High-field conductivity test electrode system with accidental discharge protection function

Abstract

The invention relates to the field of insulating material performance testing, in particular to a high-field conductivity testing electrode system with an accidental discharge protection function, which comprises a cylindrical to-be-tested sample, a low-voltage electrode, the to-be-tested sample and a high-voltage electrode which are coaxially and sequentially arranged from bottom to top, an inner shielding electrode coaxially inserted into a cylindrical cavity of the to-be-tested sample, and an outer shielding electrode coaxially inserted into the cylindrical cavity of the to-be-tested sample. The annular protection electrode is coaxially arranged on the outer ring of the to-be-tested sample, the inner diameter of the protection electrode is larger than the outer diameter of the to-be-tested sample, the protection electrode, the inner shielding electrode and the low-voltage electrode are all supported and fixed by the support, the support is made of an insulating material, and the protection electrode and the inner shielding electrode are both grounded. The surface conductivity and the volume conductivity of the insulating material can be measured under the working condition of high field intensity, and the safety of a test system is greatly improved.

Description

Technical Field

[0001] The invention relates to the field of insulating material performance testing, in particular to a high-field conductivity testing electrode system with an accidental discharge protection function. Background Art

[0002] Volume conductivity and surface conductivity are key indicators for measuring the conductive properties and insulating properties of insulating materials. By measuring volume conductivity, we can understand the charge transfer capacity inside the insulating material, and by measuring surface conductivity, we can understand the charge accumulation and dissipation capacity on the surface of the insulating material, thereby judging the quality of the insulating material's insulating properties. The conductivity of the insulating structure is closely related to the stability and reliability of electrical equipment. If the conductivity of the insulating structure is too high, it may cause the charge to move freely inside the material, which in turn may cause ionization, charge accumulation and other phenomena, which may eventually lead to failure or short circuit of the electrical equipment. Therefore, regular measurement of conductivity can promptly detect the decline in insulation performance, so as to take necessary preventive measures to avoid electrical failures.

[0003] At present, the test of the conductivity of insulating materials mostly adopts a three-electrode system, which consists of a high-voltage electrode, a measuring electrode and a shielding electrode. The high-voltage electrode is used to apply voltage to the insulating material, the measuring electrode is used to measure the current passing through the insulating material, and the shielding electrode is used to absorb the surface current of the insulating material to prevent the surface current from interfering with the measurement. The shielding electrode directly excludes the surface current of the insulating material as interference current from the measurement, and the surface conductivity of the insulating material cannot be measured by the three-electrode system; in addition, under high field strength, when high voltage is applied to the insulating material, the insulating material is prone to accidental discharge, which cannot protect the test system and poses a safety hazard, which needs to be solved urgently. Summary of the invention

[0004] In order to avoid and overcome the technical problems existing in the prior art, the present invention provides a high-field conductivity test electrode system with an accidental discharge protection function. The present invention can measure the surface conductivity and volume conductivity of insulating materials under high field strength conditions and greatly improve the safety of the test system.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A high-field conductivity test electrode system with an accidental discharge protection function comprises a cylindrical sample to be tested, a low-voltage electrode, the sample to be tested and a high-voltage electrode coaxially arranged in sequence from bottom to top, an inner shielding electrode coaxially inserted into the cylindrical cavity of the sample to be tested, an annular protection electrode coaxially arranged on the outer ring of the sample to be tested, the inner diameter of the protection electrode is larger than the outer diameter of the sample to be tested, the protection electrode, the inner shielding electrode and the low-voltage electrode are all supported and fixed by a bracket, the bracket is made of insulating material, and the protection electrode and the inner shielding electrode are all grounded.

[0007] As a further solution of the present invention: the low-voltage electrode is disc-shaped, the diameter of the low-voltage electrode is larger than the diameter of the sample to be tested, and the low-voltage electrode is provided with low-voltage electrode terminals evenly arranged around the circumference of the sample to be tested.

[0008] As a further solution of the present invention: a threaded hole is opened on the top of the low-voltage electrode, and each low-voltage electrode terminal is fixed with the threaded hole of the low-voltage electrode by threaded cooperation; a low-voltage electrode support is arranged on the bracket along the vertical direction, and a slot is opened at the bottom of the low-voltage electrode so as to be plugged and positioned with the low-voltage electrode support.

[0009] As a further solution of the present invention: a threaded hole is axially opened at the top of the high-voltage electrode, and a stud is provided at the bottom of the spherical high-voltage electrode terminal, which is fixed by threading the stud and the threaded hole of the high-voltage electrode; the outer diameter of the high-voltage electrode is equal to that of the sample to be tested.

[0010] As a further solution of the present invention: a slot is provided at the bottom of the bracket, and the grounding plate is fixed in the slot. A protective electrode support and an inner shielding electrode support that penetrate the low-voltage electrode are provided on the grounding plate in the vertical direction. The protective electrode and the inner shielding electrode are supported and fixed by the protective electrode support and the inner shielding electrode support respectively.

[0011] As a further solution of the present invention: pins are evenly arranged along the circumferential direction at the bottom of the protective electrode, the number of the protective electrode pillars corresponds to the number of the pins of the protective electrode, and each pin of the protective electrode is plugged and positioned one by one with each protective electrode pillar.

[0012] As a further solution of the present invention: the inner shielding electrode has a two-stage stepped columnar structure that is wide at the top and narrow at the bottom; the inner shielding electrode pillar is coaxially arranged with the inner shielding electrode; a positioning hole corresponding to the diameter of the lower half of the inner shielding electrode is opened on the top of the inner shielding electrode pillar for the lower half of the inner shielding electrode to be plugged in and positioned; the inner diameter of the sample to be tested, the outer diameter of the inner shielding electrode pillar and the outer diameter of the upper half of the inner shielding electrode correspond to each other.

[0013] As a further solution of the present invention: the slot is a cross slot, and the grounding plate is a cross-shaped metal plate.

[0014] As a further solution of the present invention: when measuring the volume conductivity of the sample to be tested, aluminum foil is attached to the outer surface of the sample to be tested, the surface current of the sample to be tested is connected to the ground through a lead wire, and the low-voltage electrode terminal is connected to the current measuring device to measure the volume current of the sample to be tested. The volume conductivity of the sample to be tested is:

[0015]

[0016] Among them, γ ViIndicates the volume conductivity of the sample to be tested at the i-th voltage level;

[0017] U i Indicates the voltage magnitude of the i-th voltage applied to the sample to be tested;

[0018] I i is the actual current value of the current measuring device under the i-th voltage level;

[0019] D is the outer diameter of the sample to be tested;

[0020] d is the inner diameter of the sample to be tested;

[0021] h is the length of the sample to be tested.

[0022] As a further solution of the present invention: when measuring the surface conductivity of the sample to be tested, aluminum foil is pasted on the outer surface of the sample to be tested, the surface current of the sample to be tested is connected to the current measuring device through the lead wire, and the low-voltage electrode terminal is connected to the ground. The surface conductivity of the sample to be tested is:

[0023]

[0024] Among them, γ Si represents the surface conductivity of the sample to be tested at the i-th voltage level;

[0025] U i Indicates the voltage magnitude of the i-th voltage applied to the sample to be tested;

[0026] I i is the actual current value of the current measuring device under the i-th voltage level;

[0027] D is the outer diameter of the sample to be tested;

[0028] h is the length of the sample to be tested.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] 1. The present invention can measure the surface conductivity and volume conductivity of insulating materials under high field strength conditions, comprehensively quantify and evaluate the performance of insulating materials, protect the interior of the test sample by an inner shielding electrode, and protect the exterior of the test sample by an annular protective electrode, thereby preventing accidental discharge of the test sample from both inside and outside, and ensuring the safety of the test system.

[0031] 2. The high-voltage electrodes, low-voltage electrodes, high-voltage electrode terminals and the upper and lower edges of the low-voltage electrode terminals of the present invention all adopt a rounded corner design, which effectively improves the electric field distribution on the electrode surface; the high-voltage electrode terminals and the low-voltage electrode terminals are fixed by threads, which is convenient for disassembly and installation of the system; each electrode is supported by an insulating bracket, which improves the safety of the test process.

[0032] 3. The protective electrode of the present invention is fixed by inserting a pin into the protective electrode support, thereby being coaxially fixed to the outer ring of the sample to be tested, attracting the unexpected discharge current outside the sample, and introducing the unexpected discharge current outside the sample into the grounding terminal to prevent the external unexpected discharge current from damaging the measuring equipment.

[0033] 4. The inner shielding electrode of the present invention is used to attract the accidental discharge current inside the sample and introduce the accidental discharge current inside the sample into the ground terminal to prevent the internal accidental discharge current from damaging the measuring equipment. At the same time, the inner shielding electrode fits the inner wall of the sample and can also connect the current on the inner wall surface of the sample to the ground to prevent the current on the inner wall surface of the sample from affecting the accuracy of the measurement result. The two-stage columnar structure of the inner shielding electrode can be directly inserted into the inner shielding electrode support, and the inner shielding electrode and the inner shielding electrode support can form support for the sample to be tested. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a structural schematic diagram of the present invention.

[0035] Figure 2 It is a structural schematic diagram of another viewing angle of the present invention.

[0036] Figure 3 It is a schematic diagram of the installation position of the inner shielding electrode in the present invention.

[0037] Figure 4 It is a schematic diagram of the structure of the inner shielding electrode in the present invention.

[0038] In the figure:

[0039] 1. Bracket; 11. Card slot; 12. Ground plate;

[0040] 2. Low voltage electrode; 21. Low voltage electrode terminal; 22. Low voltage electrode support;

[0041] 3. Sample to be tested; 4. High voltage electrode; 41. High voltage electrode terminal;

[0042] 5. Protective electrode; 51. Protective electrode support;

[0043] 6. Inner shielding electrode; 61. Inner shielding electrode support. DETAILED DESCRIPTION

[0044] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0045] See also Figures 1 to 4 In an embodiment of the present invention, a high-field conductivity test electrode system with an accidental discharge protection function includes an insulating bracket 1, and the bracket 1 is preferably made of polytetrafluoroethylene. The bracket 11 is a flat cylindrical structure, and a cross-shaped card slot 11 is opened at the bottom. The grounding plate 12 is fixed in the card slot 11, and the grounding plate 12 leads out a wire connected to the grounding terminal.

[0046] The bracket 11 is provided with a plurality of groups of low-voltage electrode pillars 22 arranged vertically, and each low-voltage electrode pillar 22 is evenly spaced around the axis of the bracket 11. The low-voltage electrode 2 is supported and fixed by each low-voltage electrode pillar 22. A slot matching the shape of the low-voltage electrode pillar 22 is provided at the bottom of the low-voltage electrode 2, for the low-voltage electrode pillar 22 to be inserted and positioned from bottom to top.

[0047] The low-voltage electrode 2 is in the shape of a flat cylinder, and the top and bottom circumferences thereof are rounded. A plurality of groups of threaded holes are provided on the top of the low-voltage electrode 2, and the studs at the bottom of each low-voltage electrode terminal 21 are fixed to the low-voltage motor 2 through the threaded holes. The number of low-voltage electrode terminals 21 preferably corresponds to the number of low-voltage electrode pillars 22, and each group of low-voltage electrode terminals 21 is coaxially arranged with a corresponding group of low-voltage electrode pillars 22. The low-voltage electrode terminal 21 is in the shape of a flat cylinder, and the top and bottom circumferences thereof are rounded to improve the electric field distribution on the surface of the low-voltage electrode terminal 21.

[0048] An inner shielding electrode support 61 with both ends open and in a cylindrical shape is fixed to the bracket 11 in the axial direction. A hole is opened at the axis center of the bracket 11 for the columnar inner shielding electrode 6 to pass through. After the inner shielding electrode 6 passes through the inner shielding electrode support 61 and the bracket 11 from top to bottom, its lower section is connected to the grounding plate 12. The inner shielding electrode 6 is a two-stage stepped columnar structure with a wide top and a narrow bottom. The diameter of the lower section is narrower, corresponding to the inner diameter of the inner shielding electrode support 61, and the diameter of the lower section of the inner shielding electrode 6 is wider, corresponding to the outer diameter of the inner shielding electrode support 61. The inner shielding electrode support 61 passes through the low-voltage electrode 2, and its top extends to the top of the low-voltage electrode 2.

[0049] The sample to be tested 3 is an insulating cylindrical sample with two ends open, and the inner diameter of the sample to be tested 3 corresponds to the outer diameter of the inner shielding electrode 6. The upper section of the inner shielding electrode 6 and the inner shielding electrode support 61 are inserted into the cylindrical cavity of the sample to be tested 3 to support the sample to be tested 3, and the bottom surface of the sample to be tested 3 abuts against the upper surface of the low-voltage electrode 2.

[0050] The high-voltage electrode 4 is coaxially fixed on the top of the test sample 3, and the outer diameter of the high-voltage electrode 4 corresponds to that of the test sample 3. A threaded hole is provided at the top of the high-voltage electrode 4 along the axial direction, and a stud is provided at the bottom of the spherical high-voltage electrode terminal 41, which is fixed by threading with the threaded hole of the high-voltage electrode 4.

[0051] The low-voltage electrode 2, the sample to be tested 3 and the high-voltage motor 4 are coaxially arranged in sequence from bottom to top.

[0052] A protective electrode 5 is also provided above the low-voltage electrode 2 and is coaxially arranged on the outer ring of the sample to be tested 3. The protective electrode 5 is annular, and multiple groups of pins are evenly arranged at its bottom along the vertical direction. After the multiple groups of protective electrode pillars 15 pass through the grounding plate 12 and the low-voltage electrode 2, they support the pins of the protective electrode 5. The top of the protective electrode pillar 15 has an axial opening for the pins of the protective electrode 5 to be inserted and positioned.

[0053] When measuring the volume conductivity of the sample 3 to be tested, aluminum foil is pasted on the outer surface of the sample 3 to be tested, and the surface current of the sample 3 to be tested is connected to the ground through the lead wire to avoid interference with the measurement of the volume current. The low-voltage electrode terminal 21 is connected to the current measuring device to measure the volume current of the sample 3 to be tested. The volume conductivity of the sample 3 to be tested is:

[0054]

[0055] Among them, γ Vi It represents the volume conductivity of the test sample 3 at the i-th voltage level; the unit is S / m, i=1,2,3…

[0056] U i It indicates the voltage magnitude of the i-th voltage applied to the test sample 3, in V;

[0057] I i is the actual current value of the current measuring device under the i-th voltage level, in A;

[0058] D is the outer diameter of the sample to be tested, in m;

[0059] d is the inner diameter of the sample to be tested, in m;

[0060] h is the length of the sample to be tested, in meters.

[0061] When measuring the surface conductivity of the sample 3 to be tested, aluminum foil is attached to the outer surface of the sample 3 to be tested, and the surface current of the sample 3 to be tested is led to the current measuring device through the lead wire. The low-voltage electrode terminal 21 is connected to the ground to realize the separate measurement of the surface current. The surface conductivity of the sample 3 to be tested is:

[0062]

[0063] where γ Si represents the surface conductivity of the sample 3 to be tested under the voltage of the i-th gear; the unit is S / m, and i = 1, 2, 3...

[0064] U i represents the magnitude of the voltage of the i-th gear applied to the sample 3 to be tested, and the unit is V;

[0065] I i is the measured current value of the current measuring device under the voltage of the i-th gear, and the unit is A;

[0066] D is the outer diameter size of the sample 3 to be tested, and the unit is m;

[0067] h is the length of the sample 3 to be tested, and the unit is m.

[0068] The high-voltage electrode 4, the high-voltage electrode terminal 41, the low-voltage electrode 2, the low-voltage electrode terminal 21, the protection electrode 5, the inner shielding electrode 6 and the grounding plate 12 are all made of copper material.

[0069] The bracket 11, the low-voltage electrode support 22 on the bracket 11, the protection electrode support 51 and the inner shielding electrode support 61 are all made of polytetrafluoroethylene.

[0070] When measuring the volume conductivity or surface conductivity, control the high-voltage power supply to increase the voltage. The voltage applied by the high-voltage electrode 4 to the sample 3 to be tested increases in i gear gradients. The voltage of each gear is pressurized for N minutes, and the average current value in the last n minutes of the voltage pressurization of each gear is taken as the quasi-steady-state current measurement value of this gear voltage, where n < N; the sample 3 to be tested is tested m times in the same measurement environment. Each test obtains the quasi-steady-state current measurement values of the voltages of each gear. The average value of the quasi-steady-state current measurement values obtained from m tests of the voltages of each gear is taken as the final current measurement value of this gear voltage. After the measurement is completed, turn off the high-voltage power supply and conduct the residual charge of the system to the grounding terminal.

[0071] The basic principles of the present application are described above in conjunction with specific embodiments. However, it should be noted that the advantages, strengths, effects, etc. mentioned in the present application are only examples and not limitations, and it cannot be considered that these advantages, strengths, effects, etc. are required by each embodiment of the present application. In addition, the specific details disclosed above are only for the purpose of illustration and ease of understanding, not for limitation, and the above details do not limit the present application to being implemented by adopting the above specific details.

[0072] The block diagrams of the devices, apparatuses, equipment, and systems involved in this application are only illustrative examples and are not intended to require or imply that they must be connected, arranged, and configured in the manner shown in the block diagram. As will be appreciated by those skilled in the art, these devices, apparatuses, equipment, and systems can be connected, arranged, and configured in any manner. Words such as "including", "comprising", "having", etc. are open words, referring to "including but not limited to", and can be used interchangeably with them. The words "or" and "and" used here refer to the words "and / or" and can be used interchangeably with them, unless the context clearly indicates otherwise. The words "such as" used here refer to the phrase "such as but not limited to", and can be used interchangeably with them.

Claims

1. A high-field conductivity test electrode system with accidental discharge protection function, characterized in that: The invention comprises a cylindrical test sample (3), a low voltage electrode (2), a test sample (3) and a high voltage electrode (4) which are coaxially arranged in sequence from bottom to top, an inner shielding electrode (6) which is coaxially inserted into the cylindrical cavity of the test sample (3), an annular protective electrode (5) which is coaxially arranged on the outer ring of the test sample (3), the inner diameter of the protective electrode (5) being larger than the outer diameter of the test sample (3), the protective electrode (5), the inner shielding electrode (6) and the low voltage electrode (2) are all supported and fixed by a bracket (1), the bracket (1) is made of insulating material, and the protective electrode (5) and the inner shielding electrode (6) are all grounded.

2. A high-field conductivity test electrode system with accidental discharge protection function according to claim 1, characterized in that: The low-voltage electrode (2) is in the shape of a disk, the diameter of the low-voltage electrode (2) is larger than the diameter of the sample to be tested (3), and the low-voltage electrode (2) is provided with low-voltage electrode connection terminals (21) evenly arranged around the circumference of the sample to be tested (3).

3. The high-field conductivity test electrode system with accidental discharge protection function according to claim 2, characterized in that: A threaded hole is provided at the top of the low-voltage electrode (2), and each low-voltage electrode terminal (21) is threadedly matched and fixed with the threaded hole of the low-voltage electrode (2); a low-voltage electrode support (22) is provided on the bracket (1) along the vertical direction, and a slot is provided at the bottom of the low-voltage electrode (2) so as to be plugged and positioned with the low-voltage electrode support (22).

4. The high-field conductivity test electrode system with accidental discharge protection function according to claim 1, characterized in that: A threaded hole is provided at the top of the high-voltage electrode (4) along the axial direction, and a stud is provided at the bottom of the spherical high-voltage electrode terminal (41), which is fixed by threaded engagement with the threaded hole of the high-voltage electrode (4); the outer diameters of the high-voltage electrode (4) and the sample to be tested (3) are correspondingly equal.

5. A high-field conductivity test electrode system with accidental discharge protection function according to any one of claims 1 to 4, characterized in that: A slot (11) is provided at the bottom of the bracket (1), a grounding plate (12) is fixedly fastened in the slot (11), a protective electrode support (51) and an inner shielding electrode support (61) penetrating the low-voltage electrode (2) are arranged on the grounding plate (12) in a vertical direction, and the protective electrode (5) and the inner shielding electrode (6) are supported and fixed by the protective electrode support (51) and the inner shielding electrode support (61), respectively.

6. A high-field conductivity test electrode system with accidental discharge protection function according to claim 5, characterized in that: The bottom of the protection electrode (5) is evenly provided with pins along the circumferential direction, the number of the protection electrode pillars (51) corresponds to the number of the pins of the protection electrode (5), and each pin of the protection electrode (5) is plugged and positioned in a one-to-one correspondence with each protection electrode pillar (51).

7. The high-field conductivity test electrode system with accidental discharge protection function according to claim 5, characterized in that: The inner shielding electrode (6) is in a two-stage stepped columnar structure that is wide at the top and narrow at the bottom. The inner shielding electrode pillar (61) is coaxially arranged with the inner shielding electrode (6). A positioning hole corresponding to the diameter of the lower half of the inner shielding electrode (6) is provided at the top of the inner shielding electrode pillar (61) for the lower half of the inner shielding electrode (6) to be inserted and positioned. The inner diameter of the sample to be tested (3), the outer diameter of the inner shielding electrode pillar (61) and the outer diameter of the upper half of the inner shielding electrode (6) correspond to each other.

8. The high-field conductivity test electrode system with accidental discharge protection function according to claim 5, characterized in that: The clamping slot (11) is a cross slot, and the grounding plate (12) is a cross-shaped metal plate.

9. A high-field conductivity test electrode system with accidental discharge protection function according to any one of claims 1 to 4, characterized in that: When measuring the volume conductivity of the sample to be tested (3), aluminum foil is attached to the outer surface of the sample to be tested (3), the surface current of the sample to be tested (3) is connected to the ground through a lead wire, and the low-voltage electrode terminal (21) is connected to a current measuring device to measure the volume current of the sample to be tested (3). The volume conductivity of the sample to be tested (3) is: Among them, γ Vi represents the volume conductivity of the sample to be tested (3) at the i-th voltage level; U i represents the voltage magnitude of the i-th voltage applied to the sample to be tested (3); I i is the actual current value of the current measuring device under the i-th voltage level; D is the outer diameter of the sample to be tested (3); d is the inner diameter of the sample to be tested (3); h is the length of the sample to be tested (3).

10. A high-field conductivity test electrode system with accidental discharge protection function according to any one of claims 1 to 4, characterized in that: When measuring the surface conductivity of the sample to be tested (3), aluminum foil is attached to the outer surface of the sample to be tested (3), the surface current of the sample to be tested (3) is connected to the current measuring device through the lead wire, and the low-voltage electrode terminal (21) is connected to the ground. The surface conductivity of the sample to be tested (3) is: Among them, γ Si represents the surface conductivity of the sample to be tested (3) at the i-th voltage level; U i represents the voltage magnitude of the i-th voltage applied to the sample to be tested (3); I i is the actual current value of the current measuring device under the i-th voltage level; D is the outer diameter of the sample to be tested (3); h is the length of the sample to be tested (3).

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