A withstand voltage test device for cables

Abstract

The present invention relates to the technical field of cable testing, and particularly relates to a withstand voltage testing device for cables. It includes: a folding frame; an isolation shell fixedly connected to the folding frame, and a through hole is provided on the isolation shell; a first fixing frame fixedly connected inside the isolation shell, a fixing rod is fixedly connected inside the isolation shell, mounting rods are arranged on both the first fixing frame and the fixing rod in a circumferentially arrayed manner, a circumferentially arrayed first electric push rod is fixedly connected to the first fixing frame, a clamping shell is fixedly connected to the mounting rod, a conductive sheet is slidably connected to the clamping shell, mirror-image distributed first fixing shells are fixedly connected to the clamping shell, and a first liquid sac is fixedly connected to the first fixing shell. The present invention squeezes the conductive sheet through the first liquid sac, so that the conductive sheet adaptively wraps according to its specific shape when connecting the test cable, reducing the possibility of air breakdown between the conductive sheet and the test cable and improving the test safety.

Description

Technical Field

[0001] The present invention relates to the technical field of cable testing, and particularly to a voltage withstand test device for cables. Background Art

[0002] DC voltage withstand test of cables is an important test method for evaluating the insulation performance of cables. It detects whether there are potential insulation defects in the cables by applying a DC voltage higher than the normal working voltage, ensuring its safety and reliability during actual operation.

[0003] During the cable laying process, in order to ensure that the insulation performance of each section of the cable meets the requirements, a voltage withstand test needs to be carried out before making the joints. The current industry-standard cable voltage withstand test process mainly includes the following operation procedures: First, the cable ends are pre-treated, and the terminal insulation sheath layer is removed by mechanical stripping; then, the three-phase cables (phases A, B, and C) are physically separated; finally, a high-voltage generator is directly connected to the cable metal wire core for voltage withstand testing. However, in the traditional process, there is a mechanical fit gap when the test joint of the high-voltage generator is connected to the cable metal wire core. When a high voltage is applied during the test, the electric field strength at the gap will increase sharply. According to Paschen's law, when the gap field strength reaches the breakdown threshold of the air medium, the following chain reaction will occur:

[0004] Ionization of the air medium generates partial discharge phenomena (i.e., air breakdown);

[0005] An ionization region forms a low-impedance conductive channel;

[0006] The discharge current triggers the Joule heat effect, causing a sharp rise in local temperature;

[0007] This phenomenon will directly lead to two serious consequences: First, the transient overvoltage generated by the discharge may damage the test equipment, posing a serious safety risk; second, the abnormal discharge during the test will interfere with the acquisition of real voltage withstand data, causing deviation of the test results and significantly reducing the reliability of the test system. Summary of the Invention

[0008] In order to overcome the above-mentioned drawbacks, the present invention provides a voltage withstand test device for cables.

[0009] Technical Solution: A voltage withstand test device for cables, comprising:

[0010] A folding rack;

[0011] An isolation shell, fixedly connected to the folding rack, and a through hole is provided on the isolation shell;

[0012] The first fixing bracket is fixedly connected inside the isolation shell. A fixing rod is fixedly connected inside the isolation shell. Mounting rods are arranged on both the first fixing bracket and the fixing rod in a circumferentially arrayed manner. First electric push rods are fixedly connected to the first fixing bracket in a circumferentially arrayed manner. The telescopic ends of the first electric push rods are fixedly connected to the adjacent mounting rods. The mounting rods are fixedly connected with clamping shells. Conductive sheets are slidably connected to the clamping shells. Tension springs are arranged between both sides of the conductive sheets and the adjacent clamping shells. The clamping shells are fixedly connected with mirror-image distributed first fixing shells. The first fixing shells are fixedly connected with first liquid sacs. The first liquid sacs are used to squeeze and wrap the conductive sheets. A control mechanism is arranged inside the first liquid sacs. The control mechanism is used to control the flattening and inflation sequence of the first liquid sacs.

[0013] Preferably, the control mechanism includes:

[0014] A partition member is fixedly connected inside the first liquid sac;

[0015] A pressure valve is fixedly connected to the side of the partition member away from the first fixing shell. And the length of the first liquid sac on the axis of the fixing rod is greater than the length of the conductive sheet on the axis of the fixing rod. A one-way valve is arranged on the side of the partition member close to the adjacent first fixing shell;

[0016] A transmission assembly is arranged on the clamping shell and is used to provide pressure for the first liquid sac when the conductive sheet clamps the cable.

[0017] Preferably, the transmission assembly includes:

[0018] A spring telescopic rod is fixedly connected to the clamping shell. The fixed part of the spring telescopic rod is fixedly connected to the mounting rod. The mirror-image distributed first fixing shells are both communicated with the fixed part of the spring telescopic rod through pipelines;

[0019] A second fixing bracket is fixedly connected to the telescopic end of the spring telescopic rod. The second fixing bracket is fixedly connected with a second liquid sac. The second liquid sac is used to squeeze the conductive sheet.

[0020] Preferably, the isolation shell is threadedly connected with a sealing cover. The sealing cover is slidably connected to the fixing rod. Both the isolation shell and the sealing cover are made of insulating materials.

[0021] Preferably, it further includes:

[0022] A position-changing mechanism is arranged on the fixing rod and is used to switch the electrodes of the test cable. The position-changing mechanism includes:

[0023] A conductive bracket is fixedly connected to the fixing rod. The conductive bracket is fixedly connected to the first fixing bracket;

[0024] A rotating ring is rotatably connected to the fixed rod. Circumferentially arrayed conductive blocks are provided on both the conductive frame and the rotating ring, and the conductive blocks on the conductive frame and the conductive blocks on the rotating ring are used for contacting and conducting electricity.

[0025] A power assembly is provided on the fixed rod and is used to control the relative rotation angle between the conductive frame and the rotating ring.

[0026] Preferably, a conductive rod is provided on the rotating ring, and discharge rods are provided on the rotating ring in a mirror image distribution.

[0027] Preferably, the power assembly includes:

[0028] A second electric push rod is fixedly connected inside the fixed rod;

[0029] A spline rod is spline-connected inside the fixed rod, and the spline rod is fixedly connected to the telescopic end of the second electric push rod;

[0030] A first extrusion rod is fixedly connected to the rotating ring. An arc-shaped through groove is provided on the fixed rod for the first extrusion rod to pass through. An inclined groove is provided on the spline rod, and the first extrusion rod slides in the inclined groove on the spline rod.

[0031] Preferably, it further includes:

[0032] A discharge mechanism is provided on the fixed rod and is used to switch the discharge mode of the discharge rod. The discharge mechanism includes:

[0033] A fixed ring is rotatably connected to the fixed rod, and both the conductive rod and the discharge rod are fixedly connected to the fixed ring;

[0034] Resistance blocks in mirror image distribution are respectively slidably connected to adjacent discharge rods. The resistance blocks are fixedly connected with a first conductive member, and the discharge rods are fixedly connected with a second conductive member. The second conductive member slides inside the resistance block and the first conductive member. The resistance block and the first conductive member are jointly fixedly connected with a sliding shell;

[0035] A switching assembly is provided on the fixed rod and is used to change the relative position between the resistance block and the second conductive member.

[0036] Preferably, the switching assembly includes:

[0037] An extrusion frame is fixedly connected to the fixed rod. The sliding shell is fixedly connected with a second extrusion rod, and the second extrusion rod is used to drive the sliding shell to move by squeezing the extrusion frame;

[0038] A delay component is provided on the fixed ring and is used to control the slow reset of the resistance block.

[0039] Preferably, the delay component includes:

[0040] Second fixed shells distributed in mirror image, both fixedly connected to the fixed ring. The sliding shell is fixedly connected with a sliding rod, the sliding rod is slidably connected with the second fixed shell, a spring is arranged between the second fixed shell and the sliding rod, a plurality of through holes are arranged on the sliding rod, and check valves are arranged in some of the through holes on the sliding rod.

[0041] The beneficial effects of the present invention are as follows: By squeezing the conductive sheet with the first liquid sac, the conductive sheet is adaptively wrapped according to its specific shape when connecting the test cable, reducing the possibility of air breakdown between the conductive sheet and the test cable. During the extrusion process of the conductive sheet and the first liquid sac, the first liquid sac is extruded and bulges to wrap both sides of the conductive sheet, further isolating the contact between the conductive sheet and the external environment and improving the test safety; By the cooperation of the spline rod and the first extrusion rod to drive the rotation ring to rotate, the rotation ring and two adjacent conductive blocks on the conductive frame are switched according to the test process, so that the device does not require the complicated steps of repeated disassembly when switching the test cable, further ensuring the stability of the connection between the conductive sheet and the cable; By the cooperation of the second fixed shell and the sliding rod, the switching between the cable resistance discharge and the direct discharge is automatically completed after the cable test, improving the simplicity of the test process of the device. Description of the Drawings

[0042] Figure 1 It is a three-dimensional structural schematic diagram of the present invention;

[0043] Figure 2 It is a three-dimensional structural schematic diagram of the internal structure of the isolation shell of the present invention;

[0044] Figure 3 It is a three-dimensional structural schematic diagram of the mounting rod and the clamping shell of the present invention;

[0045] Figure 4 It is a three-dimensional structural sectional view of the clamping shell and the conductive sheet of the present invention;

[0046] Figure 5 It is a three-dimensional structural sectional view of the first liquid sac in the expanded state of the present invention;

[0047] Figure 6 It is a three-dimensional structural sectional view of the positional relationship between the first liquid sac and the partition member of the present invention;

[0048] Figure 7 It is a three-dimensional structural schematic diagram of the second electric push rod and the spline rod of the present invention;

[0049] Figure 8 It is a three-dimensional structural schematic diagram of the sliding shell and the extrusion frame of the present invention;

[0050] Figure 9Schematic three-dimensional structure diagram of the resistor block and the first conductive member of the present invention;

[0051] Figure 10 Exploded view of the parts at the discharge rod of the present invention.

[0052] Reference numerals in the drawings: 1: folding frame, 2: isolation shell, 3: first fixing frame, 301: first electric push rod, 4: fixing rod, 5: mounting rod, 6: clamping shell, 7: conductive sheet, 8: first fixing shell, 9: first liquid sac, 10: partition member, 11: pressure valve, 12: spring telescopic rod, 13: second fixing frame, 14: second liquid sac, 15: sealing cover, 16: conductive frame, 17: rotating ring, 18: conductive block, 19: conductive rod, 20: discharge rod, 21: second electric push rod, 22: spline rod, 23: first extrusion rod, 24: fixing ring, 25: resistor block, 26: first conductive member, 261: second conductive member, 27: sliding shell, 28: extrusion frame, 29: second extrusion rod, 30: second fixing shell, 31: sliding rod. Detailed implementation manners

[0053] The present invention will be further described below in conjunction with specific embodiments. The illustrative embodiments and explanations of the present invention are used to explain the present invention, but do not limit the present invention.

[0054] A voltage withstand test device for cables, as Figures 1-6 shown, includes: a folding frame 1; an isolation shell 2 fixedly connected to the folding frame 1, and a through hole is provided on the isolation shell 2; a first fixing frame 3 fixedly connected inside the isolation shell 2, a fixing rod 4 is fixedly connected inside the isolation shell 2, mounting rods 5 distributed in a circumferential array are provided on both the first fixing frame 3 and the fixing rod 4, a circumferentially arrayed first electric push rod 301 is fixedly connected to the first fixing frame 3, the telescopic end of the first electric push rod 301 is fixedly connected to the adjacent mounting rod 5, a clamping shell 6 is fixedly connected to the mounting rod 5, a conductive sheet 7 is slidably connected to the clamping shell 6, tension springs are provided between both sides of the conductive sheet 7 and the adjacent clamping shell 6, mirror-image distributed first fixing shells 8 are fixedly connected to the clamping shell 6, a first liquid sac 9 is fixedly connected to the first fixing shell 8, the first liquid sac 9 is used to squeeze and wrap the conductive sheet 7, and a control mechanism is provided inside the first liquid sac 9, and the control mechanism is used to control the flattening and inflation sequence of the first liquid sac 9.

[0055] As Figure 5 and Figure 6 shown, the control mechanism includes: a partition member 10 fixedly connected inside the first liquid sac 9; a pressure valve 11 fixedly connected to the side of the partition member 10 away from the first fixing shell 8, and the length of the first liquid sac 9 on the axis of the fixing rod 4 is greater than the length of the conductive sheet 7 on the axis of the fixing rod 4, a one-way valve is provided on the side of the partition member 10 close to the adjacent first fixing shell 8; a transmission assembly is provided on the clamping shell 6 and is used to provide pressure for the first liquid sac 9 when the conductive sheet 7 clamps the cable.

[0056] In the above solution, the conductive sheet 7 is a flexible aluminum alloy sheet, which is used to fit the exposed metal wire core on the surface of the cable. The number of mounting rods 5 on the first fixing frame 3 and the fixing rod 4 is three. When the clamping shells 6 on the first fixing frame 3 are in contact with the adjacent clamping shells 6 on the fixing rod 4, they are combined into a detection cylinder together (that is, six clamping shells 6 are combined into three detection cylinders to clamp the A, B, and C phase cables respectively). After the first liquid bag 9 expands, it squeezes the conductive sheet 7 towards the cable, so that the conductive sheet 7 deforms and is embedded into the gap between the metal wire cores in the cable, increasing the conductive contact area and reducing the gap between the conductive sheet 7 and the cable, thereby reducing the probability of electric sparks occurring during the test (that is, reducing the air breakdown probability). The number of through holes on the isolation shell 2 is three, and the A, B, and C phase cables respectively pass through the three through holes on the isolation shell 2 and enter it. The isolation shell 2 is made of insulating and transparent material (in this solution, the material of the isolation shell 2 is high-strength tempered glass). Both the first liquid bag 9 and the partition 10 are made of elastic materials. The partition 10 divides the first liquid bag 9 into two chambers, and the expansion rate of the chamber on the side of the partition 10 close to the conductive sheet 7 is less than that of the other chamber. The flow direction of the one-way valve on the partition 10 is from the chamber far from the conductive sheet 7 to the other chamber.

[0057] As Figure 4 and Figure 5 shown, the transmission component includes: a spring telescopic rod 12, fixed on the clamping shell 6. The fixed part of the spring telescopic rod 12 is fixedly connected to the mounting rod 5. The mirror-image distributed first fixed shells 8 are all connected to the fixed part of the spring telescopic rod 12 through pipelines, and the fixed part of the spring telescopic rod 12 and the mirror-image distributed first fixed shells 8 are all filled with transmission medium; a second fixing frame 13, fixed to the telescopic end of the spring telescopic rod 12. The second fixing frame 13 is fixedly connected with a second liquid bag 14, and the second liquid bag 14 is used to squeeze the conductive sheet 7. The isolation shell 2 is threadedly connected with a sealing cover 15, and the sealing cover 15 is slidably connected to the fixing rod 4. Both the isolation shell 2 and the sealing cover 15 are made of insulating materials.

[0058] In the above solution, the transmission medium in the fixed part of the spring telescopic rod 12 and the mirror-image distributed first fixed shells 8 is insulating oil, which is used for hydraulic transmission while ensuring the safety of the test. The second liquid bag 14 is also filled with insulating oil, and the second liquid bag 14 is located in the middle of the conductive sheet 7. The sealing cover 15 is used to separate the test environment from the external environment during the test to improve the safety during the test. If necessary, an air drying device can be installed in the isolation shell 2 to reduce the air humidity in the test environment, thereby reducing the air breakdown probability.

[0059] Specific working principle: When it is necessary to use this device to perform a withstand voltage test on the cable during the field cable laying process, the user first unfolds the folding frame 1 and places it at the cable test site, and sets the cable to the upper side of the folding frame 1. The user respectively passes the three-phase A, B, and C branches prepared in the cable into the isolation shell 2 through the three through holes on the isolation shell 2. Taking the A-phase cable as an example, the user moves the A-phase cable connector through the upper through hole to between the two conductive sheets 7 on the upper side of the isolation shell 2. Then the user controls the telescopic end of the first electric push rod 301 to extend and drive the clamp The shell 6 moves downward, and the clamping shell 6 drives the conductive sheet 7 to move gradually downward. During this process, the two conductive sheets 7 gradually squeeze the A-phase cable, and the two sides of the conductive sheet 7 gradually move outside the clamping shell 6. At the same time, the tension spring between the conductive sheet 7 and the clamping shell 6 is stretched, and the upper and lower conductive sheets 7 gradually wrap the A-phase cable until the two clamping shells 6 are in contact. At this time, the A-phase cable is connected, and then the user repeats the above steps to install the B and C phase cables. After the installation is completed, the user fixes the external cable to prevent external factors from interfering with the test process.

[0060] In the process that the two upper conductive sheets 7 gradually squeeze the A-phase cable, taking the lower conductive sheet 7 as an example, the conductive sheet 7 is squeezed downward by the A-phase cable, and when the conductive sheet 7 contacts the second liquid capsule 14, the conductive sheet 7 drives the second fixed frame 13 and the telescopic end of the spring telescopic rod 12 to move downward through the second liquid capsule 14, and the insulating oil in the fixed part of the spring telescopic rod 12 flows into the first fixed shell 8 through the pipeline between the fixed part of the spring telescopic rod 12 and the first fixed shell 8 after being squeezed, and the insulating oil flows into the first liquid capsule 9 through the first fixed shell 8. When the insulating oil is injected into the first liquid capsule 9, the upper part of the first liquid capsule 9 expands first, so that the first liquid capsule 9 gradually stretches and fits to the surface of the conductive sheet 7, until the first liquid capsule 9 is stretched completely, and the upper part of the first liquid capsule 9 Part of the insulating oil enters the lower chamber of the first liquid capsule 9 through the pressure valve 11, and the lower chamber of the first liquid capsule 9 gradually expands and squeezes the clamping shell 6 (that is, the first liquid capsule 9 gradually fills the gap between the conductive sheet 7 and the clamping shell 6), thereby squeezing the conductive sheet 7 and the A-phase cable. By virtue of the deformability of the structure of the first liquid capsule 9 and the flowability of the internal insulating oil, the conductive sheet 7 is squeezed to make it fit the A-phase cable more closely (the conductive sheet 7 adaptively wraps the shape of the A-phase cable), reducing the possibility of air breakdown between the conductive sheet 7 and the A-phase cable. During the squeezing process of the conductive sheet 7 and the first liquid capsule 9, the left and right sides of the first liquid capsule 9 are squeezed and raised and wrap the two sides of the conductive sheet 7, further isolating the conductive sheet 7 from the external environment, thereby improving the test safety.

[0061] After fixing the external cable, the user electrically connects the external DC high-voltage generating device to the conductive sheet 7. Subsequently, the DC withstand voltage test is carried out on the A, B, and C-phase cables one by one. At the same time, the user observes the cable data according to the indication of the high-voltage generating device. After the test is completed, the user controls the telescopic end of the first electric push rod 301 to retract and reset. The telescopic end of the first electric push rod 301 drives the clamping shell 6 and its components thereon to reset. The conductive sheet 7 loses the clamping of the cable and resets under the action of the tension spring between it and the clamping shell 6. The spring telescopic rod 12 pumps the insulating oil out of the first liquid sac 9, and the first liquid sac 9 gradually resets. The insulating oil in the chamber of the first liquid sac 9 away from the adjacent conductive sheet 7 flows back through the one-way valve on the partition 10. The second liquid sac 14 and the second fixing frame 13 gradually reset under the drive of the telescopic part of the spring telescopic rod 12. Subsequently, the user pulls out the cable from the isolation shell 2, and at this time, the device is used up.

[0062] As Figure 3 , Figure 7 and Figure 8 shown, it further includes: a commutation mechanism, arranged on the fixed rod 4, used for switching the electrodes of the test cable. The commutation mechanism includes: a conductive frame 16, fixedly connected to the fixed rod 4, and the conductive frame 16 is fixedly connected to the first fixing frame 3; a rotating ring 17, rotatably connected to the fixed rod 4. Conductive blocks 18 are arranged on both the conductive frame 16 and the rotating ring 17 in a circumferentially arrayed manner. The conductive blocks 18 on the conductive frame 16 and the conductive blocks 18 on the rotating ring 17 are used for conducting electricity; a power component, arranged on the fixed rod 4, used for controlling the relative rotation angle of the conductive frame 16 and the rotating ring 17. A conductive rod 19 is arranged on the rotating ring 17, and discharge rods 20 are arranged on the rotating ring 17 in a mirror image distribution.

[0063] As Figure 3 and Figure 7 shown, the power component includes: a second electric push rod 21, fixedly connected inside the fixed rod 4; a spline rod 22, spline-connected inside the fixed rod 4, and the spline rod 22 is fixedly connected to the telescopic end of the second electric push rod 21; a first extrusion rod 23, fixedly connected to the rotating ring 17. An arc-shaped through groove is arranged on the fixed rod 4 for the first extrusion rod 23 to pass through. An inclined groove is arranged on the spline rod 22, and the first extrusion rod 23 slides in the inclined groove on the spline rod 22.

[0064] In the above solution, the conductive rod 19 is directly connected to the high-voltage output terminal of an external DC high-voltage generator, and both discharge rods 20 are grounded. The conductive rod 19 and the discharge rods 20 are respectively electrically connected to adjacent conductive blocks 18 by wires (not shown in the figure). The conductive frame 16 is electrically connected to the conductive sheet 7. The adjacent two conductive blocks 18 on the conductive frame 16 and the rotating ring 17 conduct electricity in a contact manner. In this embodiment, the number of conductive blocks 18 on both the conductive frame 16 and the rotating ring 17 is three. The inclined groove on the spline rod 22 cooperates with the first extrusion rod 23 to switch the two conductive sheets 7 electrically connected to the conductive rod 19, so as to gradually perform DC withstand voltage detection on the three phases A, B, and C of the cable without changing the cable clamping state.

[0065] As Figure 9 and Figure 10 shown, it further includes: a discharge mechanism arranged on the fixed rod 4 for switching the discharge mode of the discharge rod 20. The discharge mechanism includes: a fixed ring 24 rotatably connected to the fixed rod 4, and both the conductive rod 19 and the discharge rod 20 are fixedly connected to the fixed ring 24; mirror-image distributed resistance blocks 25 respectively slidably connected to adjacent discharge rods 20. The resistance blocks 25 are fixedly connected with a first conductive member 26, and the discharge rods 20 are fixedly connected with a second conductive member 261. The second conductive member 261 slides within the resistance blocks 25 and the first conductive member 26. The resistance blocks 25 and the first conductive member 26 are jointly fixedly connected with a sliding shell 27; a switching component arranged on the fixed rod 4 for changing the relative positions of the resistance blocks 25 and the second conductive member 261.

[0066] As Figures 8-10 shown, the switching component includes: an extrusion frame 28 fixedly connected to the fixed rod 4. The sliding shell 27 is fixedly connected with a second extrusion rod 29, and the second extrusion rod 29 is used to drive the sliding shell 27 to move by extruding the extrusion frame 28; a delay component arranged on the fixed ring 24 for controlling the slow reset of the resistance blocks 25.

[0067] As Figures 8-10 shown, the delay component includes: mirror-image distributed second fixed shells 30 both fixedly connected to the fixed ring 24. The sliding shell 27 is fixedly connected with a sliding rod 31, and the sliding rod 31 is slidably connected to the second fixed shells 30. A spring is arranged between the second fixed shells 30 and the sliding rod 31. The sliding rod 31 is provided with a plurality of through holes, and one-way valves are arranged in some of the through holes on the sliding rod 31. The second fixed shells 30 are filled with a transmission medium.

[0068] In the above solution, both the resistor block 25 and the first conductive member 26 are electrically connected to the second conductive member 261 by contact. Moreover, the greater the distance between the second conductive member 261 and the first conductive member 26, the greater the real-time resistance of the resistor block 25 when transmitting current. The extrusion frame 28 has four protrusions, where every two adjacent protrusions form a group, and two adjacent protrusions are respectively located on both sides of the adjacent second extrusion rod 29, and are used to extrude the second extrusion rod 29 to drive the sliding shell 27 to move, so as to change the resistance value during discharge. The sliding rod 31 is composed of an L-shaped rod and a piston plate, and the through hole on it is located on the piston plate part. The through holes on the piston plate part of the sliding rod 31 are two large and two small. The one-way valves are located in the two larger through holes, and the flow direction of the one-way valves is from left to right.

[0069] Specific working principle: After the above cable is installed, the user rotates the sealing cover 15 and removes it. Subsequently, the user connects the high-voltage output terminal of an external DC high-voltage generator to the conductive rod 19, and connects the ground wires of the external DC high-voltage generator to the two discharge rods 20 respectively. Then, the user reinstalls the sealing cover 15 onto the isolation shell 2. The user starts the external DC high-voltage generator and conducts a withstand voltage test on the phase A cable. When the detection of the phase A cable is completed, at this time, it is necessary to switch the detected cable and discharge the phase A cable. Taking the subsequent withstand voltage test on the phase B cable (located at the lower front side) as an example, the user controls the telescopic end of the second electric push rod 21 to retract. The telescopic end of the second electric push rod 21 drives the spline rod 22 to move leftward. During this process, the inclined chute on the spline rod 22 drives the rotating ring 17 to rotate by extruding the first extrusion rod 23. The rotating ring 17 drives the three conductive blocks 18 on it to rotate clockwise (in the direction from left to right), so that the conductive block 18 electrically connected to the conductive rod 19 loses contact with the upper conductive block 18 on the conductive frame 16 (i.e., the conductive block 18 corresponding to the phase A cable). The rotating ring 17 drives the fixed ring 24, the resistor block 25, the first conductive member 26 and the sliding shell 27 to rotate synchronously through the conductive rod 19 and the discharge rod 20. The sliding shell 27 drives the second extrusion rod 29 on it to rotate. The second extrusion rod 29 and the protrusions on the extrusion frame 28 mutually extrude and drive the sliding shell 27 to move leftward. The sliding shell 27 drives the sliding rod 31 to move leftward synchronously. The hydraulic oil on the left part of the sliding rod 31 flows to its right side through the through hole and the one-way valve on it, and at the same time compresses the spring between the sliding rod 31 and the second fixed shell 30.

[0070] During the leftward movement of the sliding housing 27 described above, the sliding housing 27 drives the resistance block 25 and the first conductive member 26 to move leftward synchronously, so that the second conductive member 261 gradually contacts the right end of the resistance block 25. At this time, the protrusion on the extrusion frame 28 loses contact with the adjacent second extrusion rod 29, and the resistance block 25 is connected to the grounding line. Moreover, the discharge rod 20 at the lower rear rotates to the upper side (i.e., the position corresponding to the A-phase cable, and the conductive block 18 at the lower rear of the rotating ring 17 rotates to contact the upper conductive block 18 on the conductive frame 16). At this time, the residual current in the A-phase cable is discharged through the two conductive blocks 18, the discharge rod 20, the second conductive member 261, and the resistance block 25. At this time, the conductive rod 19 corresponds to the B-phase cable, and the rotating ring 17 is driven to rotate by the cooperation of the spline rod 22 and the first extrusion rod 23, and the adjacent two conductive blocks 18 on the rotating ring 17 and the conductive frame 16 are switched according to the test process, so that the device does not require the cumbersome steps of repeated disassembly when switching the test cable, further ensuring the stability of the connection between the conductive sheet 7 and the cable.

[0071] During the discharge of the A-phase cable, the spring between the second fixed housing 30 and the sliding rod 31 drives the sliding rod 31 to gradually move rightward and reset. The hydraulic oil on the right side of the sliding rod 31 only flows to its left side through the two through holes on it. Due to the restriction of the one-way valve of the sliding rod 31, the sliding rod 31 slowly moves leftward and resets. During this process, the resistance of the grounding wire corresponding to the A-phase cable gradually decreases until the first conductive member 26 and the second conductive member 261 contact again, and the A-phase cable conducts direct discharge. At this time, the voltage release of the A-phase cable is completed. Through the cooperation of the second fixed housing 30 and the sliding rod 31, the switching between the resistance discharge and the direct discharge of the cable is automatically completed after the cable test, improving the simplicity of the test process of the device. When the test of the B-phase cable is completed, the user controls the telescopic end of the second electric push rod 21 to extend, and the spline rod 22 drives the rotating ring 17 to reverse through the first extrusion rod 23, so that the conductive block 18 electrically connected to the conductive rod 19 rotates to contact the conductive block 18 corresponding to the C-phase cable (the conductive block 18 at the lower rear). Subsequently, the above-mentioned discharge operation is performed on the B-phase cable, and the above-mentioned test steps are repeated after the discharge contact to test the C-phase cable.

[0072] The above are only examples of the present invention and are not intended to limit the present invention. All equivalent replacements made within the principle of the present invention shall be included in the protection scope of the present invention. The content not elaborated in detail in the present invention belongs to the known prior art of those skilled in the art.

Claims

1. A voltage withstand test device for cables, characterized in that, Comprising: Folding rack (1); Isolation shell (2), fixedly connected to the folding rack (1), and through holes are provided on the isolation shell (2); First fixing rack (3), fixedly connected inside the isolation shell (2), a fixing rod (4) is fixedly connected inside the isolation shell (2), mounting rods (5) are arranged on both the first fixing rack (3) and the fixing rod (4) in a circumferentially arrayed manner, first electric push rods (301) are fixedly connected to the first fixing rack (3) in a circumferentially arrayed manner, the telescopic ends of the first electric push rods (301) are fixedly connected to the adjacent mounting rods (5), clamping shells (6) are fixedly connected to the mounting rods (5), conductive sheets (7) are slidably connected to the clamping shells (6), tension springs are arranged between both sides of the conductive sheet (7) and the adjacent clamping shells (6), the clamping shells (6) are fixedly connected with mirror-image distributed first fixing shells (8), first liquid sacs (9) are fixedly connected to the first fixing shells (8), the first liquid sacs (9) are used to squeeze and wrap the conductive sheets (7), a control mechanism is arranged inside the first liquid sacs (9), and the control mechanism is used to control the flattening and inflation sequence of the first liquid sacs (9); Further comprising: A position-changing mechanism, arranged on the fixing rod (4), for switching the electrodes of the test cable, and the position-changing mechanism comprises: Conductive rack (16), fixedly connected to the fixing rod (4), and the conductive rack (16) is fixedly connected to the first fixing rack (3); Rotating ring (17), rotatably connected to the fixing rod (4), conductive blocks (18) are arranged on both the conductive rack (16) and the rotating ring (17) in a circumferentially arrayed manner, and the conductive blocks (18) on the conductive rack (16) and the conductive blocks (18) on the rotating ring (17) are used for conductive contact; Power assembly, arranged on the fixing rod (4), for controlling the relative rotation angle between the conductive rack (16) and the rotating ring (17); The power assembly comprises: Second electric push rod (21), fixedly connected inside the fixing rod (4); Spline rod (22), spline-connected inside the fixing rod (4), and the spline rod (22) is fixedly connected to the telescopic end of the second electric push rod (21); First extrusion rod (23), fixedly connected to the rotating ring (17), an arc-shaped through groove is provided on the fixing rod (4) for the first extrusion rod (23) to pass through, an inclined groove is provided on the spline rod (22), and the first extrusion rod (23) slides in the inclined groove on the spline rod (22).

2. The voltage withstand test device for a cable according to claim 1, characterized in that, The control mechanism comprises: Partition member (10), fixedly connected inside the first liquid sac (9); Pressure valve (11), fixedly connected to the side of the partition member (10) away from the first fixing shell (8), and the length of the first liquid sac (9) on the axis of the fixing rod (4) is greater than the length of the conductive sheet (7) on the axis of the fixing rod (4), and a one-way valve is arranged on the side of the partition member (10) close to the adjacent first fixing shell (8). The transmission assembly is arranged on the clamping shell (6) and is used to provide pressure for the first liquid sac (9) when the conductive sheet (7) clamps the cable.

3. The voltage withstand test device for a cable according to claim 2, characterized in that, The transmission assembly includes: A spring telescopic rod (12) is fixedly connected to the clamping shell (6). The fixed part of the spring telescopic rod (12) is fixedly connected to the mounting rod (5). The mirror-image distributed first fixed shells (8) are all communicated with the fixed part of the spring telescopic rod (12) through pipelines; A second fixed bracket (13) is fixedly connected to the telescopic end of the spring telescopic rod (12). The second fixed bracket (13) is fixedly connected with a second liquid sac (14), and the second liquid sac (14) is used to extrude the conductive sheet (7).

4. The voltage withstand test device for a cable according to claim 3, characterized in that, The isolation shell (2) is threadedly connected with a sealing cover (15). The sealing cover (15) is slidably connected to the fixed rod (4). Both the isolation shell (2) and the sealing cover (15) are made of insulating materials.

5. A voltage withstand test device for a cable according to claim 1, characterized in that, A conductive rod (19) is arranged on the rotating ring (17), and discharge rods (20) are arranged on the rotating ring (17) in a mirror-image distribution.

6. The withstand voltage test device for a cable according to claim 5, characterized in that, It further includes: A discharge mechanism is arranged on the fixed rod (4) and is used to switch the discharge mode of the discharge rod (20). The discharge mechanism includes: A fixed ring (24) is rotatably connected to the fixed rod (4). The conductive rod (19) and the discharge rod (20) are both fixedly connected to the fixed ring (24); Mirror-image distributed resistance blocks (25) are respectively slidably connected to adjacent discharge rods (20). The resistance block (25) is fixedly connected with a first conductive part (26). The discharge rod (20) is fixedly connected with a second conductive part (261). The second conductive part (261) slides within the resistance block (25) and the first conductive part (26). The resistance block (25) and the first conductive part (26) are jointly fixedly connected with a sliding shell (27); A switching assembly is arranged on the fixed rod (4) and is used to change the relative position between the resistance block (25) and the second conductive part (261).

7. The voltage withstand test device for a cable according to claim 6, characterized in that, The switching assembly includes: An extrusion frame (28) is fixedly connected to the fixed rod (4). The sliding shell (27) is fixedly connected with a second extrusion rod (29). The second extrusion rod (29) is used to drive the sliding shell (27) to move by extruding the extrusion frame (28); A delay component is arranged on the fixed ring (24) and is used to control the slow reset of the resistance block (25).

8. A voltage withstand test device for a cable according to claim 7, characterized in that, The delay component includes: Mirror-image distributed second fixed shells (30) are all fixedly connected to the fixed ring (24). The sliding shell (27) is fixedly connected with a sliding rod (31). The sliding rod (31) is slidably connected to the second fixed shell (30). A spring is arranged between the second fixed shell (30) and the sliding rod (31). A plurality of through holes are arranged on the sliding rod (31), and check valves are arranged in some of the through holes on the sliding rod (31).

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