Cable overheating cracking simulation device

Abstract

The invention relates to a cable overheating cracking simulation device in the technical field of cable performance testing, and the cable overheating cracking simulation device comprises a testing tank, a monitoring analysis system and an environment adjusting system, the monitoring analysis system and the environment adjusting system are correspondingly connected with the testing tank, the testing tank comprises a tank body with an open upper end, and the open end of the tank body is detachably and hermetically connected with a cover body; a hollow telescopic rod is arranged at the bottom in the tank body, a lower heating piece is arranged at the upper end of a telescopic part of the hollow telescopic rod, an upper heating piece coaxial with the lower heating piece is arranged on the lower cover surface of the cover body, and the lower heating piece and the upper heating piece are each provided with a heat conduction clamping piece capable of correspondingly clamping the end of a cable core to be detected; the heat generated by the heating element is transmitted to the cable core to be tested, the heat of the cable core to be tested directly affects the interior of the cable insulation material to be tested, the function that the cable insulation material to be tested is heated from inside to outside is achieved, and the heating condition of the cable insulation material to be tested is infinitely close to the actual operation environment; and the accuracy of test results is ensured.

Description

Technical Field

[0001] The invention relates to the technical field of cable performance testing, and in particular to a cable overheating cracking simulation device. Background Art

[0002] Power cables are widely used in power systems and are the basic components of power systems. The safety and reliability of their equipment is the key to ensuring the normal operation of the entire power system. However, actual operation results in recent years have shown that due to the local high temperature of overheating faults, cable insulation materials may crack, causing fires, explosions and other accidents. Therefore, it is necessary to simulate the overheating cracking of cables.

[0003] In the existing overheat cracking test, the cable to be tested is mostly fixed in a closed space. During the test, the temperature environment in the closed space is changed and the cable cracking process is observed. The insulation material of the cable to be tested is heated from the outside to the inside. Since there are certain differences between the inner and outer surfaces of the cable insulation material, and the cracking of the cable insulation material is generally caused by the heating of the cable core, the overheat cracking test of heating from the outside to the inside is different from the actual heating direction of the cable insulation material, which affects the accuracy of the test results. For example, a Chinese patent application with publication number CN108956689A discloses a cable overheating fault simulation device and simulation method. When the simulation device is used, the cable to be tested is placed in a groove opened on the top surface of a heating element, and the heating element heats the cable to be tested from the outside to the inside. Another example is a Chinese invention patent with publication number CN112697953B discloses a cable combustion and pyrolysis characteristics test system and test method under multi-variable parameter environmental conditions. When the test system is used, the cable to be tested is placed and fixed on a sample rack, and the inside of the test box is heated to a set ambient temperature by a radiation source, that is, the cable to be tested is also heated from the outside to the inside.

[0004] Therefore, we designed a cable overheating cracking simulation device. Summary of the invention

[0005] In order to overcome the deficiencies in the background technology, the present invention discloses a cable overheating cracking simulation device.

[0006] In order to achieve the above-mentioned invention object, the present invention adopts the following technical scheme: A cable overheat cracking simulation device, comprising a test tank, a monitoring and analysis system and an environmental adjustment system connected to the test tank, wherein the test tank comprises a tank body with an open upper end, the open end of the tank body is detachably and sealedly connected with a cover body, a hollow telescopic rod is provided at the bottom of the tank body, a lower heating element is provided at the upper end of the telescopic portion of the hollow telescopic rod, an upper heating element coaxial with the lower heating element is provided on the lower cover surface of the cover body, and both the lower heating element and the upper heating element are provided with a heat-conducting clamping element capable of correspondingly clamping the end of a cable core to be tested; Among them, a through hole is provided at the bottom of the tank body corresponding to the telescopic part of the hollow telescopic rod, and the through hole is detachably connected to an external plug. A memory spring located in the inner cavity of the hollow telescopic rod and capable of shortening at high temperature is provided above the external plug, and the upper end of the memory spring is correspondingly connected to the telescopic part of the hollow telescopic rod.

[0007] Preferably, the lower heating element, the upper heating element and the heat-conducting clamping element are surrounded by a heat-insulating sleeve.

[0008] Preferably, the heat-conducting clamping member comprises a connecting section, and both ends of the connecting section are provided with a covering section so as to cover the heating element or the core of the cable to be tested accordingly.

[0009] Preferably, a reflective sleeve is provided in the inner cavity of the tank body corresponding to a position between the hollow telescopic rod and the cover body.

[0010] Preferably, both ends of the inner wall of the reflective sleeve are curved surfaces or conical surfaces.

[0011] Preferably, a support frame for supporting the reflective sleeve is provided at the bottom of the inner cavity of the tank.

[0012] Preferably, the support frame comprises a stabilizing ring, a top surface of which is evenly spaced along its circumference with a plurality of upwardly biased inwardly directed connecting rods, and an upper end of all connecting rods is provided with a supporting ring coaxial with the stabilizing ring.

[0013] Preferably, the inner cavity of the telescopic portion of the hollow telescopic rod is located between the lower heating element and the memory spring and is provided with a plurality of heat insulating sheets.

[0014] Preferably, a heat-insulating mounting sleeve is provided on the lower cover surface of the cover body, and an upper heating element is coaxially mounted on the lower section of the heat-insulating mounting sleeve.

[0015] Preferably, the inner cavity of the heat-insulating mounting sleeve is provided with a plurality of heat-insulating sheets spaced apart along its axial direction.

[0016] Due to the adoption of the above-mentioned technical solution, the present invention has the following beneficial effects: 1. During the simulation process, the heat generated by the heating element is transferred to the cable core to be tested through the corresponding heat-conducting clamp. Since the cable core to be tested is made of metal material and has good thermal conductivity, the heat of the cable core to be tested directly affects the inside of the cable insulation material to be tested, realizing the function of heating the cable insulation material to be tested from the inside to the outside, making the heating condition of the cable insulation material to be tested infinitely close to the actual working environment, ensuring the accuracy of the test results; 2. The setting of the external plug and the memory spring can enable the memory spring to press the telescopic part of the hollow telescopic rod again after the test is completed and the temperature drops. The hollow telescopic rod extends, so that the heat-conducting clamp, the tested cable, etc. extend out of the tank body. At this time, the tested cable can be installed and removed, which can effectively prevent the staff from being burned by misoperation. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of a first structure of the present invention; Figure 2 is a schematic diagram of a second structure of the present invention; Figure 3 A schematic diagram of the tank at room temperature in the second structure of the present invention; Figure 4 It is a schematic diagram of the support frame in the second structure of the present invention.

[0018] In the figure: 1. test tank; 11. tank body; 12. cover body; 13. support frame; 131. stabilizing ring; 132. connecting rod; 133. support ring; 14. thermal insulation mounting sleeve; 2. hollow telescopic rod; 3. lower heating element; 4. upper heating element; 5. heat-conducting clamping member; 51. connecting section; 52. covering section; 6. external plug; 7. memory spring; 8. thermal insulation sleeve; 9. reflective sleeve; 10. thermal insulation sheet. DETAILED DESCRIPTION

[0019] The present invention can be explained in detail through the following embodiments. The purpose of disclosing the present invention is to protect all technical improvements within the scope of the present invention. In the description of the present invention, it should be understood that if there are terms such as "upper", "lower", "front", "back", "left", "right", etc. indicating directions or positional relationships, they only correspond to the drawings of the present application and are for the convenience of describing the present invention; it should be understood that if there are terms such as "end", "side", "end portion", "lateral", "lateral", "transverse", "longitudinal", etc. indicating directions or positional relationships, they only correspond to the length and width of the corresponding components, that is, the "end portion" indicates the head and tail areas in the length direction of the corresponding component, and the "side portion" indicates the head and tail areas in the width direction of the corresponding component; this is for the convenience of describing the present invention and is not to indicate or imply that the device or element referred to must have a specific direction.

[0020] Embodiment 1, in combination with the attached Figure 1-3 A cable overheating cracking simulation device includes a test tank 1, a monitoring and analysis system and an environmental adjustment system (not shown in the figure) connected to the test tank 1. According to needs, the monitoring and analysis system and the environmental adjustment system can adopt the system used in the cable overheating cracking test in the prior art, which will not be described in detail here.

[0021] The test tank 1 includes a tank body 11 with an open upper end, and the open end of the tank body 11 is detachably and hermetically connected to a cover body 12. If necessary, the open end of the tank body 11 is provided with a flange, and the cover body 12 is connected to the flange by a clamp, bolts, etc. in a manner that allows the cover body 12 to be detached.

[0022] According to the needs, in order to reduce the heat dissipation in the inner cavity of the test tank 1 during the simulation process, a heat insulation layer is provided on the surface of the test tank 1. Preferably, the heat insulation layer is attached to the inner surface of the test tank 1.

[0023] A hollow telescopic rod 2 is provided at the bottom of the tank body 11, a lower heating element 3 is provided at the upper end of the telescopic portion of the hollow telescopic rod 2, an upper heating element 4 coaxial with the lower heating element 3 is provided on the lower cover surface of the cover body 12, and both the lower heating element 3 and the upper heating element 4 are provided with a heat-conducting clamping member 5 capable of correspondingly clamping the end of the cable core to be tested; that is, during the simulation process, the heat generated by the heating element is transferred to the cable core to be tested through the corresponding heat-conducting clamping member. Since the cable core to be tested is made of metal material and has good thermal conductivity, the heat of the cable core to be tested directly affects the inside of the cable insulation material to be tested, thereby realizing the function of heating the cable insulation material to be tested from the inside to the outside, so that the heating condition of the cable insulation material to be tested is infinitely close to the actual operating environment, thereby ensuring the accuracy of the test results.

[0024] In a possible implementation, the heat-conducting clamp 5 includes a connecting section 51, and both ends of the connecting section 51 are provided with a covering section 52, so as to cover the surrounding of the heating element or the cable core to be tested. As required, the covering section 52 is a sheet-like structure that can be bent and deformed, and the sheet-like structure is bent so that the sheet-like structure is covered around the corresponding heating element or the cable core to be tested.

[0025] It should be noted that: before simulation, the insulation material of the cable to be tested needs to be trimmed, that is, the two ends of the cable core to be tested extend out of the sheath of the insulation material of the cable to be tested, and the sheathing section 52 of the thermally conductive clamp 5 corresponds to the position where the cable core to be tested extends out of the insulation material of the cable to be tested.

[0026] As required, the heating element is an electric heating element, and the wire connected to the lower heating element 3 extends out of the tank body 11 through the hollow telescopic rod 2; specifically, the wire connected to the upper heating element 4 passes through the cover body 12.

[0027] In a possible implementation, the heating element may be a resistor, and the heat-conducting clamp 5 is made of a conductive material, so that the lower heating element 3, the heat-conducting clamp 5, the cable core to be tested, the heat-conducting clamp 5 and the upper heating element 4 form an energized circuit to achieve a real actual working environment.

[0028] In a possible embodiment, in order to reduce the heat transfer from the upper heating element 4 to the cover body 12, a heat-insulating mounting sleeve 14 is provided on the lower cover surface of the cover body 12, and the upper heating element 4 is coaxially mounted on the lower section of the heat-insulating mounting sleeve 14. Furthermore, a plurality of heat-insulating sheets 10 are provided at intervals along the axial direction of the inner cavity of the heat-insulating mounting sleeve 14. In this embodiment, the heat-insulating sheet 10 has a hole for the wire connected to the upper heating element 4 to pass through.

[0029] Among them, a through hole is provided at the bottom of the tank body 11 corresponding to the telescopic part of the hollow telescopic rod 2, and the through hole is detachably connected to an external plug 6. A memory spring 7 is provided above the external plug 6 and is located in the inner cavity of the hollow telescopic rod 2 and can be shortened at high temperature, and the upper end of the memory spring 7 is correspondingly connected to the telescopic part of the hollow telescopic rod 2.

[0030] As required, the outer plug 6 is a hollow stud, and in order to facilitate twisting of the outer plug 6, the lower end of the outer plug 6 has a convenient twisting structure, for example, a hexagonal head.

[0031] In the example, the memory spring 7 is made of CuZnAl memory alloy wire, and utilizes the two-way memory effect of the shape memory alloy, that is, it is in a free state at low temperature (room temperature) and in a shortened state at high temperature.

[0032] In a possible implementation, in order to prevent the temperature of the inner cavity of the hollow telescopic rod 2 from being too high, the hollow telescopic rod 2 can be made of a material with a certain heat insulation function. As needed, the inner cavity of the telescopic part of the hollow telescopic rod 2 is located between the lower heating element 3 and the memory spring 7 and is provided with a plurality of heat insulation sheets 10. It should be noted that: since the existing heat insulation materials are almost not absolutely heat-insulating, the temperature of the inner cavity of the hollow telescopic rod 2 will still rise in the simulation test to ensure that the memory spring 7 is heated up to a shortened state. In the example, if the hollow telescopic rod 2 and the heat insulation sheet 10 act, resulting in the inner cavity temperature of the hollow telescopic rod 2 not reaching the temperature of the memory spring 7 to be heated up to a shortened state, the hollow telescopic rod 2 and / or the heat insulation sheet 10 can be punched with small holes so that the inner cavity temperature of the hollow telescopic rod 2 can reach the temperature of the memory spring 7 to be heated up to a shortened state.

[0033] When in use, first open the cover 12. At this time, the temperatures inside and outside the test tank 1 are both room temperature, the memory spring 7 is in a free state, and the memory spring 7 presses the telescopic portion of the hollow telescopic rod 2, so that the telescopic portion of the hollow telescopic rod 2 extends out of the tank 11. At this moment, the lower end of the cable core to be tested can be connected to the lower heating element 3 through the corresponding heat-conducting clamp 5, and then the upper end of the cable core to be tested can be connected to the upper heating element 4 through the corresponding heat-conducting clamp 5. At this moment, the outer plug 6 is removed from the bottom of the tank 11, and the telescopic portion of the hollow telescopic rod 2 loses the pressure of the memory spring 7. Then the cover 12 is installed on the open section of the tank 11. At this moment, the hollow telescopic rod 2 is in a contracted state under the action of gravity, and a simulation test can be performed.

[0034] During the simulation test, as the temperature of the inner cavity of the test tank 1 rises, the temperature of the memory spring 7 gradually increases and becomes shortened. After the lower end of the memory spring 7 completely enters the inner cavity of the hollow telescopic rod 2, the outer plug 6 is assembled to the through hole.

[0035] After the simulation test is completed and before the temperature drops, even if the connection of the cover body 12 is released, the memory spring 7 does not apply a top pressure to the telescopic portion of the hollow telescopic rod 2, and the hollow telescopic rod 2 does not extend. Therefore, the heat-conducting clamp 5 with a higher temperature and the tested cable will not freely extend out of the tank body 11, which can effectively prevent the staff from being burned due to misoperation; after the temperature drops, the memory spring 7 begins to press the telescopic portion of the hollow telescopic rod 2, and the hollow telescopic rod 2 extends, so that the heat-conducting clamp 5, the tested cable, etc. extend out of the tank body 11, and the tested cable can now be installed and removed.

[0036] Embodiment 2, combined with the attached Figure 1 A cable overheat cracking simulation device is provided. On the basis of the first embodiment, in order to reduce the heat of the lower heating element 3, the upper heating element 4 and the heat-conducting clamping element 5 from being dissipated into the test tank 1 through the gas, the lower heating element 3, the upper heating element 4 and the heat-conducting clamping element 5 are covered with a heat insulating sleeve 8.

[0037] Embodiment 3, in combination with the attached Figure 2-4 , a cable overheat cracking simulation device, which is different from the second embodiment in that a reflective sleeve 9 is provided at a position between the hollow telescopic rod 2 and the cover 12 in the inner cavity of the tank body 11; specifically, the inner wall of the reflective sleeve 9 has a reflective layer. The heat radiated from the lower heating element 3, the upper heating element 4 and the heat-conducting clamping element 5 to the inner cavity of the tank body 11 is reflected to the surface of the insulating material of the cable to be tested through the reflective sleeve 9, and the space where the cable to be tested is located can be effectively reduced.

[0038] Furthermore, both ends of the inner wall of the reflective sleeve 9 are curved surfaces or conical surfaces, so that the heat radiation received by the reflective sleeve 9 can be concentratedly reflected in the direction of the cable to be tested.

[0039] As needed, a support frame 13 for supporting the reflective sleeve 9 is provided at the bottom of the inner cavity of the tank body 11. This arrangement can connect the reflective sleeve 9 to the tank body 11 without other connecting parts, thereby improving the integrity of the insulation layer and further improving the insulation effect of the tank body 11.

[0040] In a possible embodiment, the support frame 13 includes a stabilizing ring 131, and a plurality of connecting rods 132 that are evenly spaced upward and inward along the circumference of the top surface of the stabilizing ring 131 are provided, and a support ring 133 that is coaxial with the stabilizing ring 131 is provided at the upper end of all the connecting rods 132; specifically, the outer diameter of the stabilizing ring 131 is slightly smaller than the inner diameter of the tank body 11, that is, the stabilizing ring 131 cannot move radially or only in a small range.

[0041] It should be noted that the stabilizing ring 131 and the lower port of the reflecting sleeve 9 are larger than the diameter of the hollow telescopic rod 2, so that the parts of the monitoring and analysis system and the environmental adjustment system that need to extend into the inner cavity of the reflecting sleeve 9 can extend into the inner cavity of the reflecting sleeve 9 from the stabilizing ring 131 and the lower port of the reflecting sleeve 9.

[0042] The parts of the present invention that are not described in detail are prior art. It is obvious to those skilled in the art that the present invention is not limited to the details of the above-mentioned exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic characteristics of the present invention; therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive, and it is intended that all changes that fall within the meaning and scope of equivalent elements are included in the present invention.

Claims

1. A cable overheat cracking simulation device, comprising a test tank (1), a monitoring and analysis system and an environmental adjustment system connected to the test tank (1), characterized in that: The test tank (1) comprises a tank body (11) with an open upper end, the open end of the tank body (11) being detachably and hermetically connected to a cover body (12), a hollow telescopic rod (2) being provided at the bottom of the tank body (11), a lower heating element (3) being provided at the upper end of the telescopic portion of the hollow telescopic rod (2), an upper heating element (4) being coaxial with the lower heating element (3) being provided on the lower cover surface of the cover body (12), and both the lower heating element (3) and the upper heating element (4) being provided with a heat-conducting clamping element (5) capable of correspondingly clamping the end of a cable core to be tested; A through hole is provided at the bottom of the tank body (11) at a position corresponding to the telescopic portion of the hollow telescopic rod (2), the through hole being detachably connected to an external plug (6), a memory spring (7) located in the inner cavity of the hollow telescopic rod (2) and capable of being shortened at high temperature being provided above the external plug (6), and the upper end of the memory spring (7) being correspondingly connected to the telescopic portion of the hollow telescopic rod (2).

2. The cable overheating cracking simulation device according to claim 1, characterized in that: The lower heating element (3), the upper heating element (4) and the heat-conducting clamping element (5) are covered with a heat-insulating sleeve (8) on their outer peripheries.

3. The cable overheating cracking simulation device according to claim 1, characterized in that: The heat-conducting clamp (5) comprises a connecting section (51), and both ends of the connecting section (51) are provided with a covering section (52) so as to cover the heating element or the core of the cable to be tested accordingly.

4. The cable overheating cracking simulation device according to claim 1, characterized in that: A reflective sleeve (9) is provided at a position of the inner cavity of the tank body (11) corresponding to the position between the hollow telescopic rod (2) and the cover body (12).

5. The cable overheating cracking simulation device according to claim 4, characterized in that: Both ends of the inner wall of the reflection sleeve (9) are curved surfaces or conical surfaces.

6. The cable overheating cracking simulation device according to claim 4, characterized in that: A support frame (13) for supporting the reflective sleeve (9) is provided at the bottom of the inner cavity of the tank body (11).

7. The cable overheating cracking simulation device according to claim 6, characterized in that: The support frame (13) comprises a stabilizing ring (131), the top surface of the stabilizing ring (131) being provided with a plurality of upwardly biased inwardly arranged evenly spaced along its circumference, and the upper ends of all the connecting rods (132) being provided with a supporting ring (133) coaxial with the stabilizing ring (131).

8. The cable overheating cracking simulation device according to claim 1, characterized in that: The inner cavity of the telescopic portion of the hollow telescopic rod (2) is located between the lower heating element (3) and the memory spring (7), and is provided with a plurality of heat insulating sheets (10) at intervals.

9. The cable overheating cracking simulation device according to claim 1, characterized in that: The lower cover surface of the cover body (12) is provided with a heat-insulating mounting sleeve (14), and the upper heating element (4) is coaxially mounted on the lower section of the heat-insulating mounting sleeve (14).

10. The cable overheating cracking simulation device according to claim 9, characterized in that: The inner cavity of the heat-insulating mounting sleeve (14) is provided with a plurality of heat-insulating sheets (10) at intervals along the axial direction thereof.

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