Plant oil paper composite insulation electrical performance test device and method

Abstract

The present application belongs to the field of insulation test, and relates to a plant oil paper composite insulation electrical performance test device and method. The test device comprises an upper section test oil tank and a lower section oil storage oil tank. A support frame is fixedly installed inside the upper section test oil tank, and an electrode device is fixedly installed on the support frame. The electrode device comprises a windowed insulation paper board, two voltage grading rings and an electrode. The electrode is a copper conductor with insulation, which is bent into a T-shaped hanger shape. The test method comprises the following steps: press the plant insulation liquid dielectric from the lower section oil storage oil tank into the upper section test oil tank through a connecting pipe until the electrode device is covered; simulate the change of the electrode gap, i.e. the oil gap, by adjusting the distance between the long oval circles of the electrode; simulate the change of the turn insulation specification by changing the thickness of the insulation paper of the electrode; and realize the test under different operating conditions. The test device is convenient to disassemble and oil injection, strictly controls a single variable, and reduces the influence of the oxidation degree of the insulation oil and impurities on the test.

Description

Technical Field

[0001] This invention belongs to the field of insulation testing technology, and in particular relates to a device and method for testing the electrical performance of vegetable oil paper composite insulation. Background Technology

[0002] As the power grid transforms towards a more environmentally friendly, efficient, and intensive green grid, higher demands are placed on the safety and reliability of power transformers. This requires both environmentally friendly insulation materials and equipment using such materials to operate stably under harsh conditions. Insulating oil in transformers plays a role in electrical insulation and heat dissipation. Traditional mineral insulating oil has a flash point of approximately 160°C. When a transformer experiences a fault and a rapid temperature rise, it can lead to equipment explosions and oil leaks, causing serious environmental pollution. Vegetable-based insulating oil, a high-flash-point, low-toxicity, and renewable environmentally friendly liquid insulating medium, is increasingly being used in power distribution and transformers to replace mineral oil. This improves fire safety, environmental benefits, ecological sustainability, and extends insulation life.

[0003] To date, most research on the electrical performance of oil-paper composite insulation has focused on traditional mineral-insulated oil transformers. Research on the characteristics of vegetable oil-paper composite insulation has been conducted separately in the fields of vegetable oil and insulating paper, and discussions on the specifications of insulating paper are relatively limited.

[0004] For practical engineering applications, this study systematically investigates the various properties of vegetable insulating oil and the interaction between oil and paper insulation, particularly focusing on the breakdown characteristics of oil-paper insulation. This research is of great significance for the structural design and safe operation of vegetable insulating oil transformers. Generally, the inter-insulation of transformer discs is a quasi-uniform field. However, due to the limited number of large-capacity vegetable oil transformers connected to the grid in China, there is a lack of in-depth research and systematic theory regarding their insulation structure design and safety distances. Therefore, it is necessary to conduct in-depth research on the insulation performance of vegetable oil transformers under lightning impulse voltage.

[0005] Chinese invention patent 201810072542.8 provides a method for testing the performance of insulating liquid and insulating paper for power equipment. It conducts aging performance tests on a new type of high-temperature resistant insulating paper and insulating liquid, and upgrades the mineral oil-impregnated kraft paper insulation system of traditional distribution transformers based on the test data. However, it does not conduct further testing and research on vegetable oil. The test requires wrapping the insulating paper around the entire copper conductor, and the test involves insulating papers A / B / C / D / E. The operation is not easy to simplify in terms of replacing insulating paper, repeating the test, and improving the accuracy of the test results.

[0006] Chinese invention patent 201810966206.8 provides a test fixture for lightning impulse testing of high-voltage electrical insulation components, including a bushing assembly, a housing, and a steel base frame. The test fixture is filled with sulfur hexafluoride gas. The designed housing structure is compact and easy to assemble and disassemble, enabling lightning impulse testing of insulation components with low cost and convenient installation. However, no further testing and research were conducted on vegetable oil and oil-paper insulation. Summary of the Invention

[0007] To address the aforementioned technical problems, this invention provides a testing apparatus and method for the electrical performance of vegetable oil paper composite insulation. The technical solution adopted by this invention is as follows:

[0008] A device for testing the electrical performance of vegetable oil paper composite insulation includes an upper test tank and a lower oil storage tank. The side wall of the upper test tank has openings from top to bottom for the sequential installation of pipe joints and valves S1, S0, and S2. The upper and lower side wall of the lower oil storage tank has openings for the sequential installation of pipe joints and valves S5 and S4. A connecting pipe is fixedly installed between valves S2 and S4. A support frame is fixedly installed inside the upper test tank, and an electrode device is fixedly installed on the support frame. The electrode device includes: a windowed insulating paperboard and two equalizing electrodes. The device consists of a plate and an electrode. The high-voltage and low-voltage ends of the electrode are insulated copper wires bent into a T-shape, resembling a coat hanger. Each electrode includes an elongated elliptical ring and an extension rod that is perpendicular to the middle of the elongated elliptical ring and integrally formed. Two equalizing plates are symmetrically fixed on both sides of the upper end of the support frame. Windowed insulating cardboard is placed between the two equalizing plates on the support frame and fixed by bakelite screws. The two ends of the electrode are placed symmetrically on the windowed insulating cardboard in opposite directions. The elongated elliptical rings at both ends of the electrode are parallel to each other. The ends of the extension rods at both ends of the electrode are electrically connected to the equalizing plates respectively.

[0009] The equalizing plate is an elliptical cylinder made of metal, with a slit on one side. An electrical clamp is welded inside the slit, and the electrical clamp is also made of metal.

[0010] The top of the oil tank used in the previous test section is open and a sealed cover is fixedly installed. An observation window is provided on the side of the oil tank used in the previous test section.

[0011] The side of the oil tank used in the previous test is connected to the inclined riser. The sleeve is fixed and installed on the inclined riser by bolts. The pipe joint and valve S3 are fixed and installed by opening the upper part of the side wall of the inclined riser.

[0012] Preferably, the electrodes are fixed to the windowed insulating cardboard using high-temperature resistant nylon cable ties.

[0013] Preferably, the insulated copper wire is made by wrapping bare copper wire with insulating paper.

[0014] Preferably, the observation window is made of tempered glass.

[0015] A method for testing the electrical performance of vegetable oil paper composite insulation, using the aforementioned testing apparatus for the electrical performance of vegetable oil paper composite insulation, includes the following steps:

[0016] Step 1: Remove the insulating paper from the end of the electrode extension rod. Name the end of the extension rod at one end of the electrode the high-voltage end lead and the end of the extension rod at the other end of the electrode the low-voltage end lead. Connect the high-voltage wire introduced by the sleeve to the left side of the adjacent equalizing plate and fix it with metal bolts. Connect the high-voltage end lead of the adjacent electrode to the right side of the equalizing plate and fix it with electrical clamps. Connect the low-voltage end lead of the electrode to another equalizing plate and ground it.

[0017] Step 2: Open valve S1 of the upper test oil tank and valve S3 of the inclined riser. Use the pipes connected to these valves to release air and observe the oil level. Open valve S2 of the upper test oil tank and valve S4 of the lower oil storage tank. Connect the pipe to the nitrogen device at valve S5 of the lower oil storage tank. By controlling the flow rate of valve S5 and the nitrogen device, inject nitrogen into the lower oil storage tank. Then, pressurize the plant-based insulating liquid dielectric from the lower oil storage tank into the upper test oil tank through the connecting pipe until the upper test oil tank is full.

[0018] Step 3: By adjusting the distance between the elongated elliptical rings of the electrodes, the electrode gap (oil gap) is simulated to change; by changing the thickness of the insulating paper of the electrodes, the turn insulation specification is simulated to change. The electrical environment under different oil gaps and different turn insulation conditions is simulated respectively, thereby realizing the test under different environments.

[0019] Step 4: Disconnect the nitrogen device connected to valve S5 of the lower oil storage tank, open valves S5 and S1 to depressurize the upper test oil tank and the lower oil storage tank, open valves S2 and S4, and inject vegetable oil from the upper test oil tank into the lower oil storage tank through the connecting pipe until the electrode device is exposed.

[0020] Preferably, before the test begins, vegetable oil is first injected into the lower section oil storage tank and left to stand. The vegetable oil is then injected into the upper section test tank through an external connecting pipe until it is full. The tank is left to stand until the oil sample meets the standard. An oil sample can be taken through valve S0. After one test is completed, the vegetable oil is returned from the upper section test tank to the lower section oil storage tank until the electrode device is exposed. The sealed box cover is then opened to replace the electrode device.

[0021] Preferably, the vegetable oil paper insulation sample is pretreated before the test. First, the impurity particles in the vegetable oil sample are filtered out using a filtration device until they meet the standard. The windowed insulation paperboard used for the test is cut and polished according to the required size. The electrodes are then made and tied to the windowed insulation paperboard. The windowed insulation paperboard test sample with electrodes is placed in a vacuum drying oven at 50Pa / 90℃ for 48 hours. After that, it is cooled to room temperature under vacuum conditions. The pretreated test sample is then sealed and stored under vacuum conditions.

[0022] The beneficial effects of this invention are:

[0023] The oil tank of this test apparatus has a two-part structure, which simplifies the replacement and storage of insulating oil; the electrical clamps facilitate electrode replacement. Overall, this invention optimizes the test apparatus and disassembly process, reduces the contact between the insulating oil and air inside the apparatus, reduces the degree of oxidation of the insulating oil, and minimizes the impact of impurities on performance testing.

[0024] The apparatus and method of this invention for testing the electrical performance of vegetable oil paper composite insulation enrich the theory and practical application in this case, and are used to explore the electrical performance of oil paper composite insulation under different oil gaps and different turns of insulation, providing technical and theoretical support for the subsequent design and manufacture of natural ester insulating oil transformers. Attached Figure Description

[0025] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some specific embodiments of the present invention. For those skilled in the art, other drawings falling within the scope of protection of this application can be obtained based on these drawings without any creative effort.

[0026] Figure 1 This is a front view of the test apparatus according to an embodiment of the present invention;

[0027] Figure 2 This is a top view of the test apparatus according to an embodiment of the present invention;

[0028] Figure 3 This is a schematic diagram of the electrode device according to an embodiment of the present invention;

[0029] Figure 4 This is a schematic diagram of the preprocessing flow of the experimental method according to an embodiment of the present invention;

[0030] In the diagram, 1 is the sleeve, 2 is the inclined riser, 3 is the sealed box cover, 4 is the upper test oil tank, 5 is the observation window, 6 is the connecting pipe, 7 is the lower oil storage tank, 8 is the electrode device, 9 is the support frame, 10 is the windowed insulating paperboard, 11 is the equalizing plate, and 12 is the electrode. Detailed Implementation

[0031] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0032] like Figure 1 The image shown is a front view of the experimental apparatus according to an embodiment of the present invention. Figure 1 The device includes a perspective effect, with the support frame 9 fixedly installed in the upper test oil tank 4, and the electrode device 8 fixedly installed on the support frame 9. A vegetable oil-paper composite insulation electrical performance testing device includes an upper test oil tank 4 and a lower oil storage tank 7, with vegetable oil stored in the lower oil storage tank 7. The contact surfaces between the upper test oil tank 4 and the lower oil storage tank 7 are not interconnected; they are connected as a single unit by flanges and bolts. The outer wall of the oil tank is equipped with valves and connecting pipes to form a pipeline system. Specifically, the side wall of the upper test oil tank 4 is opened from top to bottom and fixedly installed with pipe joints and valves S1, S0 and S2. Valve S1 is connected to the vent pipe. The upper and lower parts of the side wall of the lower oil storage tank 7 are opened and fixedly installed with pipe joints and valves S5 and S4 respectively. A through connecting pipe 6 is fixedly installed between valves S2 and S4. The connecting pipe 6 connects the upper test oil tank 4 and the lower oil storage tank 7. The pipe joints and valves are fixedly connected by flanges.

[0033] The top of the test tank 4 is open and a sealed cover 3 is fixedly installed to maintain a vacuum test environment. An observation window 5, made of tempered glass, is provided on the side of the test tank 4 to facilitate observation of the discharge process during the test. An electrode device 8 is fixedly installed inside the test tank 4.

[0034] The side of the oil tank 4 used in the previous test is connected to the inclined riser 2. The sleeve 1 is fixedly installed on the inclined riser 2 by bolts. The sleeve 1 serves to connect to the external power supply and ground. The upper part of the side wall of the inclined riser 2 has an opening to fix and install the pipe joint and valve S3. The valve S3 is connected to the external vent pipe.

[0035] like Figure 2 The image shown is a top view of the experimental apparatus according to an embodiment of the present invention. Figure 2 It includes perspective effects. Figure 2The structure within the dashed circle is a view of the interior of the upper-section test oil tank 4. A support frame 9 is fixedly installed inside the upper-section test oil tank 4. The support frame 9 is a frame structure, with its lower part fixed to the bottom of the upper-section test oil tank 4. The electrode device 8 is fixedly mounted on the support frame 9. Figure 3 The diagram shows a schematic representation of the electrode device according to an embodiment of the present invention. The electrode device 8 includes: a windowed insulating paperboard 10, equalizing plates 11, and electrodes 12. The high-voltage and low-voltage ends of the electrodes 12 are each formed by two insulated copper wires bent into a T-shape resembling a coat hanger. Each electrode includes an elongated elliptical loop and an extension rod integrally formed perpendicular to the middle of the elliptical loop. The electrodes 12 are used to test the influence of different electrode turn insulation and electrode gaps on the withstand voltage characteristics of the vegetable oil insulation system. Two equalizing plates 11 are symmetrically fixed on both sides of the upper end of the support frame 9. The windowed insulating paperboard 10 is placed between the two equalizing plates 11 on the support frame 9 and fixed in place by bakelite screws. Electrode 12 is placed symmetrically on the windowed insulating cardboard 10 with its two ends facing opposite directions. The elongated elliptical rings at both ends of electrode 12 are parallel to each other. The ends of the extension rods at both ends of electrode 12 are electrically connected to the equalizing plate 11, serving as the high-voltage and low-voltage ends of the electrode. Electrode 12 is fixed to the windowed insulating cardboard 10 with high-temperature resistant nylon cable ties. The parallel gap between the elongated elliptical rings at both ends of electrode 12 represents the oil gap between electrodes, simulating the uniform electric field environment during transformer operation. The non-uniformity coefficient of the electrode is reduced by standardizing the manufacturing process and increasing the length of the parallel parts. The insulated copper conductor is made of bare copper conductor wrapped with insulating paper. The thickness of the insulating paper wrapping the surface represents the turn insulation thickness.

[0036] The equalizing plate 11 is an elliptical cylinder made of metal, which is conductive and serves to distribute voltage evenly. It has a slit on one side and an electrical clip welded inside. The electrical clip is also made of metal and is conductive.

[0037] A method for testing the electrical performance of vegetable oil paper composite insulation, using the aforementioned testing apparatus for the electrical performance of vegetable oil paper composite insulation, includes the following steps:

[0038] Step 1: Remove the insulating paper from the end of the extension rod of electrode 12 to facilitate insertion into the electrical clamp for secure connection. Name the end of the extension rod at one end of electrode 12 the high-voltage end lead, and the end of the extension rod at the other end of electrode 12 the low-voltage end lead. Connect the high-voltage wire introduced through sleeve 1 to the left side of the adjacent equalizing plate 11 and secure it with metal bolts. Connect the high-voltage end lead of the adjacent electrode 12 to the right side of the equalizing plate 11 and secure it with the electrical clamp. Similarly, connect the low-voltage end lead of electrode 12 to another equalizing plate 11 and ground it.

[0039] Step 2: Open valve S1 of the upper test oil tank 4 and valve S3 of the inclined riser 2. Open valve S2 of the upper test oil tank 4 and valve S4 of the lower oil storage tank 7. Connect the pipeline of the nitrogen device to valve S5 of the lower oil storage tank 7. By controlling the flow rate of valve S5 and the nitrogen device, inject nitrogen into the lower oil storage tank 7. This will force the plant insulating liquid dielectric (i.e., vegetable oil) from the lower oil storage tank 7 into the upper test oil tank 4 through the connecting pipe 6 until the upper test oil tank 4 is full. This completes the oil filling operation of the upper test oil tank 4.

[0040] Before the test begins, vegetable oil is first injected into the lower section oil tank 7 and allowed to stand. The electrode device 8 is then installed with bolts. Nitrogen gas is injected into the lower section oil tank 7 to pressurize it. Vegetable oil is then injected into the upper section test oil tank 4 through the external connecting pipe 6 until it is full. The tank is allowed to stand until the oil sample meets the standards. An oil sample can be taken through valve S0. If the oil sample indicators (see Table 1) meet the standards, the test can be carried out.

[0041] Table 1 Oil Sample Indicators

[0042] Serial Number Indicator Name Indicator value 1 Dielectric loss tgδ(90℃)% ＜3 2 Breakdown voltage (kV) ≥50 3 Moisture content (ppm) ＜50 4 Acid value (mgKOH / g) ≤0.03

[0043] Step 3: By adjusting the distance between the elongated elliptical rings of electrode 12, the electrode gap (oil gap) is simulated to change; by changing the thickness of the insulating paper of electrode 12, the turn insulation specification is simulated to change. The electrical environment under different oil gaps and different turn insulation conditions is simulated respectively, thus achieving experimental research under different environments. The specific experimental steps are as follows:

[0044] S3.1. Sample pretreatment.

[0045] To avoid moisture and other influencing factors in the insulating vegetable oil, the vegetable oil paper insulation samples were pretreated before the experiment. First, impurities and particles in the vegetable oil samples were filtered out using a filtration device, according to the oil sample indicators in Table 1, until the standards were met. The windowed insulating paperboard 10 used in the experiment was cut and polished to the required dimensions. Electrodes 12 were then fabricated and bound to the windowed insulating paperboard 10. The windowed insulating paperboard 10 test sample with electrodes 12 was placed in a vacuum drying oven at 50 Pa / 90℃ for 48 hours, and then cooled to room temperature under vacuum conditions. Figure 4 The diagram shown is a schematic of the pretreatment process of the test method according to an embodiment of the present invention. After pretreatment, the oil-paper insulation meets the standard requirements for conducting the test. The pretreated test samples are sealed and stored under vacuum conditions.

[0046] S3.2. Pressure application method.

[0047] Currently, the main testing methods for lightning impulse breakdown field strength of liquid insulating dielectrics include the step-up method, the step-down method, and the multi-stage method. For lightning impulse discharge tests on vegetable oil paper insulation, it is necessary to conduct comparative experiments to determine whether different step-up methods significantly affect the breakdown voltage of vegetable oil paper insulation, and how to select the appropriate test voltage method for different types of oil paper insulation tests.

[0048] S3.3. Formal lightning impulse breakdown test.

[0049] The lightning impulse breakdown test of plant-based insulating oil can be measured and analyzed from multiple perspectives, including different gap lengths, different electrode insulation thicknesses, different polarities, and different temperatures. The specific test steps are as follows:

[0050] S3.3.1 Record the moisture content and dielectric constant in the oil, the moisture content in the insulating paper, the average degree of polymerization of the oil-impregnated insulating paper, and the tensile strength and other relevant parameters before and after pretreatment to ensure that the relevant test requirements are met before the formal test.

[0051] S3.3.2 Install the electrode 12 and the windowed insulating paperboard 10, adjust the insulation gap, inject the pretreated test oil sample into the test oil tank, and let it stand to eliminate the air bubbles generated during the injection process.

[0052] S3.3.3 Conduct lightning impulse breakdown characteristic tests using appropriate pressure methods and record the data. Perform 10 repeatable tests for each defect.

[0053] S3.3.4, Replace electrode 12, replace insulating oil, adjust oil gap, adjust lightning impulse voltage polarity, and repeat steps 1 to 3 (each adjustment is only for a single variable).

[0054] S3.3.5 After the simulation test, the moisture content in the oil, the moisture content in the paper, the degree of polymerization, the tensile strength, the acid value, and the composition were tested, and the influence of electrical stress on the relevant parameters was analyzed.

[0055] S3.3.6 All test data shall be recorded, organized and stored by the relevant test personnel.

[0056] S3.4. Test data recording table.

[0057] During the experiment, the breakdown voltage of different insulating oils under different insulation defects, different oil gaps, and different polarity lightning impulse voltages needs to be recorded; after the experiment, the relevant physicochemical properties need to be recorded. The experimental record table is shown in Table 2 below.

[0058] Table 2 Test Record Sheet

[0059]

[0060] Step 4: Disconnect the nitrogen device connected to valve S5 of the lower oil storage tank 7, and open valves S5 and S1 to depressurize the upper test oil tank 4 and the lower oil storage tank 7. Open valves S2 and S4, and vegetable oil is injected from the upper test oil tank 4 into the lower oil storage tank 7 through connecting pipe 6 until the electrode device 8 is exposed. This completes the oil draining operation of the upper test oil tank 4.

[0061] After one test is completed, the vegetable oil is transferred from the upper test oil tank 4 back to the lower storage oil tank 7 until the electrode device 8 is exposed. At this point, the sealed cover 3 is opened to replace the electrode device 8. After the electrode device 8 is installed, the above oil filling process is repeated for a new test. Designing the oil tank into two sections (upper and lower) can speed up the test process and reduce the number of times the oil filter is used.

[0062] The connecting pipe 6 in the pipeline system works in conjunction with the valves to inject and discharge oil; the observation window 5 is installed in the middle of the side of the test oil tank 4 in the upper section, and can be used to observe the discharge process during the test.

[0063] The electrode device 8 is installed on the support frame 9 inside the upper oil tank and is immersed in vegetable oil for testing. It is used to test the influence of different electrode turn insulation and electrode gap on the withstand voltage characteristics of the vegetable oil insulation system.

[0064] The key technological innovations of this invention include:

[0065] 1. The apparatus and method of the present invention realize the electrical performance test study of oil-paper composite insulation under different oil gaps and different turns of insulation conditions. It adopts the single variable method and considers the test influencing factors such as air and electrode replacement, strictly controls the test conditions, and simplifies the operation and reduces the influence of influencing factors on the test through the comprehensive consideration of the apparatus.

[0066] 2. The oil tank is divided into an upper oil tank and a lower oil tank. The upper oil tank is used for testing, and the lower oil tank is used for oil storage. The upper and lower oil tanks are connected by valves and pipelines to realize the injection and discharge of insulating oil in different test rooms, which simplifies the replacement and storage of insulating oil, reduces the contact between insulating oil and air, and reduces the influence of impurities and oxidation of insulating oil.

[0067] 3. The wires are connected to the equalizing plate through electrical clamps. The purpose of the electrical clamps is to facilitate electrode replacement, reduce the time the test is exposed to air, and reduce the impact of impurities on the performance test.

[0068] 4. Vegetable oils have poor antioxidant properties compared to mineral oils. Therefore, the experimental apparatus must be well-sealed, and the internal materials of the apparatus must be compatible with vegetable oils. Appropriate materials should be selected.

[0069] Example: Using bare copper conductors of the same specification but with different insulation paper thicknesses, tests were conducted on different oil gap distances (4-10mm) and different turn insulation specifications (9 types).

[0070] In the embodiments of the present invention, all technical features not described in detail are existing technologies or conventional technical means, and will not be repeated here.

[0071] Finally, it should be noted that the above embodiments are merely specific implementations of the present invention, used to illustrate the technical solutions of the present invention, and not to limit them. The scope of protection of the present invention is not limited thereto. Those skilled in the art should understand that any person skilled in the art can modify or easily conceive of changes to the technical solutions described in the foregoing embodiments within the technical scope disclosed in the present invention, or make equivalent substitutions for some of the technical features; and these modifications, changes, 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, and should all be covered within the scope of protection of the present invention.

Claims

1. A plant oil paper composite insulation electrical property test device comprising an upper section test oil tank (4) and a lower section oil storage oil tank (7), characterized by, The side wall of the upper section test oil tank (4) is sequentially fixedly installed with pipe joints and valves S1, S0 and S2 from top to bottom, the upper and lower portions of the side wall of the lower section oil storage tank (7) are fixedly installed with pipe joints and valves S5 and S4, respectively, a through connecting pipe (6) is fixedly installed between the valves S2 and S4, a support frame (9) is fixedly installed inside the upper section test oil tank (4), and an electrode device (8) is fixedly installed on the support frame (9); the electrode device (8) comprises a windowed insulating paperboard (10), two equalizing discs (11) and electrodes (12), the high-voltage and low-voltage ends of the electrodes (12) are respectively in the shape of a hanger with T-shaped copper wires with insulation, each end of the electrode (12) comprises an oblong circle and an extension rod integrally formed and perpendicularly intersecting the middle position of the oblong circle, the two equalizing discs (11) are symmetrically fixedly installed on the two sides of the upper end of the support frame (9), the windowed insulating paperboard (10) is placed between the two equalizing discs (11) on the support frame (9) and is fixedly installed by means of a bakelite screw rod, the two ends of the electrode (12) are reversely and symmetrically placed on the windowed insulating paperboard (10), the oblong circles at the two ends of the electrode (12) are parallel to each other, and the ends of the extension rods at the two ends of the electrode (12) are respectively electrically connected to the equalizing discs (11); The equalizing disc (11) is an elliptical cylinder made of metal material, one side of which is slitted, and an electrical clamp is welded inside the slit, the electrical clamp being made of metal material; A sealing tank cover (3) is fixedly installed at the top position of the upper section test oil tank (4), and an observation window (5) is arranged on the side of the upper section test oil tank (4); A slanting lifting seat (2) is communicated with the side of the upper section test oil tank (4), a sleeve pipe (1) is fixedly installed on the slanting lifting seat (2) by means of a bolt, and a pipe joint and a valve S3 are fixedly installed on the upper portion of the side wall of the slanting lifting seat (2) through a hole.

2. The plant oil paper composite insulation electrical property test device according to claim 1, characterized in that, The electrode (12) is fixedly bound on the windowed insulating paperboard (10) by means of a high-temperature-resistant nylon strap.

3. The plant oil paper composite insulation electrical property test device according to claim 2, characterized in that, The copper wire with insulation is made of a copper bare wire wrapped with insulating paper.

4. The plant oil paper composite insulation electrical property test device according to claim 1, characterized in that, The observation window (5) is a tempered glass window.

5. A method of testing the electrical properties of a vegetable oil paper composite insulation, characterized in that, The plant oil-paper composite insulation electrical performance test device according to claim 1 comprises the following steps: Step 1: the end portion of the extension rod of the electrode (12) is removed of the insulating paper, the end portion of the extension rod at one end of the electrode (12) is named as a high-voltage end wire outlet, the end portion of the extension rod at the other end of the electrode (12) is named as a low-voltage end wire outlet, the high-voltage wire introduced by the sleeve pipe (1) is connected to the left side of the adjacent equalizing disc (11) through a metal bolt, the high-voltage end wire outlet of the adjacent electrode (12) is connected to the right side of the equalizing disc (11) through an electrical clamp, and the low-voltage end wire outlet of the electrode (12) is connected to another equalizing disc (11) and grounded; Step 2, open the valve S1 of the upper test oil tank (4) and the valve S3 of the inclined riser (2), open the valve S2 of the upper test oil tank (4) and the valve S4 of the lower oil storage tank (7), connect the pipeline of the valve S5 of the lower oil storage tank (7) to the nitrogen device, inject nitrogen into the lower oil storage tank (7) by controlling the flow rate of the valve S5 and the nitrogen device, and then press the plant insulation liquid dielectric from the lower oil storage tank (7) into the upper test oil tank (4) through the connecting pipe (6) until the upper test oil tank (4) is filled; Step 3, by adjusting the distance between the long oval circles of the electrode (12), the oil gap between the electrodes is simulated; by changing the thickness of the insulation paper of the electrode (12), the turn insulation specification is simulated, and the electrical environment under different oil gaps and different turn insulation conditions is simulated respectively, so as to realize the test under different environments; Step 4, remove the nitrogen device connected to the valve S5 of the lower oil storage tank (7), open the valve S5 and the valve S1, and make the upper test oil tank (4) and the lower oil storage tank (7) depressurized, open the valve S2 and S4, and then pour the plant oil from the upper test oil tank (4) into the lower oil storage tank (7) through the connecting pipe (6) until the electrode device (8) is exposed.

6. The method of claim 5, wherein the plant oil paper composite insulation is subjected to an electrical property test. Before the test, first pour the plant oil into the lower oil storage tank (7) and stand still, then pour the plant oil into the upper test oil tank (4) through the external connecting pipe (6) until it is filled, stand still until the oil sample meets the standard, and then take the oil sample through the valve S0; after the test is completed, pour the plant oil from the upper test oil tank (4) back into the lower oil storage tank (7) until the electrode device (8) is exposed, and then open the sealed tank cover (3) to replace the electrode device (8).

7. The method of claim 5, wherein the plant oil paper composite insulation is subjected to electrical performance test. Before the test, the plant oil paper insulation sample is pretreated, first, the impurity particles in the plant oil sample are filtered out until the standard is met by using a filtering device, the windowed insulation paper board (10) used for the test is cut and polished according to the required size, the electrode (12) is made and bound on the windowed insulation paper board (10), and then the windowed insulation paper board (10) with the electrode (12) is placed in a vacuum drying box at 50 Pa / 90℃ for 48 hours, and then cooled to room temperature under vacuum condition, and the pretreated test sample is sealed and stored under vacuum condition.

Images