A high field conductivity test electrode system with accidental discharge protection

Abstract

The application relates to the field of insulation material performance testing, and particularly relates to a high-field conductance test electrode system with unexpected discharge protection function, which comprises a cylinder-shaped sample to be tested, a low-voltage electrode, the sample to be tested and a high-voltage electrode which are coaxially arranged in sequence from bottom to top, an inner shielding electrode is coaxially inserted into the cylinder cavity of the sample to be tested, a ring-shaped protection electrode is coaxially arranged at the outer circle 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 support, the support is made of insulating material, and the protection electrode and the inner shielding electrode are both grounded. The application can measure the surface conductivity and the volume conductivity of the insulation material under the working condition of high field intensity, and greatly improves the safety of the test system.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of insulation material performance testing, and particularly relates to a high-field conductivity test electrode system with accidental discharge protection function. BACKGROUND

[0002] Volume conductivity and surface conductivity are key indicators for measuring the conductivity and insulation performance of insulation materials. By measuring the volume conductivity, the charge transport capacity inside the insulation material can be understood. By measuring the surface conductivity, the charge accumulation and dissipation capacity on the surface of the insulation material can be understood, so as to judge the advantages and disadvantages of the insulation performance of the insulation material. The conductivity of the insulation structure is closely related to the stability and reliability of the electrical equipment. If the conductivity of the insulation structure is too high, the charges may move freely inside the material, which may cause ionization, charge accumulation and other phenomena, and eventually may cause failure or short circuit of the electrical equipment. Therefore, regular measurement of the conductivity can timely find the decline of the insulation performance, so as to take necessary preventive measures to avoid electrical faults.

[0003] At present, the test of the conductivity of the insulation material mostly adopts a three-electrode system. The three electrodes are composed of a high-voltage electrode, a measurement electrode and a shielding electrode. The high-voltage electrode is used to apply voltage to the insulation material, the measurement electrode is used to measure the current passing through the insulation material, and the shielding electrode is used to absorb the surface current of the insulation material to prevent the surface current from interfering with the measurement. The shielding electrode directly excludes the surface current of the insulation material as interference current from the measurement, and the surface conductivity of the insulation material cannot be measured by the three-electrode system. In addition, under high field strength, when high voltage is applied to the insulation material, accidental discharge phenomenon of the insulation material is easy to occur, which cannot protect the test system and has safety hazards, so it is urgent to be solved. SUMMARY

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

[0005] To achieve the above-mentioned purpose, the present application provides the following technical scheme:

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

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

[0008] As a further scheme of the present application: a threaded hole is formed in the top of the low-voltage electrode, each low-voltage electrode terminal is threadedly fixed with the threaded hole of the low-voltage electrode, a low-voltage electrode support is arranged on the support in the vertical direction, and a slot is formed in the bottom of the low-voltage electrode to be inserted and positioned with the low-voltage electrode support.

[0009] As a further scheme of the present application: a threaded hole is formed in the top of the low-voltage electrode, each low-voltage electrode terminal is threadedly fixed with the threaded hole of the low-voltage electrode, a low-voltage electrode support is arranged on the support in the vertical direction, and a slot is formed in the bottom of the low-voltage electrode to be inserted and positioned with the low-voltage electrode support.

[0010] As a further scheme of the present application: a threaded hole is formed in the top of the low-voltage electrode, each low-voltage electrode terminal is threadedly fixed with the threaded hole of the low-voltage electrode, a low-voltage electrode support is arranged on the support in the vertical direction, and a slot is formed in the bottom of the low-voltage electrode to be inserted and positioned with the low-voltage electrode support.

[0011] As a further scheme of the present application: a threaded hole is formed in the top of the low-voltage electrode, each low-voltage electrode terminal is threadedly fixed with the threaded hole of the low-voltage electrode, a low-voltage electrode support is arranged on the support in the vertical direction, and a slot is formed in the bottom of the low-voltage electrode to be inserted and positioned with the low-voltage electrode support.

[0012] As a further scheme of the present application: the inner shielding electrode is in a two-section stepped columnar structure with the upper section wider and the lower section narrower, the inner shielding electrode support is arranged coaxially with the inner shielding electrode, a positioning hole corresponding to the diameter of the lower section of the inner shielding electrode is formed in the top of the inner shielding electrode support for the lower section of the inner shielding electrode to be inserted and positioned, and the inner diameter of the sample to be tested, the outer diameter of the inner shielding electrode support, and the outer diameter of the upper section of the inner shielding electrode correspond in size.

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

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

[0015]

[0016] wherein γ Virepresents the volume conductivity of the sample to be tested under the i-th gear voltage;

[0017] U i represents the voltage size of the i-th gear voltage applied on the sample to be tested;

[0018] I i represents the measured current value of the current measuring device under the i-th gear voltage;

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

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

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

[0022] As a further scheme of the present application: when measuring the surface conductivity of the sample to be tested, an aluminum foil is attached to the outer surface of the sample to be tested, the surface current of the sample to be tested is led to the current measuring device through a lead wire, and the low-voltage electrode terminal is led into the ground, and the surface conductivity of the sample to be tested is:

[0023]

[0024] wherein γ Si represents the surface conductivity of the sample to be tested under the i-th gear voltage;

[0025] U i represents the voltage size of the i-th gear voltage applied on the sample to be tested;

[0026] I i represents the measured current value of the current measuring device under the i-th gear voltage;

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

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

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

[0030] 1. The present application can measure the surface conductivity and volume conductivity of the insulating material under high field strength working conditions, comprehensively quantize and evaluate the performance of the insulating material, protect the inside of the sample to be tested through the inner shielding electrode, protect the outside of the sample to be tested through the annular protection electrode, prevent the sample to be tested from accidental discharge from inside and outside at the same time, and ensure the safety of the test system.

[0031] 2、The high-voltage electrode, the low-voltage electrode, the high-voltage electrode terminal and the low-voltage electrode terminal of the application are all designed with round edges on the upper and lower end edges, effectively improving the electric field distribution on the electrode surface; the high-voltage electrode terminal and the low-voltage electrode terminal are fixed by screwing, facilitating the disassembly and installation of the system; each electrode is supported by an insulating support, improving the safety of the test process.

[0032] 3、The protective electrode of the application is fixed by inserting the pin into the protective electrode support post, thereby being coaxially fixed to the outer circle of the sample to be tested, attracting the accidental discharge current outside the sample, introducing the accidental discharge current outside the sample into the grounding terminal, and preventing the accidental discharge current outside the sample from damaging the measuring equipment.

[0033] 4、The inner shielding electrode of the application is used to attract the accidental discharge current inside the sample, introduce the accidental discharge current inside the sample into the grounding terminal, prevent the accidental discharge current inside the sample from damaging the measuring equipment, and at the same time, the inner shielding electrode is in close contact with the inner wall of the sample, which can also introduce the surface current of the inner wall of the sample into the ground to prevent the surface current of the inner wall of the sample from affecting the accuracy of the measurement results; the two-section columnar structure of the inner shielding electrode can be directly inserted into the inner shielding electrode support post, and the inner shielding electrode and the inner shielding electrode support post can form support for the sample to be tested. BRIEF DESCRIPTION OF DRAWINGS

[0034] Fig. 1 The figure is a structural schematic diagram of the application.

[0035] Fig. 2 The figure is a structural schematic diagram of another view of the application.

[0036] Fig. 3 The figure is a schematic diagram of the installation position of the inner shielding electrode in the application.

[0037] Fig. 4 The figure is a structural schematic diagram of the inner shielding electrode in the application.

[0038] In the figure:

[0039] 1, support; 11, clamping groove; 12, grounding plate;

[0040] 2, low-voltage electrode; 21, low-voltage electrode terminal; 22, low-voltage electrode support post;

[0041] 3, sample to be tested; 4, high-voltage electrode; 41, high-voltage electrode terminal;

[0042] 5, protective electrode; 51, protective electrode support post;

[0043] 6, inner shielding electrode; 61, inner shielding electrode support post. DETAILED DESCRIPTION

[0044] With reference to the drawings of the embodiments of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of the present application.

[0045] Please refer to Figs. 1-4 In the embodiments of the present application, a high-field conductance test electrode system with unexpected discharge protection function comprises an insulating support 1, which is preferably made of polytetrafluoroethylene. The support 11 is in a flat cylindrical structure, and a cross-shaped clamping groove 11 is formed in the bottom of the support 11. A grounding plate 12 is clamped and fixed in the clamping groove 11, and the grounding plate 12 is connected to a grounding terminal through a lead-out wire.

[0046] A plurality of low-voltage electrode support columns 22 are arranged vertically on the support 11, and each low-voltage electrode support column 22 is uniformly and spacedly arranged around the axis of the support 11. A low-voltage electrode 2 is supported and fixed by each low-voltage electrode support column 22. A plug-in slot matching the shape of the low-voltage electrode support column 22 is formed in the bottom of the low-voltage electrode 2, for the low-voltage electrode support column 22 to be inserted and positioned from bottom to top.

[0047] The low-voltage electrode 2 is in a flat cylindrical shape, and the top and bottom circumferences thereof are rounded. A plurality of threaded holes are formed in the top of the low-voltage electrode 2, and the threaded holes are threadedly fixed with threaded studs at the bottom of low-voltage electrode connection terminals 21. The low-voltage electrode connection terminals 21 are preferably corresponding in number to the low-voltage electrode support columns 22, and each group of low-voltage electrode connection terminals 21 is coaxially arranged with a corresponding group of low-voltage electrode support columns 22. The low-voltage electrode connection terminals 21 are in a flat cylindrical shape, and the top and bottom circumferences thereof are rounded to improve the surface electric field distribution of the low-voltage electrode connection terminals 21.

[0048] An inner shielding electrode support column 61, which is open at both ends and in a cylindrical shape, is fixed axially on the support 11. A hole is formed at the center of the support 11 for a cylindrical inner shielding electrode 6 to pass through. After the inner shielding electrode 6 passes through the inner shielding electrode support column 61 and the support 11 from top to bottom, the lower section thereof is connected to the grounding plate 12. The inner shielding electrode 6 is in a two-section stepped columnar structure with a wide upper section and a narrow lower section. The diameter of the lower section is relatively narrow, corresponding to the inner diameter of the inner shielding electrode support column 61, and the diameter of the lower section of the inner shielding electrode 6 is relatively wide, corresponding to the outer diameter of the inner shielding electrode support column 61. The inner shielding electrode support column 61 penetrates the low-voltage electrode 2, and the top end thereof extends above the low-voltage electrode 2.

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

[0050] The high-voltage electrode 4 is coaxially fixed to 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 axially opened at the top of the high-voltage electrode 4, and a stud is provided at the bottom of the spherical high-voltage electrode terminal 41, which is threadedly engaged with the threaded hole of the high-voltage electrode 4 to secure it.

[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 guard electrode 5 is coaxially arranged above the low-voltage electrode 2 and around the outer ring of the test sample 3. The guard electrode 5 is annular, with multiple sets of pins arranged evenly along its base in the vertical direction. Multiple sets of guard electrode supports 15 extend through the ground plate 12 and the low-voltage electrode 2 to support the pins of the guard electrode 5. Axially, holes are opened at the top of the guard electrode supports 15 to allow the pins of the guard electrode 5 to be inserted and positioned.

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

[0054]

[0055] Among them, γ Vi Indicates 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 Indicates the voltage of the i-th level applied to the test sample 3, in V;

[0057] I i is the measured current value of the current measuring device at 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 test sample 3, the outer surface of the test sample 3 is pasted with an aluminum foil, the surface current of the test sample 3 is connected to the current measuring device through the lead-out wire, and the low-voltage electrode connection terminal 21 is connected to the ground, so as to realize the separate measurement of the surface current. The surface conductivity of the test sample 3 is:

[0062]

[0063] wherein γ Si represents the surface conductivity of the test sample 3 under the i-th gear voltage; the unit is S / m, i = 1, 2, 3, ….

[0064] U i represents the voltage value of the i-th gear voltage applied to the test sample 3; the unit is V;

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

[0066] D represents the outer diameter of the test sample; the unit is m;

[0067] h represents the length of the test sample; the unit is m.

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

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

[0070] When measuring the volume conductivity or the surface conductivity, the high-voltage power supply is controlled to increase the voltage, the voltage applied to the test sample 3 by the high-voltage electrode 4 is increased in i gear gradients, the voltage of each gear is applied for N minutes, the average value of the current in the last n minutes of the voltage application of each gear is taken as the quasi-steady-state current measurement value of the voltage of the gear, n < N; the test sample 3 is tested m times under the same measurement environment, and the quasi-steady-state current measurement value of each gear voltage is obtained each time. The average value of the quasi-steady-state current measurement values obtained by m times of testing is taken as the final current measurement value of the voltage of each gear. After the measurement is completed, the high-voltage power supply is turned off and the residual charge of the system is led to the ground terminal.

[0071] The basic principles of the application are described above by way of example in connection with specific embodiments, but it should be noted that the advantages, benefits, effects and the like mentioned in the present application are only examples and are not intended to be limiting, and it cannot be considered that these advantages, benefits, effects and the like are necessarily possessed by each embodiment of the present application. In addition, the specific details of the above disclosure are only for the purpose of example and for the purpose of understanding, and are not limiting, and the above details do not limit the present application to necessarily adopt the above specific details for implementation.

[0072] The block diagrams of the devices, apparatuses, equipment, systems involved in the present application are only illustrative examples and are not intended to require or imply that the connections, arrangements, configurations must be as shown in the block diagrams. As those skilled in the art will recognize, these devices, apparatuses, equipment, systems can be connected, arranged, configured in any manner. Words such as "include", "contain", "have" and the like are open-ended words, mean "including but not limited to", and can be used interchangeably. The words "or" and "and" used herein mean the word "and / or", and can be used interchangeably unless the context clearly indicates otherwise. The word "such as" used herein means the phrase "such as but not limited to", and can be used interchangeably.

Claims

1. A high field conductance test electrode system with accidental discharge protection, characterized by, The application relates to a kind of electrode structures for measuring volumetric conductivity of sample, comprising a cylindrical sample to be tested (3), a low-voltage electrode (2), the sample to be tested (3) and a high-voltage electrode (4) are arranged coaxially from bottom to top in sequence, the inner shielding electrode (6) is coaxially inserted into the cylindrical cavity of the sample to be tested (3), the annular protective electrode (5) is coaxially arranged outside the sample to be tested (3), the inner diameter of the protective electrode (5) is larger than the outer diameter of the sample to be tested (3), the protective electrode (5), the inner shielding electrode (6) and the low-voltage electrode (2) are all supported and fixed by the support (1), the support (1) is made of insulating material, the protective electrode (5) and the inner shielding electrode (6) are both grounded. The inner shielding electrode (6) is in the form of a two-section stepped column with a wide upper part and a narrow lower part, the inner shielding electrode support (61) is coaxially arranged with the inner shielding electrode (6), the top of the inner shielding electrode support (61) is provided with a positioning hole corresponding to the diameter of the lower half of the inner shielding electrode (6) for inserting and positioning the lower half of the inner shielding electrode (6), and the inner diameter of the sample to be tested (3), the outer diameter of the inner shielding electrode support (61) and the outer diameter of the upper half of the inner shielding electrode (6) are corresponding in size.

2. The 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 form of a disc, 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 terminals (21) arranged uniformly around the sample to be tested (3).

3. A high field conductivity test electrode system with accidental discharge protection according to claim 2, characterized in that The top of the low-voltage electrode (2) is provided with a threaded hole, each low-voltage electrode terminal (21) is threadedly fixed with the threaded hole of the low-voltage electrode (2), the support (1) is provided with a low-voltage electrode support (22) in the vertical direction, and the bottom of the low-voltage electrode (2) is provided with a slot for inserting and positioning the low-voltage electrode support (22).

4. The high field conductivity test electrode system with accidental discharge protection of claim 1, wherein, The top of the high-voltage electrode (4) is provided with a threaded hole in the axial direction, the bottom of the spherical high-voltage electrode terminal (41) is provided with a stud, and the stud is threadedly fixed with the threaded hole of the high-voltage electrode (4), and the outer diameter of the high-voltage electrode (4) is equal to the outer diameter of the sample to be tested (3).

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

6. A high field conductivity test electrode system with accidental discharge protection according to claim 5, wherein, The bottom of the protective electrode (5) is uniformly provided with pins in the circumferential direction, the number of the pins of the protective electrode (5) corresponds to the number of the protective electrode supports (51), and each pin of the protective electrode (5) is one-to-one inserted and positioned with each protective electrode support (51).

7. The high field conductivity test electrode system with accidental discharge protection of claim 5, wherein, The clamping groove (11) is a cross groove, and the grounding plate (12) is a cross-shaped metal plate.

8. A high field conductivity test electrode system with accidental discharge protection according to any one of claims 1 to 4, characterized in that When measuring the volumetric conductivity of the sample to be tested (3), an 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 introduced into the ground through a lead wire, the low-voltage electrode terminal (21) is connected with a current measuring device to measure the volumetric current of the sample to be tested (3), and the volumetric conductivity of the sample to be tested (3) is: wherein γ Vi represents the volume conductivity of the sample (3) to be tested at the i-th gear voltage; U i V represents the voltage magnitude of the i-th voltage applied on the sample (3) to be tested; I i Ii is the measured current value of the current measuring device for the i-th gear voltage; 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 (3) to be tested.

9. A high field conductivity test electrode system with accidental discharge protection according to any one of claims 1 to 4, characterized in that When measuring the surface conductivity of the sample (3) to be tested, an aluminum foil is attached to the outer surface of the sample (3) to be tested, the surface current of the sample (3) to be tested is connected to the current measuring device through the lead-out wire, the low-voltage electrode connection terminal (21) is connected to the ground, and the surface conductivity of the sample (3) to be tested is: wherein γ Si is the surface conductivity of the sample (3) to be tested at the i-th gear voltage; U i V represents the voltage magnitude of the i-th voltage applied on the sample (3) to be tested; I i Ii is the measured current value of the current measuring device for the i-th gear voltage; D is the outer diameter of the sample (3) to be tested; h is the length of the sample (3) to be tested.

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