherical electrodes are connected by copper rods; the length of the copper rods is from 8 mm to 12 mm, the diameter of the spherical electrodes is from 23 mm to 27 mm, and the electrode spacing is from 80 mm to 120 mm.

[0024] Based on another aspect of the present invention, the present invention provides a computer-readable storage medium storing a computer program for executing a long-term breakdown test method for a cable insulation sample.

[0025] Based on another aspect of the present invention, the present invention provides an electronic device, which includes: a processor and a memory; wherein,

[0026] The memory is used for storing the executable instructions that can be executed by the processor;

[0027] The processor is used for reading the executable instructions from the memory and executing the instructions to implement a long-term breakdown test method for a cable insulation sample.

[0028] The technical solution of the present invention provides a long-term breakdown test method and system for cable insulation specimens. The method includes: introducing the output terminal of the AC / DC power supply into the high-voltage isolation oven through a high-voltage bushing and connecting it to the test multi-electrode arranged in the high-voltage isolation oven; dividing multiple test specimens into multiple regions respectively, the test multi-electrode increases the test voltage based on a preset step size, and conducts breakdown tests on the first regions of multiple test specimens respectively, and records the breakdown voltages of different test specimens; processing the multiple breakdown voltages of different test specimens, and determining the first insulation breakdown voltage of different test specimens based on the parameters obtained after processing; through the test multi-electrode, conducting breakdown tests on multiple regions of multiple test specimens except the first region based on different proportions of the first insulation breakdown voltage, and recording the breakdown times of the breakdown voltages occurring in multiple regions of multiple test specimens at different proportions of the first insulation breakdown voltage; processing the breakdown times of different proportions of the first insulation breakdown voltage, and determining the insulation breakdown times of different proportions of the first insulation breakdown voltage based on the parameters obtained after processing. The technical solution of the present invention provides a long-term breakdown test method and system for cable insulation specimens, which is used to evaluate and analyze the long-term electrical resistance performance of cable insulation sheet specimens to verify whether they meet the requirements of cable insulation and support the selection and design of different materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The exemplary embodiments of the present invention can be more fully understood by referring to the following drawings:

[0030] Figure 1 It is a flowchart of a long-term breakdown test method for a cable insulation specimen according to a preferred embodiment of the present invention;

[0031] Figure 2 It is a structural diagram of a long-term breakdown test system for a cable insulation specimen according to a preferred embodiment of the present invention;

[0032] Figure 3 It is a structural diagram of a high-voltage isolation oven according to a preferred embodiment of the present invention;

[0033] Figure 4 It is a structural diagram of a test multi-electrode according to a preferred embodiment of the present invention;

[0034] Figure 5 It is a schematic diagram of the regional division of a test specimen according to a preferred embodiment of the present invention;

[0035] Figure 6 It is a schematic diagram of a spherical-spherical electrode according to a preferred embodiment of the present invention;

[0036] Figure 7 It is a schematic diagram of the breakdown failure time of a test specimen when YHC is 30°C according to a preferred embodiment of the present invention;

[0037] Figure 8 Schematic diagram of breakdown failure time when the test sample YHC is 50 °C according to a preferred embodiment of the present invention;

[0038] Figure 9 Schematic diagram of breakdown failure time when the test sample SSH is 30 °C according to a preferred embodiment of the present invention; and

[0039] Figure 10 Schematic diagram of breakdown failure time when the test sample SSH is 50 °C according to a preferred embodiment of the present invention. Detailed implementation manners

[0040] Now, exemplary embodiments of the present invention will be introduced with reference to the accompanying drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. These embodiments are provided to disclose the present invention in detail and completely, and to fully convey the scope of the present invention to those skilled in the art. The terms in the exemplary embodiments shown in the drawings are not limitations on the present invention. In the drawings, the same units / components are denoted by the same reference numerals.

[0041] Unless otherwise specified, the terms (including scientific and technical terms) used herein have the ordinary meaning understood by those skilled in the art. Additionally, it can be understood that the terms defined in the commonly used dictionary should be construed to have a meaning consistent with the context of their related fields, and should not be construed as idealized or overly formal meanings.

[0042] Figure 1 Flowchart of a long-term breakdown test method for a cable insulation sample according to a preferred embodiment of the present invention.

[0043] The present invention provides a long-term breakdown test method for a cable insulation sample, which is used to evaluate and analyze the long-term electrical resistance performance of a cable insulation sheet sample, verify whether it meets the requirements of cable insulation, and support the selection and design of different materials.

[0044] The long-term breakdown test system of the sample of the present invention includes a high-voltage isolation oven, a test multi-electrode, an AC / DC power supply, etc. Among them, the AC / DC output terminal is connected to the outside of the high-voltage isolation oven, introduced into the oven through the high-voltage bushing of the oven, and connected to the test multi-electrode to apply a high voltage to the sample.

[0045] As Figure 1 shown, the present invention provides a long-term breakdown test method for a cable insulation sample, and the method includes:

[0046] Step 101: Introduce the output terminal of the AC / DC power supply into the high-voltage isolation oven through the high-voltage bushing and connect it to the test multi-electrode provided in the high-voltage isolation oven;

[0047] Step 102: Divide multiple test specimens into multiple regions respectively. Test the multi-electrode to increase the test voltage based on a preset step size, and conduct breakdown tests on the first regions of multiple test specimens respectively, and record the breakdown voltages of different test specimens.

[0048] Step 103: Process the multiple breakdown voltages of different test specimens, and determine the first insulation breakdown voltage of different test specimens based on the parameters obtained after processing.

[0049] Step 104: Through the test multi-electrode, conduct breakdown tests on multiple regions of multiple test specimens except the first region based on different proportions of the first insulation breakdown voltage, and record the breakdown times when the breakdown voltages occur in multiple regions of multiple test specimens with different proportions of the first insulation breakdown voltage.

[0050] Step 105: Process the breakdown times with different proportions of the first insulation breakdown voltage, and determine the insulation breakdown times with different proportions of the first insulation breakdown voltage based on the parameters obtained after processing.

[0051] Preferably, the AC-DC power supply is an AC-DC integrated transformer, including a step-up transformer and a control cabinet; the maximum AC voltage value is 50 kV to 70 kV, and the maximum DC voltage value is 70 kV to 100 kV.

[0052] Preferably, processing the multiple breakdown voltages of different test specimens and determining the first insulation breakdown voltage of different test specimens based on the parameters obtained after processing includes:

[0053] Process the multiple breakdown voltages of different test specimens through the Weibull function to obtain the shape parameter, and determine the shape parameter as the first insulation breakdown voltage of different test specimens.

[0054] Preferably, the first insulation breakdown voltage is the insulation breakdown voltage with a breakdown probability of 63.5%.

[0055] Preferably, the different proportions of the first insulation breakdown voltage are three values between 70% and 90%. The pressing size of the insulation specimen in the present invention is 10*10*0.2 mm, and each specimen is divided into 9 regions (as Figure 5 shown), and a pressure test is carried out:

[0056] In the present invention, the ① regions of 8 specimens are placed in the test multi-electrode for direct voltage step-up breakdown, that is, directly step up the voltage from 0 kV to the breakdown of the sample. The recommended AC step-up rate is 2 kV / mm, and the DC step-up rate is 5 kV / mm. After the specimen breaks down, disconnect the electrodes of this sample, re-step up the voltage for other specimens to break down, repeat the above process, and record the breakdown voltages U100-1, U100-2······U100-8 of different specimens;

[0057] The present invention performs Weibull distribution processing on the breakdown voltage. Specifically, the data is input into an Excel file, "Other Functions" is selected in the "Formula" menu, then the "WEIBULL" function is selected, and then the cumulative distribution function or probability density is calculated to obtain output parameters such as the shape parameter k and the scale parameter λ. The shape parameter is denoted as U100, which is the insulation breakdown voltage with a breakdown probability of 63.5%.

[0058] The present invention conducts a test on the grading voltage based on U100. The high-voltage generator is connected to the top of the oven, and the inside is connected to the test multi-electrodes. During the test, the test always starts from point ②. If breakdown occurs in one of the samples, the withstand voltage time is statistically recorded, and then the withstand voltage test at point ③ is carried out, and the tests are sequentially carried out downward until there are more than 8 breakdown time data points at this voltage. Preferably, the grading voltages are selected as 90%, 80%, and 70% of U100, and the statistical times are denoted as T90-1, T90-2······T90-8; T80-1, T80-2······T80-8; T70-1, T70-2······T70-8.

[0059] The present invention performs Weibull distribution processing on the breakdown times at different grading voltages. Specifically, the data is input into an Excel file, "Other Functions" is selected in the "Formula" menu, then the "WEIBULL" function is selected, and then the cumulative distribution function or probability density is calculated to obtain output parameters such as the shape parameter k and the scale parameter λ. The shape parameters are respectively denoted as T90, T80, and T70, which are the insulation breakdown times with a breakdown probability of 63.5%.

[0060] The AC / DC power supply of the present invention adopts a portable AC / DC integrated transformer, and its core components include a step-up transformer and a control cabinet. It is recommended that the maximum AC voltage can reach 50 kV, and the maximum DC voltage can reach 70 kV.

[0061] Preferably, the high-voltage bushings are arranged on both sides of the top of the high-voltage isolation oven through the openings at the top of the high-voltage isolation oven. The outer wall-piercing bushings of the high-voltage bushings are arranged outside the top of the high-voltage isolation oven, and the inner wall-piercing bushings of the high-voltage bushings are arranged inside the top of the high-voltage isolation oven.

[0062] Preferably, the lengths of the outer wall-piercing bushings and the inner wall-piercing bushings are 0.4 m to 0.6 m, the nominal creepage distance is 750 nm to 1000 nm, the power-frequency dry withstand voltage is 50 kV to 75 kV, the power-frequency wet withstand voltage is 50 kV to 75 kV, and the full-wave impulse withstand voltage is 125 kV to 150 kV.

[0063] Preferably, the internal dimensions of the high-voltage isolation oven are not less than 1m × 1m × 1m, the maximum temperature is not less than 100 °C, and the temperature control accuracy is not less than 0.5 °C.

[0064] The high-voltage isolation oven of the present invention is different from the traditional air circulation oven. The high-voltage isolation oven needs to be able to connect a high-voltage power supply to the inside without short circuit or grounding. Therefore, improvements are needed in the structure. The use of a through-wall bushing can achieve the isolation of high and low potentials. Specifically, a hole is opened at the top of the oven, and the through-wall bushing is installed on both sides of the top cover. The isolation of AC voltages below 50 kV and below 70 kV is achieved through the internal and external insulation of the bushing. The specific structure is as follows:

[0065] The length of the bushing of the present invention is selected as 1 m (0.5 m inside and outside each), its nominal creepage distance height: 750 mm, power frequency dry withstand: 75 kV, power frequency wet withstand voltage 0 kV, full-wave impulse withstand voltage 125 kV.

[0066] The oven of the present invention is selected with internal dimensions not less than 1m × 1m × 1m, the maximum temperature is not less than 100 °C, and the temperature control accuracy is not less than 0.5 °C.

[0067] Preferably, the test multi-electrode includes two rows, with 4 spherical electrodes arranged in each row;

[0068] The spherical electrodes are connected by copper rods; the length of the copper rods is 8 mm to 12 mm, the diameter of the spherical electrodes is 23 mm to 27 mm, and the electrode spacing is 80 mm to 120 mm.

[0069] The electrode structure of the present invention is as Figure 5 shown.

[0070] In order to facilitate repeated tests on multiple samples, a multi-electrode device needs to be designed. There are two rows of electrodes, with 4 ball-ball electrodes in each row. The yellow part is the conductive copper rod and copper ball. The upper copper rod uses a pressure spring to pressurize the sample and can be connected to a wire to make it parallel. In order to facilitate the observation of discharge and the replacement of samples, the upper electrode fixing plate adopts a middle hollow structure. If breakdown occurs during the test, the discharge situation of the electrodes can be seen. The entire electrode is immersed in transformer oil, and an oil bath pool wider than the electrode size needs to be designed, made of epoxy material, with a sealed stainless steel shell externally mounted to prevent surface flashover discharge and transformer oil leakage during the test. The specific structure is as follows:

[0071] The present invention recommends that the length of the copper rod is 10 mm, the diameter of the spherical electrode is 25 mm, the electrode spacing is 100 mm, and the upper and lower supports are made of high-temperature resistant epoxy material.

[0072] The present invention uses pressed sample pieces of different materials for polarity testing. The pressing temperature is 220 °C, the pressing pressure is 10 MPa, pre-pressing for 10 min, and pressing for 5 min.

[0073] Table 1 Types and Quantities of Specimens

[0074]

[0075] Dielectric Withstand Test Conditions:

[0076] Selection of Temperature:

[0077] Set two test temperatures of 30°C and 70°C

[0078] Selection of Voltage:

[0079] 60% of the breakdown field strength of the sampling chip (E1) is used as the lowest voltage level for the constant voltage test. A total of two voltage levels, E1 and E1 + 10, are selected to conduct the dielectric withstand test. The AC breakdown field strengths of each specimen at different temperatures are shown in Table 2, and the settings of the constant voltage dielectric withstand test electric field are shown in Table

[0080] Table 2 AC Breakdown Field Strengths of Each Specimen

[0081]

[0082]

[0083] Table 3 Dielectric Withstand Test Voltage Settings

[0084]

[0085] Required Equipment:

[0086] (1) Place the specimen in insulating oil for the experiment. Oven size (one layer): 725 (width) × 715 (depth) × 1000 (height)

[0087] (2) Dimensions of a spherical electrode:

[0088] (4) Design the electrode based on the above spherical electrode: There are two rows of electrodes, with 4 spherical electrodes in each row.

[0089] Breakdown Test Results:

[0090] The Weibull distribution of the failure time of HC in the constant voltage accelerated aging experiment at 30°C is as Figure 7 shown, and the dielectric withstand at 50°C is as Figure 8 shown. The breakdown electric field at 30°C is 87.50 kV / mm (21 / 0.24), and the breakdown electric field at 50°C is 84.50 kV / mm

[0091] The Weibull distribution of the failure time of SSH in the constant voltage accelerated aging experiment at 30°C is as Figure 9 , and the dielectric withstand at 50°C is as Figure 10The breakdown electric field of SSH is 77.42 kV / mm (24 / 0.31) at 30 °C and 74.42 kV / mm at 50 °C.

[0092] It can be seen from the breakdown results that the temperature stability of YHC is not as good as that of SSH, and the dispersion of long-term tolerance is large, and the performance is poor.

[0093] Figure 2 It is a structural diagram of a long-term breakdown test system for a cable insulation sample according to a preferred embodiment of the present invention;

[0094] As Figure 2 shown, the present invention provides a long-term breakdown test system for a cable insulation sample. The system includes: an AC-DC power supply, a high-voltage bushing, a high-voltage isolation oven, and a test multi-electrode. The output end of the AC-DC power supply is introduced into the high-voltage isolation oven through the high-voltage bushing and is connected to the test multi-electrode arranged in the high-voltage isolation oven;

[0095] The test multi-electrode is used to increase the test voltage based on a preset step size and perform breakdown tests on the first regions of multiple test samples respectively; and is used to perform breakdown tests on multiple regions of the multiple test samples except the first region based on different proportions of the first insulation breakdown voltage;

[0096] The AC-DC power supply is used to record the breakdown voltages of different test samples; process the multiple breakdown voltages of different test samples, and determine the first insulation breakdown voltage of different test samples based on the parameters obtained after processing; record the breakdown times of the breakdown voltages occurring in multiple regions of multiple test samples at different proportions of the first insulation breakdown voltage; process the breakdown times of different proportions of the first insulation breakdown voltage, and determine the insulation breakdown times of different proportions of the first insulation breakdown voltage based on the parameters obtained after processing.

[0097] Preferably, the AC-DC power supply is an AC-DC integrated transformer, including a step-up transformer and a control cabinet; the maximum AC voltage value is 50 kV to 70 kV, and the maximum DC voltage value is 70 kV to 100 kV.

[0098] Preferably, the high-voltage bushing is arranged on both sides of the top of the high-voltage isolation oven through the opening on the top of the high-voltage isolation oven. The outer wall-piercing bushing of the high-voltage bushing is arranged outside the top of the high-voltage isolation oven, and the inner wall-piercing bushing of the high-voltage bushing is arranged inside the top of the high-voltage isolation oven.

[0099] Preferably, the lengths of the outer wall-piercing bushing and the inner wall-piercing bushing are 0.4 m to 0.6 m, the nominal creepage distance height is 750 nm to 1000 nm, the power frequency dry withstand voltage is 50 kV to 75 kV, the power frequency wet withstand voltage is 50 kV to 75 kV, and the full-wave impulse withstand voltage is 125 kV to 150 kV.

[0100] Preferably, the internal size of the high-voltage isolation oven is not less than 1m×1m×1m, the maximum temperature is not less than 100°C, and the temperature control accuracy is not less than 0.5°C.

[0101] Preferably, the test multi-electrodes include two rows, with 4 spherical electrodes arranged in each row; as Figure 4 , Figure 5 shown.

[0102] The spherical electrodes are connected by copper bars; the length of the copper bars is 8 mm to 12 mm, the diameter of the spherical electrodes is 23 mm to 27 mm, and the electrode spacing is 80 mm to 120 mm.

[0103] The present invention provides a computer-readable storage medium storing a computer program for executing a long-term breakdown test method for a cable insulation sample.

[0104] The present invention provides an electronic device, which includes: a processor and a memory; wherein,

[0105] the memory for storing instructions executable by the processor;

[0106] the processor for reading the executable instructions from the memory and executing the instructions to implement a long-term breakdown test method for a cable insulation sample.

[0107] Those skilled in the art should understand that the embodiments of the present invention can be provided as a method, a system, or a computer program product. Therefore, the present invention can take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present invention can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk memories, CD-ROMs, optical memories, etc.) containing computer-usable program codes. The solutions in the embodiments of the present invention can be implemented in various computer languages, for example, object-oriented programming languages such as Java and interpreted scripting languages such as JavaScript.

[0108] The present invention is described with reference to the flowcharts and / or block diagrams of methods, apparatuses (systems), and computer program products according to embodiments of the present invention. It should be understood that each flow and / or block in the flowcharts and / or block diagrams, and the combination of flows and / or blocks in the flowcharts and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to the processors of general-purpose computers, special-purpose computers, embedded processors, or other programmable data processing devices to generate a machine, such that the instructions executed by the processors of the computer or other programmable data processing devices generate for implementing in the process Figure 1 one process or multiple processes and / or blocks Figure 1means for the functions specified in one or more blocks.

[0109] These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to operate in a particular manner, such that the instructions stored in the computer-readable memory produce a manufacture including an instruction means that implements the functions specified in one Figure 1 one or more processes and / or blocks Figure 1 one or more blocks.

[0110] These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus, such that a series of operational steps are performed on the computer or other programmable apparatus to produce a computer-implemented process, whereby the instructions executed on the computer or other programmable apparatus provide steps for implementing the functions specified in one Figure 1 one or more processes and / or blocks Figure 1 one or more blocks.

[0111] Although the preferred embodiments of the present invention have been described, additional changes and modifications can be made by those skilled in the art once they learn of the basic inventive concept. Therefore, the appended claims are intended to be construed to include the preferred embodiments as well as all changes and modifications that fall within the scope of the present invention.

[0112] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention is also intended to include these modifications and variations.

[0113] The present invention has been described by reference to a few embodiments. However, as is well known to those skilled in the art, other embodiments equivalent to those disclosed above of the present invention equally fall within the scope of the present invention as defined by the appended patent claims.

[0114] Generally, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field, unless otherwise clearly defined therein. All references to "a / the [device, component, etc.]" are to be construed openly as at least one instance of the device, component, etc., unless otherwise explicitly stated. The steps of any method disclosed herein need not be performed in the exact order disclosed, unless explicitly stated.

Claims

1. A long-term breakdown test method for a cable insulation sample, characterized in that: The method comprises: The output end of the AC and DC power supply is introduced into the high-voltage isolation oven through a high-voltage bushing, and connected to the test multi-electrode arranged in the high-voltage isolation oven; The plurality of test samples are respectively divided into a plurality of regions, the test multi-electrode increases the test voltage based on a preset step length, a breakdown test is performed on the first region of the plurality of test samples respectively, and the breakdown voltages of different test samples are recorded; Processing a plurality of breakdown voltages of different test samples, and determining first insulation breakdown voltages of the different test samples based on parameters obtained after the processing; By means of the test multi-electrode, a breakdown test is performed on a plurality of regions other than the first region of a plurality of test samples based on different proportions of the first insulation breakdown voltage, and the breakdown time when the breakdown voltage occurs in a plurality of regions of the plurality of test samples at different proportions of the first insulation breakdown voltage is recorded; The breakdown times of different proportions of the first insulation breakdown voltage are processed, and the insulation breakdown times of different proportions of the first insulation breakdown voltage are determined based on parameters obtained after the processing.

2. The method according to claim 1, characterized in that The step of processing a plurality of breakdown voltages of different test samples and determining a first insulation breakdown voltage of the different test samples based on parameters obtained after the processing includes: A plurality of breakdown voltages of different test samples are processed by a Weibull function to obtain shape parameters, and the shape parameters are determined as first insulation breakdown voltages of the different test samples.

3. The method according to claim 2, characterized in that The first insulation breakdown voltage is an insulation breakdown voltage with a breakdown probability of 63.5%.

4. The method according to claim 1, characterized in that: The different proportions of the first insulation breakdown voltage are three values ​​between 70% and 90%.

5. A long-term breakdown test system for cable insulation samples, characterized in that: The system comprises: an AC / DC power supply, a high-voltage bushing, a high-voltage isolation oven and a test multi-electrode; the output end of the AC / DC power supply is introduced into the high-voltage isolation oven through the high-voltage bushing and connected to the test multi-electrode arranged in the high-voltage isolation oven; The test multi-electrode is used to increase the test voltage based on a preset step length, and respectively perform a breakdown test on the first area of ​​the plurality of test samples; and is used to perform a breakdown test on the plurality of areas of the plurality of test samples other than the first area based on different proportions of the first insulation breakdown voltage; The AC / DC power supply is used to record the breakdown voltages of different test samples; process multiple breakdown voltages of different test samples, and determine the first insulation breakdown voltage of the different test samples based on the parameters obtained after the processing; and record the breakdown time of the breakdown voltage occurring in multiple areas of multiple test samples at different proportions of the first insulation breakdown voltage; process the breakdown time of different proportions of the first insulation breakdown voltage, and determine the insulation breakdown time of different proportions of the first insulation breakdown voltage based on the parameters obtained after the processing.

6. The system according to claim 5, characterized in that The AC / DC power supply is an AC / DC integrated transformer, the maximum AC voltage value is 50kV to 70kV, and the maximum DC voltage value is 70kV to 100kV.

7. The system according to claim 5, characterized in that The high-voltage bushing is arranged on both sides of the top of the high-voltage isolation oven through the opening at the top of the high-voltage isolation oven, the outer wall bushing of the high-voltage bushing is arranged on the outer side of the top of the high-voltage isolation oven, and the inner wall bushing of the high-voltage bushing is arranged on the inner side of the top of the high-voltage isolation oven.

8. The system according to claim 7, characterized in that The length of the outer wall bushing and the inner wall bushing is 0.4m to 0.6m, the nominal creepage distance height is 750nm to 1000nm, the power frequency dry withstand voltage is 50kV to 75kV, the power frequency wet withstand voltage is 50kV to 75kV, and the full-wave impulse withstand voltage is 125kV to 150kV.

9. The system according to claim 5, characterized in that The internal dimensions of the high-pressure isolation oven are not less than 1m×1m×1m, the maximum temperature is not less than 100°C, and the temperature control accuracy is not less than 0.5°C.

10. The system according to claim 5, characterized in that The test multi-electrode comprises two rows, each row being provided with four ball electrodes; The ball electrodes are connected by copper rods; the length of the copper rods is 8 mm to 12 mm, the diameter of the ball electrodes is 23 mm to 27 mm, and the electrode spacing is 80 mm to 120 mm.

11. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and the computer program is used to execute the method according to any one of claims 1 to 4.

12. An electronic device, characterized in that: The electronic device comprises: a processor and a memory; wherein, The memory is a memory for storing instructions executable by the processor; The processor is configured to read the executable instructions from the memory and execute the instructions to implement the method according to any one of claims 1 to 4.

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