Device and method for testing voltage breakdown performance of cable in high-temperature environment

Abstract

The invention discloses a device and method for testing the voltage breakdown performance of a cable in a high-temperature environment, and belongs to the technical field of electrical insulation, the device comprises an insulation bin, the two sides of the insulation bin are fixedly connected with an access bin and an outlet bin respectively, connecting holes are formed in the connecting positions of the access bin and the insulation bin and the connecting positions of the outlet bin and the insulation bin, and the connecting holes are communicated with the insulation bin. An insulating base is arranged at the bottom in the insulating bin, two grooves are formed in the upper surface of the insulating base, a supporting bracket is clamped in each groove, the upper parts of the supporting brackets are in contact with a cable to be tested, a conductive mechanism is arranged on the front side of the insulating base, and the conductive mechanism is connected with the insulating base. According to the test equipment, the voltage breakdown phenomenon of the cable under the real use condition can be simulated, the obtained test data is closer to the real use condition, and the electrical strength performance of the cable insulation material can be better evaluated.

Description

Technical Field

[0001] This invention relates to the field of electrical insulation technology, specifically to a device and method for testing the voltage breakdown performance of cables under high-temperature conditions. Background Technology

[0002] The essence of cable voltage breakdown is the physical process by which the conductivity of the insulating medium increases dramatically under the influence of a strong electric field, thus abruptly changing from an insulating state to a conductive state. During normal operation, the cable insulation layer withstands the working electric field, with only a weak leakage current present, maintaining excellent insulation performance. However, when the electric field strength applied to the insulation layer exceeds its inherent critical withstand threshold, this balance is completely disrupted. The microscopic mechanism mainly involves the following levels: First, driven by a strong electric field, the initial free electrons existing inside or on the surface of the insulating medium are accelerated and gain enormous kinetic energy. When they collide with the lattice or molecules, they generate new electron-ion pairs. These newly generated charge carriers are further accelerated and collide to generate more charge carriers, forming the so-called "electron avalanche" effect, causing a sharp increase in current. Second, cable insulation is not ideally pure; trace bubbles, impurities, moisture, or microscopic voids generated during manufacturing may exist within it, becoming focal points for local electric field distortion. At these defects, the electric field strength is much higher than the average field strength, making it easier to induce partial discharge. This continuous, minute discharge gradually erodes and carbonizes the insulating material, forming conductive electrical dendritic channels, paving the way for eventual complete breakdown. In addition, overvoltage generates extremely high transient electric fields, which may directly lead to instantaneous breakdown of the insulation structure; while long-term AC stress may cause dielectric loss heating, resulting in thermal breakdown.

[0003] Once a cable experiences voltage breakdown, it triggers a series of chain reactions, posing a serious threat to the power system itself, related equipment, and public safety. The most direct harm is permanent damage to the cable itself. The breakdown point generates a high-temperature electric arc, instantly burning away the insulation layer and even the conductor and metal shielding layer, rendering the cable unusable and requiring replacement of the entire cable. This not only incurs high material and construction costs but also causes prolonged power outages, affecting normal electricity use and industrial production. Breakdown accidents severely impact the stable operation of the power system. Cable breakdown typically manifests as phase-to-phase short circuits or single-phase grounding faults, generating huge short-circuit currents. This can cause line protection devices to trip, leading to large-scale power outages. If the electric arc at the fault point cannot be extinguished in time, in the case of a non-effectively grounded neutral point, it may trigger dangerous intermittent arc overvoltages, expanding the fault range to other intact equipment in the system, such as damaging connected transformers, switchgear, and other valuable assets. Even more seriously, the high-temperature electric arc generated at the breakdown point can easily ignite the cable's insulation, sheath, and even surrounding flammable materials, causing fires or even explosions, posing an extreme threat to the safety of people, property, and facilities. In densely populated urban pipe networks, tunnels, or substations, the consequences of such accidents are unimaginable.

[0004] Most existing equipment is designed for breakdown tests of insulation materials, rather than directly testing cables. Breakdown tests of insulation materials cannot directly reflect the voltage breakdown phenomena that cables may experience in practice. Therefore, there is a need for equipment that can simulate the actual use of cables and test the voltage breakdown of cables at high temperatures. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a device and method for testing the voltage breakdown performance of cables under high-temperature conditions.

[0006] The technical solution of the present invention is: a voltage breakdown performance testing device for cables under high temperature environment, comprising an insulating chamber, an inlet chamber and an outlet chamber fixedly connected to both sides of the insulating chamber respectively, and connection holes provided at the connection points between the inlet chamber and the outlet chamber and the insulating chamber. An insulating base is provided at the bottom of the insulating chamber, and two grooves are provided on the upper surface of the insulating base. A support bracket is snapped into each groove. The upper part of the support bracket is in contact with the cable to be tested. A conductive mechanism is provided on the front side of the insulating base, and the conductive mechanism is grounded. A heating mechanism for heating the cable to be tested is fixed on the inner wall of the insulating chamber. A power distribution device is fixed on one side of the insulating chamber and is electrically connected to the inlet chamber. A sealed door is hinged to the front side of the insulating chamber.

[0007] Furthermore, the conductive mechanism includes a sliding groove, in which a sliding block is slidably engaged, and two fixing brackets are fixedly connected to the upper sides of the sliding block, with a metal rod electrically connected to the ground wire fixedly connected to the fixing bracket.

[0008] Note: The current leaking from the cable is conducted to the ground wire through a conductive mechanism to avoid damage to equipment or personnel. The sliding groove and sliding block are made of insulating materials, such as insulating ceramic materials.

[0009] Furthermore, a metal nut is embedded in the upper part of one of the fixing frames, the metal rod is threaded to the metal nut, a conductive plate is electrically connected to the lower part of the metal nut, the conductive plate is fixedly connected inside the fixing frame, a contact piece is provided at the bottom of the sliding block, the lower end of the conductive plate is electrically connected to the contact piece, a conductive plate that is electrically in contact with the contact piece is embedded in the sliding groove, and a wire channel is provided inside the front side of the insulating base, and a conductive wire that is electrically connected to the front end of the conductive plate is provided in the wire channel.

[0010] Explanation: If the current is directly drawn from the metal rod to the ground wire through a wire, the insulation layer of the wire is prone to peeling and softening in a high-temperature environment. Secondly, the movement of the sliding block is not conducive to fixing the wire. Therefore, the above problem can be solved by having the current pass through the conductive sheet and contact sheet to the conductive plate, and then from the conductive plate to the conductive wire, and from the conductive wire to the ground wire.

[0011] Furthermore, a detection chamber is fixed to the front side of the insulating chamber. The detection chamber is equipped with a voltage transformer for detecting the voltage of the conductive line and a current transformer for detecting the conductive current. A terminal block is fixedly connected to the side wall of the detection chamber and electrically connected to the conductive line. The outer end of the terminal block is grounded.

[0012] Note: The voltage and current transformers in the testing chamber can detect the magnitude of current and voltage generated when voltage breakdown occurs. Both the current and voltage transformers are commercially available products, such as the Itai Electronics ETCR050A current transformer and the Xi'an Hengtai JSZV16-10R voltage transformer.

[0013] Furthermore, the heating mechanism includes a heating bracket fixed to the inner wall of the insulating chamber, a heating plate fixedly connected to the heating bracket, a plurality of heating slots provided on the heating plate, heating resistance wires being snapped into the heating slots, and the heating resistance wires being electrically connected to the power distribution device.

[0014] Note: The heating bracket is used to fix the heating plate. The heating bracket can be a fixed structure or a movable structure, which is not limited here. The heating plate can block heat and allow the heat generated by the electric heating wire to dissipate downwards to heat the cable under test.

[0015] Furthermore, an infrared temperature sensor is fixed to the top of the insulating chamber, and a PLC controller for electrical connection with the infrared temperature sensor, the power distribution device, and the heating mechanism is fixed to the right side of the insulating chamber. The PLC controller is connected to a computer for communication.

[0016] Note: Ordinary temperature sensors need to be close to the heat source. Since the probe of an ordinary temperature sensor is usually made of conductive material, when voltage breakdown occurs, the current can easily be guided to the temperature sensor, causing damage. Therefore, an infrared temperature sensor is used, which can detect the temperature of the heat source from a distance, and adjust the voltage and current parameters and record the experimental data through a computer.

[0017] Furthermore, the access compartment includes an insulating shell, an insulating column is fixedly connected inside the insulating shell, a connector is embedded and fixedly connected on the insulating column, the outer end of the connector is electrically connected to the power distribution device, a connector is electrically connected above the connector via a screw, the inner end of the connector is electrically connected to the cable to be tested, and a cover plate is hinged to the top of the insulating shell.

[0018] Note: Connector 1 and connector 2 are fixed by screws for easy detachment, making it easier to connect connector 2 to the end of the cable under test.

[0019] Furthermore, the outlet chamber includes an insulating shell II, a cover plate II is hinged to the top of the insulating shell II, and a buckle for fixing the end of the cable to be tested is fixedly connected inside the insulating shell II.

[0020] Note: The other end of the cable under test is secured by a clip to prevent the cable from shifting due to softening of the insulation and lack of support, which could cause unnecessary safety accidents.

[0021] Furthermore, the power distribution device includes a power distribution housing, an emergency stop switch and a main power switch are fixedly connected to the outer wall of the power distribution housing, and a power generator is provided inside the power distribution housing that is electrically connected to the emergency stop switch, the main power switch and the PLC controller.

[0022] Note: The emergency stop switch is used for emergency power cut-off in case of emergency. It is easy to operate. The main power switch is used for start and stop control of each test. It will not cause the power to be turned on due to accidental contact. Both the emergency stop switch and the main power switch are commercially available products and are not limited here.

[0023] This invention also provides a method for testing the voltage breakdown performance of cables under high-temperature conditions, based on the aforementioned cable voltage breakdown performance testing device under high-temperature conditions, comprising the following steps: S1. Peel off the outer sheath of one end of the cable to be tested to expose the conductor. Insert the exposed conductor end into the outlet compartment and fix it to the inlet compartment through the two connection holes. Place the middle part of the cable to be tested on the support bracket. Adjust the distance between the metal rod and the cable to be tested by pushing the sliding groove. Start the power distribution device to energize the cable to be tested. S2. The power distribution device generates a high-voltage current through an external power source. The high-voltage current is conducted to the cable under test through the access compartment. By adjusting the voltage generated by the power distribution device, the breakdown voltage of the cable under test is tested. By controlling the heating temperature of the heating mechanism, the breakdown voltage of the cable under test at different temperatures is tested. By adjusting the distance between the metal rod and the cable under test, the breakdown voltage of the cable under test and the conductor at different distances is tested. S3. When the cable under test breaks down, the current in the cable under test is transmitted to the ground wire through the metal rod, conductive plate, contact plate and conductive wire. The voltage and current magnitude of the cable under test when voltage breakdown occurs are detected by voltage transformer and current transformer.

[0024] The beneficial effects of this invention are: (1) The present invention can test the breakdown voltage at different temperatures, the breakdown voltage at different conductor spacings, and the breakdown voltage of different cable materials at the same temperature and the same conductor spacing by using the controlled variable method. The parameters of the present invention for testing the breakdown voltage of cables are controllable, the operation is convenient, and multiple parameters can be tested and studied.

[0025] (2) The test equipment of the present invention can simulate the voltage breakdown phenomenon of cables under real use conditions, and the experimental data obtained are closer to the actual use conditions, and can better evaluate the electrical strength performance of cable insulation materials. Attached Figure Description

[0026] Figure 1 This is a top view of the structure of the present invention.

[0027] Figure 2 This is a schematic diagram of the main structure of the present invention.

[0028] Figure 3 yes Figure 2 Enlarged view of point A in the middle.

[0029] Figure 4 This is a left view of the support bracket of the present invention.

[0030] Figure 5 This is a front cross-sectional view of the conductive mechanism of the present invention.

[0031] Figure 6 This is a bottom view of the heating plate of the present invention.

[0032] Among them, 1-insulating chamber, 2-access chamber, 3-outlet chamber, 11-connection hole, 4-insulating base, 12-groove, 13-support bracket, 5-conductive mechanism, 6-heating mechanism, 7-power distribution device, 14-sealed door, 51-sliding groove, 52-sliding block, 53-fixed frame, 54-metal rod, 55-metal nut, 56-conductive sheet, 57-contact piece, 58-conductive plate, 59-conductive wire, 81-voltage transformer, 82-current transformer, 8 3-Terminal, 61-Heating bracket, 62-Heating plate, 63-Heating tank, 64-Heating resistance wire, 15-Infrared temperature sensor, 16-PLC controller, 9-Computer terminal, 21-Insulating shell one, 22-Insulating column, 23-Connecting piece one, 24-Screw, 25-Connecting piece two, 26-Cover plate one, 31-Insulating shell two, 32-Cover plate two, 33-Snap fastener, 71-Distribution shell, 72-Emergency stop switch, 73-Main power switch, 74-Power generator. Detailed Implementation

[0033] Example 1: like Figure 1 , Figure 2 , Figure 4 As shown, a voltage breakdown performance testing device for cables under high temperature conditions includes an insulating chamber 1. An inlet chamber 2 and an outlet chamber 3 are fixedly connected to both sides of the insulating chamber 1. The inlet chamber 2 and outlet chamber 3 are provided with connection holes 11 at the connection points with the insulating chamber 1. An insulating base 4 is provided at the bottom of the insulating chamber 1. Two grooves 12 are provided on the upper surface of the insulating base 4. A support bracket 13 is snapped into each groove 12. The upper part of the support bracket 13 is in contact with the cable to be tested. A conductive mechanism 5 is provided on the front side of the insulating base 4. The conductive mechanism 5 is grounded. A heating mechanism 6 for heating the cable to be tested is fixed on the inner wall of the insulating chamber 1. A power distribution device 7 is fixed on one side of the insulating chamber 1. The power distribution device 7 is electrically connected to the inlet chamber 2. A sealed door 14 is hinged to the front side of the insulating chamber 1.

[0034] The conductive mechanism 5 includes a sliding groove 51, in which a sliding block 52 is slidably engaged. Two fixing brackets 53 are fixedly connected to the upper sides of the sliding block 52, and a metal rod 54 electrically connected to the ground wire is fixedly connected to the fixing bracket 53.

[0035] The current leaked from the cable is conducted to the ground wire through the conductive mechanism 5. One end of the metal rod 54 is directly connected to the ground wire through a wire to avoid damage to equipment or personnel. The sliding groove 51 and the sliding block 52 are both made of insulating materials, such as insulating ceramic materials.

[0036] like Figure 6As shown, the heating mechanism 6 includes a heating bracket 61 fixed to the inner wall of the insulating chamber 1. A heating plate 62 is fixedly connected to the heating bracket 61. The heating plate 62 is provided with a plurality of heating grooves 63. A heating resistance wire 64 is snapped into the heating groove 63. The heating resistance wire 64 is electrically connected to the power distribution device 7.

[0037] The heating bracket 61 is used to fix the heating plate 62. The heating bracket 61 can be a fixed structure or a movable structure, which is not limited here. The heating plate 62 can block the heat and allow the heat generated by the electric heating wire 64 to dissipate downwards to heat the cable under test.

[0038] like Figure 3 As shown, the access chamber 2 includes an insulating shell 21. An insulating column 22 is fixedly connected inside the insulating shell 21. A connector 23 is embedded and fixedly connected on the insulating column 22. The outer end of the connector 23 is electrically connected to the power distribution device 7. A connector 25 is electrically connected above the connector 23 via a screw 24. The inner end of the connector 25 is electrically connected to the cable under test. A cover plate 26 is hinged to the top of the insulating shell 21.

[0039] Connector 1 23 and connector 25 are detachably fixed by screw 24, which makes it easier for connector 25 to be electrically connected to the end of the cable under test.

[0040] The outlet chamber 3 includes an insulating shell 31, a cover plate 32 is hinged to the top of the insulating shell 31, and a clip 33 for fixing the end of the cable to be tested is fixedly connected inside the insulating shell 31.

[0041] The other end of the cable under test is secured by the clip 33 to prevent the cable from shifting due to softening of the insulation layer and lack of support, thus avoiding unnecessary safety accidents.

[0042] The power distribution device 7 includes a power distribution housing 71. An emergency stop switch 72 and a main power switch 73 are fixedly connected to the outer wall of the power distribution housing 71. A power generator 74 is provided inside the power distribution housing 71 and is electrically connected to the emergency stop switch 72, the main power switch 73, and the PLC controller 16.

[0043] Emergency stop switch 72 is used for emergency power cut-off in case of emergency. It is easy to operate. The main power switch 73 is used for start and stop control of each test. It will not cause the power to be turned on due to accidental contact. Emergency stop switch 72, main power switch 73 and power generator 74 are all commercially available products. No restrictions are imposed here.

[0044] Example 2: The difference between this embodiment and Embodiment 1 is that, Figure 5As shown, a metal nut 55 is embedded in the upper part of one of the fixing brackets 53, and a metal rod 54 is threadedly connected to the metal nut 55. A conductive sheet 56 is electrically connected to the lower part of the metal nut 55. The conductive sheet 56 is fixedly connected inside the fixing bracket 53. A contact piece 57 is provided at the bottom of the sliding block 52. The lower end of the conductive sheet 56 is electrically connected to the contact piece 57. A conductive plate 58 that is electrically in contact with the contact piece 57 is embedded in the sliding groove 51. A wire channel 41 is provided inside the front side of the insulating base 4. A conductive wire 59 that is electrically connected to the front end of the conductive plate 58 is provided in the wire channel 41.

[0045] Compared to Embodiment 1, in Embodiment 1, the current is directly drawn from the metal rod 54 to the ground wire via a wire. In high-temperature environments, the insulation layer of the wire is prone to peeling and softening. Furthermore, the movement of the sliding block 52 is not conducive to fixing the wire. Therefore, in this embodiment, the current is transmitted through the conductive sheet 56 and the contact sheet 57 to the conductive plate 58, and then from the conductive plate 58 to the conductive wire 59, and finally from the conductive wire 59 to the ground wire, which solves the above-mentioned problem.

[0046] Example 3: The difference between this embodiment and embodiment 2 is that, in this embodiment, an infrared temperature sensor 15 is fixed on the top of the insulating chamber 1, and a PLC controller 16 is fixed on the right side of the insulating chamber 1 for electrical connection with the infrared temperature sensor 15, the power distribution device 7, and the heating mechanism 6. The PLC controller 16 is connected to the computer terminal 9 for communication.

[0047] Compared to Example 2, in this embodiment, a conventional temperature sensor needs to be close to the heat source. Since the probe of a conventional temperature sensor is usually made of conductive material, when voltage breakdown occurs, the current can easily be guided to the temperature sensor, causing damage. Therefore, in this embodiment, an infrared temperature sensor 15 is used, which can detect the temperature of the heat source from a distance. The voltage and current parameters are adjusted and the experimental data is recorded through the computer terminal 9. The infrared temperature sensor 15 used is a commercially available product, such as the American Raytek 3ILRSC / L2.

[0048] Example 4: The difference between this embodiment and embodiment 3 is that, in this embodiment, a detection chamber 8 is fixed to the front side of the insulating chamber 1. The detection chamber 8 is equipped with a voltage transformer 81 for detecting the voltage of the conductive wire 59 and a current transformer 82 for detecting the conductive current. The side wall of the detection chamber 8 is fixedly connected to a terminal 83 that is electrically connected to the conductive wire 59, and the outer end of the terminal 83 is grounded.

[0049] Compared to Example 3, in this embodiment, the voltage transformer 81 and current transformer 82 in the detection chamber can detect the magnitude of current and voltage generated when voltage breakdown occurs. Both the current transformer 82 and the voltage transformer 81 are commercially available products, such as the current transformer ETCR050A from Yitai Electronics and the voltage transformer JSZV16-10R from Xi'an Hengtai.

[0050] Example 5: This embodiment provides a method for testing the voltage breakdown performance of cables under high-temperature conditions, based on the cable voltage breakdown performance testing device under high-temperature conditions in Embodiment 4 above, including the following steps: S1. Peel off the outer sheath of one end of the cable to be tested to expose the conductor. Insert the exposed conductor end into the outlet compartment 3 and fix it to the inlet compartment 2 through the two connection holes 11. Place the middle part of the cable to be tested above the support bracket 13. Adjust the distance between the metal rod 54 and the cable to be tested by pushing the sliding groove 51. Start the power distribution device 7 to energize the cable to be tested. S2. The power distribution device 7 generates a high-voltage current through an external power source. The high-voltage current is conducted to the cable under test through the access compartment 2. By adjusting the voltage generated by the power distribution device 7, the breakdown voltage of the cable under test is tested. By controlling the heating temperature of the heating mechanism 6, the breakdown voltage of the cable under test at different temperatures is tested. The temperature of the outer wall of the cable is detected by the infrared temperature sensor 15. By adjusting the distance between the metal rod 54 and the cable under test, the breakdown voltage of the cable under test and the conductor at different distances is tested. S3. When the cable under test breaks down, the current in the cable under test is transmitted to the ground wire through the metal rod 54, conductive piece 56, contact piece 57, and conductive wire 59. The voltage and current magnitude of the cable under test when it breaks down are detected by the voltage transformer 81 and the current transformer 82.

[0051] The heating resistance wire 64 and PLC controller 16 used in the above embodiments are all commercially available products. The support bracket 13, insulating base 4, sliding block 52, fixing bracket 53, cover plate 1 26, cover plate 2 32, and buckle 33 are all made of insulating materials. As long as the function of the present invention can be achieved, those skilled in the art can choose to use them according to common sense, and no special limitation is made here.

Claims

1. A device for testing the voltage breakdown performance of cables under high-temperature conditions, characterized in that, The device includes an insulating chamber (1), with an access chamber (2) and an output chamber (3) fixedly connected to its two sides respectively. The access chamber (2) and the output chamber (3) are connected to the insulating chamber (1) with connection holes (11). An insulating base (4) is provided at the bottom of the insulating chamber (1). Two grooves (12) are provided on the upper surface of the insulating base (4). A support bracket (13) is snapped into each groove (12). The upper part of the support bracket (13) is in contact with the cable to be tested. A conductive mechanism (5) is provided on the front side of the insulating base (4). The conductive mechanism (5) is grounded. A heating mechanism (6) for heating the cable to be tested is fixed on the inner wall of the insulating chamber (1). A power distribution device (7) is fixed on one side of the insulating chamber (1). The power distribution device (7) is electrically connected to the access chamber (2). A sealed door (14) is hinged on the front side of the insulating chamber (1).

2. The cable voltage breakdown performance testing device under high temperature environment as described in claim 1, characterized in that, The conductive mechanism (5) includes a sliding groove (51), in which a sliding block (52) is slidably engaged, and two fixing frames (53) are fixedly connected to the upper sides of the sliding block (52), and a metal rod (54) electrically connected to the ground wire is fixedly connected to the fixing frame (53).

3. The cable voltage breakdown performance testing device under high temperature environment as described in claim 2, characterized in that, A metal nut (55) is embedded in the upper part of one of the fixing frames (53), and the metal rod (54) is threaded to the metal nut (55). A conductive sheet (56) is electrically connected to the lower part of the metal nut (55). The conductive sheet (56) is fixedly connected inside the fixing frame (53). A contact piece (57) is provided at the bottom of the sliding block (52). The lower end of the conductive sheet (56) is electrically connected to the contact piece (57). A conductive plate (58) that is electrically in contact with the contact piece (57) is embedded in the sliding groove (51). A wire channel (41) is provided inside the front side of the insulating base (4). A conductive wire (59) that is electrically connected to the front end of the conductive plate (58) is provided in the wire channel (41).

4. The cable voltage breakdown performance testing device under high temperature environment as described in claim 3, characterized in that, The front side of the insulating chamber (1) is fixed with a detection chamber (8). The detection chamber (8) is equipped with a voltage transformer (81) for detecting the voltage of the conductive line (59) and a current transformer (82) for detecting the conductive current. The side wall of the detection chamber (8) is fixedly connected with a terminal (83) that is electrically connected to the conductive line (59). The outer end of the terminal (83) is grounded.

5. The cable voltage breakdown performance testing device under high temperature environment as described in claim 1, characterized in that, The heating mechanism (6) includes a heating bracket (61) fixed to the inner wall of the insulating chamber (1), a heating plate (62) fixedly connected to the heating bracket (61), a plurality of heating grooves (63) provided on the heating plate (62), a heating resistance wire (64) snapped into the heating groove (63), and the heating resistance wire (64) electrically connected to the power distribution device (7).

6. The cable voltage breakdown performance testing device under high temperature environment as described in claim 1, characterized in that, An infrared temperature sensor (15) is fixed on the top of the insulating chamber (1), and a PLC controller (16) is fixed on the right side of the insulating chamber (1) for electrical connection with the infrared temperature sensor (15), the power distribution device (7), and the heating mechanism (6). The PLC controller (16) is connected to the computer terminal (9) for communication.

7. The cable voltage breakdown performance testing device under high temperature environment as described in claim 1, characterized in that, The access compartment (2) includes an insulating shell (21), an insulating column (22) is fixedly connected inside the insulating shell (21), a connector (23) is embedded and fixedly connected on the insulating column (22), the outer end of the connector (23) is electrically connected to the power distribution device (7), a connector (25) is electrically connected above the connector (23) via a screw (24), the inner end of the connector (25) is electrically connected to the cable to be tested, and a cover plate (26) is hinged above the insulating shell (21).

8. The cable voltage breakdown performance testing device under high temperature environment as described in claim 1, characterized in that, The outlet compartment (3) includes an insulating shell two (31), and a cover plate two (32) is hinged above the insulating shell two (31). A buckle (33) for fixing the end of the cable to be tested is fixedly connected inside the insulating shell two (31).

9. The cable voltage breakdown performance testing device under high temperature environment as described in claim 6, characterized in that, The receiving chamber (3) includes an insulating shell two (31), a cover plate two (32) is hinged to the top of the insulating shell two (31), and a buckle (33) is fixedly connected inside the insulating shell two (31).

10. A method for testing the voltage breakdown performance of cables under high-temperature conditions, based on the cable voltage breakdown performance testing device under high-temperature conditions as described in claim 4, characterized in that... Includes the following steps: S1. Peel off the outer sheath of one end of the cable to be tested to expose the conductor. Insert the exposed conductor end into the outlet compartment (3) and fix it to the inlet compartment (2) through the two connection holes (11). Place the middle part of the cable to be tested above the support bracket (13). Adjust the distance between the metal rod (54) and the cable to be tested by pushing the sliding groove (51). Start the power distribution device (7) to energize the cable to be tested. S2. The power distribution device (7) generates a high-voltage current through an external power source. The high-voltage current is conducted to the cable under test through the access compartment (2). By adjusting the voltage generated by the power distribution device (7), the breakdown voltage of the cable under test is tested. By controlling the heating temperature of the heating mechanism (6), the breakdown voltage of the cable under test at different temperatures is tested. By adjusting the distance between the metal rod (54) and the cable under test, the breakdown voltage of the cable under test and the conductor at different distances is tested. S3. When the cable under test breaks down, the current on the cable under test is transmitted to the ground wire through the metal rod (54), conductive sheet (56), contact sheet (57), and conductive wire (59). The voltage and current magnitude of the cable under test when it breaks down are detected by the voltage transformer (81) and the current transformer (82).

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