A sample high-voltage resistivity testing device

Abstract

This invention discloses a high-voltage resistivity testing device for samples. The small sample to be tested consists of an insulating cardboard with a pre-cut opening in the middle, a small sample of a pre-sized size, and polyimide tape. The small sample is attached to the opening of the insulating cardboard with the polyimide tape, allowing for volume resistivity measurement even on small samples. The insulating cardboard increases the creepage distance and reduces leakage current. The spring ensures full contact between the protective electrode and the measuring electrode and the small sample. The current flowing through the sample is exactly the current flowing on the electrode in contact with the small sample. The full contact between the protective electrode and the insulating cardboard effectively conducts surface current. This invention solves the technical problem of traditional solid insulating material resistivity testing methods, which are prone to creepage and even surface discharge under high voltage, high field strength, and small sample size conditions, affecting the accuracy of the test.

Description

Technical Field

[0001] This invention relates to the field of resistivity measurement device technology, and in particular to a sample high-voltage resistivity testing device. Background Technology

[0002] With the continuous increase in power grid transmission voltage levels and the development of DC transmission technology, new challenges have been posed to the design of insulation structures for transmission equipment, and higher requirements have been placed on the performance of absolute materials. Unlike AC transmission, under DC voltage, the electric field distribution within high-voltage equipment depends on the resistivity of the materials, such as the main insulation of high-voltage DC bushings and the main insulation of high-voltage cable accessories.

[0003] Traditional methods for testing the resistivity of solid insulating materials involve applying a high DC voltage to a sheet-like sample of the solid insulating material under high temperature and normal pressure using a standard three-electrode insulation resistance testing system. A galvanometer is used to measure the current flowing through the insulating material, thereby calculating the resistivity under different electric field strengths and identifying its nonlinear characteristics. This method typically requires a high DC voltage to obtain a sufficient number of data points. However, when the applied DC voltage is too high, the electric field strength is too large, or the sample size is too small, the leakage current on the surface of the tested sample increases, leading to surface creepage and even surface discharge, affecting the accuracy of the test. In severe cases, it can even burn out the testing equipment, making the test impossible. This presents significant challenges for testing the resistivity of small samples under high electric field strength. Therefore, it is necessary to research high-voltage resistivity testing technology for small samples to address the problems of surface creepage and even surface discharge that easily occur under high voltage, high field strength, and small sample size conditions, thus affecting the accuracy of the test. Summary of the Invention

[0004] This invention provides a sample high-voltage resistivity testing device to solve the technical problem that traditional solid insulating material resistivity testing methods are prone to surface creepage and even surface discharge under high voltage, high field strength and small sample size conditions, which affects the accuracy of the test.

[0005] In view of this, the present invention provides a sample high-voltage resistivity testing device, comprising:

[0006] The small sample under test, host computer, electrometer, DC power amplifier and resistivity testing platform;

[0007] The small sample to be tested includes an insulating cardboard with a pre-sized opening in the middle, a small sample of a pre-sized size, and polyimide tape. The small sample is placed in the opening of the insulating cardboard, and the polyimide tape is looped around the periphery of the small sample to fix the small sample to the insulating cardboard.

[0008] The resistivity testing platform includes a resistivity testing chamber shell, a resistivity testing chamber, a high-voltage electrode, a measuring electrode, a protective electrode, a spring, a polytetrafluoroethylene sheath, a first epoxy resin block, a second epoxy resin block, and a non-metallic sheath.

[0009] A high-voltage electrode, a measuring electrode, a protective electrode, a spring, a polytetrafluoroethylene sheath, a first epoxy resin block, a second epoxy resin block, and a non-metallic sheath are arranged inside the resistivity testing chamber. The top of the resistivity testing chamber has a first opening and a second opening, through which the first epoxy resin block and the second epoxy resin block are respectively inserted. The bottom of the resistivity testing chamber has a third opening. The high-voltage electrode has a T-shaped structure, with its vertical end extending out of the resistivity chamber from the third opening.

[0010] The small sample to be tested is placed between the high voltage electrode and the measuring electrode. The measuring electrode and the high voltage electrode work together to press the small sample to be tested. The protective electrodes are set on the left and right sides of the measuring electrode and work together with the high voltage electrode to press the insulating cardboard of the small sample to be tested.

[0011] The protective electrode is connected to the top of the resistivity chamber through a polytetrafluoroethylene (PTFE) sheath and is fixed to the PTFE sheath through a non-metallic sheath. PTFE sheaths are provided inside the resistivity testing chamber corresponding to the upper left and upper right of the measuring electrode. The PTFE sheaths are fixed to the top of the resistivity testing chamber through a non-metallic sheath. One end of the spring is fixed to the top of the measuring electrode, and the other end is fixed to the upper end of the corresponding PTFE sheath. The bottom of the high-voltage electrode is connected to the outer shell of the resistivity testing chamber through a PTFE sheath.

[0012] The electrometer is connected to the host computer. The top of the first epoxy resin block is connected to the electrometer, and the bottom is connected to the measuring electrode via a lead wire. The top of the second epoxy resin block is connected to the electrometer, and the bottom is connected to the right protection electrode via a lead wire. The bottom of the vertical end of the high voltage electrode is connected to the DC power amplifier. The electrometer is grounded.

[0013] Optionally, the size of the small sample is 7mm×7mm×2mm, and the measuring electrode is a circular electrode with a diameter of 7mm.

[0014] Optionally, the insulating cardboard has a size of 100mm × 100mm × 2mm.

[0015] Optionally, the electrometer is a 6514 programmable electrometer.

[0016] Optionally, the resistivity test chamber housing is made of stainless steel.

[0017] Optionally, the resistivity test chamber housing is integrated with support feet.

[0018] Optionally, the support feet are equipped with detachable casters at the bottom.

[0019] As can be seen from the above technical solutions, the sample high-voltage resistivity testing device provided by the present invention has the following advantages:

[0020] The high-voltage resistivity testing device for samples provided by this invention comprises an insulating cardboard with a pre-cut opening in the center, a small sample of a pre-cut size, and polyimide tape. The small sample is attached to the opening of the insulating cardboard with the polyimide tape, allowing for the measurement of volume resistivity even on small samples. The insulating cardboard increases the creepage distance and reduces leakage current. The spring ensures full contact between the protective electrode and the measuring electrode and the small sample. The current flowing through the sample is exactly the current flowing through the electrode in contact with the small sample. The full contact between the protective electrode and the insulating cardboard effectively conducts surface current. Therefore, the high-voltage resistivity testing device provided by this invention offers a solution for testing the resistivity of small samples under high electric field strength. It solves the technical problem that traditional solid insulating material resistivity testing methods are prone to creepage and even surface discharge under high voltage, high field strength, and small sample size conditions, affecting the accuracy of the test. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the structure of the small sample under test in the sample high-voltage resistivity testing device provided in this invention.

[0023] Figure 2 This is a schematic diagram of the overall structure of the sample high-voltage resistivity testing device provided in this invention.

[0024] The attached figures are labeled as follows:

[0025] 1. Host computer; 22. Electrometer; 3. DC power amplifier; 4. Resistivity testing chamber; 5. Resistivity testing chamber shell; 6. Measuring electrode; 7. Protective electrode; 8. Small sample to be tested; 8-1. Insulating cardboard; 8-2. Polyimide tape; 8-3. Small sample; 9. PTFE sheath; 10. Support foot; 11. Lead wire; 12. High voltage electrode; 13. Second epoxy resin block; 14. Spring; 15. Non-metallic sheath; 16. First epoxy resin block. Detailed Implementation

[0026] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] For easier understanding, please refer to Figure 1 and Figure 2 This invention provides an embodiment of a sample high-voltage resistivity testing device, comprising:

[0028] The test components include: 8 small sample parts, 1 host computer, 2 electrometer, 3 DC power amplifier, and resistivity testing platform.

[0029] The small sample 8 to be tested includes an insulating cardboard 8-1 with a pre-sized opening in the middle, a small sample 8-3 of a pre-sized size, and a polyimide tape 8-2. The small sample 8-3 is placed in the opening of the insulating cardboard 8-1, and the polyimide tape 8-2 is wrapped around the periphery of the small sample 8-3 to fix the small sample 8-3 to the insulating cardboard 8-1.

[0030] The resistivity testing platform includes a resistivity testing chamber shell 5, a resistivity testing chamber 4, a high-voltage electrode 12, a measuring electrode 6, a protective electrode 7, a spring 14, a polytetrafluoroethylene sheath 9, a first epoxy resin block 16, a second epoxy resin block 13, and a non-metallic sheath 15.

[0031] The high voltage electrode 12, measuring electrode 6, protective electrode 7, spring 15, polytetrafluoroethylene sheath 9, first epoxy resin block 16, second epoxy resin block 13 and non-metallic sheath 15 are arranged inside the resistivity testing chamber 4. The top of the resistivity testing chamber 4 is provided with a first opening and a second opening. The first epoxy resin block 16 and the second epoxy resin block 13 are respectively arranged through the first opening and the second opening. The bottom of the resistivity testing chamber 4 is provided with a third opening. The high voltage electrode 12 has a T-shaped structure and its vertical end extends out of the resistivity chamber from the third opening.

[0032] The small sample to be tested is placed between the high voltage electrode 12 and the measuring electrode 6. The measuring electrode 6 and the high voltage electrode 12 work together to press the small sample 8-3 of the small sample 8 to be tested. The protective electrode 7 is set on the left and right sides of the measuring electrode 6 and works with the high voltage electrode 6 to press the insulating cardboard 8-1 of the small sample 8 to be tested.

[0033] The protective electrode 7 is connected to the top of the resistivity chamber 4 through the polytetrafluoroethylene (PTFE) sheath 9 and is fixed to the PTFE sheath 9 through the non-metallic sheath 15. PTFE sheaths 9 are provided inside the resistivity test chamber 4 corresponding to the upper left and upper right of the measuring electrode 6. The PTFE sheath 9 is fixed to the top of the resistivity test chamber 4 through the non-metallic sheath 15. One end of the spring 14 is fixed to the top of the measuring electrode 6, and the other end is fixed to the upper end of the corresponding PTFE sheath 9. The bottom of the high voltage electrode 12 is connected to the outer shell 5 of the resistivity test chamber through the PTFE sheath 9.

[0034] Electrometer 2 is connected to host computer 1. The top of the first epoxy resin block 16 is connected to electrometer 2, and the bottom is connected to measuring electrode 6 through lead wire 11. The top of the second epoxy resin block 13 is connected to electrometer 2, and the bottom is connected to right protection electrode 7 through lead wire 11. The bottom of the vertical end of the high voltage electrode 12 is connected to DC power amplifier 3. Electrometer 2 is grounded.

[0035] It should be noted that, in this embodiment of the invention, the tested small sample 8 consists of an epoxy resin small sample 8-3 with dimensions of 7mm×7mm×2mm, an insulating cardboard 8-1 with dimensions of 100mm×100mm×2mm, and polyimide tape 8-2. An opening of 7mm×7mm×2mm is cut out in the center of the insulating cardboard 8-1. The epoxy resin small sample 8-3 is placed in the center of the insulating cardboard 8-1, and the connection between the epoxy resin small sample 8-3 and the insulating cardboard 8-1 is sealed with polyimide tape 8-2 to ensure sufficient contact between the epoxy resin small sample 8-3 and the insulating cardboard 8-1 and to provide a certain degree of fixation. In practical applications, the small sample 8-3 can also be selected from other insulating materials, and its size can also be selected from other sizes; no specific limitation is made here. The small sample 8 being tested can be exactly the same size as the original design for the resistivity test. When placed in the resistivity test chamber 4, it can be ensured that it is in a horizontal position during the resistivity test. This way, the electrodes will make full contact with the small sample 8-3, reducing the error caused by the measurement of volume resistivity.

[0036] The resistivity testing chamber housing 5 can be made of stainless steel. Support feet 10 can be provided at the bottom of the resistivity testing chamber housing 5. The support feet 10 can be integrated with the resistivity testing chamber housing 5 or can be detached from the resistivity testing chamber housing 5. For easy movement and transportation, casters can also be provided at the bottom of the support feet 10.

[0037] The spring 14 ensures that the protective electrode 7 and the measuring electrode 6 make full contact with the insulating cardboard 8-1 and the small sample 8-3 of the tested small sample 8, respectively. The current flowing through them is exactly the same as the current flowing through the measuring electrode 6, which is in contact with the small sample 8-3. The protective electrode 7 makes full contact with the insulating cardboard 8-1, effectively conducting the surface current. The protective electrode 7 and the measuring electrode 6 are designed according to national standards. The outer side of the protective electrode 7 is fixed to the lead wire 11 and leads out to the resistivity insulating cavity 4 through the second epoxy resin block 14, which provides insulation. The high-voltage electrode 12 inside the resistivity cavity 4 is connected to the power amplifier 3. The measuring electrode 6 of the resistivity testing cavity 4 leads out through the first epoxy resin block 16 and connects to the electrometer 2. The electrometer 2 is a 6514 type programmable electrometer. The electrometer 2 is connected to the host computer 1 and matched with the resistivity measurement software of the host computer 1, which is a PC. The PTFE sheath 9 isolates the resistivity testing chamber shell 5 from the protective electrode, high-voltage electrode, and measuring electrode, respectively. The PTFE sheath 9, fixed to the protective electrode, high-voltage electrode, and measuring electrode, provides electrical insulation. The electrometer 2 and the DC power amplifier 3 are properly grounded. The PTFE sheath 9 connecting the protective electrode 7 and the resistivity testing chamber shell 5 can be an inverted L-shaped structure; the PTFE sheath 9 connecting the measuring electrode 6 and the resistivity testing chamber shell 5 can be a T-shaped structure; and the PTFE sheath 9 connecting the high-voltage electrode 12 and the resistivity testing chamber shell 5 can be a rectangular structure.

[0038] When using the high-voltage resistivity testing device provided in this embodiment of the invention to test the resistivity of a small sample 8-3, the small sample 8 to be tested is first placed between the high-voltage electrode 12 and the measuring electrode 6 inside the resistivity testing chamber 4. A certain pressure is applied by the spring 14 and acts for a certain period of time. Then, the DC power amplifier 3 is turned on, the voltage value is adjusted, and the resistivity measurement software in the electrometer 2 and the host computer 1 is turned on to obtain the volume resistivity detection value R of the small sample 8-3. Then, based on the thickness L of the small sample 8-3 and the effective area A of the measuring electrode 6, the resistivity is calculated according to the formula... Calculate the volume resistivity ρ of the small sample 8-3.

[0039] In one embodiment, the measuring electrode 6 is a circular electrode with a diameter of 7 mm, which is in complete contact with the surface of a small sample 8-3 measuring 7 mm × 7 mm × 2 mm. At this point, the shortest creepage distance between the upper and lower electrodes is only 2 mm above the sample height. Adding insulating cardboard 8-1 to cover the small sample 8-3 increases the shortest creepage distance between electrodes from 2 mm to 95 mm (i.e., (50 mm - 3.5 mm) × 2 + 2 mm). This creepage distance at this voltage meets the creepage distance and leakage current requirements for sample resistivity testing. The sample high-voltage resistivity testing device provided in this embodiment can withstand a 6 kV DC voltage without surface creepage, protecting the device from harmful discharges during resistivity measurement.

[0040] The sample high-voltage resistivity testing device provided in this embodiment of the invention can be used to measure the resistivity of a small sample 8-3 under different field strengths. It only requires disassembling the small sample 8-3, calculating the appropriate creepage distance along the surface, and designing a reasonable size for the insulating cardboard 8-1 for splicing. This device can meet the requirements for measuring resistivity under various high field strengths and has wide applicability.

[0041] The high-voltage resistivity testing device for samples provided by this invention comprises an insulating cardboard with a pre-cut opening in the center, a small sample of a pre-cut size, and polyimide tape. The small sample is attached to the opening of the insulating cardboard with the polyimide tape, allowing for the measurement of volume resistivity even on small samples. The insulating cardboard increases the creepage distance and reduces leakage current. The spring ensures full contact between the protective electrode and the measuring electrode and the small sample. The current flowing through the sample is exactly the current flowing through the electrode in contact with the small sample. The full contact between the protective electrode and the insulating cardboard effectively conducts surface current. Therefore, the high-voltage resistivity testing device provided by this invention offers a solution for testing the resistivity of small samples under high electric field strength. It solves the technical problem that traditional solid insulating material resistivity testing methods are prone to creepage and even surface discharge under high voltage, high field strength, and small sample size conditions, affecting the accuracy of the test.

[0042] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A sample high pressure resistivity testing apparatus, characterized by, The utility model relates to a small sample piece resistance rate test platform, including: The measured small sample piece includes the insulating paperboard with the pre -set size opening in the middle, the small sample with the pre -set size and the polyimide adhesive tape, the small sample is placed in the opening of the insulating paperboard, and the polyimide adhesive tape is fixed on the insulating paperboard with the circumferential side of small sample; The resistance rate test platform includes the resistance rate test cavity shell, the resistance rate test cavity, the high -voltage electrode, the measuring electrode, the protection electrode, the spring, the polytetrafluoroethylene sheath, the first epoxy resin block, the second epoxy resin block and the non -metal sheath; The high -voltage electrode, the measuring electrode, the protection electrode, the spring, the polytetrafluoroethylene sheath, the first epoxy resin block, the second epoxy resin block and the non -metal sheath are arranged inside the resistance rate test cavity, the top of the resistance rate test cavity is provided with first opening and second opening, first opening and second opening are respectively through the first epoxy resin block and the second epoxy resin block are provided, the bottom of the resistance rate test cavity is provided with third opening, the high -voltage electrode is T type structure, and the vertical end is from the third opening and is stretched outside the resistance rate cavity; The measured small sample piece is placed between the high -voltage electrode and the measuring electrode, the measuring electrode and the high -voltage electrode are compressed to the small sample of the measured small sample piece, and the protection electrode is arranged on the left and right sides of the measuring electrode and is compressed to the insulating paperboard of the measured small sample piece; The protection electrode is connected with the top of the resistance rate cavity through the polytetrafluoroethylene sheath, and is fixed with the polytetrafluoroethylene sheath through the non -metal sheath, the upper left and right of the measuring electrode in the resistance rate test cavity is provided with the polytetrafluoroethylene sheath, the polytetrafluoroethylene sheath is fixed on the top of the resistance rate test cavity through the non -metal sheath, one end of the spring is fixed on the top of the measuring electrode, and the other end is fixed on the upper end of the corresponding polytetrafluoroethylene sheath, the bottom of the high -voltage electrode is connected with the resistance rate test cavity shell through the polytetrafluoroethylene sheath; The electrometer is connected with the host computer, the top of the first epoxy resin block is connected with the electrometer, the bottom is connected with the measuring electrode through the lead, the top of the second epoxy resin block is connected with the electrometer, the bottom is connected with the right protection electrode through the lead, the vertical end bottom of the high -voltage electrode is connected with the DC power amplifier, and the electrometer is grounded; The size of the small sample is 7mm * 7mm * 2mm, and the measuring electrode is a 7mm diameter circular electrode; The size of the insulating paperboard is 100mm * 100mm * 2mm. The electrometer is a 6514 type editable electrometer.

2. The sample high pressure resistivity testing device of claim 1, wherein, The resistance rate test cavity shell is stainless steel material.

3. The sample high pressure resistivity testing device of claim 1, wherein, The resistance rate test cavity shell is integrally provided with the supporting leg.

4. The sample high pressure resistivity testing device of claim 3, wherein, The supporting leg bottom is provided with detachable mounting universal wheel.

5. The sample high pressure resistivity testing device of claim 4, wherein, ​

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