A power cable insulation performance comprehensive testing device and testing method

Abstract

The present application relates to the technical field of cable insulation performance detection, in particular to a power cable insulation performance comprehensive testing device and testing method, comprising a support, a test bin for placing the cable to be tested is connected to the support through a rotating assembly, a sealing frame cover is slidably inserted on the test bin through a driving assembly, a simulation assembly simulating the actual working condition of the direct buried cable is arranged on the sealing frame cover, backfill soil is gathered in the sealing frame cover under the action of gravity when the present application is inverted, and the cable to be tested can be filled after the sealing frame cover is separated by the driving assembly; after being placed upright, the backfill soil automatically slides into the test bin under the action of gravity and buries the cable, thereby simulating the actual laying environment of the direct buried cable; on this basis, the vibration assembly transmits vibration to the backfill soil, and the extrusion assembly applies alternating stress to the backfill soil, thereby comprehensively testing the insulation performance of the cable under the highly simulated direct buried working condition.

Description

Technical Field

[0001] This invention relates to the field of cable insulation performance testing technology, specifically a comprehensive testing device and method for the insulation performance of power cables. Background Technology

[0002] Power cables, especially direct-buried cables, are a key component of urban power grids and power supply systems for industrial and mining enterprises. Their long-term operational reliability is directly related to the safety and stability of the power system. After being laid, direct-buried cables are subjected to a complex mechanical stress environment for a long time, including the continuous static pressure applied by the backfill soil, the alternating compressive stress caused by ground subsidence or nearby construction activities, and the vibration generated by traffic loads and mechanical equipment operation. The long-term effect of these composite mechanical stresses will cause mechanical fatigue of the cable insulation material, leading to the generation and propagation of microcracks, exacerbating partial discharge phenomena, and ultimately causing accelerated deterioration of insulation performance, or even sudden insulation breakdown faults, resulting in safety hazards and economic losses.

[0003] Therefore, it is crucial to test and evaluate the insulation performance of power cables under simulated actual working conditions. For example, Chinese invention patent application number CN202511148559.3 discloses a testing device for testing the withstand voltage performance of cables. It achieves swinging in two directions through a swing support and combines it with a pressure block to squeeze the cable to simulate the combined mechanical stress state that the cable may be subjected to during operation. Conducting a withstand voltage test on the cable under this simulated stress state can provide certain reference data and reliable basis for evaluating the evolution of the insulation performance of the cable under dynamic mechanical stress.

[0004] However, the aforementioned and similar existing testing techniques are difficult to simulate the specific working conditions of directly buried power cables. First, they cannot effectively simulate the environmental characteristics of directly buried cables being surrounded by backfill soil, as well as the dynamic alternating loads and random vibrations exerted on the cables by the backfill soil. Therefore, their testing process and results cannot truly reflect the insulation performance of cables under direct burial conditions.

[0005] Secondly, most existing cable testing equipment is designed as professional laboratory instruments, with the core design goal of obtaining accurate performance data rather than for teaching demonstrations or personnel skills training. The insulation deterioration and failure process of power cables occurs internally and cannot be observed intuitively, making it difficult for trainees or instructors to establish an intuitive and clear causal relationship between external mechanical stress and internal insulation deterioration.

[0006] In conclusion, developing a technology and device that can more realistically simulate the complex mechanical stress conditions experienced by directly buried power cables during actual operation and can intuitively demonstrate the changes in cable condition during testing is of significant engineering practical importance and urgent practical need for determining the insulation performance of directly buried cables and strengthening the technical training and emergency response capabilities of relevant personnel. Summary of the Invention

[0007] In view of the above problems, embodiments of the present invention provide a comprehensive testing device and method for the insulation performance of power cables to solve the aforementioned technical problems.

[0008] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: The first aspect of the present invention provides a comprehensive testing device for the insulation performance of power cables, including a bracket, a test chamber for placing the cable to be tested is connected to the bracket through a rotating assembly, a sealing frame cover is slidably inserted into the test chamber through a driving component, and a simulation assembly simulating the actual working conditions of a direct-buried cable is provided on the sealing frame cover.

[0009] The inner cavity formed by the test chamber and the sealing frame cover contains backfill soil for burying the cable, and this inner cavity is also used to place the test part of the cable.

[0010] The simulation assembly includes a soil-pressing plate that is slidably connected to the sealing frame cover, with the outer wall of the soil-pressing plate attached to the inner wall of the sealing frame cover. The simulation assembly also includes a vibration assembly for vibrating the backfill soil and a compression assembly for applying alternating compressive stress to the backfill soil.

[0011] The cable under test is placed in the test chamber and the sealing frame cover. The rotating assembly rotates the test chamber and the sealing frame cover, so that the backfill soil buries the cable under test under gravity. The vibration component and the extrusion component simulate the actual working conditions of the direct-buried cable, thereby conducting a comprehensive test of the cable insulation performance under the direct-buried condition.

[0012] Preferably, the test chamber consists of an outer support frame and a bottom observation plate, the observation plate being made of a transparent material.

[0013] Preferably, the bearing frame has several U-shaped grooves arranged at equal intervals along the front-back direction and extending through the left and right sides, and the sealing frame cover has a semi-circular groove on the lower side that matches the U-shaped grooves for sealing and limiting the cable.

[0014] Preferably, the observation plate has several limiting grooves arranged at equal intervals along the front-back direction and extending through the left and right sides. During testing, the cable is squeezed and adhered to the limiting grooves by the backfill soil, and the cable can be observed from the bottom of the observation plate.

[0015] Preferably, the rotating assembly includes annular plates fixedly installed on the left and right sides of the test chamber, and a number of rotatably connected rollers are arranged circumferentially in the annular structure on the upper part of the support, with the rollers rolling against the outer side of the corresponding annular plates.

[0016] Preferably, a driven gear is fixedly installed on the outer side of the circular plate on the right, a drive motor is fixedly installed on the right side of the bracket, and a driving gear that meshes with the driven gear is fixedly installed on the output shaft of the drive motor.

[0017] Preferably, the drive assembly includes a plurality of hydraulic cylinders arranged in a matrix and fixedly installed on the outside of the test chamber, and the telescopic sections of the hydraulic cylinders are all fixedly connected to the sealing frame cover.

[0018] Preferably, the vibration assembly includes a base plate fixedly installed on the side of the soil compaction plate away from the sealing frame cover, and two symmetrically arranged vibration motors are fixedly installed on the base plate.

[0019] Preferably, the extrusion assembly includes a second hydraulic cylinder fixedly installed on the side of the sealing frame cover away from the test chamber, wherein the telescopic section of the second hydraulic cylinder extends into the sealing frame cover and is not connected to the soil pressing plate.

[0020] The second aspect of the present invention provides a comprehensive test method for the insulation performance of power cables. The specific test method steps are as follows: S1, by rotating the assembly to invert the test chamber, so that the test chamber is on top and the sealing frame cover is on the bottom, so that the backfill soil slides into the inside of the sealing frame cover under the action of gravity.

[0021] S2. After inverting the test chamber, the sealing frame cover is pushed downward by the drive component to separate it from the test chamber. Then, the operator places the cable to be tested into the test chamber from bottom to top.

[0022] S3. After the cable is placed in the test chamber, the sealing frame cover is reset by the drive component, so that the sealing frame cover and the test chamber abut and limit the cable, and then the test chamber is upright.

[0023] S4. After the test chamber is placed upright, the backfill soil inside the sealed frame cover slides down into the test chamber under the action of gravity, thereby burying the cable under test, simulating the working environment of a direct-buried cable, and passing high voltage electricity to the left end of the cable under test.

[0024] S5. After the cable is energized with high voltage, the cable under test is continuously vibrated through the vibration component and the backfill soil. At the same time, alternating compressive stress is applied to the cable under test through the extrusion component and the backfill soil.

[0025] S6. Continue with S5 until the cable experiences insulation breakdown, flashover, or reaches the preset test duration, then stop the test.

[0026] The beneficial effects of this invention are as follows: First, this invention uses a rotating assembly to set the combination of the test chamber and the sealing frame cover into two states: inverted and upright. When inverted, the backfill soil gathers in the sealing frame cover under the action of gravity, which facilitates the filling of the cable to be tested after the sealing frame cover is separated by the drive component. When upright, the backfill soil automatically slides into the test chamber under the action of gravity and buries the cable, thereby simulating the actual laying environment of direct-buried cables. On this basis, the vibration component transmits vibration to the backfill soil, and the extrusion component applies alternating compressive stress to the backfill soil, which can comprehensively simulate the combined mechanical stress conditions such as alternating load and environmental vibration experienced by direct-buried cables during operation, thereby conducting comprehensive testing of cable insulation performance under highly simulated direct-buried conditions.

[0027] Second, this invention uses an observation plate made of transparent material as the bottom of the test chamber, and a limiting groove is opened on its surface for supporting and positioning the cable. During the test, the cable is stably attached to the limiting groove under the pressure of the backfill soil, so that the operator can directly and clearly observe the real-time state changes of the cable body and its surface under the combined stress through the observation plate from the bottom. This design links the internal visible insulation degradation process with the external mechanical stress, which greatly facilitates intuitive teaching and enables trainees to directly observe and understand the insulation failure mode and evolution process of the cable in a simulated direct burial environment.

[0028] Third, this invention employs a telescopic section of hydraulic cylinder two that can extend and press against the soil-pressing plate, causing it to squeeze the backfill soil. By periodically changing the thrust of hydraulic cylinder two, the backfill soil can be subjected to dynamically changing compressive stress on the cable. At the same time, the vibration component is fixed on the soil-pressing plate, and the vibration force generated by its vibration motor is continuously transmitted to the backfill soil through the soil-pressing plate. The combination of these two mechanisms enables the cable testing environment to simulate the stress changes and vibration transmission of the soil in real direct burial conditions to a very high degree. Attached Figure Description

[0029] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0030] Figure 1 This is a schematic diagram of the overall structure of the present invention when the test chamber is upright.

[0031] Figure 2 This is a schematic diagram of the structure when the sealing frame cover is separated from the test chamber in this invention.

[0032] Figure 3 This is a schematic diagram of the test chamber inverted in this invention.

[0033] Figure 4 This is a cross-sectional view of the bracket, bearing frame, observation plate, and annular plate in this invention.

[0034] Figure 5This is a side view of the test chamber, sealing frame cover, hydraulic cylinder, and base plate in this invention.

[0035] Figure 6 This is a cross-sectional view of the soil pressing plate, sealing frame cover, hydraulic cylinder II, and vibration motor in this invention.

[0036] Figure 7 This is a cross-sectional view of the inverted test chamber and the sealing frame cover combined in this invention.

[0037] Figure 8 This is a schematic diagram of the structure of the upright test chamber and the sealing frame cover combined in this invention.

[0038] Figure 9 This is a cross-sectional view of the sealing frame cover, the soil pressing plate, the base plate, and the hydraulic cylinder 2 in this invention.

[0039] In the diagram: 1. Support; 2. Rotating assembly; 3. Test chamber; 4. Sealing frame cover; 5. Simulation assembly; 21. Circular plate; 22. Roller; 23. Driven gear; 24. Drive motor; 25. Drive gear; 31. Drive assembly; 32. Bearing frame; 33. Observation plate; 51. Soil pressing plate; 52. Vibration assembly; 53. Extrusion assembly; 311. Hydraulic cylinder one; 521. Base plate; 522. Vibration motor; 531. Hydraulic cylinder two. Detailed Implementation

[0040] The embodiments of the present invention are described in detail below. The embodiments described below are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention. Where specific techniques or conditions are not specified in the embodiments, they shall be performed in accordance with the techniques or conditions described in the literature in the art or in accordance with the product manual.

[0041] See Figure 1 and Figure 2 A comprehensive testing device for the insulation performance of power cables includes a support 1. A test chamber 3 for placing the cable to be tested is connected to the support 1 via a rotating assembly 2. A sealing frame cover 4 is slidably inserted into the test chamber 3 via a drive assembly 31. A simulation assembly 5 simulating the actual working conditions of a directly buried cable is provided on the sealing frame cover 4.

[0042] See Figure 1 , Figure 2 , Figure 6 and Figure 7 The inner cavity formed by the test chamber 3 and the sealing frame cover 4 contains backfill soil for burying the cable, and this inner cavity is also used to place the test part of the cable.

[0043] During testing, the test chamber 3 and the sealing frame cover 4 are first inverted by rotating assembly 2, so that the test chamber 3 is on top and the sealing frame cover 4 is on the bottom. When inverted, the backfill soil gathers in the sealing frame cover 4 under the action of gravity. Then, the sealing frame cover 4 is pushed down by drive component 31 to separate it from the test chamber 3, so that the operator can place the cable to be tested in the test chamber 3. Then, the sealing frame cover 4 is reset, so that the sealing frame cover 4 pushes the cable to be tested and limits it in the test chamber 3.

[0044] Then, by rotating the assembly 2 to the upright test chamber 3 and the sealing frame cover 4, the backfill soil automatically slides into the test chamber 3 under the action of gravity and buries the cable, thereby simulating the actual laying environment of the direct-buried cable. Subsequently, the simulation assembly 5 transmits vibration to the backfill soil and applies alternating compressive stress, comprehensively simulating the combined mechanical stress conditions such as alternating load and environmental vibration experienced by the direct-buried cable during operation.

[0045] In this embodiment, a high-voltage generator (not shown in the figure) is placed on the left side of the bracket 1. During the test, the high-voltage generator is connected to the left end of the cable under test, and the right end of the cable under test is suspended in the air. The right ends of each cable under test can be separated by ropes to prevent different cables under test from being connected to each other. Then, high voltage is passed into the cable simulating direct burial conditions through the high-voltage generator, so as to conduct a comprehensive test of the cable insulation performance under highly simulated direct burial conditions.

[0046] To facilitate switching between inverted and upright states of the test chamber 3 and the sealing frame cover 4, the present invention designs the following structure: (See attached diagram) Figure 1 , Figure 2 , Figure 3 and Figure 4 The rotating assembly 2 includes annular plates 21 fixedly installed on the left and right sides of the test chamber 3. Several rotatably connected rollers 22 are arranged circumferentially on the inner circumference of the annular structure on the upper part of the bracket 1. The rollers 22 roll against the outer side of the corresponding annular plates 21, so that the annular plates 21 can rotate smoothly. A driven gear 23 is fixedly installed on the outer side of the right annular plate 21. A drive motor 24 is fixedly installed on the right side of the bracket 1. A drive gear 25 that meshes with the driven gear 23 is fixedly installed on the output shaft of the drive motor 24.

[0047] When it is necessary to switch the test chamber 3 and the sealing frame cover 4 from the upright position to the inverted position, the drive motor 24 is started to rotate forward, so that the drive motor 24 drives the drive gear 25 to rotate 180° through the driven gear 23. The drive gear 25 drives the test chamber 3 to rotate synchronously through the ring plate 21 on the right. The test chamber 3 drives the sealing frame cover 4 to rotate synchronously, so that the test chamber 3 and the sealing frame cover 4 rotate half a turn, switching from the upright position to the inverted position. When it is necessary to switch the test chamber 3 and the sealing frame cover 4 from the inverted position to the upright position, the drive motor 24 is reversed, and the principle is the same as above.

[0048] It is worth noting that the number of teeth of the driven gear 23 is much greater than that of the driving gear 25, which makes the transmission from the driving gear 25 to the driven gear 23 a deceleration motion that can amplify the torque. Therefore, a common three-phase asynchronous motor can be used for the drive motor 24.

[0049] To facilitate the separation of the test chamber 3 and the sealing frame cover 4, the present invention designs the following structure: (See attached diagram) Figure 2 , Figure 5 , Figure 6 and Figure 7 The drive assembly 31 includes a plurality of hydraulic cylinders 311 arranged in a matrix and fixedly installed on the outside of the test chamber 3. The telescopic sections of the hydraulic cylinders 311 are all fixedly connected to the sealing frame cover 4.

[0050] When the cable needs to be tested, the forward drive motor 24 inverts the test chamber 3 and the sealing frame cover 4. At this time, the backfill soil in the combined cavity of the test chamber 3 and the sealing frame cover 4 slides down into the sealing frame cover 4 under the action of gravity. Then, the extension section of the hydraulic cylinder 311 pushes the sealing frame cover 4 down to move it completely to the lower part of the test chamber 3, so that the sealing frame cover 4 is separated from the test chamber 3. By retracting the extension section of the hydraulic cylinder 311, the sealing frame cover 4 can be inserted back into the test chamber 3 and combined together.

[0051] To facilitate the fixing and confinement of the testing section of the cable under test within the test chamber 3, the present invention designs the following structure: (See attached diagram) Figure 3 , Figure 4 , Figure 5 , Figure 6 , Figure 7 and Figure 8 The test chamber 3 consists of an outer support frame 32 and a bottom observation plate 33. The support frame 32 has several U-shaped grooves arranged at equal intervals along the front-back direction and extending through the left and right sides. The sealing frame cover 4 has a semi-circular groove on the lower side that matches the U-shaped grooves for sealing and limiting the cable.

[0052] When the sealing frame cover 4 is separated from the test chamber 3, the operator places the cable under test into the bearing frame 32 from bottom to top along the U-shaped groove, so that the test part of the cable under test is located in the bearing frame 32. By limiting the position of each cable under test through the U-shaped groove, the actual separation arrangement scenario of power cables in direct burial can be simulated. Then, the repositioned and moved sealing frame cover 4 pushes the cable under test upward through the semi-circular groove on it to the arc section position of the U-shaped groove. At this time, the sealing frame cover 4 presses against the test chamber 3, and the semi-circular groove and the arc section of the U-shaped groove combine and seal against the outer wall of the cable under test, thereby limiting the position of the cable under test.

[0053] It should be noted that when placing the cable under test, the cable under test is inserted inside the two annular plates 21, and the end connector of the cable under test is prevented from contacting any component except the high voltage generator. All metal parts in this embodiment are coated with an insulating coating on the outside.

[0054] See Figure 1 , Figure 6 , Figure 7 , Figure 8 and Figure 9 The simulation assembly 5 includes a soil pressing plate 51 that is slidably connected to the sealing frame cover 4. The outer wall of the soil pressing plate 51 is attached to the inner wall of the sealing frame cover 4. When the sealing frame cover 4 is inverted, the soil pressing plate 51 moves downward under its own weight and the weight of the backfill soil, so that when inverted, the soil pressing plate 51 abuts against the bottom wall of the sealing frame cover 4. At the same time, the upper side of the soil pressing plate 51 and the four side walls of the sealing frame cover 4 are used to contain and limit the backfill soil.

[0055] See Figure 1 , Figure 2 , Figure 5 , Figure 6 , Figure 7 and Figure 8 The simulation assembly 5 also includes a vibration assembly 52 for vibrating the backfill soil and a compression assembly 53 for applying alternating compressive stress to the backfill soil. The vibration assembly 52 includes a base plate 521 fixedly installed on the side of the soil compression plate 51 away from the sealing frame cover 4, and two symmetrically arranged vibration motors 522 are fixedly installed on the base plate 521.

[0056] See Figure 1 , Figure 2 , Figure 6 , Figure 7 and Figure 9 The extrusion assembly 53 includes a hydraulic cylinder 531 fixedly installed on the side of the sealing frame cover 4 away from the test chamber 3. The telescopic section of the hydraulic cylinder 531 extends into the sealing frame cover 4 and is not connected to the soil pressing plate 51.

[0057] When the sealing frame cover 4 and the test chamber 3 are in the correct position, the backfill soil automatically slides into the test chamber 3 under the action of gravity and buries the cable, thereby simulating the actual laying environment of the direct-buried cable. At the same time, the soil pressing plate 51 moves downward under its own weight and the gravity of the vibration motor 522 and the base plate 521, so that the soil pressing plate 51 presses down on the backfill soil, so that the backfill soil applies static load pressure to the cable.

[0058] Based on the above, the vibration motor 522 is activated, so that the vibration force of the vibration motor 522 is transmitted to the soil pressing plate 51 through the base plate 521. The vibration force is then transmitted to the backfill soil through the soil pressing plate 51, simulating the environmental vibration conditions experienced by the direct-buried cable during operation. At the same time, the telescopic section of the extended hydraulic cylinder 531 is pressed against and pushed against the soil pressing plate 51, causing the soil pressing plate 51 to squeeze the backfill soil. The thrust of the hydraulic cylinder 531 is periodically changed, so that the backfill soil can apply dynamically changing compressive stress to the cable. This comprehensively simulates the combined mechanical stress conditions such as alternating loads and environmental vibrations experienced by the direct-buried cable during operation, thereby conducting a comprehensive test of the cable insulation performance under highly simulated direct-buried conditions.

[0059] To facilitate real-time observation of cable changes and failure modes during testing, this invention designs the following structure: (See attached diagram) Figure 6 , Figure 7 , Figure 8 and Figure 9 The observation plate 33 is made of high-strength transparent glass. Several limiting grooves are arranged at equal intervals along the front-back direction and are connected from left to right on the upper side of the observation plate 33. During the test, the cable is squeezed and adhered to the limiting groove by the backfill soil, and then the cable can be observed from the bottom of the observation plate 33.

[0060] The insulation performance test of the cable under simulated direct burial conditions is continuously carried out until the operator observes insulation breakdown or flashover phenomena in the cable body from the bottom through the observation board 33, or when the preset test time is reached. If insulation breakdown or flashover phenomena do not occur in the cable body within the preset test time, the cable is judged to be qualified under simulated direct burial conditions; otherwise, it is unqualified.

[0061] In addition, the present invention also provides a comprehensive test method for the insulation performance of power cables. The specific test method steps are as follows: S1, the test chamber 3 and the sealing frame cover 4 are inverted by the forward rotation drive motor 24, so that the test chamber 3 is on top and the sealing frame cover 4 is on the bottom, so that the backfill soil slides into the interior of the sealing frame cover 4 under the action of gravity.

[0062] S2. After inverting the test chamber 3, the telescopic section of the extended hydraulic cylinder 311 pushes the sealing frame cover 4 downward to separate from the test chamber 3. Then, the operator places the cable to be tested into the U-shaped groove of the test chamber 3 from bottom to top.

[0063] S3. After the cable is located in the test chamber 3, the telescopic section of the retractable hydraulic cylinder 311 resets the sealing frame cover 4, so that the semi-circular groove on the sealing frame cover 4 is combined with the U-shaped groove of the test chamber 3, thereby limiting the cable under test. Then, the reverse drive motor 24 is reversed to position the test chamber 3 upright.

[0064] S4. After the test chamber 3 is placed upright, the backfill soil in the sealing frame cover 4 slides down into the test chamber 3 under the action of gravity, thereby burying the cable under test, simulating the working environment of a direct-buried cable, and passing high voltage electricity to the left end of the cable under test through a high voltage generator.

[0065] S5. When the cable under test is energized with high voltage, the vibration motor 522 is started and the vibration force is transmitted to the cable under test through the backfill soil. At the same time, the extension section of the hydraulic cylinder 2 531 is extended to abut against and push the soil pressing plate 51, and the thrust of the hydraulic cylinder 2 531 is periodically changed, so that the backfill soil applies dynamically changing compressive stress to the cable.

[0066] S6. Continue with S5 until the cable experiences insulation breakdown, flashover, or reaches the preset test duration, then stop the test.

[0067] In summary, although the comprehensive testing device and method for the insulation performance of power cables provided by this invention have increased the manufacturing cost slightly by adding structures such as a rotatable test chamber 3 and a separable sealing frame cover 4 compared with traditional testing methods, its core design concept and the technical effects achieved have clear practicality and economy.

[0068] This invention does not aim to completely replicate the direct burial environment in a one-to-one physical manner. Instead, it addresses the specific needs of direct burial cable insulation performance testing and personnel training by constructing a controllable soil burial space through the test chamber 3 and the sealing frame cover 4. Vibration components 52 and extrusion components 53 are used to actively apply vibration and alternating compressive stress to the backfill soil. In this way, the most critical composite mechanical stress factors affecting cable insulation performance in real direct burial conditions are efficiently and centrally reproduced through simplified engineering methods.

[0069] This design aims to rapidly, safely, and repeatably simulate the main stress conditions that lead to cable insulation degradation in a laboratory environment, rather than constructing a completely realistic soil geological environment. At the same time, the design of the transparent observation panel 33 allows for indirect observation and correlation analysis of the invisible insulation failure process, greatly enhancing the intuitiveness and effectiveness of teaching and training.

[0070] Therefore, this invention is an optimized balance between cost control, ease of operation and functional implementation, while ensuring the scientific validity and effectiveness of the test. It is specifically designed to solve the problems of insulation performance evaluation and personnel training for directly buried cables under specific working conditions, and has good practical value and prospects for promotion.

[0071] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0072] Furthermore, the terms "first," "second," "number one," and "number two" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first," "second," "number one," or "number two" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0073] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0074] The embodiments described herein are preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, all equivalent changes made in accordance with the structure, shape, and principle of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A comprehensive testing device for the insulation performance of power cables, comprising a support frame, characterized in that, The bracket is connected to a test chamber for placing the cable under test via a rotating assembly. A sealing frame cover is slidably inserted into the test chamber via a drive component. The sealing frame cover is equipped with a simulation assembly that simulates the actual working conditions of a direct-buried cable. The inner cavity formed by the test chamber and the sealing frame cover contains backfill soil for burying the cable, and this inner cavity is also used to place the test part of the cable. The simulation assembly includes a soil-pressing plate that is slidably connected to the sealing frame cover. The outer wall of the soil-pressing plate is attached to the inner wall of the sealing frame cover. When the sealing frame cover is inverted, the upper side of the soil-pressing plate and the four side walls of the sealing frame cover confine and limit the backfill soil. The simulation assembly also includes a vibration component for vibrating the backfill soil and a compression component for applying alternating compressive stress to the backfill soil. The rotating assembly includes annular plates fixedly installed on the left and right sides of the test chamber; a driven gear is fixedly installed on the outer side of the right annular plate, a drive motor is fixedly installed on the right side of the bracket, and a drive gear that meshes with the driven gear is fixedly installed on the output shaft of the drive motor, the number of teeth of the driven gear being greater than that of the drive gear. The drive assembly includes several hydraulic cylinders arranged in a matrix and fixedly installed on the outside of the test chamber. The telescopic sections of the hydraulic cylinders are all fixedly connected to the sealing frame cover. The vibration assembly includes a base plate fixedly installed on the side of the soil compaction plate away from the sealing frame cover, and two symmetrically arranged vibration motors are fixedly installed on the base plate. The extrusion assembly includes a hydraulic cylinder two fixedly installed on the side of the sealing frame cover away from the test chamber. The telescopic section of the hydraulic cylinder two extends into the sealing frame cover and is not connected to the soil pressing plate. The cable under test is placed in the test chamber and sealed frame cover combination. The rotating assembly rotates the test chamber and sealed frame cover, causing the backfill soil to bury the cable under test under gravity. The vibration component simulates the environmental vibration conditions experienced by the direct-buried cable during operation, while the compression component applies dynamically changing compressive stress to the cable by the backfill soil. This comprehensively simulates the combined mechanical stress conditions of alternating loads and environmental vibrations experienced by the direct-buried cable during operation. By simulating the actual working conditions of the direct-buried cable through the vibration component and compression component, the comprehensive insulation performance of the cable can be tested under direct-buried conditions.

2. The comprehensive testing device for the insulation performance of power cables according to claim 1, characterized in that, The test chamber consists of an outer support frame and a bottom observation plate, which is made of transparent material.

3. The comprehensive testing device for the insulation performance of power cables according to claim 2, characterized in that, The bearing frame has several U-shaped grooves arranged at equal intervals along the front-back direction and extending through the left and right sides. The sealing frame cover has a semi-circular groove on the lower side that matches the U-shaped grooves and is used to seal and limit the cable.

4. The comprehensive testing device for the insulation performance of power cables according to claim 2, characterized in that, The observation plate has several limiting grooves arranged at equal intervals along the front-back direction and extending through the left and right sides. During testing, the cable is squeezed and adhered to the limiting grooves by the backfill soil, and the cable can then be observed from the bottom of the observation plate.

5. The comprehensive testing device for the insulation performance of power cables according to claim 1, characterized in that, The upper part of the support has several rotatably connected rollers arranged in the inner circumference of the annular structure. The rollers roll against the outer side of the corresponding circular plate.

6. A comprehensive testing method for the insulation performance of power cables, using the comprehensive testing device for the insulation performance of power cables according to any one of claims 1 to 5, characterized in that, The specific testing method and steps are as follows: S1. By rotating the assembly to invert the test chamber, so that the test chamber is on top and the sealing frame cover is on the bottom, the backfill soil slides down into the sealing frame cover under the action of gravity. S2. After inverting the test chamber, the sealing frame cover is pushed downward by the drive component to separate it from the test chamber. Then the operator places the cable to be tested into the test chamber from bottom to top. S3. After the cable is placed in the test chamber, the sealing frame cover is reset by the drive component, so that the sealing frame cover and the test chamber abut and limit the cable. Then the test chamber is upright. S4. After the test chamber is placed upright, the backfill soil inside the sealed frame cover slides down into the test chamber under the action of gravity, thereby burying the cable under test, simulating the working environment of a direct-buried cable, and passing high voltage to the left end of the cable under test. S5. After the cable is energized with high voltage, it is continuously vibrated through the vibration component and backfill soil, while alternating compressive stress is applied to the cable under test through the extrusion component and backfill soil. S6. Continue with S5 until the cable experiences insulation breakdown, flashover, or reaches the preset test duration, then stop the test.

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