Cable insulation dielectric strength testing device and testing method

Abstract

The invention relates to the technical field of dielectric strength testing of insulating materials, and provides a cable insulation dielectric strength testing device and a cable insulation dielectric strength testing method, and the cable insulation dielectric strength testing device comprises a boosting device, an insulating oil pool and a sample piece placing platform; an upper electrode and a lower electrode are oppositely arranged in the insulating oil pool up and down, an insulating cylinder is arranged on the upper electrode, and a sample placing platform is arranged between the upper electrode and the lower electrode; a sample to be tested is soaked in the insulating oil and is tightly pressed between the upper electrode and the lower electrode through the column body; the boosting device is respectively connected with the upper electrode and the lower electrode, so that a uniform electric field is formed between the two electrodes to act on the sample to be tested. Considering that burrs may exist on the surface of the to-be-tested sample wafer and the to-be-tested sample wafer is also subjected to buoyancy when being placed in the insulating oil, the insulating cylinder is arranged on the upper electrode, so that certain pressure can be provided, the creepage distance between the upper electrode and the lower electrode is increased, accurate measurement of the electrical connection insulating dielectric strength can be realized, and the measurement accuracy is improved. And the test safety can be improved.

Description

Technical Field

[0001] The present disclosure relates to the technical field related to dielectric strength testing of insulating materials, and in particular to a device and method for testing the dielectric strength of cable insulation. Background Art

[0002] The statements in this section merely provide background information related to the present disclosure and do not necessarily constitute prior art.

[0003] The insulation dielectric strength of cables is an important technical parameter to ensure the safe and reliable operation of power systems. Especially in the design of new cables, the reference standard of insulation dielectric strength is crucial to the safety and stability of cables. The insulation layer of cables usually uses polymer materials (such as cross-linked polyethylene, rubber, etc.), which need to have sufficient dielectric strength to withstand high voltage without breakdown. During the cable manufacturing and design process, the insulation material must be strictly tested for dielectric strength to ensure that it meets the relevant standards and procurement requirements.

[0004] The inventors found in their research that in the existing test methods, the test accuracy is not high and the results are biased, especially based on traditional DC or AC breakdown tests. Poor electrode contact, uneven sample placement or changes in the external environment often lead to deviations in the test results. The contact method between the electrode and the sample and the voltage application method may not fully simulate the actual use environment, resulting in the inability to accurately evaluate the dielectric strength of the material in different working environments. Due to the use of high voltage to test insulating materials, existing equipment has defects in safety design. For example, problems such as poor electrode contact and unstable equipment voltage control increase the safety risks of operators, especially when working in a high-voltage electric field environment. Equipment failure or unstable voltage during testing may cause safety accidents. Summary of the invention

[0005] In order to solve the above problems, the present disclosure proposes a cable insulation dielectric strength testing device and a testing method. Through the set testing device, the accurate measurement of the cable insulation dielectric strength can be achieved and the safety of the test can be improved.

[0006] In order to achieve the above objectives, the present disclosure adopts the following technical solutions:

[0007] One or more embodiments provide a cable insulation dielectric strength testing device, including a booster device, an insulating oil pool and a sample placement platform; an upper electrode and a lower electrode are arranged opposite to each other in the insulating oil pool, an insulating column is arranged on the upper electrode, and a sample placement platform is arranged between the upper electrode and the lower electrode; the sample to be tested is immersed in the insulating oil and pressed between the upper electrode and the lower electrode by the column; the booster device is respectively connected to the upper electrode and the lower electrode, so that a uniform electric field is formed between the two electrodes to act on the sample to be tested.

[0008] One or more embodiments provide a test method for a cable insulation dielectric strength test device based on the above, including the following steps:

[0009] Apply pressure to the insulating particles to be tested to form a sample piece with a set thickness, and cut it to obtain a test sample piece with a set shape;

[0010] Place the test sample piece at a constant temperature according to set conditions;

[0011] Place the test sample piece on the sample placement platform, and press the sample with the upper electrode to ensure that the sample is immersed in the insulating oil, so that the test sample piece is in contact and connected with the upper electrode;

[0012] Control the voltage boosting device to increase the voltage applied to the upper electrode and the lower electrode, obtain the voltage at breakdown, and calculate the dielectric constant of the test sample piece.

[0013] Compared with the prior art, the beneficial effects of the present disclosure are as follows:

[0014] For the test device of the present disclosure, considering that there may be burrs on the surface of the test sample piece and the test sample piece is also affected by buoyancy when placed in the insulating oil, an insulating cylinder is provided on the upper electrode to provide appropriate pressure, which can achieve the purpose of stable fixation. In addition, the provided cylinder is an insulator and it will not affect the electric field distribution between the upper and lower electrodes, thereby ensuring the uniformity of the electric field in the test area, which can improve the accuracy of the test results.

[0015] The advantages of the present disclosure and the advantages of the additional aspects will be described in detail in the following specific embodiments. Description of the Drawings

[0016] The specification drawings constituting a part of the present disclosure are used to provide a further understanding of the present disclosure. The schematic embodiments of the present disclosure and their descriptions are used to explain the present disclosure and do not constitute a limitation to the present disclosure.

[0017] Figure 1 It is a schematic structural diagram of a cable insulation dielectric strength test device according to Embodiment 1 of the present disclosure;

[0018] Figure 2 It is an overall view of a cable insulation dielectric strength test device according to Embodiment 1 of the present disclosure connected to a host computer;

[0019] Among them: 1. Upper electrode, 2. Accommodating housing, 3. Insulating oil, 4. Insulating support column, 5. Upper plastic cylinder, 6. Lower plastic cylinder, 7. Lower electrode, 8. Lower electrode fixing plate, 10. Upper electrode fixing plate, 11. Host computer, 12. Outer housing. Detailed Description of the Embodiments

[0020] The present disclosure is further described below in conjunction with the accompanying drawings and embodiments.

[0021] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present disclosure. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present disclosure belongs.

[0022] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present disclosure. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof. It should be noted that, in the absence of conflict, the various embodiments in the present disclosure and the features in the embodiments can be combined with each other. The embodiments will be described in detail below in conjunction with the accompanying drawings.

[0023] Example 1

[0024] In the technical solutions disclosed in one or more embodiments, Figure 1 to Figure 2 As shown, a cable insulation dielectric strength test device comprises: a booster device, an insulating oil pool and a sample placement platform; an upper electrode 1 and a lower electrode 7 are arranged opposite to each other in the insulating oil pool, an insulating column is arranged on the upper electrode 1, and a sample placement platform is arranged between the upper electrode 1 and the lower electrode 7; the sample to be tested is immersed in the insulating oil and pressed between the upper electrode 1 and the lower electrode 7 by the column; the booster device is respectively connected to the upper electrode 1 and the lower electrode 7, so that a uniform electric field is formed between the two electrodes to act on the sample to be tested;

[0025] In this embodiment, the cable insulation dielectric strength test device provided can accurately test the sample to be tested in a uniform electric field, and effectively isolate environmental interference through the effect of insulating oil, thereby ensuring the safety of the test process and the accuracy of the results. Based on applying a certain voltage to the upper electrode 1 and the lower electrode 7 through a booster device, a uniform electric field is formed between the two electrodes. The sample to be tested is placed on a sample placement platform between the upper and lower electrodes and pressed by a column to ensure that the sample is fixed and in good contact during the test. The creepage distance between the upper and lower electrodes is increased, and the risk of surface discharge or breakdown that may occur in a high-voltage electric field environment is reduced; the sample and the electrode are both immersed in insulating oil 3, which can prevent high voltage from breaking through the ambient air, improve safety, and ensure the accuracy of the dielectric strength test. The voltage is gradually increased by the booster device, and the breakdown voltage of the sample is observed, so as to evaluate the insulation performance and dielectric strength of the sample.

[0026] In this embodiment, considering that there may be burrs on the surface of the sample to be tested and the sample to be tested is also affected by buoyancy when placed in insulating oil, an insulating column is set on the upper electrode to provide appropriate pressure, which can achieve the purpose of stable fixation. The additional column is an insulator, which will not affect the electric field distribution between the upper and lower electrodes, thereby ensuring the uniformity of the electric field in the test area, which can improve the accuracy of the test results.

[0027] In this embodiment, the upper electrode 1 and the lower electrode 7 are in direct contact with the upper and lower surfaces of the sample to be tested respectively, so that a direct action of voltage can be achieved.

[0028] In some embodiments, the column can be made of any insulating material, such as plastic, ceramic, glass, etc.;

[0029] In this embodiment, preferably, the column is made of plastic material and is arranged as a cylinder to form a plastic cylinder, including an upper plastic cylinder 5 and a lower plastic cylinder 6, and the upper plastic cylinder 5 and the lower plastic cylinder 6 are sleeved on the pole of the upper electrode 1. The pole of the upper electrode 1 passes through the lower plastic cylinder 6 and contacts with the sample to be tested;

[0030] A plastic cylinder of a certain mass is put on the pole of the upper electrode 1 to ensure that the upper electrode copper rod is in close contact with the sample to be tested, thereby ensuring the accuracy of the dielectric strength test results of the insulating sample.

[0031] In a further technical solution, the cross-sectional area of ​​the upper plastic cylinder 5 is larger than the cross-sectional area of ​​the lower plastic cylinder 6, so that the sample to be tested is stably fixed in the insulating oil;

[0032] In the above scheme, a plastic cylinder 5 is installed at the upper electrode 1. The plastic cylinder 5 is made of a material with good insulation performance and does not degrade in the insulating oil. After installation, the plastic material can ensure that the upper electrode has sufficient weight, and ensure that the upper electrode 1 and the lower electrode 7 are in good contact with the test sample in the insulating oil 3, without bubbles or uncontacted areas in the middle, and at the same time, the weight is light and will not form a dent on the insulating sample to be tested. It can also increase the creepage distance between the electrodes to ensure the safety of the test.

[0033] In this embodiment, the sample placement platform is the upper surface of the lower electrode 7;

[0034] It can be realized that the insulating oil pool includes a containing shell 2, and the insulating oil 3 is arranged in the containing shell 2;

[0035] The insulating oil 3 is filled in the housing 2 to insulate and isolate the influence of the electric field on the environment, and at the same time provide a uniform electric field environment for the sample to ensure the accuracy of the test.

[0036] Specifically, the housing 2 is a glass housing, which serves to carry the insulating oil and the sample, can withstand high voltage and provides a transparent observation window, so as to facilitate real-time monitoring of the test status.

[0037] The feasible technical solution further comprises an upper electrode fixing plate 10 and a lower electrode fixing plate 8; the upper electrode 1 is connected and arranged on the upper electrode fixing plate 10, and the lower electrode 7 is arranged on the lower electrode fixing plate 8; the upper electrode 1 and the lower electrode 7 are respectively made of copper rods;

[0038] In the above solution, the upper electrode fixing plate 10 and the lower electrode fixing plate 8 are made of insulating materials to achieve stable support of the device;

[0039] A feasible technical solution is further provided with a plurality of insulating support columns 4, which are respectively arranged on the lower surface of the upper electrode fixing plate 10 or the lower electrode fixing plate 8 to support the upper electrode fixing plate 10 and the lower electrode fixing plate 8;

[0040] It is feasible that each insulating support column 4 supports the upper electrode fixing plate 10 and the lower electrode fixing plate 8 at the same time; each insulating support column 4 is connected to the upper electrode fixing plate 10 or the lower electrode fixing plate 8 through an insulating material, such as an insulating rubber sleeve; this method can realize the overall structure of the supporting device and connect the upper electrode fixing plate 10 and the lower electrode fixing plate 8 to ensure the stability and high voltage resistance of the device;

[0041] An alternative technical solution is to use different insulating support columns 4 to support the upper electrode fixing plate 10 or the lower electrode fixing plate 8 to improve insulation;

[0042] Preferably, the insulating support column 4 is made of plastic;

[0043] In the above scheme, by setting the plastic insulating support column 4, the positions of the upper and lower electrode plates are fixed, thereby ensuring the stability of the sample and avoiding errors caused by sample movement or poor contact during the test. The overall device has a simple structure and is easy to use, and is suitable for dielectric strength evaluation of various cable insulation materials.

[0044] The overall structure is simple in design and has clear functional distribution. The uniformity of electric field distribution and the fixing effect of the sample are ensured by the reasonable layout of the upper plastic cylinder 5 and the lower plastic cylinder 6. The combination of the housing 2 and the insulating oil 3 not only improves the safety of the device, but also provides a stable working environment for the test. The arrangement of the upper and lower electrodes and their electrode plates ensures the efficiency and reliability of the test.

[0045] In some embodiments, the boost device can use a stabilized power supply, including a transformer, a rectifier and a voltage divider circuit, the output end of the voltage divider circuit is connected to the upper electrode 1 and the lower electrode 7; the transformer is connected to the alternating current through a protection circuit; the rectifier converts the alternating current into direct current; the voltage divider circuit is used to adjust the output voltage.

[0046] Furthermore, it also includes a communication-connected dielectric strength tester and a host computer 11. The connection of the dielectric strength tester is set between the upper electrode 1 and the lower electrode 7, and is used to measure whether the sample is broken down. The moment of breakdown is equivalent to being short-circuited, so that the voltage at the moment before the breakdown is the breakdown voltage; the host computer 11 divides the voltage at the time of breakdown by the thickness of the insulating sample according to the thickness of the sample to be tested and the voltage data detected by the dielectric strength tester to obtain the insulating dielectric strength.

[0047] Optionally, an outer shell 12 is also included, which is used to arrange various components of the test device in the outer shell to further improve safety.

[0048] Example 2

[0049] Based on Example 1, this embodiment provides a testing method for a cable insulation dielectric strength testing device based on Example 1, comprising the following steps:

[0050] Step 1, applying pressure to the insulating particles to be tested to make a sample with a set thickness, and cutting to obtain a sample with a set shape to be tested;

[0051] Step 2: Place the sample to be tested at a constant temperature according to the set conditions;

[0052] Step 3, place the sample to be tested on the sample placement platform, and press the sample with the upper electrode 1 to ensure that the sample is immersed in the insulating oil, so that the sample to be tested is in contact with the upper electrode 1;

[0053] Step 4, controlling the voltage boosting device to increase the voltage applied to the upper electrode and the lower electrode, obtaining the voltage at the breakdown, and calculating the dielectric constant of the sample to be tested;

[0054] In step 1, specifically:

[0055] Step 11, placing the insulating particles in a flat vulcanizer;

[0056] Step 12, after vulcanization, the material can be preheated in a hydraulic press without pressure for 10 minutes, and the preheating temperature can be set to 115-120°C;

[0057] Step 13: After preheating, apply pressure to the insulating particles, cool to room temperature after molding, and prepare a sample with a set thickness;

[0058] Optionally, the thickness can be set to millimeter level, preferably, set to 1 mm;

[0059] Specifically, the pressure applied to the insulating particles can be set to be greater than 15 MPa;

[0060] Step 14: Screen the prepared samples and select those that are smooth, uniform in thickness and free of bubbles.

[0061] Specifically, for the screened sample, a round sample is cut from the sample using a punching machine, and the diameter of the round sample can be set to 5cm-8cm;

[0062] In step 2, the sample is placed in a constant temperature chamber for 3 hours to keep the surface and overall temperature uniform at 20°C.

[0063] In step 3, the sample can be placed on the insulating sample storage platform of the dielectric strength tester using tweezers, immersed in insulating oil, and the upper electrode presses the sample to ensure that the sample fits tightly with the upper electrode.

[0064] In step 4, the booster can be manually reduced in sequence. After the sample is installed, turn on the main power of the equipment. Turn on the switch lock of the test device, and the equipment is online with the host computer. Perform high-voltage start, manual start and stop, and manual boost operations in sequence. After the sample breaks down, click high-voltage stop and manual voltage reduction in sequence.

[0065] The test device of this embodiment installs a plastic cylinder on the copper rod pole of the upper electrode 1, which solves the problem of possible gaps between the copper rod and the insulating sample, and improves the accuracy of the insulation dielectric strength test. The test instrument installs a plastic cylinder on the copper rod and also increases the creepage distance between the upper and lower copper rods of the upper electrode, making the test safer and more reliable.

[0066] The above description is only a preferred embodiment of the present disclosure and is not intended to limit the present disclosure. For those skilled in the art, the present disclosure may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present disclosure shall be included in the protection scope of the present disclosure.

[0067] Although the above describes the specific implementation methods of the present disclosure in conjunction with the accompanying drawings, it is not intended to limit the scope of protection of the present disclosure. Technical personnel in the relevant field should understand that on the basis of the technical solution of the present disclosure, various modifications or variations that can be made by those skilled in the art without creative work are still within the scope of protection of the present disclosure.

Claims

1. A cable insulation dielectric strength testing device, characterized in that: The invention comprises a booster device, an insulating oil pool and a sample placement platform; an upper electrode and a lower electrode are arranged opposite to each other in the insulating oil pool, an insulating column is arranged on the upper electrode, and a sample placement platform is arranged between the upper electrode and the lower electrode; the sample to be tested is immersed in the insulating oil and pressed between the upper electrode and the lower electrode by the column; the booster device is respectively connected to the upper electrode and the lower electrode, so that a uniform electric field is formed between the two electrodes to act on the sample to be tested.

2. A cable insulation dielectric strength testing device as claimed in claim 1, characterized in that: The column is made of plastic material and is arranged as a cylinder to form a plastic cylinder, including an upper plastic cylinder and a lower plastic cylinder, and the upper plastic cylinder and the lower plastic cylinder are sleeved on the pole of the upper electrode.

3. A cable insulation dielectric strength testing device as claimed in claim 2, characterized in that: The cross-sectional area of ​​the upper plastic cylinder is greater than the cross-sectional area of ​​the lower plastic cylinder.

4. A cable insulation dielectric strength testing device as claimed in claim 1, characterized in that: The insulating oil pool comprises a containing shell, and insulating oil is arranged in the containing shell.

5. A cable insulation dielectric strength testing device as claimed in claim 1, characterized in that: An upper electrode fixing plate and a lower electrode fixing plate are also provided; the upper electrode is connected and arranged on the upper electrode fixing plate, and the lower electrode is arranged on the lower electrode fixing plate.

6. A cable insulation dielectric strength testing device as claimed in claim 5, characterized in that: A plurality of insulating support columns are also provided, and the plurality of insulating support columns are respectively arranged on the lower surface of the upper electrode fixing plate or the lower electrode fixing plate.

7. A cable insulation dielectric strength testing device as claimed in claim 5, characterized in that: A plurality of insulating support columns are also provided, each of which supports the upper electrode fixing plate and the lower electrode fixing plate at the same time; each insulating support column is connected to the upper electrode fixing plate or the lower electrode fixing plate through insulating material.

8. A cable insulation dielectric strength testing device as claimed in claim 5, characterized in that: It also includes a communication-connected dielectric strength tester and a host computer. The dielectric strength tester is connected to the upper electrode and the lower electrode and is used to measure whether the sample to be tested is broken down. The host computer divides the breakdown voltage by the thickness of the insulating sample based on the thickness of the sample to be tested and the voltage data detected by the dielectric strength tester to obtain the insulating dielectric strength.

9. A testing method for a cable insulation dielectric strength testing device according to any one of claims 1 to 8, characterized in that: The steps include: Applying pressure to the insulating particles to be tested to make a sample with a set thickness, and cutting to obtain a sample with a set shape to be tested; Place the sample to be tested at a constant temperature according to the set conditions; Place the sample to be tested on the sample placement platform and press the sample with the upper electrode to ensure that the sample is immersed in the insulating oil and that the sample to be tested is in contact with the upper electrode; The voltage boosting device is controlled to increase the voltage applied to the upper electrode and the lower electrode, the voltage at the time of breakdown is obtained, and the dielectric constant of the sample to be tested is calculated.

10. The testing method according to claim 9, characterized in that: A method for applying pressure to insulating particles to be tested to make a sample with a set thickness, and cutting to obtain a sample with a set shape to be tested, specifically: The insulating particles are placed in a flat plate curing instrument; The vulcanized pellets were preheated in a hydraulic press without pressure for 10 minutes, and the preheating temperature was set to 115-120°C; After preheating, pressure is applied to the insulating particles, and after molding, they are cooled to room temperature to form a specimen of a set thickness; The prepared samples were screened.

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