GIS cable terminal interface defect simulation and multivariate detection method and device

Abstract

The invention discloses a GIS cable terminal interface defect simulation and multi-element detection method, cable terminal interface defects are accurately simulated through modular design, multi-element sensing monitoring technologies are integrated, comprehensive monitoring of multiple operating parameters of a cable terminal is realized, and the method comprises the following steps of: combining actual operating conditions and research requirements to obtain a multi-element sensing monitoring system; according to the method, through modularized air gap simulation and stress regulation and control functions, flexible modularized design is adopted, a user can adjust the air gap form and stress distribution according to the experiment requirement, and the test accuracy is improved. Therefore, the working states of the cable terminal under different working conditions are simulated, meanwhile, a multi-state monitoring system is integrated, multiple key parameters such as temperature, pressure and partial discharge at the interface of the cable terminal can be synchronously detected, comprehensive operation data can be acquired in real time, and accurate support is provided for equipment performance evaluation.

Description

Technical Field

[0001] The present invention relates to the technical field of power systems, and in particular to a method and device for GIS cable terminal interface defect simulation and multivariate detection. Background Art

[0002] With the continuous expansion and modernization of power systems, the application of GIS (gas insulated switch) cable terminals in high-voltage power transmission has gradually increased. As an important part of power transmission, the insulation performance of cable terminals directly determines the stability and safety of the system. However, the air gap defects at the cable terminal interface not only affect the stress distribution of the cable terminal interface, but also may cause partial discharge, increasing the risk of power system failure.

[0003] At present, the common simulation methods for GIS cable terminal interface defects mainly rely on simple models, such as artificially adding air gaps, bubbles and other defects to simulate the interface. However, these methods are often difficult to accurately control the morphology and distribution of defects, and cannot fully simulate the various complex working conditions that cable terminals may encounter in actual operation. In addition, existing simulation devices can usually only simulate a single type of defect, lack of comprehensive simulation of the interaction of multiple defects, and it is difficult to reflect the defect formation and development process in real working conditions. For the simulation of cable joint interface stress, existing research mainly relies on traditional mechanical models and finite element simulation methods, but these methods are often difficult to accurately control and adjust the interface. The stress distribution at the cable terminals is not flexible and cannot be quickly adjusted according to different experimental requirements. Although finite element simulation can simulate stress distribution, it still lacks actual measurement methods that can be directly combined with experimental verification results, and its adaptability to experimental scenarios is poor. For real-time monitoring of multi-dimensional parameters such as temperature and pressure at GIS cable terminals, independent sensor systems are usually required to monitor parameters such as temperature, pressure and partial discharge respectively. Such monitoring schemes not only increase the complexity of the system, but also increase the cost and difficulty of data processing. In addition, existing monitoring systems often lack the ability to comprehensively evaluate the interactions between multiple physical parameters, making it difficult to fully understand the comprehensive performance of cable joints under actual working conditions. Summary of the invention

[0004] The present invention provides a method and device for GIS cable terminal interface defect simulation and multivariate detection, which can effectively solve the problem proposed in the above background technology that the current research methods for cable terminal interface defects mostly use sheet samples for simulation, but this method is difficult to accurately reproduce the air gap and stress distribution characteristics under actual working conditions, and cannot effectively evaluate the performance of the cable terminal under complex working conditions. In addition, traditional monitoring systems can usually only measure a single parameter and lack the ability to comprehensively monitor multiple key performances of the cable terminal, resulting in an incomplete evaluation of the equipment status.

[0005] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a method for GIS cable terminal interface defect simulation and multivariate detection, which accurately simulates the cable terminal interface defects through modular design, and integrates multivariate sensing monitoring technology to achieve comprehensive monitoring of multiple operating parameters of the cable terminal;

[0006] The steps include:

[0007] Step 1: Based on the actual operating conditions and research requirements, select the type and morphology of interface defects, plan the loading mode of the experiment, and determine the arrangement of sensors and monitoring accuracy requirements;

[0008] Step 2: Complete the processing and preparation of the experimental samples, including the preparation of the silicone rubber stress cone and the epoxy resin sleeve, and determine the replaceable defect simulation module of the silicone rubber stress cone mold to generate interface defects to simulate the interface defect behavior in actual operation;

[0009] Step 3: After the sample is assembled, install the thin film pressure sensor, infrared temperature sensor and partial discharge sensor at the designated location according to the experimental purpose;

[0010] Step 4: Select the loading mode according to the experimental objectives to simulate the complex stress state under actual working conditions;

[0011] Step 5: Collect data from each sensor, including interface pressure distribution, temperature field changes, and partial discharge behavior. The data of each physical field parameter is transmitted to the central control system after time synchronization processing to form real-time monitoring capabilities;

[0012] Step 6: After data acquisition is completed, the data is analyzed, including a comprehensive study of the multi-physics field coupling behavior of pressure, temperature and electric field, and the results are combined for further theoretical derivation or experimental improvement.

[0013] According to the above technical solution, in step 1, a replaceable mold module is specifically designed to simulate different defect forms at the interface of the cable joint, and the simulation conditions of the interface defects are flexibly controlled by adjusting the shape and configuration of the module. The types of interface defects include air gaps and bubbles, and the support conditions of the cable joint are accurately controlled to adjust the interface stress, thereby evaluating the actual working conditions of the cable joint;

[0014] At the same time, multi-sensor integration technology is used to realize real-time monitoring of cable joint temperature, pressure and partial discharge.

[0015] According to the above technical solution, in step 2, the silicone rubber stress cone is an important component responsible for electric field balance and insulation in the GIS cable terminal. The mold design focuses on reproducing its geometric characteristics and interface defects. During the preparation of the silicone rubber stress cone, a hole runs through the center of the silicone rubber stress cone mold for placing a metal wire core. The metal wire core is energized as a heat source in the experiment to simulate the heating characteristics of the cable conductor during operation. The presence of the heat source can truly reproduce the temperature distribution of the defect area and its influence on stress and partial discharge.

[0016] Secondly, when preparing the silicone rubber stress cone, an interface defect is formed by embedding a protrusion module in the mold, while ensuring the uniformity and mechanical properties of the silicone rubber material. The protrusion module is first installed in the inner wall embedding groove of the silicone rubber stress cone mold. The shape, size and position of the protrusion module are precisely designed to simulate the interface defects under actual working conditions. After the module is embedded, the slot position is adjusted to ensure that it fits tightly with the inner wall of the mold to avoid displacement or leakage during the material injection process. Subsequently, the pre-mixed liquid silicone rubber is injected into the mold cavity through the injection port, and the residual bubbles in the material are removed by a vacuum degassing process.

[0017] After the injection is completed, the mold is placed in a constant temperature curing box for curing. The specific temperature range is 80-120℃ and the curing time is 4-8 hours. After the curing is completed, the mold is cooled by slow cooling. After the silicone rubber reaches the designed strength, demoulding is performed. During the demoulding process, special tools are used to easily separate the silicone rubber and the mold to ensure that the defect morphology generated by the protrusion module is clearly visible on the sample surface and there is no damage or cracks. The surface defects of the silicone rubber stress cone sample finally obtained are highly consistent with the geometric parameters of the experimental design, providing a reliable basis for interface defect simulation;

[0018] The epoxy resin sleeve is prepared by an epoxy resin sleeve mold. The epoxy resin sleeve mold is a hollow conical structure, which can effectively simulate the mechanical and electrical properties of the epoxy resin insulation layer. The inner cavity size of the mold is completely matched with the shape of the silicone rubber stress cone to form a tightly fitting interface. The inner wall of the mold is polished to ensure that the epoxy resin has uniform surface quality and mechanical strength after pouring and curing.

[0019] In the specific preparation process of the epoxy resin sleeve, the epoxy resin mold is first installed on the supporting device, and the hollow inner cavity of the mold is precisely adjusted to fully match the shape of the silicone rubber stress cone. The inner cavity of the mold is polished with high precision, and the roughness of its inner wall is controlled within the micron range to ensure that the cured surface after the epoxy resin is poured is smooth and defect-free. Subsequently, the epoxy resin material mixed in proportion is injected into the mold cavity. During the injection process, a vacuum degassing device is used to remove tiny bubbles in the epoxy resin.

[0020] After injection, the mold and the support device are placed in a constant temperature curing box for curing. The curing temperature is set between 60-80°C, the specific temperature is determined by the material properties of the epoxy resin, and the curing time is usually 6-12 hours;

[0021] The curing process is divided into two stages: the initial curing stage and the final curing stage. The initial curing stage eliminates internal stress through lower temperature, while the final curing stage enhances the mechanical properties and thermal stability of the epoxy resin through high temperature. After the curing is completed, the mold needs to be gradually cooled to room temperature to avoid cracks inside the material due to excessive temperature difference. During the demolding process, a slow and uniform separation method is adopted to ensure the integrity of the hollow conical structure of the sleeve and the smooth surface of the outer wall. The final epoxy resin sleeve has an inner cavity shape that is completely consistent with the shape of the silicone rubber stress cone, providing good size matching and contact conditions for interface assembly.

[0022] According to the above technical solution, in step 2, after the silicone rubber stress cone and the epoxy resin sleeve are prepared, they need to be assembled. The interface assembly between the silicone rubber stress cone and the epoxy resin sleeve is an important link in achieving the overall performance of the simulated sample.

[0023] During the specific assembly process, the silicone rubber stress cone is first embedded into the epoxy resin sleeve by axial insertion. To ensure the accuracy of the interface fitting, a special alignment device is used to precisely adjust the position of the cone and the sleeve to ensure that there is no gap or misalignment in the interface contact area, avoiding stress concentration or uneven distribution caused by assembly errors.

[0024] According to the above technical solution, in the step 2, when determining the replaceable defect simulation module of the silicone rubber stress cone mold, the inner wall of the silicone rubber stress cone mold is designed with an embedded groove for installing a replaceable protrusion module to simulate the air gap or bubble defect at the interface. The shape and size of the protrusion module can be flexibly adjusted according to experimental requirements, including multiple forms such as dots, strips and meshes;

[0025] The dot-shaped protrusions are used to simulate local small bubble defects. Such defects usually come from local uneven mixing or gas residue during the manufacturing process, which causes local stress concentration at the interface and affects the thermal conductivity.

[0026] Strip-shaped protrusions are used to simulate linear air gaps. Such defects are mostly caused by insufficient bonding or operating errors, which increase the interfacial electric field strength and may cause partial discharge.

[0027] The mesh protrusions are used to simulate complex defect networks. When multiple defects interact, nonlinear thermal-mechanical-electrical effects will occur, significantly affecting the performance and life of the terminal. Through the mesh protrusion design, the interface behavior under multiple defect states can be comprehensively studied.

[0028] According to the above technical solution, in step 3, after the silicone rubber stress cone and the epoxy resin sleeve are assembled, the thin film pressure sensor is arranged at the interface between the silicone rubber stress cone and the epoxy resin sleeve and fixed by a special clamp to ensure that the sensor and the interface material are closely attached and do not affect the interface characteristics;

[0029] In addition, an infrared temperature sensor is arranged outside the interface to record the temperature field distribution at the interface. At the same time, a partial discharge sensor is installed around the metal wire core to monitor the impact of interface defects on electrical performance. The metal wire core is inserted into the central hole of the silicone rubber stress cone and generates heat by energizing it to simulate the heating characteristics of the conductor during operation.

[0030] After assembly, the base support system provides precise and controllable axial pressure to the silicone rubber stress cone, simulating the stress environment at the interface under actual operating conditions. The thin film pressure sensor can record the pressure changes at the interface in real time and provide accurate stress distribution data, especially around the defects generated by the protrusion module. Its high-resolution measurement capability can capture the local stress concentration caused by the defects.

[0031] According to the above technical solution, in step 4, specifically, the pressure distribution at the interface and its dynamic change over time are measured by a thin film pressure sensor. The thin film pressure sensor is designed based on the principle of piezoresistive effect. The film is deformed by external pressure to change the internal resistance. The relationship between pressure and resistance change is highly linear.

[0032] The sensitivity of the sensor can be expressed by the following formula:

[0033]

[0034] Where ΔR is the resistance change under pressure, and R0 is the initial resistance;

[0035] Based on the thermal radiation principle of the infrared temperature sensor, the temperature value is calculated by detecting the infrared radiation intensity on the surface of the interface material. The measurement formula of the sensor can be expressed by the following formula:

[0036] P=ò·σ·T 4 ;

[0037] Where P is the radiation power per unit area, ∈ is the emissivity of the material surface, σ is the Stefan-Boltzmann constant, and T is the absolute temperature;

[0038] The partial discharge sensor detects abnormal interface electric field distribution and captures the partial discharge phenomenon caused by interface defects. Partial discharge is a common insulation failure warning signal in high-voltage electrical equipment. Its essence is a tiny discharge phenomenon caused by the local enhancement of electric field strength exceeding the dielectric strength of the material. The partial discharge sensor collects transient current pulses through high-frequency electromagnetic wave signals. The amplitude of the discharge signal is directly related to the rate of change of the electric field strength, which can be expressed by the following formula:

[0039]

[0040] Where I(t) is the transient current, ∈ is the dielectric constant, and dE / dt is the rate of change of the electric field;

[0041] The partial discharge sensor is installed around the metal wire core, and the discharge signal is detected by a high-frequency probe. The key parameters of discharge starting voltage, discharge amplitude and frequency are extracted by combining the time domain and frequency domain characteristics. The detection frequency range of the partial discharge sensor is usually at the MHz level, with high time resolution and signal sensitivity, and can accurately capture the changes in electrical properties in the interface defect area.

[0042] According to the above technical solution, in step 5, during the data collection process, the thin film pressure sensor is arranged in the interface area, and provides two-dimensional data of pressure distribution through an array design. After these data are pre-processed by the signal acquisition module, a pressure distribution map is generated;

[0043] The multi-point detection head of the infrared temperature sensor synchronously records the dynamic changes of the interface temperature and converts the discrete temperature point data into a temperature field image through an interpolation algorithm;

[0044] The partial discharge sensor collects high-frequency electromagnetic signals in real time and extracts key parameters through time domain analysis, including discharge amplitude, frequency and time distribution. The key parameter data combined with the characteristics of the electric field distribution provide quantitative indicators for the electrical behavior of the defect;

[0045] After the independent signal acquisition modules of the thin film pressure sensor, infrared temperature sensor and partial discharge sensor convert the physical quantity into electrical signals, the signals are transmitted to the central control system.

[0046] According to the above technical solution, in step 6, after the central control system receives the data information collected and converted by the thin film pressure sensor, infrared temperature sensor and partial discharge sensor, the central control system performs denoising, interpolation, calibration and formatting processing on various types of data based on high-performance digital signal processing technology and stores them, and generates a multi-dimensional physical field distribution map to provide high-precision experimental data for the dynamic study of defect behavior.

[0047] A device for GIS cable terminal interface defect simulation and multi-element detection, comprising a GIS cable terminal and a multi-element sensor monitoring device, wherein the GIS cable terminal comprises a cable core, a top fixing device, an epoxy resin sleeve, a silicone rubber stress cone, a silicone rubber lifting base, and an epoxy resin supporting base;

[0048] The multi-sensor monitoring includes an ultrasonic probe, an infrared sensor, a thin film pressure sensor, and a partial discharge sensor;

[0049] The cable core is placed in the middle of the silicone rubber stress cone, the bottom of the silicone rubber stress cone is supported by a silicone rubber lifting base, the outer side of the silicone rubber stress cone is sleeved with an epoxy resin sleeve, the bottom of the epoxy resin sleeve is supported by an epoxy resin supporting base, and the outer side of the top of the epoxy resin sleeve is fixed by a top fixing device;

[0050] An ultrasonic probe is installed on one side end of the top fixing device, an infrared sensor is arranged on the outside of the other side of the ultrasonic probe, a thin film pressure sensor is arranged in the gap between the epoxy resin sleeve and the silicone rubber stress cone, and a local discharge sensor is arranged on the inner side of the bottom of the epoxy resin sleeve.

[0051] Compared with the prior art, the present invention has the following beneficial effects:

[0052] The present invention adopts a flexible modular design through modular air gap simulation and stress control functions. Users can adjust the air gap morphology and stress distribution according to experimental requirements, thereby simulating the working state of the cable terminal under different working conditions. At the same time, it also integrates a multi-state monitoring system, which can synchronously detect multiple key parameters such as temperature, pressure and partial discharge at the cable terminal interface, and obtain comprehensive operating data in real time, thereby providing accurate support for equipment performance evaluation.

[0053] In addition, modular design is used to accurately simulate cable terminal interface defects, and multiple monitoring functions are integrated into the same device, which not only provides a more scientific data basis for cable terminal design optimization, material selection and fault prediction, but also provides a reliable technical means for long-term operation monitoring and safety assessment of power system equipment. Compared with the traditional method of independently installing multiple devices to measure a single parameter, the present invention uses replaceable mold modules and a multi-sensor integrated system to achieve real-time monitoring of multiple physical quantities with one system, simplifies the experimental process, reduces equipment complexity and cost, and has higher flexibility and adaptability. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] The accompanying drawings are used to provide further understanding of the present invention and constitute a part of the specification. They are used to explain the present invention together with the embodiments of the present invention and do not constitute a limitation of the present invention.

[0055] In the attached picture:

[0056] Figure 1 It is a schematic diagram of the process of the present invention;

[0057] Figure 2 is a schematic diagram of a GIS cable terminal of the present invention;

[0058] Figure 3 is a schematic diagram of a multi-sensor monitoring device of the present invention;

[0059] Figure 4 Schematic diagram of a mold for preparing a silicone rubber stress cone of the present invention;

[0060] Figure 5 It is a schematic diagram of a mold for preparing an epoxy sleeve of the present invention;

[0061] Figure 6 It is a schematic diagram of the replaceable defect simulation mold of the present invention.

[0062] Numbers in the figure: 1. Cable core; 2. Top fixing device; 3. Epoxy resin sleeve; 4. Silicone rubber stress cone; 5. Silicone rubber lifting base; 6. Epoxy resin support base; 7. Ultrasonic probe; 8. Infrared sensor; 9. Thin film pressure sensor; 10. Partial discharge sensor. DETAILED DESCRIPTION

[0063] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0064] Example: Figure 1-6 As shown, the present invention provides a technical solution, a method for GIS cable terminal interface defect simulation and multi-element detection, which accurately simulates the cable terminal interface defects through modular design, and integrates multi-element sensing monitoring technology to achieve comprehensive monitoring of multiple operating parameters of the cable terminal;

[0065] The steps include:

[0066] Step 1: Based on the actual operating conditions and research requirements, select the type and morphology of interface defects, plan the loading mode of the experiment, and determine the arrangement of sensors and monitoring accuracy requirements;

[0067] Step 2: Complete the processing and preparation of the experimental samples, including the preparation of the silicone rubber stress cone and the epoxy resin sleeve, and determine the replaceable defect simulation module of the silicone rubber stress cone mold to generate interface defects to simulate the interface defect behavior in actual operation;

[0068] Step 3: After the sample is assembled, install the thin film pressure sensor, infrared temperature sensor and partial discharge sensor at the designated location according to the experimental purpose;

[0069] Step 4: Select the loading mode according to the experimental objectives to simulate the complex stress state under actual working conditions;

[0070] Step 5: Collect data from each sensor, including interface pressure distribution, temperature field changes, and partial discharge behavior. The data of each physical field parameter is transmitted to the central control system after time synchronization processing to form real-time monitoring capabilities;

[0071] Step 6: After data acquisition is completed, the data is analyzed, including a comprehensive study of the multi-physics field coupling behavior of pressure, temperature and electric field, and the results are combined for further theoretical derivation or experimental improvement.

[0072] Based on the above technical solution, in step 1, a replaceable mold module is specifically designed to simulate different defect forms at the interface of the cable joint, and the simulation conditions of the interface defects are flexibly controlled by adjusting the shape and configuration of the module. The types of interface defects include air gaps and bubbles, and the support conditions of the cable joint are precisely controlled to adjust the interface stress, thereby evaluating the actual working conditions of the cable joint;

[0073] At the same time, multi-sensor integration technology is used to realize real-time monitoring of cable joint temperature, pressure and partial discharge.

[0074] Based on the above technical solution, in step 2, the silicone rubber stress cone is an important component responsible for electric field balance and insulation in the GIS cable terminal. The mold design focuses on reproducing its geometric characteristics and interface defects. During the preparation process of the silicone rubber stress cone, a hole runs through the center of the silicone rubber stress cone mold for placing the metal wire core. The metal wire core is energized as a heat source in the experiment to simulate the heating characteristics of the cable conductor during operation. The presence of the heat source can truly reproduce the temperature distribution of the defect area and its influence on stress and partial discharge.

[0075] Secondly, when preparing the silicone rubber stress cone, an interface defect is formed by embedding a protrusion module in the mold, while ensuring the uniformity and mechanical properties of the silicone rubber material. The protrusion module is first installed in the inner wall embedding groove of the silicone rubber stress cone mold. The shape, size and position of the protrusion module are precisely designed to simulate the interface defects under actual working conditions. After the module is embedded, the slot position is adjusted to ensure that it fits tightly with the inner wall of the mold to avoid displacement or leakage during the material injection process. Subsequently, the pre-mixed liquid silicone rubber is injected into the mold cavity through the injection port, and the residual bubbles in the material are removed by a vacuum degassing process.

[0076] After the injection is completed, the mold is placed in a constant temperature curing box for curing treatment. The specific temperature is 90°C and the curing time is 6 hours. After the curing is completed, the mold is cooled by slow cooling. After the silicone rubber reaches the designed strength, the demoulding operation is carried out. During the demoulding process, a special tool is used to easily separate the silicone rubber and the mold to ensure that the defect morphology generated by the protrusion module is clearly visible on the sample surface and there is no damage or cracks. The surface defects of the silicone rubber stress cone sample finally obtained are highly consistent with the geometric parameters of the experimental design, providing a reliable basis for interface defect simulation;

[0077] The epoxy resin sleeve is prepared by an epoxy resin sleeve mold. The epoxy resin sleeve mold is a hollow cone structure, which can effectively simulate the mechanical and electrical properties of the epoxy resin insulation layer. The inner cavity size of the mold is completely matched with the shape of the silicone rubber stress cone to form a close fit interface. The inner wall of the mold is polished to ensure that the epoxy resin has uniform surface quality and mechanical strength after pouring and curing.

[0078] In the specific preparation process of the epoxy resin sleeve, the epoxy resin mold is first installed on the supporting device, and the hollow inner cavity of the mold is precisely adjusted to fully match the shape of the silicone rubber stress cone. The inner cavity of the mold is polished with high precision, and the roughness of its inner wall is controlled within the micron range to ensure that the cured surface after the epoxy resin is poured is smooth and defect-free. Subsequently, the epoxy resin material mixed in proportion is injected into the mold cavity. During the injection process, a vacuum degassing device is used to remove tiny bubbles in the epoxy resin.

[0079] After the injection is completed, the mold and the support device are placed in a constant temperature curing box for curing. The curing temperature is set at 70°C. The specific temperature is determined by the material properties of the epoxy resin. The curing time is usually 9 hours to ensure the overall strength of the epoxy resin material.

[0080] The curing process is divided into two stages: the initial curing stage and the final curing stage. The initial curing stage eliminates internal stress through lower temperature, while the final curing stage enhances the mechanical properties and thermal stability of the epoxy resin through high temperature. After the curing is completed, the mold needs to be gradually cooled to room temperature to avoid cracks inside the material due to excessive temperature difference. During the demolding process, a slow and uniform separation method is adopted to ensure the integrity of the hollow conical structure of the sleeve and the smooth surface of the outer wall. The final epoxy resin sleeve has an inner cavity shape that is completely consistent with the shape of the silicone rubber stress cone, providing good size matching and contact conditions for interface assembly.

[0081] Based on the above technical solution, in step 2, after the silicone rubber stress cone and the epoxy resin sleeve are prepared, they need to be assembled. The interface assembly between the silicone rubber stress cone and the epoxy resin sleeve is an important link to achieve the overall performance of the simulated sample;

[0082] During the specific assembly process, the silicone rubber stress cone is first embedded into the epoxy resin sleeve by axial insertion. To ensure the accuracy of the interface fitting, a special alignment device is used to precisely adjust the position of the cone and the sleeve to ensure that there is no gap or misalignment in the interface contact area, avoiding stress concentration or uneven distribution caused by assembly errors.

[0083] Based on the above technical solution, in step 2, when determining the replaceable defect simulation module of the silicone rubber stress cone mold, the inner wall of the silicone rubber stress cone mold is designed with an embedded groove for installing a replaceable protrusion module to simulate the air gap or bubble defect at the interface. The shape and size of the protrusion module can be flexibly adjusted according to experimental requirements, including multiple forms such as dots, strips and meshes;

[0084] The dot-shaped protrusions are used to simulate local small bubble defects. Such defects usually come from local uneven mixing or gas residue during the manufacturing process, which causes local stress concentration at the interface and affects the thermal conductivity.

[0085] Strip-shaped protrusions are used to simulate linear air gaps. Such defects are mostly caused by insufficient bonding or operating errors, which increase the interfacial electric field strength and may cause partial discharge.

[0086] The mesh protrusions are used to simulate complex defect networks. When multiple defects interact, nonlinear thermal-mechanical-electrical effects will occur, significantly affecting the performance and life of the terminal. Through the mesh protrusion design, the interface behavior under multiple defect states can be comprehensively studied.

[0087] Based on the above technical solution, in step 3, after the silicone rubber stress cone and the epoxy resin sleeve are assembled, the thin film pressure sensor is arranged at the interface between the silicone rubber stress cone and the epoxy resin sleeve and fixed by a special clamp to ensure that the sensor fits tightly with the interface material without affecting the interface characteristics;

[0088] In addition, an infrared temperature sensor is arranged outside the interface to record the temperature field distribution at the interface. At the same time, a partial discharge sensor is installed around the metal wire core to monitor the impact of interface defects on electrical performance. The metal wire core is inserted into the central hole of the silicone rubber stress cone and generates heat by energizing it to simulate the heating characteristics of the conductor during operation.

[0089] After assembly, the base support system provides precise and controllable axial pressure to the silicone rubber stress cone, simulating the stress environment at the interface under actual operating conditions. The thin film pressure sensor can record the pressure changes at the interface in real time and provide accurate stress distribution data, especially around the defects generated by the protrusion module. Its high-resolution measurement capability can capture the local stress concentration caused by the defects.

[0090] Based on the above technical solution, in step 4, specifically, the pressure distribution at the interface and its dynamic change over time are measured by a thin film pressure sensor. The thin film pressure sensor is designed based on the principle of piezoresistive effect. The external pressure causes the film to deform, thereby changing the internal resistance. The relationship between the pressure and the resistance change is highly linear.

[0091] The sensitivity of the sensor can be expressed by the following formula:

[0092]

[0093] Where ΔR is the resistance change under pressure, and R0 is the initial resistance;

[0094] The thickness of the film is usually controlled at the micron level to ensure its high sensitivity and flexible adaptability. The sensor is arranged at the interface contact area between the silicone rubber stress cone and the epoxy resin sleeve, and covers the entire interface through a distributed array to provide a high-resolution pressure distribution map. For defective areas such as air gaps or bubbles in the interface, the thin film pressure sensor can reflect its stress concentration effect through significant pressure anomalies.

[0095] Based on the thermal radiation principle of the infrared temperature sensor, the temperature value is calculated by detecting the infrared radiation intensity on the surface of the interface material. The measurement formula of the sensor can be expressed by the following formula:

[0096] P=ò·σ·T 4 ;

[0097] Where P is the radiation power per unit area, ∈ is the emissivity of the material surface, σ is the Stefan-Boltzmann constant, and T is the absolute temperature;

[0098] The infrared temperature sensor adopts a non-contact measurement method, which ensures the measurement accuracy while avoiding the interference of mechanical sensors on the sample interface. The sensor records the temperature distribution through a multi-point detection head array and generates a two-dimensional temperature field image of the interface in combination with an interpolation algorithm. The high spatial resolution and fast response time of the infrared temperature sensor enable it to capture subtle changes in the interface temperature field, especially when the conductor generates heat when it is energized or the interface pressure changes cause changes in thermal conductivity. The recorded temperature distribution data provides an important basis for the study of thermodynamic behavior;

[0099] The partial discharge sensor detects abnormal interface electric field distribution and captures the partial discharge phenomenon caused by interface defects. Partial discharge is a common insulation failure warning signal in high-voltage electrical equipment. Its essence is a tiny discharge phenomenon caused by the local enhancement of electric field strength exceeding the dielectric strength of the material. The partial discharge sensor collects transient current pulses through high-frequency electromagnetic wave signals. The amplitude of the discharge signal is directly related to the rate of change of the electric field strength, which can be expressed by the following formula:

[0100]

[0101] Where I(t) is the transient current, ∈ is the dielectric constant, and dE / dt is the rate of change of the electric field;

[0102] The partial discharge sensor is installed around the metal wire core, and the discharge signal is detected by a high-frequency probe. The key parameters of discharge starting voltage, discharge amplitude and frequency are extracted by combining the time domain and frequency domain characteristics. The detection frequency range of the partial discharge sensor is usually at the MHz level, with high time resolution and signal sensitivity, and can accurately capture the changes in electrical properties in the interface defect area.

[0103] Based on the above technical solution, in step 5, during the data collection process, the thin film pressure sensor is arranged in the interface area, and provides two-dimensional data of pressure distribution through an array design. After these data are pre-processed by the signal acquisition module, a pressure distribution map is generated;

[0104] The multi-point detection head of the infrared temperature sensor synchronously records the dynamic changes of the interface temperature and converts the discrete temperature point data into a temperature field image through an interpolation algorithm;

[0105] The partial discharge sensor collects high-frequency electromagnetic signals in real time and extracts key parameters through time domain analysis, including discharge amplitude, frequency and time distribution. The key parameter data combined with the characteristics of the electric field distribution provide quantitative indicators for the electrical behavior of the defect;

[0106] After the independent signal acquisition modules of the thin film pressure sensor, infrared temperature sensor and partial discharge sensor convert the physical quantity into electrical signals, the signals are transmitted to the central control system.

[0107] Based on the above technical solution, in step 6, after the central control system receives the data information collected and converted by the thin film pressure sensor, infrared temperature sensor and partial discharge sensor, the central control system denoises, interpolates, calibrates and formats various types of data based on high-performance digital signal processing technology and stores them, and generates a multi-dimensional physical field distribution map to provide high-precision experimental data for the dynamic study of defect behavior.

[0108] A device for GIS cable terminal interface defect simulation and multi-element detection, comprising a GIS cable terminal and a multi-element sensor monitoring device, wherein the GIS cable terminal comprises a cable core 1, a top fixing device 2, an epoxy resin sleeve 3, a silicone rubber stress cone 4, a silicone rubber lifting base 5, and an epoxy resin support base 6;

[0109] The multi-sensor monitoring includes an ultrasonic probe 7, an infrared sensor 8, a thin film pressure sensor 9, and a partial discharge sensor 10;

[0110] The cable core 1 is placed in the middle of the silicone rubber stress cone 4, the bottom of the silicone rubber stress cone 4 is supported by a silicone rubber lifting base 5, the outer side of the silicone rubber stress cone 4 is sleeved with an epoxy resin sleeve 3, the bottom of the epoxy resin sleeve 3 is supported by an epoxy resin supporting base 6, and the top outer side of the epoxy resin sleeve 3 is fixed by a top fixing device 2;

[0111] An ultrasonic probe 7 is installed on one side end of the top fixing device 2, an infrared sensor 8 is arranged on the outside of the other side of the ultrasonic probe 7, a thin film pressure sensor 9 is arranged in the gap between the epoxy resin sleeve 3 and the silicone rubber stress cone 4, and a local discharge sensor 10 is arranged on the inner side of the bottom of the epoxy resin sleeve 3.

[0112] Finally, it should be noted that the above description is only a preferred example of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for GIS cable terminal interface defect simulation and multivariate detection, characterized in that: Through modular design, the cable terminal interface defects are accurately simulated, and multi-sensor monitoring technology is integrated to achieve comprehensive monitoring of multiple operating parameters of the cable terminal; The steps include: Step 1: Based on the actual operating conditions and research requirements, select the type and morphology of interface defects, plan the loading mode of the experiment, and determine the arrangement of sensors and monitoring accuracy requirements; Step 2: Complete the processing and preparation of the experimental samples, including the preparation of the silicone rubber stress cone and the epoxy resin sleeve, and determine the replaceable defect simulation module of the silicone rubber stress cone mold to generate interface defects to simulate the interface defect behavior in actual operation; Step 3: After the sample is assembled, install the thin film pressure sensor, infrared temperature sensor and partial discharge sensor at the designated location according to the experimental purpose; Step 4: Select the loading mode according to the experimental objectives to simulate the complex stress state under actual working conditions; Step 5: Collect data from each sensor, including interface pressure distribution, temperature field changes, and partial discharge behavior. The data of each physical field parameter is transmitted to the central control system after time synchronization processing to form real-time monitoring capabilities; Step 6: After data acquisition is completed, the data is analyzed, including a comprehensive study of the multi-physics field coupling behavior of pressure, temperature and electric field, and the results are combined for further theoretical derivation or experimental improvement.

2. The method for GIS cable terminal interface defect simulation and multivariate detection according to claim 1 is characterized in that: In the step 1, a replaceable mold module is specifically designed to simulate different defect forms at the interface of the cable joint, and the simulation conditions of the interface defects are flexibly controlled by adjusting the shape and configuration of the module. The types of interface defects include air gaps and bubbles, and the support conditions of the cable joint are accurately controlled to adjust the interface stress, thereby evaluating the actual working conditions of the cable joint; At the same time, multi-sensor integration technology is used to realize real-time monitoring of cable joint temperature, pressure and partial discharge.

3. The method for GIS cable terminal interface defect simulation and multivariate detection according to claim 1 is characterized in that: In step 2, the silicone rubber stress cone is a component responsible for electric field balancing and insulation in the GIS cable terminal. The mold design focuses on reproducing its geometric characteristics and interface defects. During the preparation of the silicone rubber stress cone, a hole runs through the center of the silicone rubber stress cone mold for placing a metal wire core. The metal wire core is energized as a heat source in the experiment to simulate the heating characteristics of the cable conductor during operation. The presence of the heat source can truly reproduce the temperature distribution of the defect area and its influence on stress and partial discharge; Secondly, when preparing the silicone rubber stress cone, an interface defect is formed by embedding a protrusion module in the mold. The protrusion module is first installed in the inner wall embedding groove of the silicone rubber stress cone mold. The shape, size and position of the protrusion module are precisely designed to simulate the interface defects under actual working conditions. After the module is embedded, the slot position is adjusted to ensure that it fits tightly with the inner wall of the mold to avoid displacement or leakage during the material injection process. Subsequently, the pre-mixed liquid silicone rubber is injected into the mold cavity through the injection port, and the residual bubbles in the material are removed by a vacuum degassing process. After the injection is completed, the mold is placed in a constant temperature curing box for curing. The specific temperature range is 80-120°C and the curing time is 4-8 hours. After the curing is completed, the mold is cooled by slow cooling. After the silicone rubber reaches the designed strength, the demoulding operation is carried out. During the demoulding process, a special tool is used to easily separate the silicone rubber and the mold to ensure that the defect morphology generated by the protrusion module is clearly visible on the sample surface and there is no damage or cracks. The surface defects of the silicone rubber stress cone sample finally obtained are highly consistent with the geometric parameters of the experimental design. The epoxy resin sleeve is prepared by an epoxy resin sleeve mold. The epoxy resin sleeve mold is a hollow conical structure, which can effectively simulate the mechanical and electrical properties of the epoxy resin insulation layer. The inner cavity size of the mold is completely matched with the shape of the silicone rubber stress cone to form a close fit interface, and the inner wall of the mold is polished; In the specific preparation process of the epoxy resin sleeve, the epoxy resin mold is first installed on the supporting device, and the hollow inner cavity of the mold is precisely adjusted to fully match the shape of the silicone rubber stress cone. The inner cavity of the mold is polished with high precision, and the roughness of its inner wall is controlled within the micron range to ensure that the cured surface after the epoxy resin is poured is smooth and defect-free. Subsequently, the epoxy resin material mixed in proportion is injected into the mold cavity. During the injection process, a vacuum degassing device is used to remove tiny bubbles in the epoxy resin. After injection, the mold and the support device are placed in a constant temperature curing box for curing. The curing temperature is set between 60-80°C, which is determined by the material properties of the epoxy resin. The curing time is usually 6-12 hours. The curing process is divided into two stages: the initial curing stage and the final curing stage. The initial curing stage eliminates internal stress through lower temperature, while the final curing stage enhances the mechanical properties and thermal stability of the epoxy resin through high temperature. After the curing is completed, the mold needs to be gradually cooled to room temperature to avoid cracks inside the material due to excessive temperature difference. During the demolding process, a slow and uniform separation method is adopted to ensure that the hollow conical structure of the sleeve and the smooth surface of the outer wall maintain integrity. The final epoxy resin sleeve has an inner cavity shape that is completely consistent with the shape of the silicone rubber stress cone.

4. The method for GIS cable terminal interface defect simulation and multivariate detection according to claim 3 is characterized in that: In step 2, after the silicone rubber stress cone and the epoxy resin sleeve are prepared, they need to be assembled. The interface assembly between the silicone rubber stress cone and the epoxy resin sleeve is an important step in achieving the overall performance of the simulated sample. During the specific assembly process, the silicone rubber stress cone is first embedded into the epoxy resin sleeve by axial insertion. To ensure the accuracy of the interface fitting, a special alignment device is used to precisely adjust the position of the cone and the sleeve to ensure that there is no gap or misalignment in the interface contact area.

5. The method for GIS cable terminal interface defect simulation and multivariate detection according to claim 3 is characterized in that: In the step 2, when determining the replaceable defect simulation module of the silicone rubber stress cone mold, the inner wall of the silicone rubber stress cone mold is designed with an embedded groove for installing a replaceable protrusion module to simulate the air gap or bubble defect at the interface. The shape and size of the protrusion module can be flexibly adjusted according to experimental requirements, including multiple forms such as dots, strips and meshes; The dot-shaped protrusions are used to simulate local small bubble defects. Such defects usually come from local uneven mixing or gas residue during the manufacturing process, which causes local stress concentration at the interface and affects the thermal conductivity. Strip-shaped protrusions are used to simulate linear air gaps. Such defects are mostly caused by insufficient bonding or operating errors, which increase the interfacial electric field strength and may cause partial discharge. The mesh protrusions are used to simulate complex defect networks. When multiple defects interact, nonlinear thermal-mechanical-electrical effects will occur, significantly affecting the performance and life of the terminal. Through the mesh protrusion design, the interface behavior under multiple defect states can be comprehensively studied.

6. The method for GIS cable terminal interface defect simulation and multivariate detection according to claim 1 is characterized in that: In step 3, after the silicone rubber stress cone and the epoxy resin sleeve are assembled, the thin film pressure sensor is arranged at the interface between the silicone rubber stress cone and the epoxy resin sleeve and fixed by a special clamp to ensure that the sensor and the interface material are closely attached and do not affect the interface characteristics; In addition, an infrared temperature sensor is arranged outside the interface to record the temperature field distribution at the interface. At the same time, a partial discharge sensor is installed around the metal wire core to monitor the impact of interface defects on electrical performance. The metal wire core is inserted into the central hole of the silicone rubber stress cone and generates heat by energizing it to simulate the heating characteristics of the conductor during operation. After assembly, the base support system provides precise and controllable axial pressure to the silicone rubber stress cone, simulating the stress environment at the interface under actual operating conditions. The thin film pressure sensor can record the pressure changes at the interface in real time and provide accurate stress distribution data, especially around the defects generated by the protrusion module. Its high-resolution measurement capability can capture the local stress concentration caused by the defects.

7. The method for GIS cable terminal interface defect simulation and multivariate detection according to claim 1 is characterized in that: In step 4, specifically, the pressure distribution at the interface and its dynamic change over time are measured by a thin film pressure sensor. The thin film pressure sensor is designed based on the principle of piezoresistive effect. The external pressure causes the film to deform, thereby changing the internal resistance. The relationship between the pressure and the resistance change is highly linear. The sensitivity of the sensor can be expressed by the following formula: Where ΔR is the resistance change under pressure, and R0 is the initial resistance; Based on the thermal radiation principle of the infrared temperature sensor, the temperature value is calculated by detecting the infrared radiation intensity on the surface of the interface material. The measurement formula of the sensor can be expressed by the following formula: P=or·σ·T 4 4 Where P is the radiation power per unit area, ∈ is the emissivity of the material surface, σ is the Stefan-Boltzmann constant, and T is the absolute temperature; The partial discharge sensor detects abnormal interface electric field distribution and captures the partial discharge phenomenon caused by interface defects. Partial discharge is a common insulation failure warning signal in high-voltage electrical equipment. Its essence is a tiny discharge phenomenon caused by the local enhancement of electric field strength exceeding the dielectric strength of the material. The partial discharge sensor collects transient current pulses through high-frequency electromagnetic wave signals. The amplitude of the discharge signal is directly related to the rate of change of the electric field strength, which can be expressed by the following formula: Where I(t) is the transient current, ∈ is the dielectric constant, and dE / dt is the rate of change of the electric field; The partial discharge sensor is installed around the metal wire core, and the discharge signal is detected by a high-frequency probe. The key parameters of discharge starting voltage, discharge amplitude and frequency are extracted by combining the time domain and frequency domain characteristics. The detection frequency range of the partial discharge sensor is usually at the MHz level, with high time resolution and signal sensitivity, and can accurately capture the changes in electrical properties in the interface defect area.

8. The method for GIS cable terminal interface defect simulation and multivariate detection according to claim 1 is characterized in that: In step 5, during the data collection process, the thin film pressure sensor is arranged in the interface area, and provides two-dimensional data of pressure distribution through an array design. After these data are pre-processed by the signal acquisition module, a pressure distribution map is generated; The multi-point detection head of the infrared temperature sensor synchronously records the dynamic changes of the interface temperature and converts the discrete temperature point data into a temperature field image through an interpolation algorithm; The partial discharge sensor collects high-frequency electromagnetic signals in real time and extracts key parameters through time domain analysis, including discharge amplitude, frequency and time distribution. The key parameter data combined with the characteristics of the electric field distribution provide quantitative indicators for the electrical behavior of the defect; After the independent signal acquisition modules of the thin film pressure sensor, infrared temperature sensor and partial discharge sensor convert the physical quantity into electrical signals, the signals are transmitted to the central control system.

9. The method for GIS cable terminal interface defect simulation and multivariate detection according to claim 1, characterized in that: In step 6, after receiving the data information collected and converted by the thin film pressure sensor, infrared temperature sensor and partial discharge sensor, the central control system performs denoising, interpolation, calibration and formatting on various types of data based on high-performance digital signal processing technology and stores them, and generates a multi-dimensional physical field distribution map to provide high-precision experimental data for the dynamic study of defect behavior.

10. A device for GIS cable terminal interface defect simulation and multivariate detection according to any one of claims 1 to 9, characterized in that: It comprises a GIS cable terminal and a multi-sensor monitoring device, wherein the GIS cable terminal comprises a cable core (1), a top fixing device (2), an epoxy resin sleeve (3), a silicone rubber stress cone (4), a silicone rubber lifting base (5), and an epoxy resin supporting base (6); The multi-sensor monitoring comprises an ultrasonic probe (7), an infrared sensor (8), a thin film pressure sensor (9), and a partial discharge sensor (10); The cable core (1) is placed in the middle of the silicone rubber stress cone (4), the bottom of the silicone rubber stress cone (4) is supported by a silicone rubber lifting base (5), the outer side of the silicone rubber stress cone (4) is sleeved with an epoxy resin sleeve (3), the bottom of the epoxy resin sleeve (3) is supported by an epoxy resin supporting base (6), and the outer side of the top of the epoxy resin sleeve (3) is fixed by a top fixing device (2); An ultrasonic probe (7) is installed on one side of the top fixing device (2), an infrared sensor (8) is arranged on the outside of the other side of the ultrasonic probe (7), a thin film pressure sensor (9) is arranged in the gap between the epoxy resin sleeve (3) and the silicone rubber stress cone (4), and a local discharge sensor (10) is arranged on the inside of the bottom of the epoxy resin sleeve (3).

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