Auxiliary temperature control device and method for water-resistant tree test

Abstract

The invention provides an auxiliary temperature control device and method for a water-resistant tree test, and belongs to the technical field of water-resistant tree tests. The auxiliary temperature control device comprises a water adding tank, a water inlet mechanism, a mold temperature controller, a water inlet fork pipe, a water return mechanism, a temperature control system and a test guide pipe; the temperature control system comprises heat preservation layers and a lifting driving mechanism, the heat preservation layers are arranged on the upper side and the lower side of the test conduit respectively, and the lifting driving mechanism is used for controlling the heat preservation layers on the upper side and the lower side of the test conduit to be synchronously tightened or loosened so as to conduct auxiliary heat preservation on the test conduit. Circulation of a test medium in the test conduit is realized based on the water inlet mechanism and the water return mechanism, and the test medium in the test conduit reaches a specified temperature through heating of the mold temperature controller; the temperature control system assists in heat preservation of the test conduit to ensure that the medium temperature in the test conduit meets the test requirement.

Description

Technical Field

[0001] The invention belongs to the technical field of water tree resistance test, and in particular relates to an auxiliary temperature control device and method for water tree resistance test. Background Art

[0002] The statements in this section merely provide background information related to the present invention and do not necessarily constitute prior art.

[0003] During the use of wires and cables, special use environments require that the cables be immersed in solutions of specific temperature, concentration, pH value, chemical composition, etc., such as seawater, which is prone to produce water trees. The DL / T1070-2007 standard defines water trees as microchannels that develop when there is water electrical stress and certain inducing factors such as impurities, protrusions, space charges or ions in the insulation.

[0004] There is no unified conclusion on the mechanism of water tree formation. In comparison, there are two mainstream theories that are widely recognized, one is the electrical stress theory, and the other is the electrochemical oxidation theory.

[0005] The electric stress theory believes that the internal stress of the cable during production and operation is the main reason for the growth of water trees. When the cable is subjected to voltage and water, the strain of the cross-linked polyethylene insulation near the conductor will increase, and water trees will be generated in areas with greater strain (such as impurities and pores). In a high-voltage power frequency electric field, polar water molecules migrate strongly and convert the electric field energy into kinetic energy and thermal energy. The water molecules that have obtained huge energy move violently inside the insulation. When the energy of the water molecules is enough to break the cross-linked polyethylene molecular chain of the cable insulation layer, fine cracks will be generated inside the insulation.

[0006] Electrochemical oxidation theory holds that the ions in water promote the oxidation of polymers, which destroys the polymer molecular chains and forms small holes inside the polymers. The anions produced by oxidation make the pore walls of the water tree more hydrophilic, so the penetrating ions dissolve in the hydrophilic pores.

[0007] In addition, there is a theory that water tree growth and partial discharge are mutually induced. Under the high-voltage electric field of partial discharge, the water molecules inside the cable insulation obtain energy from the electric field, producing a water hammer effect. Under the impact of water molecules, the cross-linked polyethylene polymer chain breaks, and tiny air gaps appear in the cable insulation layer. The air gaps continue to grow and gradually form water trees.

[0008] The microstructure of water trees is a connected or unconnected water-filled hole with a diameter of about 0.1-1m. As the water tree grows, the electric field at the tip of the water tree becomes more concentrated. The local high electric field will eventually cause the tip of the water tree to induce electrical branches, resulting in cable breakdown and damage. At high temperatures, water trees will undergo significant oxidation, resulting in increased water absorption and conductivity, and eventually thermal breakdown. At low temperatures, water trees will oxidize or transform into electrical branches after a long time, and the destructiveness will become more serious.

[0009] Water trees take a long time to form, and the environment in which the cables are used cannot be changed multiple times in a short period of time. The cable water tree resistance test needs to be carried out for a long time. During the experiment, due to different solution compositions, seasons, and environmental temperature and humidity, the evaporation amount of the solution in the test conduit is not fixed, and it is difficult to manually monitor the liquid level in the conduit. Due to data recording during the experiment, it is easy to forget to monitor the liquid level in the conduit, which may cause the experiment to fail.

[0010] The existing water tree resistance test device ignores the influence of the medium temperature factor in the test conduit on the water tree resistance performance during the water tree resistance test. Summary of the invention

[0011] In order to overcome the above-mentioned deficiencies of the prior art, the present invention proposes an auxiliary temperature control device and method for a water tree resistance test, so as to solve the problem that the temperature of the medium in the test conduit cannot be controlled in the water tree resistance test.

[0012] To achieve the above objectives, one or more embodiments of the present invention provide the following technical solutions: In a first aspect, an auxiliary temperature control device for a water tree resistance test is disclosed, comprising: a water tank, a water inlet mechanism, a mold temperature controller, a water inlet fork pipe, a water return mechanism, a temperature control system and a test conduit; The water adding tank contains the experimental medium solution, and the water adding tank is connected to a water supply pump; The water inlet mechanism is connected to the water replenishment pump, and the water inlet mechanism is also connected to a water outlet solenoid valve; The mold temperature controller is connected to the water outlet solenoid valve; The water inlet fork pipe is connected to the mold temperature controller through a water inlet manual valve, and a water inlet solenoid valve is provided on the water inlet fork pipe, and the water inlet solenoid valve is connected to the test conduit; The water return mechanism is connected to the test conduit and is used to guide the water into the water inlet mechanism after the test conduit overflows; The temperature control system includes an insulation layer and a lifting drive mechanism. The insulation layer is respectively arranged on the upper and lower sides of the test catheter. The lifting drive mechanism is used to control the upper and lower insulation layers of the test catheter to be tightened or relaxed synchronously to assist in the insulation of the test catheter.

[0013] Furthermore, a water outlet manual valve is connected between the water filling tank and the water replenishment pump; The water tank is provided with a manual drainage valve; A manual drain valve is provided between the mold temperature controller and the manual water inlet valve.

[0014] Furthermore, the water inlet mechanism includes a first water inlet tank and a second water inlet tank, the first water inlet tank and the second water inlet tank are connected via a connecting solenoid valve, an upper float valve and a lower float valve are provided in the first water inlet tank and the second water inlet tank, and the first water inlet tank is connected to the water replenishment pump.

[0015] Furthermore, the first water inlet tank and the second water inlet tank are respectively connected to the water supply tank through overflow pipes; The first water inlet tank and the second water inlet tank are provided with manual drainage valves.

[0016] Furthermore, the water return mechanism includes a water return fork pipe, a water return pipe, a water return manual valve and a water return solenoid valve; Among them, the return water fork pipe is connected to the test conduit; one end of the return water pipe is connected to the return water fork pipe through a return water manual valve, and the other end is connected to the first water inlet tank and the second water inlet tank through a return water solenoid valve.

[0017] Furthermore, a temperature sensor is provided at the connection between the return water fork pipe and the return water pipe.

[0018] Furthermore, the insulation layer includes a hard sponge layer, a frame and an inflatable insulation layer, the inflatable insulation layer is arranged on the outside of the hard sponge layer, the hard frame is connected to the lifting drive mechanism, the inflatable insulation layer is connected to the inflation pipe, and the inflation pipe is connected to the electromagnetic on-off valve.

[0019] Furthermore, a compressed air pipe is connected between the hard sponge layer and the inflatable thermal insulation layer.

[0020] Furthermore, the test catheter is arranged on a bracket, a lifting drive mechanism is arranged on the bracket and connected to the frame, and the lifting drive mechanism includes a positioning frame, a spring return cylinder, a sprocket, a chain and a positioning member; Wherein, the positioning frame is arranged on the bracket; The spring return cylinder is arranged on the positioning frame, and a positioning piece is arranged on the piston rod of the spring return cylinder; The sprocket is arranged on the positioning frame; The chain is connected to the sprocket, the positioning piece is fixedly connected to the chain, and two ends of the chain are respectively connected to the upper and lower insulation layers of the test conduit.

[0021] In a second aspect, a temperature control method of an auxiliary temperature control device for a water tree resistance test is disclosed, comprising: The experimental solution enters the mold temperature controller from the first water inlet tank through the first water outlet solenoid valve. The mold temperature controller heats the experimental solution and presses the experimental solution into the water inlet manual valve and flows into the water inlet fork pipe and into the designated test conduit. After the test conduit is full, it flows into the return pipe through the return fork pipe and then flows back to the first water inlet tank through the first return solenoid valve to form a cycle. During the cycle, the mold temperature controller continuously heats the flowing experimental solution to the designated temperature, thereby realizing temperature rise control. The cable to be tested is powered on and heated to the set cable temperature. The temperature of the test solution in the test conduit rises, the first return water solenoid valve and the first outlet water solenoid valve are closed, and the second return water solenoid valve and the second outlet water solenoid valve are opened at the same time. The test solution in the second water inlet tank participates in the circulation to reduce the temperature of the entire system, thereby achieving temperature reduction control.

[0022] Compared with the prior art, the present invention has the following beneficial effects: The present invention realizes the circulation of the test medium in the test conduit based on the water inlet mechanism and the water return mechanism, and heats the test medium in the test conduit to a specified temperature through the mold temperature controller; The present invention is based on a temperature control system for assisting the thermal insulation test conduit, ensuring that the temperature of the medium in the test conduit meets the test requirements.

[0023] Advantages of additional aspects of the present invention will be given in part in the following description, and in part will become obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0025] Figure 1 This is a schematic diagram of an auxiliary temperature control device for water tree resistance test provided in Example 1 of the present invention.

[0026] Figure 2 This is a schematic diagram of a temperature control system provided in Embodiment 1 of the present invention.

[0027] Figure 3 This is a schematic diagram of the lifting drive mechanism provided in the first embodiment of the present invention.

[0028] Among them, 1. water tank; 11. water supply pump; 12. water outlet manual valve; 13. overflow pipe; 2. water inlet mechanism; 21. first water inlet tank; 22. second water inlet tank; 23. communication solenoid valve; 24. water outlet solenoid valve; 3. mold temperature controller; 31. water inlet manual valve; 4. water inlet fork pipe; 41. water inlet solenoid valve; 5. water return mechanism; 51. water return fork pipe; 52. water return pipe; 53. water return manual valve; 5 4. Return solenoid valve; 6. Drain manual valve; 7. Bracket; 8. Temperature control system; 81. Insulation layer; 811. Hard sponge layer; 812. Frame; 813. Inflatable insulation layer; 814. Inflatable pipe; 815. Compressed air pipe; 82. Lifting drive mechanism; 821. Positioning frame; 822. Spring return cylinder; 823. Sprocket; 824. Chain; 825. Positioning piece; 9. Test catheter. DETAILED DESCRIPTION

[0029] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0030] It should be noted that the terms used herein are for describing specific embodiments only and are not intended to be limiting of exemplary embodiments according to the present invention.

[0031] In the absence of conflict, the embodiments of the present invention and the features of the embodiments may be combined with each other.

[0032] Embodiment 1 In one or more embodiments, an auxiliary temperature control device for water tree resistance test is disclosed, such as Figure 1 As shown, including: Water tank 1, water inlet mechanism 2, mold temperature controller 3, water inlet fork pipe 4, water return mechanism 5, drainage manual valve 6, bracket 7, temperature control system 8, test catheter 9; The water tank 1 contains the experimental medium solution, and the water tank 1 is connected to a water supply pump 11; The water inlet mechanism 2 is connected to the water supply pump 11, and the water inlet mechanism 2 is also connected to a water outlet solenoid valve 24; The mold temperature controller 3 is connected to the water outlet solenoid valve 24; The water inlet fork pipe 4 is connected to the mold temperature controller 3 through the water inlet manual valve 31. The water inlet fork pipe 4 is provided with a water inlet solenoid valve 41, which is connected to the test conduit 9 and is arranged one-to-one; The water return mechanism 5 is connected to the test conduit 9 and is used to guide the water inlet mechanism 2 after the test conduit 9 overflows; like Figure 2As shown, the temperature control system 8 includes an insulation layer 81 and a lifting drive mechanism 82. The insulation layer 81 is respectively arranged above and below the test catheter. The lifting drive mechanism 82 is used to control the insulation layers 81 above and below the test catheter to be tightened or relaxed synchronously to assist in the insulation of the test catheter.

[0033] In this embodiment, the water inlet mechanism 2 and the water return mechanism 5 circulate the experimental solution and heat it through the mold temperature controller 3, so that the test medium in the test conduit 9 can reach the specified temperature; the temperature control system 8 plays an auxiliary insulation role for the medium temperature in the test conduit 9. When the medium temperature in the test conduit does not meet the test requirements, the test conduit is insulated.

[0034] Optionally, a water outlet manual valve 12 is further connected between the water filling tank 1 and the water replenishment pump 11 .

[0035] Optionally, the water inlet mechanism 2 includes a first water inlet tank 21 and a second water inlet tank 22. The first water inlet tank 21 and the second water inlet tank 22 are connected via a connecting solenoid valve 23. An upper float valve and a lower float valve are provided in the first water inlet tank 21 and the second water inlet tank 22. The first water inlet tank 21 is connected to the water replenishment pump 11.

[0036] In this embodiment, two water inlet tanks are provided and used separately. When one of the water inlet tanks participates in the circulation, the water temperature continues to rise. Thereafter, the other water inlet tank can be switched to participate in the water circulation to reduce the system temperature.

[0037] Optionally, the first water inlet tank 21 and the second water inlet tank 22 are connected to the water filling tank 1 through overflow pipes 13 respectively.

[0038] Optionally, the water return mechanism 5 includes: a water return fork pipe 51, a water return pipe 52, a water return manual valve 53 and a water return solenoid valve 54; The water return fork pipe 51 is connected to the test conduit 9; One end of the water return pipe 52 is connected to the water return fork pipe 51 through a water return manual valve 53 , and the other end is connected to the first water inlet tank 21 and the second water inlet tank 22 through a water return solenoid valve 54 .

[0039] Optionally, a temperature sensor is provided at the connection between the return water fork pipe 51 and the return water pipe 52 .

[0040] In this embodiment, the mold temperature controller continuously heats the test medium to a specified temperature, and the temperature reference point is set at the connection between the return pipe and the return fork pipe. After the water temperature continues to rise, the water inlet tank is switched to lower the test temperature.

[0041] Optionally, the water adding tank 1 , the first water inlet tank 21 , and the second water inlet tank 22 are provided with a manual drain valve 6 , and a manual drain valve 6 is provided between the mold temperature controller 3 and the water inlet manual valve 31 .

[0042] Optionally, the insulation layer 81 includes a hard sponge layer 811, a skeleton 812 and an inflatable insulation layer 813, the inflatable insulation layer 813 is arranged on the outside of the hard sponge layer 811, the skeleton 812 is penetrated through the hard sponge layer 811 and the inflatable insulation layer 813, the inflatable insulation layer 813 is also connected to an inflation tube 814, and the inflation tube 814 is connected to an electromagnetic on-off valve.

[0043] Optionally, a compressed air pipe 815 is further provided between the inflatable thermal insulation layer 813 and the hard sponge layer 811 .

[0044] Optionally, the test catheter 9 is disposed on the bracket 7, and the lifting drive mechanism 82 is disposed on the bracket 7 and connected to the frame 812; Figure 3 As shown, the lifting drive mechanism 82 includes: a positioning frame 821, a spring return cylinder 822, a sprocket 823, a chain 824 and a positioning member 825; Wherein, the positioning frame 821 is arranged on the bracket 7; The spring return cylinder 822 is arranged on the positioning frame 821, and a positioning member 825 is arranged on the piston rod of the spring return cylinder 822; The sprocket 823 is disposed on the positioning frame 821; The chain 824 is connected to the sprocket 823 , the positioning member 825 is fixedly connected to the chain 824 , and both ends of the chain 824 are respectively connected to the upper and lower insulation layers 81 of the test conduit 9 .

[0045] Embodiment 2 In one or more embodiments, a temperature control method of an auxiliary temperature control device for a water tree resistance test is disclosed, comprising: (1) Add the water tree resistance test solution into the water tank until the required liquid level is reached, and the liquid level is determined by a liquid level meter; wherein the test solution may be water; (2) Pass the cables to be tested through the test conduits in an S shape. Open the water inlet solenoid valve of the water inlet fork pipe at the lower end of the test conduit passing through the cable, and close the water inlet solenoid valves of the other water inlet fork pipes. Open the water inlet manual valves of the upper and lower test conduits, and adjust the valve core angle so that the flow rate of each branch fork pipe in the upper and lower water inlet fork pipes is basically the same. (3) Close the return solenoid valve and the outlet solenoid valve, open the connecting solenoid valve, start the water supply pump, draw the test medium from the water supply tank to the first water inlet tank, and the test medium flows from the first water inlet tank to the second water inlet tank through the connecting solenoid valve; (4) When the water in the first water inlet tank and the second water inlet tank is added to a certain height, the two upper float valves are activated, the connecting solenoid valve is closed, and the first water outlet solenoid valve and the first water return solenoid valve are opened at the same time. The upper float valve and the lower float valve adjust the water level in the first water inlet tank by controlling the power of the water supply pump; (5) When the test tube is filled with water, the first water inlet tank is gradually filled, the first floating ball valve is also started, and the water supply pump is closed; (6) Water enters the mold temperature controller from the first water inlet tank through the first water outlet solenoid valve. The mold temperature controller heats the water and presses the water into the water inlet manual valve, flows into the water inlet fork pipe, and enters the designated test conduit. After the test conduit is full, it flows into the return pipe through the return fork pipe, and then flows back to the first water inlet tank through the first return solenoid valve, forming a cycle. During the circulation process, the mold temperature controller continuously heats the water flowing through it to the designated temperature. The temperature reference point is set at the junction of the return pipe and the return fork pipe, where a temperature sensor is installed; (7) Connect both ends of the cable to be tested to the system for power heating. The cable is heated to the set temperature of the cable. During this process, the heat emitted by the cable reaches the test medium in the test conduit, and the water temperature in the test conduit rises, causing the water temperature to continue to rise during the circulation process. Close the first return water solenoid valve and the first outlet water solenoid valve, and open the second return water solenoid valve and the second outlet water solenoid valve at the same time, so that the water in the second water inlet tank participates in the circulation and reduces the temperature of the entire system. (8) Turn on the water replenishment pump for a while, add the water in the water replenishment tank to the first water inlet tank, let the water overflow back to the water replenishment tank, and perform the water replacement operation. During the water replacement process, the signal control of the first floating ball valve is not accepted; the temperature after the water replacement can be measured with a thermometer; (9) The first water inlet tank is cooled to the specified temperature, and the water is switched back to the first water inlet tank for circulation, and the second water inlet tank is cooled naturally; (10) During the circulation process, the water level in the second water inlet tank may be too high and overflow, and the overflowing water flows back to the water tank through the overflow pipe; (11) After the experiment is completed, except for the water inlet solenoid valve of the water inlet fork pipe, which remains in its original state, all other valves are opened to drain the waste water, and the mold temperature controller is drained according to the operating instructions provided by the manufacturer.

[0046] The description of each embodiment in the above embodiments has different emphases. For parts not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0047] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An auxiliary temperature control device for water tree resistance test, characterized in that: include: Water tank, water inlet mechanism, mold temperature controller, water inlet fork pipe, water return mechanism, temperature control system and test duct; The water adding tank contains the experimental medium solution, and the water adding tank is connected to a water supply pump; The water inlet mechanism is connected to the water replenishment pump, and the water inlet mechanism is also connected to a water outlet solenoid valve; The mold temperature controller is connected to the water outlet solenoid valve; The water inlet fork pipe is connected to the mold temperature controller through a water inlet manual valve, and a water inlet solenoid valve is provided on the water inlet fork pipe, and the water inlet solenoid valve is connected to the test conduit; The water return mechanism is connected to the test conduit and is used to guide the water into the water inlet mechanism after the test conduit overflows; The temperature control system includes an insulation layer and a lifting drive mechanism. The insulation layer is respectively arranged on the upper and lower sides of the test catheter. The lifting drive mechanism is used to control the upper and lower insulation layers of the test catheter to be tightened or relaxed synchronously to assist in the insulation of the test catheter.

2. The auxiliary temperature control device for water tree resistance test according to claim 1, characterized in that: A water outlet manual valve is also connected between the water adding tank and the water replenishing pump; The water tank is provided with a manual drainage valve; A manual drain valve is provided between the mold temperature controller and the manual water inlet valve.

3. The auxiliary temperature control device for water tree resistance test according to claim 1, characterized in that: The water inlet mechanism includes a first water inlet tank and a second water inlet tank. The first water inlet tank and the second water inlet tank are connected through a connecting solenoid valve. An upper float valve and a lower float valve are provided in the first water inlet tank and the second water inlet tank. The first water inlet tank is connected to the water replenishment pump.

4. The auxiliary temperature control device for water tree resistance test according to claim 3, characterized in that: The first water inlet tank and the second water inlet tank are respectively connected to the water supply tank through overflow pipes; The first water inlet tank and the second water inlet tank are provided with manual drainage valves.

5. The auxiliary temperature control device for water tree resistance test according to claim 1, characterized in that: The water return mechanism includes a water return fork pipe, a water return pipe, a water return manual valve and a water return solenoid valve; Among them, the return water fork pipe is connected to the test conduit; one end of the return water pipe is connected to the return water fork pipe through a return water manual valve, and the other end is connected to the first water inlet tank and the second water inlet tank through a return water solenoid valve.

6. The auxiliary temperature control device for water tree resistance test according to claim 5, characterized in that: A temperature sensor is provided at the connection between the water return fork pipe and the water return pipe.

7. The auxiliary temperature control device for water tree resistance test according to claim 1, characterized in that: The insulation layer includes a hard sponge layer, a frame and an inflatable insulation layer, the inflatable insulation layer is arranged on the outside of the hard sponge layer, the hard frame is connected to the lifting drive mechanism, the inflatable insulation layer is connected to the inflation pipe, and the inflation pipe is connected to the electromagnetic on-off valve.

8. The auxiliary temperature control device for water tree resistance test according to claim 1, characterized in that: A compressed air pipe is also connected between the hard sponge layer and the air-filled thermal insulation layer.

9. The auxiliary temperature control device for water tree resistance test according to claim 1, characterized in that: The test catheter is arranged on the bracket, and the lifting drive mechanism is arranged on the bracket and connected to the frame, and the lifting drive mechanism includes: a positioning frame, a spring return cylinder, a sprocket, a chain and a positioning member; Wherein, the positioning frame is arranged on the bracket; The spring return cylinder is arranged on the positioning frame, and a positioning piece is arranged on the piston rod of the spring return cylinder; The sprocket is arranged on the positioning frame; The chain is connected to the sprocket, the positioning member is fixedly connected to the chain, and two ends of the chain are respectively connected to the upper and lower insulation layers of the test conduit.

10. A temperature control method using the auxiliary temperature control device for water tree resistance test according to any one of claims 1 to 9, characterized in that: include: The experimental solution enters the mold temperature controller from the first water inlet tank through the first water outlet solenoid valve. The mold temperature controller heats the experimental solution and presses the experimental solution into the water inlet manual valve and flows into the water inlet fork pipe and into the designated test conduit. After the test conduit is full, it flows into the return pipe through the return fork pipe and then flows back to the first water inlet tank through the first return solenoid valve to form a cycle. During the cycle, the mold temperature controller continuously heats the flowing experimental solution to the designated temperature, thereby realizing temperature rise control. The cable to be tested is powered on and heated to the set cable temperature. The temperature of the test solution in the test conduit rises, the first return water solenoid valve and the first outlet water solenoid valve are closed, and the second return water solenoid valve and the second outlet water solenoid valve are opened at the same time. The test solution in the second water inlet tank participates in the circulation to reduce the temperature of the entire system, thereby achieving temperature reduction control.

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