Cable water-blocking buffer layer structure simulation test system and method with adjustable contact state and humidity

Abstract

A cable water-blocking buffer layer structure simulation test system and method with adjustable contact state and humidity, the system comprises a bottomless test box with a vent on the top surface, wherein partitions are arranged inside the box to divide the box into a monitoring area, a test area and a control area; a camera is placed in the monitoring area, an ablation platform is placed in the middle of the test area, humidifiers are placed at the four corners of the test area, electric fans are placed between the humidifiers, and a power bank is placed near the partitions; a PLC controller is placed in the control area, and the data line of the PLC controller passes through the side wall of the box to be connected to an external computer; the data lines of the humidifier and the electric fan are all connected to the PLC controller through the partitions; the system and method of the present invention effectively restore the structural characteristics of the corrugated aluminum sheath and the water-blocking buffer layer in the high-voltage cable, and better simulate the real working state of the water-blocking buffer layer under the actual cable operation condition by adjusting the external voltage and current, electrode position, pressure and ambient humidity, which is conducive to exploring and analyzing the root cause and damage mechanism of the ablation of the water-blocking buffer layer.

Description

Technical Field

[0001] The present invention relates to the technical field of cable water-blocking buffer layer structure simulation test, and in particular to a cable water-blocking buffer layer structure simulation test system and method, the contact state and ambient humidity of which can be freely adjusted. Background Art

[0002] With the rapid development of China's economy, the continuous expansion of urban scale and the continuous improvement of people's living standards, higher requirements have been placed on the transmission capacity and power supply quality of the power grid. Due to the limitations of overhead lines in terms of corridors and landscapes, underground cables are playing an increasingly important role in urban power supply systems.

[0003] Existing high voltage and extra high voltage cables usually adopt corrugated aluminum sheath structure, such as Figure 1 As shown. In this structure, the water-blocking buffer layer between the aluminum sheath and the insulation shield is an important component, which has a significant impact on the electrical, mechanical and water-blocking properties of the cable. The water-blocking buffer layer has semi-conductive properties, which effectively ensures the electrical contact between the aluminum sheath and the insulation shield; it has a fluffy structure, which significantly improves the matching between the cross-linked polyethylene insulation part and the aluminum sheath with a large difference in thermal expansion coefficient, and prevents the insulation shield and the aluminum sheath from poor contact to form an air gap when the cable is under low load, and the insulation expansion is restricted by the aluminum sheath under high load, resulting in marks on the surface of the insulation shield; it also has water absorption and expansion properties. When water penetrates from the cable end or from the defects of the aluminum sheath, the water-blocking powder in the water-blocking buffer layer absorbs water and expands rapidly, filling the space below the aluminum sheath, preventing water from diffusing longitudinally along the cable, thereby achieving the purpose of water blocking. Due to the corrugated structure of the aluminum sheath, its contact state with the water-blocking buffer layer will be different at each position after the cable is laid and in actual operation, which will have an adverse effect on the performance of the cable.

[0004] my country's current national standard for high-voltage cables has given relevant provisions for water-blocking buffer layers, but it mainly makes qualitative requirements on the system performance that the water-blocking buffer layer should have from the perspective of the overall function of the cable, and lacks quantitative indicators corresponding to special performance parameters. Most domestic cable manufacturers follow the foreign cable design model and do not understand the specific requirements for the design of water-blocking buffer layers. When purchasing water-blocking buffer tapes, the quality requirements are not clear, the control process is not strict, and there are large differences in products between different manufacturers; and due to low-price competition, it is not uncommon for manufacturers to use cheap tapes as inferior products.

[0005] In recent years, domestic power operation departments have repeatedly discovered discharge erosion of water-blocking buffer layers in high-voltage cable lines, as well as the resulting cable body breakdown failures, which has attracted widespread attention in the industry and triggered a wave of research.

[0006] At present, the industry has proposed three possible reasons for the ablation of the cable's water-blocking buffer layer: short-circuit current flows through the aluminum corrugation and burns it; the circulating current in the cable during operation causes the aluminum corrugation to heat up and burn the water-blocking buffer layer; local discharge occurs at the trough between the cable insulation shielding layer and the aluminum sheath, burning the water-blocking buffer layer. In response to the above three speculations, the researchers conducted electric field simulation and simulation experiments on the corrugated aluminum sheath structure, proving from different angles that excessive resistivity of the water-blocking buffer tape and poor contact with the aluminum sheath may cause local electric field distortion and induce local discharge. However, these studies are more of a qualitative analysis with a large degree of speculation. They have neither effectively corresponded to the structural characteristics of the corrugated aluminum sheath in the actual cable nor demonstrated the basic process of the occurrence and development of the ablation of the water-blocking buffer layer. Therefore, they lack theoretical systematization and engineering guidance.

[0007] In order to explore the root cause of the ablation of the water-blocking buffer layer in high-voltage cables, reproduce the entire process of its occurrence and development, and determine the relevant influencing factors and damage mechanisms, it is necessary to establish a water-blocking buffer layer structure simulation test system that corresponds to the actual structure of the cable, is easy to process, convenient for experiments, and can achieve condition control and full-process observation. Summary of the invention

[0008] In order to reflect the structural characteristics of the high-voltage cable and the contact characteristics between the corrugated aluminum sheath and the water-blocking buffer layer as realistically as possible, and to reproduce the basic process of ablation of the water-blocking buffer layer under actual cable operation, the purpose of the present invention is to provide a cable water-blocking buffer layer structure simulation test system and method with freely adjustable contact state and ambient humidity. The system effectively restores the structural characteristics of the corrugated aluminum sheath and the water-blocking buffer layer in the high-voltage cable, and better simulates the real working state of the water-blocking buffer layer under actual cable operation by adjusting the applied voltage and current, electrode position, pressure, and ambient humidity. Real-time monitoring of voltage, current, temperature, humidity, etc. and full-process shooting and recording of the tested sample are beneficial to exploring and analyzing the root cause and damage mechanism of the ablation of the water-blocking buffer layer.

[0009] To achieve the above object, the present invention adopts the following technical solution:

[0010] A contact state and humidity adjustable cable water blocking buffer layer structure simulation test system, comprising a bottomless test box 1, the top surface of the bottomless test box 1 is provided with a vent 2, the bottomless test box 1 is provided with a partition 3 and a glass partition 4, the partition 3 and the glass partition 4 divide the bottomless test box 1 into a monitoring area A, a test area B and a control area C; a box door 5 is arranged on the front of the bottomless test box 1; a camera 10 is placed in the monitoring area A, and a power cord passes through the side wall of the bottomless test box and is connected to an AC 220V power supply to power the camera 10; An ablation platform 11 is placed in the middle of the test area B, humidifiers 6 are placed at the four corners of the test area B, electric fans 7 are placed between the humidifiers 6, and a power bank 8 is placed near the partition 3; a plc controller 9 is placed in the control area C, and the power cord passes through the side wall of the bottomless test box and is connected to an AC 220V power supply to power the plc controller 9; the plc controller data cable passes through the side wall of the bottomless test box and is connected to an external computer 25; the data cables of the humidifier 6 and the electric fan 7 in the test area are all connected to the plc controller 9 through the partition 3.

[0011] The ablation platform 11 includes an epoxy bracket 12, a ground electrode and a plurality of high-voltage electrode devices arranged on the epoxy bracket 12; the ground electrode 16 is fixed at the bottom of the epoxy bracket 12, the sample 15 is placed on the ground electrode 16, and the grounding terminal 24 of the ground electrode 16 extends out of the epoxy bracket 12; the electrode rod 19 of each group of high-voltage electrode devices is welded with the high-voltage electrode 13, the high-voltage electrode 13 is placed on the sample 15, and the electrode rod 19 is connected to the top of the epoxy bracket 12 by a bolt 22; the bolt 22 is provided with a top screw 21 to keep the gap distance between the high-voltage electrode 13 and the sample 15 unchanged, so that the gap distance between the high-voltage electrode 13 and the sample 15 is adjustable; the electrode rod 19 is located in the ring The outer part of the oxygen support 12 is penetrated with a weight block 20, and the pressure applied by the high-voltage electrode 13 on the sample 15 is adjusted by adjusting the number of the weight blocks 20; the high-voltage electrodes 13 of each group of high-voltage electrode devices are connected by a wire 14, and the top of the electrode rod 19 of one group of high-voltage electrode devices is connected to the high-voltage terminal 23; the shape of the high-voltage electrode 13 is arc-shaped; the sample 15 is stacked by a high-voltage cable water-blocking buffer layer and a shielding layer, the water-blocking buffer layer is in contact with the high-voltage electrode 13, and the shielding layer is in contact with the ground electrode 16; a temperature sensor and a humidity sensor are placed on the epoxy support 12, and the data lines of the temperature sensor and the humidity sensor are connected to the PLC controller 9 through the partition 3;

[0012] The high voltage terminal 23 passes through the side wall of the bottomless test box 1 and is connected to the AC ammeter 26, the circuit breaker 28, the AC power supply 29 and the grounding terminal 24 in sequence through a high voltage wire; an AC voltmeter 27 is connected in parallel at both ends of the high voltage terminal 23 and the grounding terminal 24.

[0013] As a further improvement and supplement to the above technical solution, the present invention also includes the following additional technical features.

[0014] The glass baffle 4 is made of transparent glass, which is convenient for the camera 10 to monitor and photograph the ablation of the water-blocking buffer layer in the test area B in real time.

[0015] The AC voltmeter 27 can display the voltage value at both ends of the ablation platform in real time.

[0016] The AC ammeter 26 can display the main circuit current value in real time.

[0017] The circuit breaker 28 can be operated according to the current condition of the ablation platform. When the water-blocking buffer layer on the ablation platform is ablated, the high-voltage electrode 13 and the ground electrode 16 are short-circuited, and a large current will flow. To ensure the safety of the test, the circuit breaker 28 will be operated to cut off the power supply so that the test personnel can check the ablation condition of the water-blocking buffer layer.

[0018] The camera 10 adopts a dual-axis dual-motor, cantilever-free design, a 115° vertical viewing angle, and a 360° panoramic video, and can monitor every corner of the ablation platform 11. At the same time, the camera 10 is a low-light full-color camera, which can still see color images under weak light at night, realizing 24-hour uninterrupted recording.

[0019] The epoxy bracket 12 is made of epoxy material with excellent mechanical, heat-resistant and insulating properties, which effectively ensures the safety of the test platform.

[0020] The high-voltage electrode 13 and the high-voltage cable aluminum sheath are made of the same metal material, which is closer to engineering practice; preferably, the high-voltage electrode 13 is made of electrical aluminum 1060.

[0021] The arc-shaped inner diameter of the high-voltage electrode 13 is 10 mm, the outer diameter is 14 mm, the central angle is 180°, and the thickness is 2 mm, which corresponds to the corrugated aluminum sheath structure in the high-voltage cable and reflects its main characteristics.

[0022] The humidifier 6 is small in size and has its own water storage device, thus avoiding the disadvantage of a traditional water tank that occupies a large area.

[0023] The volume of the electric fan 7 is 0.01m 3 Up to 0.02m 3 It has small size and strong wind force, avoiding the shortcomings of traditional fans such as large footprint and high energy consumption.

[0024] The test method of the cable water-blocking buffer layer structure simulation test system with adjustable contact state and humidity is as follows: the test personnel sets the target humidity through the external computer 25, the humidity sensor collects humidity data and transmits it to the plc controller 9; when the humidity is lower than the set value, the test personnel closes the vent 2 to interrupt the gas exchange between the bottomless test box 1 and the outside world, the plc controller 9 starts all the humidifiers 6 to increase the humidity of the test area B by evaporating the water in the humidifier; when the humidity is higher than the set value, the test personnel opens the vent 2 to restore the gas exchange between the bottomless test box 1 and the outside world, the plc controller 9 controls to turn on the electric fan 7 and turn off the humidifier 6 to reduce the humidity in the experimental area; the plc controller 9 external The display screen of the computer 25 is connected to display the temperature and humidity of the test area in real time; if the test is carried out in a non-contact state, the electrode rod 19 is fixed at different positions by the top screw 21, and the distance between the high-voltage electrode 13 and the sample 15 is controlled between 0 and 2 mm; if the test is carried out in a contact state, the top screw 21 is unscrewed to allow the electrode rod 19 to droop naturally, and the lower surface of the high-voltage electrode 13 contacts the upper surface of the sample 15. By placing 0 to 4 weight blocks 20 on the electrode rod 19, the pressure applied to the sample 15 is adjusted to 0 to 30N; the output voltage of the AC power supply 29 is adjusted until the reading of the AC ammeter 26 or the AC voltmeter 27 is a predetermined value, and the simulated ablation test is started, and the ablation process and parameter changes are recorded.

[0025] The cable water-blocking buffer layer structure simulation test system with adjustable contact state and humidity of the present invention has at least the following advantages:

[0026] The test system of the present invention is a brand-new system not available in the prior art, comprising a test area, a control area and a monitoring area. The test area is used to apply voltage or current to the sample, apply different humidity, and adjust the contact state and pressure between the electrode and the sample surface, so as to carry out system tests; the control area is used for real-time control of the test conditions and processes; the monitoring area realizes full monitoring of the test process. The system covers all the elements of the cable water-blocking buffer layer structure simulation test research, namely voltage or current, humidity, contact state, and pressure, and integrates all relevant influencing factors into one test system, and has clear functional divisions, reasonable design layout, small space occupation, and convenient operation; by utilizing the group design of high-voltage electrodes in this system, multiple samples can be tested simultaneously under different contact states and pressures, which greatly simplifies the test procedure, shortens the test time, and improves the comparability of the test results. Through the effective combination of the real-time monitoring system and the control system, the controllability, safety and full record of the test process are guaranteed, providing comprehensive and true information for the corresponding research.

[0027] The circuit breaker selected for the test system of the present invention can connect and disconnect short-circuit current. When the ablation platform branch circuit has overcurrent, short circuit and other faults, it can automatically cut off the circuit to play a protective role. After the fault is disconnected, it can be manually reset without replacing the device, which is convenient for the test personnel to continue the test after clearing the fault; the ablation platform bracket is made of epoxy resin material, which effectively ensures the safety of the experimental platform; the ablation platform high-voltage electrode is made of electrical aluminum 1060, which is the same metal material as the aluminum sheath of the high-voltage cable, which is closer to the actual project; the electrode shape is a special arc with an inner diameter of 10mm, an outer diameter of 14mm, a central angle of 180°, and a thickness of 2mm, which corresponds to the corrugated aluminum sheath structure in the high-voltage cable, reflecting its main Main features: By adjusting the position of the electrode rod, the distance between the high-voltage electrode and the sample can be arbitrarily adjusted between 0 and 2 mm; when the high-voltage electrode is in contact with the sample, the contact pressure can be changed between 0 and 30 N by adjusting the weight block; the type, amplitude, frequency, waveform, etc. of the applied voltage or current can be adjusted as needed, which is conducive to carrying out system research; the camera can be freely rotated up and down, left and right, with a horizontal viewing angle of 360° and a vertical viewing angle of 115°, which minimizes the blind spot of shooting and realizes panoramic monitoring of every corner of the ablation platform; the humidifier is small in size and has its own water storage device, avoiding the disadvantages of traditional water tanks that occupy a large area; the electric fan is small in size and has strong wind power, avoiding the disadvantages of traditional fans that occupy a large area and consume a lot of energy.

[0028] The cable water-blocking buffer layer structure simulation test system of the present invention, in which the contact state and the ambient humidity can be freely adjusted, effectively restores the structural characteristics of the corrugated aluminum sheath and the water-blocking buffer layer in the high-voltage cable under the cooperation of the preferred embodiments, and better simulates the real working state of the water-blocking buffer layer under the actual cable operation condition by adjusting the applied voltage and current, electrode position, pressure, and ambient humidity. The real-time monitoring of the voltage, current, temperature, humidity, etc. and the full-process shooting and recording of the sample part are conducive to exploring the root cause and damage mechanism of the ablation of the water-blocking buffer layer. The existing constant temperature and humidity chamber includes a water tank, a fan and other equipment, which is large in size and high in energy consumption, and is not convenient for use in the high-voltage cable simulation ablation test; the existing heat preservation and moisture preservation chamber can only keep a certain temperature and humidity unchanged, and cannot achieve dynamic adjustment. The present invention realizes real-time monitoring of ambient temperature and dynamic adjustment of humidity under the condition of satisfying the actual high-voltage cable simulation ablation test, which not only meets the test needs but also saves area and cost; the ablation platform simulates the actual structure of the cable aluminum sheath part, which is not only a reasonable simplification of the actual structure, but also can adjust the gap distance between the electrode and the sample, the number of contact points, the different contact pressures of the electrode on the sample, etc. The system reflects the different contact conditions at the interface between the corrugated aluminum sheath of the high-voltage cable and the water-blocking buffer layer, which is of great significance for the development of related research. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1This is a schematic diagram of the structure of a high-voltage cross-linked polyethylene insulated cable, where Figure 1 (a) is the radial view, Figure 1 (b) is the axial view.

[0030] Figure 2 Schematic diagram of the test box for simulating ablation of the water-blocking buffer layer.

[0031] Figure 3 This is the main view of the water-blocking buffer layer simulated ablation test box.

[0032] Figure 4 This is a top view of the test box for simulating ablation of the water-blocking buffer layer.

[0033] Figure 5 Schematic diagram of the external circuit of the ablation platform.

[0034] Figure 6 Schematic diagram of the ablation platform structure.

[0035] Figure 7 This is a partial enlarged schematic diagram of the arc electrode.

[0036] In the figure: A-monitoring area; B-test area; C-control area; 1-bottomless test box; 2-vent; 3-partition; 4-glass partition; 5-box door; 6-humidifier; 7-electric fan; 8-power bank; 9-plc controller; 11-ablation platform; 12-epoxy bracket; 13-high voltage electrode; 14-wire; 15-sample; 16-ground electrode; 17-sensor layout point; 18-bolt; 19-electrode rod; 20-weight block; 21-top screw; 22-bolt; 23-high voltage terminal; 24-ground terminal; 25-external computer; 26-AC ammeter; 27-AC voltmeter; 28-circuit breaker; 29-AC power supply. DETAILED DESCRIPTION

[0037] The content of the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0038] The present invention discloses a cable water blocking buffer layer structure simulation test system with freely adjustable contact state and ambient humidity, comprising a bottomless test box 1 as shown in FIG. Figure 2 As shown, the external circuit is as follows Figure 5 as shown; Figure 2 As shown, the bottomless test box 1 is divided into a monitoring area A for real-time monitoring of the progress of ablation of the water-blocking buffer layer, a test area B for ablation of the water-blocking buffer layer, and a control area C for controlling the humidity of the test area and monitoring the temperature; a vent 2 is provided on the top surface of the bottomless test box 1 to facilitate gas exchange between the box and the external environment; Figure 3 As shown, a door 5 is provided on the front of the test box to facilitate the test personnel to replace the sample; Figure 4As shown, a camera 10 is placed in the monitoring area A, and a power cord passes through the side wall of the box and is connected to an AC 220V power supply to power the camera 10; Figure 4 As shown, humidifiers 6 are placed at the four corners of test area B, the humidifier power cord is connected to power bank 8, and the humidifier data line passes through the partition 3 to connect to the plc controller 9; an electric fan 7 is placed between the humidifiers, the electric fan power cord is connected to the power bank 8, and the electric fan data line passes through the partition 7 to connect to the plc controller 9; a power bank 8 is placed near the partition 7 to supply power to the humidifier 6 and the electric fan 7; a plc controller 9 is placed in control area C, and the plc controller 9 power cord passes through the side wall of the box to connect to the AC 220V power supply to supply power to the plc controller 9; the plc controller 9 data line passes through the side wall of the box to connect to the external computer 25. Figure 6 As shown in the schematic diagram of the ablation platform structure, the ablation platform 11 includes an epoxy bracket 12, a ground electrode and multiple groups of high-voltage electrode devices arranged on the epoxy bracket 12; the ground electrode 16 is fixed to the bottom of the epoxy bracket 12, the sample 15 is placed on the ground electrode 16, and the ground terminal 24 of the ground electrode 16 extends out of the epoxy bracket 12. The electrode rod 19 of each group of high-voltage electrode devices is welded to the high-voltage electrode 13, the high-voltage electrode 13 is placed on the sample 15, and the electrode rod 19 is connected to the top of the epoxy bracket 12 by a bolt 22; the bolt 22 is provided with a top screw 21, the electrode rod 19 is moved to a predetermined position, and the top screw 21 is adjusted to make By pressing the electrode rod 19 tightly to fix it, the gap distance between the high-voltage electrode 13 and the sample 15 can be kept unchanged, and the gap distance between the high-voltage electrode and the sample can be adjusted (distance 0-2mm); the electrode rod 19 is engraved with threads, and the weight block 20 is punched in the middle and engraved with threads, so that the weight block 20 can be placed on the electrode rod 19 in a screwing manner; loosen the top screw 21 to make the high-voltage electrode contact with the sample, and adjust the pressure applied by the high-voltage electrode 13 on the sample by adjusting the number of weight blocks 20 (contact pressure 0-30N); the high-voltage electrodes 13 of each group of high-voltage electrode devices are connected by wires 14; Figure 7 As shown, the high-voltage electrode 13 is in a special arc shape, with an inner diameter of 10 mm, an outer diameter of 14 mm, a central angle of 180°, and a thickness of 2 mm; the sample 15 is stacked by a water-blocking buffer layer and a shielding layer, the water-blocking buffer layer is in contact with the high-voltage electrode 13, and the shielding layer is in contact with the ground electrode 16; the two sensor placement points 17 on the epoxy bracket 12 are each placed with a temperature sensor and a humidity sensor, and the data line of the sensor is connected to the plc controller 9 through the spacer 3. The external circuit diagram of the ablation platform is shown in FIG. Figure 5 As shown, the ablation platform 11 is placed in the middle of the test area, and the high-voltage terminal 23 passes through the side wall of the box and is connected to the AC ammeter 26, the circuit breaker 28, the AC power supply 29, and the grounding terminal 24 in sequence through the high-voltage wire; the AC voltmeter 27 is connected in parallel at both ends of the high-voltage terminal 23 and the grounding terminal 24.

[0039] The test method of the cable water-blocking buffer layer structure simulation test system with adjustable contact state and humidity can monitor the ambient temperature and adjust the ambient humidity in real time. The test personnel set the target humidity through the external computer 25, and the humidity sensor collects humidity data and transmits it to the plc controller 9. When the humidity is lower than the set value, the test personnel closes the vents 2 to interrupt the gas exchange between the bottomless test box 1 and the outside world, and the plc controller 9 starts all humidifiers 6 to increase the humidity of the test area B by evaporating the water in the humidifiers; when the humidity is higher than the set value, the test personnel opens the vents 2 to restore the gas exchange between the bottomless test box 1 and the outside world, and the plc controller 9 controls the electric fan 7 to turn on and the humidifier 6 to reduce the humidity in the experimental area; the plc external computer 25 display screen displays the temperature of the test area in real time and humidity; the adjustable range of humidity is 20%-90%, with an accuracy of 1%; through the multi-electrode setting, it can effectively simulate various possible contact situations between the corrugated aluminum sheath and the water-blocking buffer layer during the actual operation of the high-voltage cable, and adjust the aluminum sheath trough to make the aluminum sheath contact with the water-blocking buffer layer in full or in part, with air gaps (distance 0-2mm) by adjusting the top screw 21; and make the aluminum sheath trough contact with the water-blocking buffer layer but with different pressures (contact pressure 0-30N) by adjusting the number of weight blocks 20; it can apply different voltages and currents to simulate the ablation test of the water-blocking buffer layer structure, and record the ablation process and parameter changes; the test system structure of the insulation shield, water-blocking buffer layer, and arc-shaped aluminum electrode completely corresponds to the actual cable structure, and is easy to build, simple to operate, small in footprint, and low in cost.

[0040] The present invention is described in more detail below in conjunction with specific operating steps.

[0041] The test system of the present invention is used to conduct an applied voltage test on a high-voltage cable water-blocking buffer layer sample at room temperature and 40% humidity, and the sample is subjected to different pressures, and a camera is used to observe and record the ablation of the sample in real time, including the following steps:

[0042] a. An insulating shielding layer is placed on the ground electrode 16, a water-blocking buffer layer sample is placed thereon, and the high-voltage electrode 13 is connected with a wire 14;

[0043] b. This embodiment has five groups of high-voltage electrode devices. In the first group of high-voltage electrode devices, the top screw 21 is loosened to move the electrode rod 19 downward, and the high-voltage electrode 13 contacts the water-blocking buffer layer sample, and no weight is placed on the electrode rod 19; in the second group of high-voltage electrode devices, the top screw 21 is loosened to move the electrode rod 19 downward, and the high-voltage electrode 13 contacts the sample 15, and a weight block 20 is placed on the electrode rod 19; in the third group of high-voltage electrode devices, the top screw 21 is loosened to move the electrode rod 19 downward, and the high-voltage electrode 13 contacts the water-blocking buffer layer sample, and two weight blocks 20 are placed on the electrode rod 19; in the fourth group of high-voltage electrode devices, the top screw 21 is loosened to move the electrode rod 19 downward, and the high-voltage electrode 13 contacts the sample 15, and three weight blocks 20 are placed on the electrode rod 19; in the fifth group of high-voltage electrode devices, the top screw 21 is loosened to move the electrode rod 19 downward, and the high-voltage electrode 13 contacts the water-blocking buffer layer sample, and four weight blocks 20 are placed on the electrode rod 19;

[0044] c. The power cord of the camera 10 is connected to an AC 220V power supply through the side wall of the bottomless test box 1; the power cord of the plc controller 9 is connected to an AC 220V power supply through the side wall of the bottomless test box 1;

[0045] d. The power line of the humidifier 6 is connected to the power bank 8, and the data line passes through the partition 3 to the plc controller 9; the power line of the electric fan 7 is connected to the power bank 8, and the data line passes through the partition 3 to the plc controller 9; the data lines of the temperature sensor and humidity sensor at the sensor placement point 17 are connected to the plc controller 9 through the partition 3; the plc controller data line passes through the side wall of the bottomless test box 1 and is connected to the external computer 25;

[0046] e. After completing the overall installation and line connection of the test system, set the target ambient humidity to 40% through the external computer 25, observe the output display of the external computer, and when the humidity reading stabilizes at 40%, the test personnel record the humidity and temperature, connect the electrode grounding terminal 24 to the ground wire, apply AC voltage to the high-voltage terminal 23, and start the water-blocking buffer layer ablation test.

[0047] The above is a preferred embodiment of the present invention. It should be pointed out that for those skilled in the art, various changes and variations may be made without departing from the principle of the present invention. Any modifications, equivalent substitutions, improvements, etc. made should be regarded as within the scope of protection of the present invention.

Claims

1. A cable water-blocking buffer layer structure simulation test system with adjustable contact state and humidity, comprising a bottomless test box (1), characterized in that: The bottomless test box (1) has a ventilating opening (2) on its top surface. A partition (3) and a glass partition (4) are arranged inside the bottomless test box (1). The partition (3) and the glass partition (4) divide the bottomless test box (1) into a monitoring area (A), a test area (B) and a control area (C). A box door (5) is arranged on the front of the bottomless test box (1). A camera (10) is placed in the monitoring area (A). A power cord passes through the side wall of the box and is connected to a power source to supply power to the camera (10). An ablation platform (11) is placed in the middle of the test area (B). Humidifiers (6) are placed at the four corners of the area (B), electric fans (7) are placed between the humidifiers (6), and a power bank (8) is placed near the partition (3); a plc controller (9) is placed in the control area (C), and a power line passes through the side wall of the bottomless test box to connect to the power supply to supply power to the plc controller (9); the plc controller data line passes through the side wall of the bottomless test box to connect to an external computer (25); the data lines of the humidifier (6) and the electric fan (7) in the test area all pass through the partition (3) to connect to the plc controller (9); The ablation platform (11) comprises an epoxy support (12), a ground electrode (16) and a plurality of groups of high-voltage electrode devices arranged on the epoxy support (12); the ground electrode (16) is fixed to the bottom of the epoxy support (12), the ground electrode (16) is used to place the sample (15), the ground terminal (24) of the ground electrode (16) extends out of the epoxy support (12), the electrode rod (19) of each group of high-voltage electrode devices is welded to the high-voltage electrode (13), the high-voltage electrode (13) is placed on the sample (15), and the electrode rod (19) is connected to the top of the epoxy support (12) by a bolt (22); the bolt (22) is provided with a top screw (21) for adjusting and fixing the gap distance between the high-voltage electrode (13) and the sample (15); the electrode rod (19) The portion located outside the epoxy support (12) is provided with an adjustable number of weight blocks (20) for adjusting the pressure applied by the high-voltage electrode (13) on the sample (15); the high-voltage electrodes (13) of each group of high-voltage electrode devices are connected by a wire (14), and the top of the electrode rod (19) of one group of high-voltage electrode devices is connected to the high-voltage terminal (23); the high-voltage electrode (13) is in an arc shape; the high-voltage electrode (13) is in contact with the water-blocking buffer layer of the sample (15), and the ground electrode (16) is in contact with the shielding layer of the sample (15); a temperature sensor and a humidity sensor are placed on the epoxy support (12), and the data lines of the temperature sensor and the humidity sensor are connected to the PLC controller (9) through the spacer (3); The high-voltage terminal (23) passes through the side wall of the bottomless test box (1) and is connected to an AC ammeter (26), a circuit breaker (28), an AC power source (29) and a grounding terminal (24) in sequence through a high-voltage wire; an AC voltmeter (27) is connected in parallel between the two ends of the high-voltage terminal (23) and the grounding terminal (24); The camera (10) adopts a dual-axis dual-motor, cantilever-free design, 115° vertical viewing angle, and 360° panoramic video; The glass partition (4) is made of transparent glass.

2. A cable water-blocking buffer layer structure simulation test system with adjustable contact state and humidity according to claim 1, characterized in that: The high-voltage electrode (13) and the high-voltage cable aluminum sheath are made of the same metal material.

3. A cable water-blocking buffer layer structure simulation test system with adjustable contact state and humidity according to claim 1, characterized in that: The arc-shaped inner diameter of the high-voltage electrode (13) is 10 mm, the outer diameter is 14 mm, the central angle is 180°, and the thickness is 2 mm.

4. A cable water-blocking buffer layer structure simulation test system with adjustable contact state and humidity according to claim 1, characterized in that: The volume of the humidifier (6) is 0.01m 3 Up to 0.02m 3 , with its own water storage device.

5. The test method of a cable water-blocking buffer layer structure simulation test system with adjustable contact state and humidity according to any one of claims 1 to 4, characterized in that: The test personnel set the target humidity through the external computer (25), and the humidity sensor collects humidity data and transmits it to the PLC controller (9). When the humidity is lower than the set value, the test personnel closes the vents (2) to interrupt the gas exchange between the bottomless test box (1) and the outside world, and the PLC controller (9) starts all humidifiers (6) to increase the humidity of the test area (B) by evaporating the water in the humidifiers; when the humidity is higher than the set value, the test personnel opens the vents (2) to restore the gas exchange between the bottomless test box (1) and the outside world, and the PLC controller (9) controls the electric fan (7) to turn on and turn off the humidifier (6) to reduce the humidity in the experimental area; the PLC controller (9) is connected to the computer (25) and the display screen displays the temperature of the test area in real time. and humidity; if the test is conducted in a non-contact state, the electrode rod (19) is fixed at different positions by means of a top screw (21), and the distance between the high-voltage electrode (13) and the sample (15) is controlled to be between 0 and 2 mm; if the test is conducted in a contact state, the top screw (21) is unscrewed to allow the electrode rod (19) to droop naturally, so that the lower surface of the high-voltage electrode (13) contacts the upper surface of the sample (15), and the pressure applied to the sample (15) is adjusted to 0 to 30 N by placing 0 to 4 weight blocks (20) on the electrode rod (19); the output voltage of the AC power supply (29) is adjusted until the reading of the AC ammeter (26) or the AC voltmeter (27) is a predetermined value, and then the simulated ablation test is started, and the ablation process and parameter changes are recorded.

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