High-voltage cable buffer waterproof layer ablation experiment device and experiment method

Abstract

The invention discloses a high-voltage cable buffer waterproof layer ablation experiment device and experiment method, and belongs to the field of high-voltage cable experiments. The aluminum sheath assembly comprises an aluminum sheath and a sheath support, wherein the aluminum sheath is mounted on the sheath support; the insulating plate assembly comprises a metal plate and a metal plate support, the metal plate is located on one side of the aluminum sheath, the surface of the metal plate is roughly parallel to the extension direction of the aluminum sheath, the metal plate is formed by splicing a plurality of metal plates, and the metal plate support is provided with an adjusting structure used for adjusting the relative distance between the metal plate and the aluminum sheath; the buffer waterproof layer is located between the metal plate and the aluminum sheath. According to the invention, ablation reproduction of the buffer waterproof layer of the high-voltage cable in a laboratory can be realized, research related to ablation can be carried out, effective data can be provided for research of the high-voltage cable, theoretical guidance can be provided for actual production, and safe operation of a power system can be guaranteed.

Description

Technical Field

[0001] The invention relates to the field of high-voltage cable experiments, and in particular to a high-voltage cable buffer water-blocking layer ablation experimental device and an experimental method. Background Art

[0002] For high-voltage and ultra-high-voltage cables, the metal sheath is an important structural component. The metal sheath can provide mechanical protection for the cable core, prevent the cable from being damaged by external forces during installation and operation, provide a radial waterproof barrier for the cable core, and prevent water vapor from entering the interior of the cable.

[0003] The buffer water barrier is the main structure of high-voltage cables and is related to the stable operation of the power system. Therefore, the study of the ablation mechanism of the cable buffer water barrier is very important. When the cable is in operation, when ablation occurs and seriously threatens the transmission of electricity, the cable can only be replaced. If it is not discovered in time, it will cause a circuit fire and bring significant losses to the national economy. Although some scholars currently believe that ablation may be caused by poor electrical contact between the aluminum sheath and the buffer water barrier, and the combined effect of electricity and heat, the poor contact includes the gap between the aluminum sheath trough and the buffer water barrier is too large, the resistivity of the water-blocking buffer water barrier is too large, the water-blocking expansion powder of the buffer water barrier is precipitated after being damp, forming a non-conductive layer, and the gold cloth has design defects, but at present, there is no laboratory ablation experimental equipment and the safety is insufficient. Only some simple analysis can be carried out based on simulation, which has little guiding significance for engineering practice. Therefore, there is a great scientific need to design a laboratory high-voltage cable buffer water barrier ablation reproduction device. Summary of the invention

[0004] In view of the above-mentioned defects of the prior art, the present invention provides a high-voltage cable buffer water-blocking layer ablation experimental device, which can reproduce the ablation of the high-voltage cable buffer water-blocking layer in the laboratory, conduct ablation-related research, and provide effective data for the research of high-voltage cables.

[0005] The first aspect of the present invention provides a high-voltage cable buffer water-blocking layer ablation experimental device, comprising: An aluminum sheath assembly comprises an aluminum sheath and a sheath bracket, wherein the aluminum sheath is mounted on the sheath bracket; An insulating plate assembly, comprising a metal plate and a conductive support for supporting the metal plate, wherein the metal plate is located on one side of the aluminum sheath, the metal plate surface is substantially parallel to the extension direction of the aluminum sheath, the metal plate is formed by splicing a plurality of metal plates, and the relative distance between the metal plate and the aluminum sheath is adjusted by adjusting the height of the conductive support; A buffer water-blocking layer, located between the metal plate and the aluminum sheath; A power supply device is provided to provide electrical energy to each conductive support.

[0006] Furthermore, the sheath bracket is installed in the first track groove.

[0007] Furthermore, the metal plate is installed on one end of the conductive support, and the other end of the conductive support is located in the second track groove.

[0008] Furthermore, the conductive support comprises at least two hollow tubes which are nested and connected in sequence, and a slot structure is provided between two adjacent hollow tubes.

[0009] Furthermore, the experimental device comprises a water spraying port, and the water flowing out of the water spraying port falls on the buffer water-blocking layer.

[0010] Furthermore, the power supply device includes a power supply and a transformer, and the power supply provides electrical energy to the conductive support through the transformer.

[0011] Furthermore, the experimental device includes an image collector.

[0012] Furthermore, the experimental device includes a smoke alarm, a protection circuit and a fan.

[0013] A second aspect of the present invention provides a high-voltage cable buffer water-blocking layer ablation test method, which is implemented based on the high-voltage cable buffer water-blocking layer ablation test device according to any one of claims 1 to 7, and includes the following steps: S1. Build a test bench, input the electric energy output by the power supply device into the second track groove, make the insulating plate assembly serve as the high-voltage electrode, the aluminum sheath serve as the grounding electrode, and make the smooth surface of the buffer water-blocking layer face the aluminum sheath, and the rough surface face the metal plate; S2, dividing the fault test area, adjusting the length of the conductive support in the fault test area and thus adjusting the distance between the metal plate and the buffer water-blocking layer; S3, adjusting the water content of the buffer water-blocking layer and conducting ablation experiments at different voltages; S4. After the water-swelling powder of the buffer water-blocking layer is precipitated after being damp, the moisture content of the buffer water-blocking layer is kept unchanged, and ablation experiments are carried out at different voltages.

[0014] Furthermore, the buffer water-blocking layer is formed with or without gold cloth, and the aluminum sheath is a smooth aluminum sheath or a wrinkled aluminum sheath.

[0015] Compared with the prior art, the present invention has the following beneficial effects: The experimental device of the present invention can realize the experimental position of the buffer water-blocking layer and the aluminum sheath of the high-voltage cable, and the contact mode between the buffer water-blocking layer and the aluminum sheath can be changed by adjusting the position of the metal plate. During the experiment, the corresponding ablation result is obtained by changing the contact mode between the buffer water-blocking layer and the aluminum sheath. The ablation mechanism is clarified by analyzing the relevant parameters of the ablation result, thereby providing reliable experimental data for the research of high-voltage cables.

[0016] The concept, specific structure and technical effects of the present invention will be further described below in conjunction with the accompanying drawings to fully understand the purpose, characteristics and effects of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the overall structure of an experimental device according to a specific embodiment of the present invention; Figure 2 It is a schematic diagram of the overall structure of a conductive support according to a specific embodiment of the present invention; Figure 3 It is a schematic diagram of the internal structure of a conductive pillar according to a specific embodiment of the present invention; Figure 4 It is a schematic structural diagram of a conductive support and a movable transmission column according to a specific embodiment of the present invention; Figure 5 It is a structural schematic diagram of a movable power transmission pole according to a specific embodiment of the present invention; Figure 6 It is an overall control principle diagram of a specific embodiment of the present invention.

[0018] Figure 7 This is the ablation result of a specific embodiment of the present invention.

[0019] In the figure, 1. conductive pillar; 1-1. inner hollow tube; 1-2. outer hollow tube 1-3. slot; 1-4. post structure; 1-5. cover panel; 2. ablation table; 3. second track slot; 4. first track slot; 5. adjustment rod; 6. sheath fixing column; 7. water nozzle; 8. metal plate; 8-1. column hole; 9. aluminum sheath; 10. water blocking tape; 11. conductive line, 12. threaded rod, 12-1. nut, 13- movable transmission column, 14- slot, 15- post, 16- power input connector, 17- sliding frame. DETAILED DESCRIPTION

[0020] The following describes the embodiments of the present invention by specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict.

[0021] It should be noted that the illustrations provided in the following embodiments are only used to illustrate the basic concept of the present invention in a schematic manner, and thus the illustrations only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0022] While some exemplary embodiments of the present invention have been described for the purpose of illustration, it should be understood that the present invention may be implemented in other ways not specifically shown in the drawings.

[0023] like Figure 1 As shown, in a specific embodiment, a high-voltage cable buffer water-blocking layer ablation experimental device is provided, including an ablation table 2, a power supply circuit, a protection circuit and a collection component. An aluminum sheath component, an insulating plate component and a buffer water-blocking layer are installed on the ablation table 2. The ablation table is made of an insulating material with high hardness, and its ignition point temperature is greater than the ignition point of the buffer water-blocking tape. The ignition point of the buffer water-blocking tape in this embodiment is 265°C. The ablation table can be a wooden ablation table or an acrylic glass plate.

[0024] The aluminum sheath assembly includes an aluminum sheath 9 and a sheath bracket, the aluminum sheath is installed on the sheath bracket, and the sheath bracket is used to carry and adjust the position of the aluminum sheath 9. The sheath bracket includes four vertically arranged sheath fixing columns 6, the lower ends of which are installed on the ablation table 2, and the four sheath fixing columns 6 are arranged opposite to each other in pairs, forming the first side and the second side of the sheath bracket, and the first side and the second side are respectively installed with horizontally installed adjustment rods 5, and the two ends of the aluminum sheath 9 are respectively fixed on the adjustment rods 5. The adjustment rod 5 is detachably connected to the sheath fixing rod. During the experiment, the position of the aluminum sheath 9 can be achieved by adjusting the adjustment rod 5, ensuring that the device can be used for experiments on aluminum sheaths and buffer layers of different structural specifications.

[0025] Due to the different models of aluminum sheaths, their appearance and structure will also be different. For different experimental processes, the clamping position of the aluminum sheath is also different. In order to be able to clamp aluminum sheaths of different specifications, a first track groove 4 is provided on the ablation table 2 in this embodiment, and the lower end of the sheath fixing column 6 is located in the first track groove 4 and can slide in the first track groove 4. During the experiment, the sheath fixing column 6 slides in the first track groove 4 to achieve the change of the relative position between the sheath fixing columns 6, so as to fix aluminum sheaths of different structural specifications. The position of the experimental aluminum sheath is adjusted by the coordinated action of the sheath fixing column 6 and the adjustment rod 5, which can not only ensure that the aluminum sheaths of different structural specifications are firmly fixed, but also ensure that the position of the aluminum sheath remains unchanged during the experiment, prevent safety accidents caused by the aluminum sheath being unrelated during the high-pressure ablation experiment, facilitate the adjustment of the relative distance between different contact points of the aluminum sheath and the buffer water-blocking layer for ablation experiments, and also ensure that when the aluminum sheath of a certain length is in poor contact with the buffer water-blocking layer, the aluminum sheath can still be fixed well to obtain accurate experimental results. When the resistivity of the buffer water-blocking layer 10 is low or the pitch and groove depth of the aluminum sheath are small, the conditions such as the time to trigger ablation will be explored multiple times through dichotomy. At this time, for convenience, the aluminum sheath needs to be lifted at different experimental stages to observe the ablation results of the aluminum sheath under different conditions in real time. Fixing the aluminum sheath can ensure that the relative positions of the buffer water-blocking layer and the aluminum sheath are the same during multiple explorations, and the experimental results are more scientific and convincing, and the experimental results are more meaningful for research.

[0026] The insulating plate assembly includes a metal plate 8 and a conductive support 1. The metal plate 8 is used to simulate an insulating outer shield. The metal plate 8 is located on one side of an aluminum sheath 9, and the surface of the metal plate 8 is roughly parallel to the extension direction of the aluminum sheath 9. A certain gap is provided between the metal plate 8 and the aluminum sheath 9, and a buffer water-blocking layer is placed in the gap.

[0027] The metal plate 8 is used as a high-voltage electrode. It adopts a multi-modular structure that moves up and down and left and right, which can fully reproduce the various complex contact conditions between the buffer layer and the aluminum sheath during the actual operation of the high-voltage cable. By adjusting the height of different metal plates, the simulated poor contact occurs in the middle or at both ends of the line section.

[0028] In this embodiment, for the sake of simplicity of the experimental structure, convenient installation and adjustment operation, the metal plate 8 is composed of several small metal plates, each of which is supported by a conductive support 1. The surface of the metal plate must be flat, without depressions and sharp protrusions. The metal plate in this embodiment is a steel plate, and the thickness of a single steel plate is 3 mm, the width is 100 mm, and the length is 35 mm. The steel plate can move up and down in the vertical direction and move left and right in the horizontal plane.

[0029] The lower end of the conductive pillar 1 is mounted on the ablation table 2, and the top of the conductive pillar 1 is fixedly connected to the metal plate 8. The gap between the metal plate 8 and the aluminum sheath 9 is achieved by adjusting the height of the conductive pillar 1, which can be used to simulate the contact mode, poor contact spacing and poor contact position between the wave trough of the aluminum sheath 9 and the buffer water-blocking layer.

[0030] In this embodiment, the conductive pillar 1 adopts a segmented sleeve structure, including at least two hollow tubes nested in sequence, and a slot structure is provided between adjacent hollow tubes to adjust the height of the conductive pillar. In a specific embodiment, the conductive pillar 1 adopts a two-stage structure, such as Figure 2 As shown, the conductive support 1 includes an inner hollow tube 1-1 and an outer hollow tube 1-2, the outer diameter of the inner hollow tube 1-1 is smaller than the inner diameter of the outer hollow tube 1-2, when the conductive support 1 is arranged in a vertical direction, the lower end of the inner hollow tube 1-1 is coaxially embedded in the outer hollow tube 1-2, and the top of the inner hollow tube 1-1 is fixedly connected to the metal plate. The outer wall of the inner hollow tube 1-1 is provided with scale lines to display the current height of the conductive support, as shown in the figure, the inner hollow tube 1-1 is marked with millimeter scales of 0-5mm from top to bottom, and 1mm is used as a scale division. At the same time, a plurality of slots 1-3 are provided on the circumferential side wall of the inner hollow tube 1-1, and an elastic post structure 1-4 is provided on the side wall of the corresponding outer hollow tube 1-2. The elastic post structure 1-4 can adopt the elastic post structure in the prior art. The slot is designed to ensure that the inner hollow tube 1-1 can be fixed by the slot 1-3 and the elastic post structure 1-4 when it is stretched up and down at different scales. When the inner hollow tube 1-1 is stretched and contracted, when its slot 1-3 coincides with the slot on the outer hollow tube 1-2, the elastic post structure 1-4 can fix the inner hollow tube 1-1 and the outer hollow tube 1-2 at the required height, thereby ensuring the accuracy of the upward and downward expansion and contraction, and realizing the adjustment of the height of the conductive pillar 1. By adjusting the 5 heights of the conductive pillar 1, the ablation conditions of the aluminum sheath and the buffer layer from interference contact to the gap width of 5mm can be fully reproduced.

[0031] like Figure 3 As shown, in a specific embodiment, the upper end of the inner hollow tube 1-1 is provided with a sealing panel 1-5 fixedly connected to the side wall of the inner hollow tube 1-1, and the sealing panel 1-5 is provided with a through hole. The lower end surface of the metal plate 8 is provided with a column hole 8-1 that matches the position of the through hole, and the column hole 8-1 is provided with a thread. When the metal plate 8 needs to be fixedly connected to the inner hollow tube 1-1, the upper end of the threaded rod 12 is screwed into the column hole 8-1 through the through hole, and the other end of the threaded rod 12 is screwed on the nut 12-1, so that the inner hollow tube 1-1 is tightly connected to the metal plate 8. In order to ensure the flatness of the metal plate surface, the depth of the column hole 8-1 is less than the thickness of the metal plate. In this embodiment, the thickness of the metal plate is 3mm, and the column hole 8-1 has a depth of 2mm and a radius of 5mm.

[0032] In a specific embodiment, in order to further flexibly adjust the relative position and distance between the buffer water-blocking layer and the aluminum sheath 9, so as to simulate the actual situation of the buffer water-blocking layer and the aluminum sheath 9 during the operation of the high-voltage cable, a second track groove 3 is provided on the ablation table 2, and the lower end of the conductive support 1 is located in the second track groove 3, and the conductive support 1 can move up and down and left and right in the second track groove 3, which can not only ensure the flexible left and right movement of the conductive cylinder 1, but also ensure that during the experiment, all the conductive supports 1 are still on the same horizontal straight line after moving left and right. It is also convenient to adjust the number of conductive supports 1 and metal 8, which is conducive to the acquisition of experimental data. The second track groove 3 inputs the second track groove voltage to the metal plate 8 through the conductive line 11, so that the conductive support can be used as the voltage receiving end of the adjustable transformer, and all the test steel plates are energized through the second track groove to ensure that the metal plate becomes a high-voltage pole.

[0033] In a specific embodiment, a movable power transmission column 13 is installed at the lower end of the outer hollow tube 1-2, and a detachable connection is established between the movable power transmission column 13 and the outer hollow tube 1-2 through a locking structure. A power input connector 16 is provided in the center of the movable power transmission column 13, and the lower end of the conductive line 11 is inserted into the power input connector 16 to realize the electrical connection of the conductive support. The lower end of the movable power transmission column 13 is uniformly connected to the adjustable transformer power supply. The power input connector is divided into two parts, the upper part fixes the wire, the bottom diameter is 5mm, the height is 5mm, and the lower part is the base, the bottom diameter is 10mm, and the height is 8mm.

[0034] The locking structure can adopt the locking structure in the prior art. In this embodiment, the locking structure includes a slot 14 and a post 15. The slot 14 is opened at the lower end of the outer hollow tube 1-2, and the post 15 is located at the upper end of the movable power transmission column 13, and the position and size of the slot 14 are matched and corresponded. Figure 4 As shown, in this embodiment, the outermost periphery of the movable power transmission pole 13 has four 10mm high clamping posts, and the corresponding conductive pillars are provided with four 10mm deep clamping slots, and the clamping slots and clamping posts are perfectly matched, ensuring the perfect fixation of the conductive pillars and the movable power transmission poles, and also ensuring the good connection of the lines. In practical applications, the positions of the clamping slots and clamping posts can be swapped, or they can be arranged alternately at intervals as needed, that is, the movable power transmission pole 13 and the outer hollow tube 1-2 are provided with clamping slots and clamping posts, so that the two can be stably connected.

[0035] The movable transmission column 13 is slidably connected between the second track groove 3, wherein the movable transmission column 13 can slide along the second track groove 3. In the present application, the lower end of the movable transmission column 13 is mounted on the upper end surface of the sliding frame 17, and the two ends of the sliding frame span the two ends of the second track groove 3. The specific structure is as follows Figure 5 As shown. The sliding connection mode ensures that the movable transmission pole 13 can be moved to any position in the left and right directions, and the conductive pillar can be moved to any position in the left and right directions. The sliding connection mode also ensures that the movable transmission pole can be added arbitrarily, and the number of modular metal plates can be adjusted, so that the present invention can measure the ablation problem of the buffer layer in a longer distance section, conduct more ablation experiments, and obtain more experimental data. In this embodiment, the track groove is 15mm high and 300mm wide, the movable transmission pole is 315mm wide and 34mm long, and the height of the left and right clamping edges is 30mm.

[0036] In a specific embodiment, in order to simulate the ablation dynamics of rainwater longitudinally penetrating the buffer water-blocking layer in a natural environment, at least one water jet 7 is provided on the ablation platform 2, and the water jet 7 is located around the aluminum sheath 9. When simulating the electrified operation, the water flowing out of the water jet 7 longitudinally penetrates into the buffer water-blocking tape 10. Through the structure of the water jet 7, the process of ablation of the buffer layer after the radial water inflow of the buffer layer in actual operation can be simulated, and based on the presence of the camera, the instantaneous power generation phenomenon of ablation can be recorded.

[0037] like Figure 6 As shown, the power supply circuit includes a power supply and an adjustable transformer, and the adjustable transformer is used to adjust the size of the power supply to ensure the accuracy of the ablation experiment.

[0038] In a specific embodiment, in order to ensure the safety of the experimental process, a protection circuit is added to the experimental device. The protection circuit includes a smoke circuit breaker, a current circuit breaker, a stopwatch and a smoke alarm, so that unmanned supervision is achieved during the experiment. When excessive smoke or a short circuit occurs during the experiment, the power supply is disconnected in time and an alarm is sounded through the smoke alarm to remind the experimenter to deal with it as soon as possible, thereby ensuring the safety of the experimental process.

[0039] The acquisition component includes a camera and a stopwatch. The camera is installed on the upper end of the ablation table 2 through a telescopic bracket to record the entire ablation experiment process, provide an influencing basis for subsequent ablation analysis, and prevent danger caused by direct observation by experimenters. The stopwatch is used to synchronously record the ablation time.

[0040] In order to simulate the windy working conditions under natural conditions, the experimental device includes a fan. By adjusting the wind force of the fan, the ablation condition of the cable buffer water-blocking layer under different windy working conditions can be simulated. The fan can also be used to blow away the smoke generated during the ablation experiment to further ensure the quality of the experiment.

[0041] Through the above embodiments, the ablation of the buffer water-blocking layer of the high-voltage cable in the laboratory can be reproduced. By changing the contact mode between the buffer water-blocking layer and the aluminum sheath, different ablation parameters are observed and the ablation mechanism is clearly identified.

[0042] Based on the high-voltage cable buffer water-blocking layer ablation test device described in the above embodiment, in a specific embodiment, a high-voltage cable buffer water-blocking layer ablation test method is provided, comprising the following steps: S1. Build a test bench, input the electric energy output by the power supply device into the second track groove, make the insulating plate assembly as the high-voltage electrode, and the aluminum sheath as the grounding electrode, make the smooth surface of the buffer water-blocking layer face the aluminum sheath, and the rough surface face the metal plate, so as to correspond to the actual relative positions of the insulating shield, buffer water-blocking layer, and aluminum sheath in the high-voltage cable.

[0043] S2. Divide the fault test area, adjust the height of the conductive pillars in the fault test area, and then adjust the distance between the metal plate and the buffer water-blocking layer, so as to adjust the spacing and position of the poor contact sections between the aluminum sheath and the buffer water-blocking layer in the fault test area, and simulate the situation where the gap between the buffer water-blocking layer and the aluminum sheath is too large; simulate the influence of the length of the ablation defect by adjusting the number of conductive pillars 1 and the distance between adjacent conductive pillars 1.

[0044] S3. The moisture content of the buffer water barrier layer is controlled by controlling the water spraying amount of the water spraying nozzle. When the resistivity of the buffer water barrier layer is too high after being dampened, ablation experiments are carried out at different voltages.

[0045] S4. After the water-swelling powder of the buffer water-blocking layer is precipitated after being damp, a non-conductive layer is formed. The moisture content of the buffer water-blocking layer is kept unchanged, and ablation experiments are carried out at different voltages. The composition of the buffer water-blocking layer sample is changed (with / without gold cloth) to simulate different buffer water-blocking layer structures, and the type of aluminum sheath (smooth aluminum / corrugated aluminum) is changed to conduct ablation experiments at different voltage amplitudes.

[0046] For aluminum sheaths with different structural specifications, the aluminum sheath can be directly moved and replaced; the buffer water barrier layer can be adjusted and replaced directly. The circuit safety is protected by smoke circuit breakers and current circuit breakers. The monitoring recorder records the entire ablation process, and the stopwatch records the ablation time. After the test, observe and record the number of ablation points, ablation point area, ablation shape and ablation position under different contact modes between the buffer water barrier layer and the aluminum sheath.

[0047] The effects of the present invention are further illustrated by the following examples.

[0048] The change of resistivity of the buffer layer is adjusted by the number of water spraying. Through multiple sampling and measurement of a company's buffer zone, the resistivity of the buffer layer under different treatment methods is obtained as shown in Table 1.

[0049] Table 1 Resistivity of buffer layer under different treatment methods

[0050] In the experiment, the voltage values ​​were 0.5V, 1V, 10V, 20V, 30V, and 35V to simulate the suspended voltage on the buffer water barrier layer. The aluminum sheath selected in the experiment was a corrugated aluminum sheath, and the pitch of the aluminum sheath was 35mm. The length of the buffer water barrier layer was 245mm (the length of 7 corrugated aluminum sheath troughs), and the contact of the three middle troughs was set to be poor and the air gap size was 2mm. That is, 7 movable transmission poles were added to the track groove, and the structure of the three middle conductive pillars dropped by 3mm. The ablation phenomenon of the buffer water barrier layer was observed within the specified time. The specific experimental conditions are shown in Table 2. The experimental results are shown in Table 2. Figure 7 shown.

[0051] Table 2 Simulation experiment condition settings

[0052] Comparing the test results of the first six groups, it can be seen that when the voltage is 0.5V and 1V, even if the ablation time is 300min, no ablation will occur, but it can be seen that at 1V, water-blocking powder particles will precipitate. Ablation will occur at voltages of 10V, 20V, 30V, and 35V, and the time and severity of obvious ablation are different. At a voltage of 10V, a circular ablation appears in the buffer water-blocking layer at the corresponding part of the trough of the aluminum sheath in the poor contact section, and the area is small. At the same time, water-blocking powder will precipitate at the corresponding part of the trough. As the voltage increases, the number of ablation increases and the ablation area becomes larger. When the voltage is 30V and 35V, large white spots of water-blocking powder appear near the axis where the ablation point is located, and some water-blocking powder turns yellow. At the same time, it can be seen that ablation first appears at the corresponding position of the trough in the middle of the poor contact, and then extends from the middle to both ends. When the voltage is 30V and 35V, the ablation at both ends also becomes serious, and at 30V, the severity of ablation in the middle and at both ends is similar. By comparing the results of the last five groups of tests, it can be seen that wrapping the buffer water barrier with gold cloth and replacing the wrinkled aluminum sheath with a smooth aluminum sheath can reduce the occurrence of ablation of the buffer water barrier. After wrapping with gold cloth, whether it is 30V or 35V, the ablation occurs at the axis of the sheath trough instead of the corresponding position of the sheath trough. The ablation is only the dense tiny electric ablation points generated when the air breaks down, but it is also obvious that the ablation is more serious at 35V. When the sheath is an aluminum sheath, the ablation phenomenon is only a few small ablation points, and the shape of the ablation points changes from a circle to a very thin rectangle. At the same time, after wrapping with gold cloth, only a small amount of water-blocking powder will precipitate on the fluffy surface of the buffer water barrier. The sound of air breakdown can be heard intermittently during the entire electric ablation process.

[0053] It can be seen from the above embodiments that the present invention can reproduce the ablation process and ablation phenomenon of the buffer layer under different reasons, different conditions or different ablation defects, and can obtain more comprehensive experimental data and ablation details, which can provide more comprehensive data support for the comprehensive analysis of the ablation mechanism of the high-voltage cable buffer layer. By setting the ablation threshold under different conditions, the ablation process can be quantitatively and qualitatively analyzed. The present invention changes the power supply output voltage amplitude, the contact mode between the buffer layer and the aluminum sheath (interference contact / gap) and the gap size, the aluminum sheath type and model, the moisture content / volume resistivity of the fault section of the buffer water-blocking layer, the gap size between the aluminum sheath and the buffer water-blocking layer in the poor contact section, and sets different test conditions for group testing, so as to reproduce all possible ablation conditions. According to the reproduction results and phenomena, the ablation mechanism and ablation problem of the high-voltage cable buffer layer can be analyzed in detail, and technical data is provided for the production of aluminum sheaths and buffer layers of different models according to the obtained experimental data, so as to provide improvement methods and directions for the ablation of the buffer layer. The present invention is suitable for sheath experiments of various specifications. The experimental results can be used to statistically analyze the relationship between the pitch and ablation results of the gold cloth, smooth aluminum, and wrinkled aluminum sheaths, and provide technical support for the production process of greening sheaths. The present invention can also evaluate the effects of improvement measures based on the ablation phenomenon observed in the ablation experiment and the ablation data obtained, and then provide theoretical guidance for actual cable production. It can be seen that the present invention makes the study of the ablation problem of the buffer layer of the high-voltage cable more intuitive, and the experimental methods are more comprehensive and diverse. By reproducing the real ablation phenomenon, experimental data for various ablation conditions are obtained, which is more convincing for the study of the ablation mechanism of high-voltage cables. It can also provide technical support for the formulation of high-voltage cable production process standards, meet the production requirements of the industry, and provide guarantees for the safe operation of the power system.

[0054] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A high-voltage cable buffer water-blocking layer ablation test device, characterized in that: include: An aluminum sheath assembly comprises an aluminum sheath and a sheath bracket, wherein the aluminum sheath is mounted on the sheath bracket; An insulating plate assembly, comprising a metal plate and a conductive support for supporting the metal plate, wherein the metal plate is located on one side of the aluminum sheath, the metal plate surface is substantially parallel to the extension direction of the aluminum sheath, the metal plate is formed by splicing a plurality of metal plates, and the relative distance between the metal plate and the aluminum sheath is adjusted by adjusting the height of the conductive support; A buffer water-blocking layer, located between the metal plate and the aluminum sheath; A power supply device is provided to provide electrical energy to each conductive support.

2. According to claim 1, a high-voltage cable buffer water-blocking layer ablation test device is characterized in that: The sheath bracket is installed in the first track groove.

3. According to the high-voltage cable buffer water-blocking layer ablation experimental device as described in claim 1, it is characterized in that: The metal plate is mounted on one end of the conductive support, and the other end of the conductive support is located in the second track groove.

4. According to claim 1, a high-voltage cable buffer water-blocking layer ablation test device is characterized in that: The conductive support comprises at least two hollow tubes which are nested and connected in sequence, and a slot structure is provided between two adjacent hollow tubes.

5. According to claim 1, a high-voltage cable buffer water-blocking layer ablation test device is characterized in that: The experimental device comprises a water spraying port, and water flowing out of the water spraying port falls on the buffer water-blocking layer.

6. A high-voltage cable buffer water-blocking layer ablation test device according to claim 1, characterized in that: The power supply device comprises a power supply and a transformer, and the power supply provides electrical energy to the conductive support through the transformer.

7. A high-voltage cable buffer water-blocking layer ablation test device according to claim 1, characterized in that: The experimental device comprises an image collector.

8. The high-voltage cable buffer water-blocking layer ablation test device according to claim 1, characterized in that: The experimental device includes a smoke alarm, a protection circuit and a fan.

9. A high-voltage cable buffer water-blocking layer ablation test method, characterized in that: The high-voltage cable buffer water-blocking layer ablation experimental device according to any one of claims 1 to 7 is implemented, comprising the following steps: S1. Build a test bench, input the electric energy output by the power supply device into the second track groove, make the insulating plate assembly serve as the high-voltage electrode, the aluminum sheath serve as the grounding electrode, and make the smooth surface of the buffer water-blocking layer face the aluminum sheath, and the rough surface face the metal plate; S2, dividing the fault test area, adjusting the length of the conductive support in the fault test area and thus adjusting the distance between the metal plate and the buffer water-blocking layer; S3, adjusting the water content of the buffer water-blocking layer and conducting ablation experiments at different voltages; S4. After the water-swelling powder of the buffer water-blocking layer is precipitated after being damp, the moisture content of the buffer water-blocking layer is kept unchanged, and ablation experiments are carried out at different voltages.

10. A high-voltage cable buffer water-blocking layer ablation test method according to claim 9, characterized in that: The buffer water-blocking layer is formed with or without gold cloth, and the aluminum sheath is a smooth aluminum sheath or a wrinkled aluminum sheath.

Images