Test medium control device and method for water treeing test

Abstract

This invention discloses a test medium control device and method for water tree resistance testing. The device includes: a water inlet tank containing the test medium; a water replenishment mechanism connected to the water inlet tank and extracting the test medium from the tank; a branch pipe connected to the water replenishment mechanism, with a water replenishment valve on the branch pipe, each valve corresponding to a test conduit; and a temperature control system including an insulation layer and a lifting drive mechanism. The insulation layer is positioned above and below the test conduit, and the lifting mechanism controls the insulation layers above and below the test conduit to simultaneously clamp or loosen, thus providing auxiliary insulation for the test conduit. This invention, based on the water replenishment mechanism extracting the test medium from the water inlet tank, automatically and promptly replenishes the solution in the test conduit when insufficient, avoiding the problem of cables being exposed to air and affecting test results. Simultaneously, based on the temperature control system, it can meet the test temperature requirements during the water tree resistance test.

Description

Technical Field

[0001] This invention belongs to the field of cable testing technology, specifically relating to a test medium control device and method for water tree resistance testing. Background Technology

[0002] The statements herein provide only background information in relation to this invention and do not necessarily constitute prior art.

[0003] During the use of wires and cables, special operating environments require immersion in solutions with specific temperatures, concentrations, pH values, and chemical compositions, such as seawater, which can easily lead to water treeing. The DL / T1070-2007 standard defines water treeing as "microchannels that develop in insulation when moisture, electrical stress, and certain inducing factors such as impurities, protrusions, space charges, or ions are present."

[0004] Regarding the mechanism of water tree formation, the electrostress theory suggests that the internal stress of cables during production and operation is the primary cause of water tree growth. When a cable is subjected to voltage and water, the strain in the cross-linked polyethylene insulation near the conductor increases, and water trees form in areas of high strain (such as impurities and pores). In a high-voltage power frequency electric field, polar water molecules undergo intense migration, converting electric field energy into kinetic and thermal energy. These water molecules, having gained significant energy, move violently within the insulation. When the energy of the water molecules is sufficient to break the cross-linked polyethylene molecular chains in the cable insulation layer, microscopic cracks are generated within the insulation.

[0005] The electrochemical oxidation theory posits that ions present in water promote the oxidation of polymers. This oxidation process breaks down the polymer molecular chains, creating micropores within the polymer. The tannic acid anions produced during oxidation make the micropore walls of the water tree more hydrophilic, allowing permeating ions to dissolve within these hydrophilic pores.

[0006] Another theory suggests that water tree growth and partial discharge are mutually reinforcing factors. Under the high-voltage electric field of partial discharge, water molecules inside the cable insulation gain energy from the electric field, generating a water hammer effect. The impact of these water molecules causes the cross-linked polyethylene polymer chains to break, creating tiny air gaps in the cable insulation layer. These air gaps grow and gradually form water trees.

[0007] The microstructure of a water tree consists of interconnected or unconnected water-filled pores with a diameter of approximately 0.1-1 μm. As the water tree grows, the electric field at its tip becomes increasingly concentrated. This localized high electric field eventually leads to electrical treeing at the tip, causing cable breakdown and damage. At high temperatures, the water tree undergoes significant oxidation, resulting in increased water absorption and conductivity, ultimately leading to thermal breakdown. At low temperatures, the water tree oxidizes over a longer period or transforms into electrical trees, making the damage more severe.

[0008] The inventors discovered the following problems with current tests for water tree resistance in cables:

[0009] (1) Water tree formation takes a long time, and the environment in which the cable is used cannot be changed multiple times in a short period of time. The cable anti-water tree test needs to be carried out for a long time. During the test, due to the different composition of the solution, season, and ambient temperature and humidity, the amount of solution evaporation in the test conduit is not fixed. It is difficult to manually monitor the liquid level in the conduit. Due to the data recording work during the test, it is easy to forget to monitor the liquid level in the conduit, which may cause the test to fail.

[0010] (2) If the solution is not replenished in time, the cable inside the test conduit will be exposed to the air. During the test, the cable inside the test conduit needs to be powered to heat up the solution inside the test conduit. However, since the cable is exposed to the air, the heat from the cable cannot be transferred in time, resulting in the temperature being higher than that in the solution, which will cause uncontrollable factors in the test.

[0011] (3) The DL / T1070-2007 standard requires the water in the test tube to be at a certain temperature during the water tree test. Currently, there is no test device that can maintain the temperature at the same time and reduce energy consumption as much as possible. Summary of the Invention

[0012] The purpose of this invention is to overcome the shortcomings of the prior art and provide a test medium control device and method for water tree resistance testing. Based on the water replenishment mechanism, the test medium is drawn from the water tank and replenished in time as the solution in the test conduit evaporates during the test, avoiding the problem of the cable in the test conduit being exposed to the air and affecting the test results. At the same time, based on the temperature control system, the problem of the test temperature requirements during the water tree resistance test is solved.

[0013] To achieve the above objectives, the present invention is implemented through the following technical solution:

[0014] On one hand, the technical solution of the present invention provides a test medium control device for water tree resistance testing, comprising:

[0015] A water inlet tank containing a test medium;

[0016] A water replenishment mechanism, which is connected to a water inlet tank and extracts the test medium from the water inlet tank;

[0017] The branch pipe is connected to the water supply mechanism, and a water supply valve is provided on the branch pipe. The water supply valve is connected to the test conduit in a one-to-one correspondence.

[0018] A temperature control system, comprising an insulation layer and a lifting drive mechanism; the insulation layer is respectively disposed above and below the test conduit, and the lifting mechanism controls the insulation layer above and below the test conduit to clamp or loosen synchronously to assist in the insulation of the test conduit.

[0019] In at least one embodiment, the water replenishment mechanism includes a water replenishment pump and a water replenishment tank; the water replenishment pump draws the test medium from the inlet tank to the water replenishment tank, and the water replenishment tank is connected to the branch pipe;

[0020] Alternatively, a float valve may be installed in the water supply tank, and the float valve may be electrically connected to the water supply pump.

[0021] In at least one embodiment, it further includes an upper fork pipe and a lower fork pipe; the upper fork pipe is vertically inserted through the test conduit, and the lower fork pipe is vertically inserted through the bottom of the test conduit; the lower fork pipe is correspondingly connected to a water supply valve.

[0022] In at least one embodiment, the physical height of the lowest liquid level in the water replenishment tank is not lower than the physical height of the lowest liquid level in the test conduit required by the test.

[0023] In at least one embodiment, the inlet tank, the replenishment tank, and the branch pipe are all equipped with drain valves;

[0024] Alternatively, the inlet tank and the replenishment tank may also be equipped with level gauges;

[0025] Alternatively, a heating device may be attached to the outside of the water inlet tank.

[0026] Alternatively, heating devices may be attached to the outside of the inlet and outlet water tanks.

[0027] In at least one embodiment, the insulation layer includes a rigid sponge layer, a skeleton, and an inflatable insulation layer; the inflatable insulation layer is disposed on the outside of the rigid sponge layer, and the skeleton passes through the rigid sponge layer and the inflatable insulation layer; the inflatable insulation layer is also connected to an inflation pipe, and the inflation pipe is connected to an electromagnetic on / off valve.

[0028] In at least one embodiment, a compressed air pipe is further provided between the inflatable insulation layer and the rigid sponge layer.

[0029] In at least one embodiment, the test catheter is disposed on a support, and the lifting drive mechanism is disposed on the support and connected to the frame.

[0030] In at least one embodiment, the lifting drive mechanism includes:

[0031] A positioning frame is mounted on the bracket, and a spring return cylinder is mounted on the positioning frame; a positioning element is mounted on the piston rod of the spring return cylinder.

[0032] A sprocket is mounted on the positioning frame, and a chain is connected to the sprocket. The chain is fixedly connected to the positioning element. The two ends of the chain are respectively connected to the insulation layers above and below the test conduit. On the other hand, the technical solution of the present invention also provides a method for controlling the test medium for a water-resistant tree test, comprising:

[0033] (1) Pass the cable to be tested through the test conduit, close the drain valve of the water tank, open the water supply valve connected to the test conduit to connect the water tank with the test conduit, and adjust the valve core angle of the water supply valve so that the flow velocity of each branch in each branch pipe is basically the same.

[0034] (2) Turn on the water supply pump to replenish the water supply tank. The water supply tank is equipped with a float valve. When the water supply tank and the connected test conduit are filled with the test medium, the float valve controls the water supply pump to stop replenishing the water.

[0035] (3) The cable is energized and heated to heat the medium to the specified test temperature;

[0036] (4) During the consumption of the test medium in the test conduit, the water replenishment tank continuously replenishes the test medium in the test conduit through the branch pipe, water replenishment valve and lower branch pipe;

[0037] (5) When the ambient temperature is high and the air flow is poor, the heat dissipation of the test tube is poor, the temperature rises quickly and tends to exceed the specified test temperature range, the lifting drive mechanism controls the opening of the insulation layer and the compressed air pipe starts to promote the air flow around the test tube and remove the heat.

[0038] (6) When the ambient temperature is low and the air flow is high, the test conduit heats up slowly and there is a tendency for the test heating time to exceed the specified heating time. The lifting drive mechanism controls the insulation layer to close, the air filling pipe is started, and a certain amount of gas is filled according to the insulation effect so that the insulation layer expands to a certain extent to provide auxiliary insulation for the test guide rail.

[0039] The beneficial effects of the above-described technical solution of the present invention are as follows:

[0040] This invention provides a test medium control device and method for water tree resistance testing. The device draws test medium from the inlet tank via a water replenishment mechanism and automatically replenishes the solution in the test conduit via a branch pipe when the liquid level is insufficient, thus avoiding test failure due to insufficient test medium level. Simultaneously, insulation layers are installed at both the top and bottom of the test conduit. A lifting mechanism controls the synchronous clamping or loosening of the insulation tank to provide auxiliary insulation for the test conduit, preventing test deviations or even test failures caused by the test medium in the test conduit not meeting the test temperature requirements. Attached Figure Description

[0041] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0042] Figure 1 This is a schematic diagram of a test medium control device for a water-resistant tree test according to the present invention;

[0043] Figure 2 This is another schematic diagram of a test medium control device for a water-resistant tree test according to the present invention;

[0044] Figure 3 This is a schematic diagram showing the connection between the water supply mechanism and the branch pipe of a test medium control device for water-resistant tree testing according to the present invention;

[0045] Figure 4 This is a schematic diagram of the lifting drive mechanism of a test medium control device for water tree resistance testing according to the present invention.

[0046] In the diagram: 1. Water inlet tank; 2. Water replenishment mechanism; 21. Water replenishment pump; 22. Water replenishment tank; 3. Branch pipe; 31. Water replenishment valve; 4. Test conduit; 41. Upper branch pipe; 42. Lower branch pipe; 5. Level gauge; 6. Drain valve; 7. Temperature control system; 71. Insulation layer; 711. Rigid sponge layer; 712. Skeleton; 713. Inflatable insulation layer; 714. Inflatable pipe; 715. Compressed air pipe; 72. Lifting drive mechanism; 721. Positioning frame; 722. Spring return cylinder; 723. Sprocket; 724. Chain; 725. Positioning component; 8. Bracket.

[0047] The distances or dimensions between parts have been exaggerated to show their positions; the diagram is for illustrative purposes only. Detailed Implementation

[0048] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0049] For ease of description, the words "up," "down," "left," and "right" appearing in this invention only indicate that they are consistent with the up, down, left, and right directions of the accompanying drawings themselves, and do not limit the structure. They are merely for the purpose of facilitating the description of this invention and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0050] Terminology Explanation: The terms "installation," "connection," "linking," and "fixing" in this invention should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal connection of two components or the interaction relationship between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0051] As described in the background section, the purpose of this invention is to overcome the shortcomings of the prior art and provide a test medium control device and method for water tree resistance testing. Based on the water replenishment mechanism, the test medium is drawn from the water tank and replenished in time as the solution in the test conduit evaporates during the test, thus avoiding the problem of the cable in the test conduit being exposed to the air and affecting the test results. At the same time, based on the temperature control system, the problem of the test temperature requirements during the water tree resistance test is solved.

[0052] Example 1

[0053] In a typical embodiment of the present invention, such as Figures 1-4 As shown, this embodiment discloses a test medium control device for a water tree resistance test, comprising: a water inlet tank 1 containing the test medium required for the cable water tree resistance test; a water replenishment mechanism 2 connected to the water inlet tank 1 and extracting the test medium from the water inlet tank 1; a branch pipe 3 connected to the water replenishment mechanism 2, and having multiple water replenishment valves 31, each water replenishment valve 31 being connected to a test conduit 4 in a one-to-one correspondence, replenishing the test medium extracted by the water replenishment mechanism 2 into the test conduit 4 through the branch pipe 3; and a temperature control system 7 comprising an insulation layer 71 and a lifting drive mechanism 72, wherein the insulation layer 71 is respectively disposed above and below the test conduit 4, and the lifting mechanism is connected to the insulation layer 71, capable of controlling the insulation layer 71 above and below the test conduit 4 to simultaneously clamp or loosen to assist in the insulation of the test conduit 4.

[0054] In this embodiment, the test medium is drawn from the water tank 1 by the water replenishment mechanism 2, and when the liquid level of the test medium in the test conduit 4 is insufficient, the solution in the test conduit 4 is automatically replenished through the water replenishment mechanism 2 and the branch pipe 3, which can avoid the problem of test failure due to insufficient liquid level of the test medium. At the same time, heat insulation layers 71 are set at both the top and bottom of the test conduit 4, and the heat insulation tank is clamped or released synchronously by the lifting mechanism to provide auxiliary heat insulation for the test conduit 4, which can avoid the problem of test results deviation or even test failure due to the test medium in the test conduit 4 not meeting the test temperature requirements.

[0055] In this embodiment, the water replenishment mechanism 2 includes a water replenishment pump 21 and a water replenishment tank 22. The water replenishment pump 21 draws the test medium from the water inlet tank 1 into the water replenishment tank 22. The water replenishment tank 22 is connected to a branch pipe 3, through which the test medium in the water replenishment tank 22 is replenished into the test conduit 4. As an optional embodiment, when conducting water tree resistance tests through multiple test conduits 4, two water replenishment tanks 22 can be provided, each equipped with a water replenishment pump 21. Each water replenishment tank 22 is connected to different branch pipes 3, enabling multiple tests to be conducted simultaneously and ensuring efficient liquid level replenishment.

[0056] In this embodiment, a float valve is installed in the water replenishment tank 22, and the float valve is electrically connected to the water replenishment pump 21. The float valve detects the liquid level of the test medium in the water replenishment tank 22. When the liquid level in the water replenishment tank 22 is insufficient, the water replenishment pump 21 is started to draw the test medium from the water inlet tank 1 into the water replenishment tank 22 to ensure the liquid level in the water replenishment tank 22, thereby ensuring the liquid replenishment needs in the test conduit 4.

[0057] In this embodiment, the device further includes multiple upper fork pipes 41 and lower fork pipes 42. The upper fork pipes 41 are vertically inserted into the test conduit 4 and extend upwards to the test conduit 4 to display the liquid level in the test conduit 4. The lower fork pipes 42 are vertically inserted into the test conduit 4 and extend downwards to the test conduit 4, and are connected to the water supply valves 31 one by one to replenish the test medium in the test conduit 4.

[0058] As an optional embodiment, the water replenishment tank 22 replenishes the test medium to the test conduit 4 sequentially through the branch pipe 3, the water replenishment valve 31, and the lower branch pipe 42. This is based on the principle of communicating vessels, where the water replenishment tank 22 is considered one side of the communicating vessel, and the test conduit 4 and the upper branch pipe 41 are considered the other side. The two sides are connected by the branch pipe 3, the water replenishment valve 31, and the lower branch pipe 42. During the consumption of the test medium in the test conduit 4, the water replenishment tank 22 continuously replenishes the test medium to the test conduit 4 based on the principle of communicating vessels. Therefore, in this embodiment, when designing the position of the water replenishment tank 22, it is necessary to ensure that the physical height of the lowest liquid level in the water replenishment tank 22 is not lower than the physical height of the lowest liquid level in the test conduit 4 as required by the test. This ensures that the water replenishment tank 22 replenishes the solution to the test conduit 4 in a timely manner, guaranteeing that the test medium in the test conduit 4 is sufficient.

[0059] In this embodiment, the inlet tank 1, the replenishment tank 22, and the branch pipe 3 are all equipped with drain valves 6. The drain valves 6 can be used to drain the liquid in the inlet tank 1, the replenishment tank 22, and the branch pipe 3. At the same time, the liquid in the test conduit 4 can also be drained through the drain valves 6 of the branch pipe 3.

[0060] In this embodiment, level gauges 5 are installed in the inlet tank 1 and the replenishment tank 22. The level gauge 5 in the inlet tank 1 clearly indicates the level of the test medium, reminding the test personnel to replenish the test medium in advance and ensuring sufficient supply throughout the test. Similarly, the level gauge 5 in the replenishment tank 22 clearly indicates the amount of test medium in the replenishment tank 22, allowing the test personnel to replenish the test medium according to the information provided. Furthermore, the information from the level gauges 5 also enables the test personnel to monitor the rate and pattern of test medium consumption during the test, providing reliable test data for the experimental process.

[0061] As an optional embodiment, a heating device is installed on the outside of the water inlet tank 1, which can preheat the test medium in case it freezes in extreme weather, ensuring that the test medium is maintained at a certain temperature before the test. Alternatively, heating devices are installed on the outside of both the water inlet tank 1 and the water replenishment tank 22, which can heat the test medium in both tanks, ensuring that the test medium in both tanks is maintained at a certain temperature before the test. Optionally, the heating devices are evenly distributed around the perimeter of the water inlet tank 1 and the water replenishment tank 22, enabling uniform heating of the test medium from outside the tank.

[0062] In this embodiment, the insulation layers 71 above and below the test conduit 4 include a rigid sponge layer 711, a skeleton 712, and an inflatable insulation layer 713. The inflatable insulation layer 713 is disposed on the outside of the rigid sponge layer 711, while the skeleton 712 passes through the rigid sponge layer 711 and the inflatable insulation layer 713. The inner side of the rigid sponge layer 711 may have a groove that matches the shape of the test conduit 4, allowing for a better fit and further ensuring the insulation effect. The inflatable insulation layer 713, disposed on the outside of the rigid sponge layer 711, is equivalent to adding an additional insulation layer 71 with better insulation performance on top of the first insulation layer 71, ensuring auxiliary insulation of the test conduit 4 during the test. In this embodiment, the inflatable insulation layer 713 is connected to an inflation pipe 714, which is connected to an electromagnetic on / off valve. When the ambient temperature is low and the air flow is high, the test conduit 4 heats up slowly and tends to exceed the specified heating time. In this case, the insulation layer 71 needs to be closed for insulation. At this time, the lifting drive mechanism 72 controls the insulation layers 71 above and below the test conduit 4 to clamp the test conduit 4 simultaneously. The inflation tube 714 is activated, and a certain amount of gas is injected according to the insulation effect, so that the inflation insulation layer 713 expands to a certain extent. The degree of expansion depends on the heating effect. For example, if the heating is slow, the expansion degree of the inflation insulation layer 713 is increased; if the heating is fast, the expansion degree of the inflation insulation layer 713 is decreased.

[0063] In this embodiment, a compressed air pipe 715 is provided between the inflatable insulation layer 713 and the rigid sponge layer 711. Compressed air is blown between the inflatable insulation layer 713 and the rigid sponge layer 711 through the compressed air pipe 715. If the temperature between the rigid sponge layer 711 and the inflatable insulation layer 713 is too high, the temperature can be effectively reduced by the circulation of compressed air, thereby ensuring the stability and controllability of the temperature in the test conduit 4 during the test. When the ambient temperature is high and the air flow is poor, the heat dissipation of the test conduit 4 is poor, the temperature rises rapidly, and there is a tendency to exceed the specified test temperature range. The test conduit 4 does not need the insulation layer 71 for auxiliary insulation. At this time, the lifting drive mechanism 72 controls the insulation layers 71 above and below the test conduit 4 to be released simultaneously and moved away from the test conduit 4. The compressed air pipe 715 is activated to promote the air flow around the test conduit 4 and remove heat.

[0064] In this embodiment, all test conduits 4 are mounted on a support 8, which can be configured as a multi-layer structure to accommodate multiple test conduits 4 for testing. A lifting drive mechanism 72 is also provided on the support 8, which is located on the outside of the support 8 and connected to the frame 712 of the insulation layer 71. The lifting drive mechanism 72 drives the frame 712, thereby causing the insulation layer 71 above and below the test conduits 4 to clamp or loosen synchronously.

[0065] In this embodiment, the lifting drive mechanism 72 includes a positioning frame 721 and a sprocket 723. The positioning frame 721 is located outside the support 8, and a spring return cylinder 722 is mounted on it. A positioning element 725 is mounted on the piston rod of the spring return cylinder 722. The sprocket 723 is mounted on the positioning frame 721 and connected to a chain 724. The chain 724 is fixedly connected to the positioning element 725 on the spring return cylinder 722. Both ends of the chain 724 are connected to the insulation layers 71 above and below the test conduit 4, respectively, enabling synchronous driving of the insulation layers 71 above and below the test conduit 4. By having the spring return cylinder 722 pull the chain 724, the insulation layers 71 above and below the test conduit 4 are driven to clamp or loosen synchronously, thereby achieving auxiliary insulation of the test conduit 4.

[0066] Example 2

[0067] In a typical embodiment of the present invention, a method for controlling the test medium for a water-resistant tree test is disclosed, comprising:

[0068] (1) Pass the cables to be tested through the test conduit 4 in an S-shape, close the drain valve 6 of the water supply tank 22, open the water supply valve 31 connected to the test conduit 4, so that the water supply tank 22 on the same floor is connected to the test conduit 4 on the same floor, and adjust the valve core angle of the water supply valve 31 so that the flow rate of each branch of the branch pipe 42 in each branch pipe 3 is basically the same.

[0069] (2) Turn on the two water pumps 21 to replenish water to the upper and lower water tanks 22 respectively. The water tank 22 is equipped with a float valve. When the water tank 22 and the connected test conduit 4 are filled with test medium, the float valve controls the water pump 21 to stop replenishing water.

[0070] (3) The cable is energized and heated to heat the medium to the specified test temperature;

[0071] (4) During the consumption of the test medium in the test conduit 4, based on the principle of communicating vessels, the water replenishment tank 22 continuously replenishes the test medium in the test conduit 4 through the branch pipe 3, the water replenishment valve 31 and the lower branch pipe 42.

[0072] (5) When the ambient temperature is high and the air flow is poor, the heat dissipation of the test conduit 4 is poor, the temperature rises quickly and tends to exceed the specified test temperature range, the elastic reset cylinder of the lifting drive mechanism 72 contracts, the insulation layer 71 opens, the compressed air pipe 715 starts, promotes the air flow around the test conduit 4, and takes away the heat.

[0073] (6) When the ambient temperature is low and the air flow is high, the test conduit 4 heats up slowly and tends to exceed the test heating time. The elastic reset cylinder of the lifting drive mechanism 72 extends, the insulation layer 71 closes, the inflation pipe 714 starts, and a certain amount of gas is injected according to the insulation effect to make the insulation layer 71 expand to a certain extent. The degree of expansion depends on the heating effect. If the heating is slow, the degree of expansion of the insulation layer 71 will increase. If the heating is fast, the degree of expansion of the insulation layer 71 will decrease.

[0074] (7) In extreme weather conditions, the test medium may freeze. Therefore, a heating device should be installed on the outside of the water inlet tank 1 and / or the water replenishment tank 22 to heat the test medium in the water inlet tank 1 and the water replenishment tank 22 evenly around the tank so that the test medium is kept at a certain temperature before the test.

[0075] This invention discloses a test medium control device and method for a water tree resistance test. The device draws the test medium from the water tank 1 through the water replenishment mechanism 2. When the liquid level of the test medium in the test conduit 4 is insufficient, it is replenished by the water replenishment mechanism 2, avoiding the problem of test result deviation or even test failure caused by the cable in the test conduit 4 being exposed to the air. At the same time, based on the temperature control system 7, the insulation layer 71 can be clamped or loosened synchronously on the test conduit 4, which can achieve auxiliary insulation of the test conduit 4 and meet the test temperature requirements during the water tree resistance test.

[0076] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A test medium control device for water-resistant tree tests, characterized in that, include: A water inlet tank containing a test medium; A water replenishment mechanism, which is connected to a water inlet tank and extracts the test medium from the water inlet tank; The branch pipe is connected to the water supply mechanism, and a water supply valve is provided on the branch pipe. The water supply valve is connected to the test conduit in a one-to-one correspondence. A temperature control system, comprising an insulation layer and a lifting drive mechanism; the insulation layer is respectively disposed above and below the test conduit, and the lifting mechanism controls the insulation layer above and below the test conduit to clamp or loosen synchronously to assist in the insulation of the test conduit.

2. The test medium control device for water tree resistance testing as described in claim 1, characterized in that, The water replenishment mechanism includes a water replenishment pump and a water replenishment tank; the water replenishment pump draws the test medium from the inlet water tank to the water replenishment tank, and the water replenishment tank is connected to the branch pipe; Alternatively, a float valve may be installed in the water supply tank, and the float valve may be electrically connected to the water supply pump.

3. The test medium control device for water-resistant tree testing as described in claim 1, characterized in that, It also includes an upper branch pipe and a lower branch pipe; the upper branch pipe is vertically inserted through the test guide pipe, and the lower branch pipe is vertically inserted through the bottom of the test guide pipe; the lower branch pipe is connected to the water supply valve.

4. The test medium control device for water tree resistance testing as described in claim 2, characterized in that, The physical height of the lowest liquid level in the water replenishment tank shall not be lower than the physical height of the lowest liquid level in the test conduit as required by the test.

5. The test medium control device for water tree resistance testing as described in claim 2, characterized in that, The inlet tank, the replenishment tank, and the branch pipe are all equipped with drain valves; Alternatively, the inlet tank and the replenishment tank may also be equipped with level gauges; Alternatively, a heating device may be attached to the outside of the water inlet tank. Alternatively, heating devices may be attached to the outside of the inlet and outlet water tanks.

6. The test medium control device for water-resistant tree testing as described in claim 1, characterized in that, The insulation layer includes a rigid sponge layer, a skeleton, and an inflatable insulation layer; the inflatable insulation layer is disposed on the outside of the rigid sponge layer, and the skeleton is inserted between the rigid sponge layer and the inflatable insulation layer; the inflatable insulation layer is also connected to an inflation pipe, and the inflation pipe is connected to an electromagnetic on / off valve.

7. The test medium control device for water-resistant tree testing as described in claim 6, characterized in that, A compressed air pipe is also provided between the inflatable insulation layer and the rigid sponge layer.

8. The test medium control device for water-resistant tree testing as described in claim 6, characterized in that, The test conduit is mounted on the support, and the lifting drive mechanism is mounted on the support and connected to the frame.

9. The test medium control device for water tree resistance testing as described in claim 8, characterized in that, The lifting drive mechanism includes: A positioning frame is mounted on the bracket, and a spring return cylinder is mounted on the positioning frame; a positioning element is mounted on the piston rod of the spring return cylinder. A sprocket is mounted on the positioning frame and connected to a chain. The chain is fixedly connected to the positioning component. The two ends of the chain are respectively connected to the insulation layers above and below the test guide tube.

10. A method for controlling the test medium in a water-resistant tree test, characterized in that, include: (1) Pass the cable to be tested through the test conduit, close the drain valve of the water tank, open the water supply valve connected to the test conduit to connect the water supply tank with the test conduit, and adjust the valve core angle of the water supply valve so that the flow velocity of each branch in each branch pipe 3 is basically the same. (2) Turn on the water supply pump to replenish the water supply tank. The water supply tank is equipped with a float valve. When the water supply tank and the connected test conduit are filled with the test medium, the float valve controls the water supply pump to stop replenishing the water. (3) The cable is energized and heated to the specified test temperature; (4) During the consumption of the test medium in the test conduit, the water replenishment tank continuously replenishes the test medium in the test conduit through the branch pipe, water replenishment valve and lower branch pipe; (5) When the ambient temperature is high and the air flow is poor, the heat dissipation of the test tube is poor, the temperature rises quickly and tends to exceed the specified test temperature range, the lifting drive mechanism controls the opening of the insulation layer and the compressed air pipe starts to promote the air flow around the test tube and remove the heat. (6) When the ambient temperature is low and the air flow is high, the test conduit heats up slowly and there is a tendency for the test heating time to exceed the specified heating time. The lifting drive mechanism controls the insulation layer to close, the air filling pipe is started, and a certain amount of gas is filled according to the insulation effect so that the insulation layer expands to a certain extent to provide auxiliary insulation for the test guide rail.

Images