Cable GIS terminal operation state inversion method, system and device and medium

Abstract

The invention discloses a cable GIS terminal operation state inversion method, system and device and a medium, and the method comprises the steps: building a simulation model of a first object, and analyzing the spatial distribution of characteristic parameters of the first object in a first operation state; comparing the actually measured characteristic parameters of the first object, and correcting the input of the simulation model to obtain first simulation of the simulation model; analyzing the first object in a second running state to obtain second simulation of the simulation model; according to the first simulation and the second simulation, model parameters are corrected by combining the measured value of the first object, and simulation reproduction and defect simulation inversion of the first object in different states are achieved. The defects of lack of normal state simulation and combination of local defects and overall analysis in the prior art are effectively overcome. The operation states of the cable GIS terminal under different working conditions can be accurately evaluated, the accuracy and efficiency of fault diagnosis are improved, and a scientific basis is provided for intelligent operation and maintenance of equipment.

Description

Technical Field

[0001] The present invention relates to the technical field of state inversion, and in particular to a method, system, device and medium for inverting the operating state of a cable GIS terminal. Background Art

[0002] As a key connection node in the power system, cable GIS terminals have always been the focus of power equipment operation and maintenance due to their complex working conditions and changeable operating environment. With the improvement of the intelligence level of the power grid, the number of GIS terminals continues to increase. Under the influence of multiple factors such as high voltage, magnetism, heat, electricity, and mechanics for a long time, the cable GIS terminal components are affected by abnormal stress and strain, and various defects will inevitably occur, such as loose bolts, displacement of stress cones, cracking of casings, etc., which may eventually lead to insulation aging or structural damage. However, current operation and maintenance detection methods, such as partial discharge, infrared thermal imaging, and ultrasound, are difficult to detect these potential faults early. In recent years, cable GIS terminal failures caused by defects in terminal components have occurred frequently, seriously threatening the safe and stable operation of the power system. Therefore, in order to ensure the normal operation of the power system and reduce the occurrence of failures, it is crucial to realize the normal state and defect fault simulation and inversion of cable GIS terminals under different working conditions.

[0003] The current patents mainly focus on testing methods for the overall performance of cable GIS terminals and simulation of local defects. No invention patent has yet proposed a full-scale inversion method for cable GIS terminals, making it impossible to perform multi-type fault analysis on in-service equipment. Summary of the invention

[0004] In view of the above-mentioned problems, the present invention is proposed.

[0005] Therefore, the technical problem solved by the present invention is that the existing operating status inversion method has the following defects: (1) there is no simulation of the normal state of the cable GIS terminal, and the influence of basic operating parameters, material parameters and environmental parameters on the cable GIS terminal is lacking; (2) the detection of the cable GIS terminal is mainly performance detection, and there is a lack of simulation inversion of various internal faults in the operating state; (3) in the existing method, the simulation results of the overall large-scale and local defects of the cable GIS terminal are not compared and combined, which has certain limitations.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions: a cable GIS terminal operation status inversion method, comprising:

[0007] Establishing a simulation model of a first object, and analyzing the spatial distribution of characteristic parameters of the first object in a first operating state;

[0008] Comparing the measured characteristic parameters of the first object, correcting the input of the simulation model, and obtaining a first simulation of the simulation model;

[0009] Obtaining a second simulation of the simulation model by analyzing the first object in a second operating state;

[0010] According to the first simulation and the second simulation, combined with the measured values ​​of the first object, the model parameters are corrected to achieve the simulation reproduction and defect simulation inversion of the first object in different states.

[0011] As a preferred scheme of the cable GIS terminal operating status inversion method described in the present invention, wherein: the simulation model includes determining a multi-physical field simulation model of the first object in the first operating state according to actual structural parameters; determining a local multi-physical field simulation model of the first object in the second operating state according to actual structural parameters; and gridding the simulation model.

[0012] As a preferred solution of the cable GIS terminal operation state inversion method of the present invention, wherein: the first operation state includes but is not limited to the normal operation state of the first object;

[0013] The second operating state includes an operating state of the first object under a local defect.

[0014] As a preferred solution of the cable GIS terminal operating state inversion method described in the present invention, the spatial distribution includes solving the simulation model under the first operating state through a simulation tool to obtain the distribution of characteristic parameters.

[0015] As a preferred solution of the cable GIS terminal operation state inversion method of the present invention, wherein: correcting the input of the simulation model includes obtaining the change of the characteristic parameter by changing the input of the first object, thereby obtaining the functional relationship between the input of the first object and the characteristic parameter;

[0016] The obtained functional relationship is applied to the simulation model to correct the input quantity corresponding to each group of characteristic parameters.

[0017] As a preferred solution of the cable GIS terminal operation state inversion method described in the present invention, wherein: the second operation state also includes performing electromagnetic thermal multi-physics field simulation of epoxy resin casing defects and electromagnetic thermal multi-physics field simulation of bolt loosening defects respectively;

[0018] The influence of heating and partial discharge of cable GIS terminals caused by loose bolts between the conductive rod and the cable terminal is analyzed, and the key characteristic quantities near the terminal under different defect states are obtained;

[0019] The correction model parameters include correcting the initial conditions of the simulation model based on the multi-physics field coupling simulation of the cable GIS terminal and the local simulation of the cable defects, combined with the measured values ​​of the cable line state parameters, to maximize the fit to the characteristic parameters of the actual cable GIS terminal;

[0020] The correction process includes: establishing an iterative optimization algorithm, taking the difference between the simulation results and the actual values ​​as the objective function, continuously reducing the objective function by correcting the initial condition parameters, and finally reaching the set stop threshold to stop the calculation.

[0021] As a preferred scheme of the cable GIS terminal operating status inversion method described in the present invention, the simulation reproduction and defect simulation inversion include inputting physical quantities into the simulation model of the first object, obtaining characteristic parameters of the model, and inferring the internal state or defect characteristics of the equipment.

[0022] A cable GIS terminal operation status inversion system using any method described in the present invention, characterized in that:

[0023] A model building unit, which builds a simulation model of a first object and analyzes the spatial distribution of characteristic parameters of the first object in a first operating state;

[0024] a first simulation unit, which compares the measured characteristic parameters of the first object, corrects the input of the simulation model, and obtains a first simulation of the simulation model;

[0025] a second simulation unit, which obtains a second simulation of the simulation model by analyzing the first object in a second operating state;

[0026] The inversion unit corrects the model parameters according to the first simulation and the second simulation in combination with the measured values ​​of the first object, so as to realize the simulation reproduction and defect simulation inversion of the first object in different states.

[0027] A computer device comprises: a memory and a processor; the memory stores a computer program, wherein: the processor implements the steps of any one of the methods of the present invention when executing the computer program.

[0028] A computer-readable storage medium stores a computer program, wherein: when the computer program is executed by a processor, the steps of any one of the methods of the present invention are implemented.

[0029] Beneficial effects of the present invention: The cable GIS terminal operation status inversion method provided by the present invention, by establishing a multi-physical field coupling simulation model of the cable GIS terminal, realizes status simulation and fault inversion in combination with measured data, effectively making up for the lack of normal state simulation, local defects and overall analysis in the prior art. Its beneficial effects are: it can accurately evaluate the operating status of the cable GIS terminal under different working conditions, locate the location and impact of typical defects (such as casing cracking, bolt loosening), improve the accuracy and efficiency of fault diagnosis, and provide a scientific basis for the intelligent operation and maintenance of equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0031] Figure 1 An overall flow chart of a cable GIS terminal operating status inversion method provided for the first embodiment of the present invention;

[0032] Figure 2 A cable accessory simulation model diagram in a cable GIS terminal operation status inversion method provided by the first embodiment of the present invention;

[0033] Figure 3 A simulation diagram of epoxy resin casing defects in a cable GIS terminal operation status inversion method provided by the first embodiment of the present invention;

[0034] Figure 4 A simulation diagram of bolt loosening defects in a cable GIS terminal operating status inversion method provided in the first embodiment of the present invention. DETAILED DESCRIPTION

[0035] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the drawings of the specification. Obviously, the described embodiments are part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary persons in the art without creative work should fall within the scope of protection of the present invention.

[0036] Example 1, reference Figure 1 , as an embodiment of the present invention, provides a cable GIS terminal operation status inversion method, comprising:

[0037] S1: Establishing a simulation model of a first object, and analyzing the spatial distribution of characteristic parameters of the first object in a first operating state.

[0038] Furthermore, the simulation model includes determining a multi-physics field simulation model of the first object in the first operating state according to actual structural parameters; determining a local multi-physics field simulation model of the first object in the second operating state according to actual structural parameters; and meshing the simulation model.

[0039] Specifically, based on the structural dimensions and geometric configuration of the GIS terminal, an accurate three-dimensional model is built, and the cable GIS terminal simulation model is meshed. Among them, the cable core, cable main insulation, cable sheath, spring, etc. are regular cylinders, and a sweeping meshing method is used; a relatively coarse tetrahedral mesh is used for the gas domain, which is beneficial to reduce the overall number of meshes; a refined tetrahedral mesh is used for shell structures such as cable tail pipes; other components can be meshed in a conventional way. The overall meshing, such as Figure 2 shown.

[0040] According to the dielectric parameters, thermal conductivity parameters, magnetic parameters, etc. of each component of the cable GIS terminal, the electromagnetic thermal multi-physics field boundary conditions and basic parameters of the simulation are set. The basic parameters are the material parameters of different components of the cable GIS cabin. The boundary condition in the mechanical field is to use the bottom of the bracket of the cable GIS cabin as a fixed constraint, the cable end as a flexible constraint, and the GIS cabin part as a spring constraint. The boundary condition in the electromagnetic field is to apply the electromagnetic force load to the metal domain that generates electromagnetic induction. The boundary condition in the temperature field is to set the ambient temperature to 20°C.

[0041] During the simulation process, the "frequency domain" and "steady state" research interfaces are used to calculate the temperature, vibration, electric field and magnetic field responses of the cable GIS terminal under different current and voltage conditions. For temperature analysis, the temperature values ​​of the cable at different positions are obtained by solving the coupling model of the electromagnetic field and heat conduction equations; in vibration analysis, the acceleration values ​​and strain values ​​at various positions of the metal parts are loaded by electromagnetic force to obtain the distribution characteristics of vibration response and natural frequency; in electric and magnetic field analysis, the spatial distribution of electric field intensity and magnetic induction intensity is obtained using current and voltage input conditions.

[0042] In this embodiment, the first operating state is the normal operating state of the first object, which refers to the stable operating state of the cable GIS terminal under the design parameters and standard working conditions. The purpose of analyzing its normal operating state is to establish a basic model to provide a reference benchmark for the subsequent simulation and inversion of abnormal states or faults.

[0043] In an optional embodiment, the first operating state may also be an overload operating state. The cable GIS terminal is subjected to an operating state exceeding the rated current or voltage for a short period of time, which usually occurs when the grid load suddenly increases or the system is abnormal. It is possible to analyze the characteristic parameter distribution of the equipment under overload conditions and evaluate its thermal stability, electrical performance and structural strength. It provides operating limit data of the equipment in emergency situations to provide a basis for the design of protection mechanisms.

[0044] S2: Compare the measured characteristic parameters of the first object, correct the input of the simulation model, and obtain a first simulation of the simulation model.

[0045] Furthermore, correcting the input of the simulation model includes obtaining a change in the characteristic parameter by changing the input of the first object, thereby obtaining a functional relationship between the input of the first object and the characteristic parameter. The obtained functional relationship is applied to the simulation model to correct the input corresponding to each group of characteristic parameters.

[0046] In this embodiment, the functional relationship is obtained in the following manner: changing the current value and the voltage value, obtaining the temperature value changes, stress strain value changes, magnetic field strength changes and electric field strength changes at different positions in the cable GIS terminal, and obtaining the functional relationship between current and voltage as inputs and temperature, mechanics and electromagnetic fields as outputs.

[0047] S3: Obtaining a second simulation of the simulation model by analyzing the first object in the second operating state.

[0048] The second operating state includes an operating state of the first object under a local defect.

[0049] Specifically, electromagnetic thermal multi-physics simulation of epoxy resin casing defects and electromagnetic thermal multi-physics simulation of bolt loosening defects were performed respectively. The influence of heating and partial discharge of cable GIS terminals caused by loose bolts between the conductive rod and the cable terminal was analyzed, and the key characteristic quantities near the terminal under different defect states were obtained.

[0050] Implementation plan for electromagnetic thermal multi-physics simulation of epoxy resin casing defects:

[0051] 1) According to the actual structure and size of the casing, an accurate three-dimensional model is built, and the casing simulation model is meshed to divide the three-dimensional structure into tetrahedral meshes.

[0052] 2) Set the material parameters of the simulation model according to the dielectric parameters, thermal conductivity parameters, and magnetic parameters of the epoxy resin used in the bushing. Set the constraints of the bushing. In the "Solid Mechanics" interface, the contact surface between the bushing and the flange is used as a fixed constraint. The boundary condition in the "Temperature Field" interface is to set the ambient temperature to 20°C.

[0053] 3) During the simulation process, the temperature field and solid mechanics field are coupled according to thermal expansion, the electromagnetic field and mechanical field are coupled according to the law of electromagnetic induction, and the temperature field and electromagnetic field are coupled according to electromagnetic heat. Use the "frequency domain" and "steady state" research interfaces to calculate the temperature, mechanics, electric field, and magnetic field responses of the bushing under different current, voltage, and external force conditions. In the mechanical analysis, the stress and strain values ​​at various locations on the outer surface of the bushing are analyzed by applying external forces to the upper surface of the bushing terminal; in the electromagnetic field analysis, the stress and temperature at different locations of the bushing due to thermal expansion are analyzed by changing the current and voltage. The abnormal stress and strain model of the bushing is as follows: Figure 3 shown.

[0054] Implementation plan for electromagnetic thermal multi-physics simulation of bolt loosening defects:

[0055] 1) According to the actual structure and size of the conductive rods, terminal blocks, bolts and nuts, an accurate three-dimensional model is built, and the simulation model is meshed to divide the three-dimensional structure into tetrahedral meshes.

[0056] 2) Set the material parameters of the simulation model according to the thermal conductivity parameters and magnetic parameters of the conductive rods, terminals, bolts and nuts. Set the constraints of the model. In the "Solid Mechanics" interface, set the conductive rods and terminals as fixed constraints. In the "Temperature Field" interface, the boundary condition is to set the ambient temperature to 20°C.

[0057] 3) During the simulation process, the temperature field and solid mechanics field are coupled according to thermal expansion, the electromagnetic field and mechanical field are coupled according to the law of electromagnetic induction, and the temperature field and electromagnetic field are coupled according to electromagnetic heat. Use the "frequency domain" and "steady state" research interfaces to calculate the temperature, mechanics, electric field and magnetic field responses of the conductive rods, terminals, bolts and nuts under different current, voltage and external force conditions. In the mechanical analysis, different bolt preloads and numbers of bolts acting on the terminals are set to analyze the stress and strain values ​​at various positions of the conductive contact interface; in the electromagnetic field analysis, the stress generated at different positions of the conductive rods and terminals due to thermal expansion is analyzed by changing the current and voltage. The defect model of the bolted connection is as follows: Figure 4 shown.

[0058] It should be noted that cracking of epoxy resin casing and loose bolts in cable GIS terminals are typical defects or faults in equipment operation. The simulation of typical defects in cable GIS terminals is an important part of the operation state inversion. The simulation model of the casing can realize the study of the influence of the insulation interface state, accessory state and operation state on the casing temperature rise, deformation and interface discharge. The simulation model of the internal terminal bolt can realize the study of the influence of the electrical contact state and operation state on the interface temperature and interface strain.

[0059] In an optional embodiment, the second operating state may also be an extreme aging operating state. After a long period of operation, the equipment is in an operating state caused by factors such as material aging, contact degradation, and increased interface defects. The characteristics are abnormal electric field distribution and decreased local insulation performance. The thermal conductivity is weakened, resulting in significant local temperature rise. The cumulative impact of aging on equipment performance is simulated to evaluate the equipment life. Provide a basis for equipment status evaluation and updated maintenance plans.

[0060] S4: According to the first simulation and the second simulation, combined with the measured values ​​of the first object, the model parameters are corrected to achieve simulation reproduction and defect simulation inversion of the first object in different states.

[0061] The correction model parameters include, based on the multi-physics field coupling simulation of the cable GIS terminal and the local simulation of the cable defects, combined with the measured values ​​of the cable line state parameters, correcting the initial conditions of the simulation model to maximize the fit with the characteristic parameters of the actual cable GIS terminal. Among them, the correction process includes: establishing an iterative optimization algorithm, taking the difference between the simulation result and the actual value as the objective function, continuously reducing the objective function by correcting the initial condition parameters, and finally reaching the set stop threshold to stop the calculation. The correction is achieved after the corrected initial conditions. The defect parameters that need to be corrected include: the force value and force position of the epoxy resin casing and the bolt preload.

[0062] The surface temperature, vibration distribution, electromagnetic field intensity distribution and other related characteristic parameters of the actual cable GIS terminal under the defects of epoxy resin casing and loose bolts are measured, and the characteristic parameters obtained by the simulation model under the same defects are compared. The initial conditions of the simulation model are corrected to maximize the fit with the characteristic parameters of the actual cable GIS terminal, and realize the operation status simulation and fault inversion of the cable GIS terminal.

[0063] Physical quantities are input into the simulation model of the first object to obtain characteristic parameters of the model, and the internal state or defect characteristics of the equipment are inferred.

[0064] Embodiment 2: This embodiment provides a cable GIS terminal operation status inversion system, which includes:

[0065] A model building unit, which builds a simulation model of a first object and analyzes the spatial distribution of characteristic parameters of the first object in a first operating state;

[0066] a first simulation unit, which compares the measured characteristic parameters of the first object, corrects the input of the simulation model, and obtains a first simulation of the simulation model;

[0067] a second simulation unit, which obtains a second simulation of the simulation model by analyzing the first object in a second operating state;

[0068] The inversion unit corrects the model parameters according to the first simulation and the second simulation in combination with the measured values ​​of the first object, so as to realize the simulation reproduction and defect simulation inversion of the first object in different states.

[0069] If the above functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk and other media that can store program codes.

[0070] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as an ordered list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by an instruction execution system, device or apparatus (such as a computer-based system, a system including a processor, or other system that can fetch instructions from an instruction execution system, device or apparatus and execute instructions), or in conjunction with such instruction execution systems, devices or apparatuses. For the purposes of this specification, "computer-readable medium" can be any device that can contain, store, communicate, propagate or transmit a program for use by an instruction execution system, device or apparatus, or in conjunction with such instruction execution systems, devices or apparatuses.

[0071] More specific examples of computer-readable media (a non-exhaustive list) include the following: an electrical connection with one or more wires (electronic device), a portable computer disk case (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disk read-only memory (CDROM). In addition, the computer-readable medium may even be a paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, deciphering or, if necessary, processing in another suitable manner, and then stored in a computer memory.

[0072] It should be understood that the various parts of the present invention can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, a plurality of steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0073] Example 3 is an example of the present invention. In order to verify the beneficial effects of the present invention, the following discussion is conducted.

[0074] Optimize models and meshing: In the meshing of complex models, adaptive meshing methods can be used to locally encrypt areas with complex structures and concentrated stress (such as contact interfaces and small parts) to ensure local calculation accuracy; and appropriately coarsen the mesh in areas with small changes to reduce the use of computing resources. In addition, multi-level meshing technology is used to retain only key geometric features to improve calculation efficiency while ensuring accuracy.

[0075] Reasonably set the order and mode of multi-physics field coupling: In the process of multi-physics field coupling, select the appropriate coupling order and coupling mode to reduce errors. For example, first perform a steady-state analysis to obtain the initial temperature field, and then set the coupling conditions between the electromagnetic field and the mechanical field to introduce the thermal expansion effect. Dynamically update the boundary conditions of different physical fields to ensure that the feedback relationship between the physical fields can truly reflect the actual working conditions. In addition, using a step-by-step iterative method to balance the influence between the coupled fields and gradually approach a stable solution can further improve the simulation accuracy.

[0076] Optimize the setting of boundary conditions and constraints: In terms of boundary condition setting, more refined constraint settings are adopted. In the loosening defects of casing and bolts, the preload and loosening state of the bolts are simulated through experimental data or literature data, and the friction contact model is used on the contact interface to simulate the actual contact situation. For changes in temperature boundary conditions, dynamic boundary conditions are set to adjust the temperature in real time during the simulation process as the environmental conditions change, so as to ensure the actual credibility of the results.

[0077] Use high-performance computing and parallel computing technology: Since frequency domain and steady-state analysis require a lot of computing resources, you can consider using high-performance computing clusters or cloud computing resources to speed up the calculation process. In addition, using parallel computing technology to split the analysis tasks under different current, voltage and external force conditions into parallel subtasks for calculation can effectively reduce the calculation time and improve the simulation efficiency. In addition, appropriate convergence criteria and error control strategies can be selected to avoid unnecessary repeated calculations, thereby improving the overall calculation efficiency.

[0078] An experiment was conducted to compare and analyze epoxy resin casing defects and bolt loosening defects. The goal of the experiment was to analyze the changes in key characteristic parameters of cable GIS terminals under different defect states through simulation, and to prove the innovation and advantages of the invention in fault identification and status assessment.

[0079] The experimental object includes a simulated high-voltage cable GIS terminal, which contains epoxy resin casing and conductive terminal blocks. Finite element simulation software is used to establish an accurate three-dimensional model to simulate the normal state, the partial cracking state of the epoxy resin casing and the loose bolt state. The following is the specific implementation process:

[0080] Simulation model establishment

[0081] First, a three-dimensional simulation model is built according to the geometric dimensions of the actual equipment, including the cable core, main insulation, outer shell, epoxy resin casing and conductive terminal blocks.

[0082] For the epoxy resin casing, the material parameters (dielectric constant, thermal conductivity and elastic modulus) are set to simulate its normal state and local cracking state.

[0083] For the conductive terminals, set the material parameters (thermal conductivity and magnetic permeability) to simulate the normal state and poor contact caused by loose bolts.

[0084] Meshing and boundary conditions

[0085] The model is meshed using tetrahedral meshes to ensure the computational accuracy of detailed parts, while the number of meshes is optimized to balance accuracy and computational efficiency.

[0086] Set constraints in the "Solid Mechanics" interface, set the bottom of the bracket as a fixed constraint, and set flexible constraints at the terminal connection; set a working voltage of 20 kV in the "Electromagnetic Field" interface, and apply thermal-electrical-mechanical coupling conditions.

[0087] Running simulations and collecting data

[0088] Under normal conditions, the temperature distribution, electric field strength and mechanical stress values ​​of the cable GIS terminal are recorded.

[0089] Under the condition of local cracking of epoxy resin casing, the stress concentration, electric field distortion and temperature rise caused by defects are simulated.

[0090] Under the condition of loose bolts, the influence of contact resistance change on current density, local temperature rise and electric field distribution is calculated.

[0091] After simulation, key characteristic data are collected, including temperature rise, maximum electric field intensity, stress value, and contact interface resistance change.

[0092] Table 1 Experimental data records

[0093]

[0094] Through the above experimental data, we can clearly see the advantages of the simulation method of the present invention in identifying and analyzing local defects of cable GIS terminals. The key data are analyzed as follows:

[0095] When the epoxy resin casing is cracked, the temperature rise reaches 32°C, which is 113% higher than the normal 15°C. When the bolts are loose, the temperature rise is 25°C, an increase of 66%. This shows that the defect state significantly affects the heat dissipation performance of the equipment, and the heat accumulation caused by local cracking is more serious. The present invention accurately captures the spatial distribution of temperature rise through a multi-physics field coupling model, which is superior to the existing single field simulation technology.

[0096] Under normal conditions, the electric field strength is stable at 2.1 kV / cm, but after the epoxy resin casing cracks, the local electric field strength rises to 5.3 kV / cm, an increase of 152%. Under the condition of loose bolts, the electric field strength reaches 3.9 kV / cm, an increase of 86%. This shows that the defect state causes significant electric field distortion, which may lead to partial discharge. The present invention accurately predicts the location of electric field enhancement through simulation, providing a reliable basis for early diagnosis of partial discharge.

[0097] Under the condition of epoxy resin casing cracking, stress concentration phenomenon is significant, with the maximum stress reaching 28MPa, while the normal state is only 12MPa. Bolt loosening also causes stress changes near the conductive rod, with a maximum value of 19MPa. The present invention successfully captures the concentration trend of mechanical stress through thermal-mechanical coupling simulation, providing guidance for material optimization design.

[0098] Under the condition of loose bolts, the contact resistance increased from the normal 0.02mΩ to 0.15mΩ, resulting in an efficiency loss of 4.8%. Local cracking has no significant effect on resistance, but causes an efficiency loss of 7.3%. The present invention combines the analysis of resistance change and temperature rise to achieve a quantitative prediction of efficiency loss, making up for the shortcoming of existing methods that are difficult to quantify the impact of local defects.

[0099] Local cracking and bolt loosening both caused partial discharges of varying degrees, with intensities reaching 18pC and 12pC respectively, showing the damage of defects to electrical performance. The present invention accurately locates the discharge source through simulation, providing technical support for real-time monitoring of electrical performance.

[0100] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A cable GIS terminal operation status inversion method, characterized in that: include: Establishing a simulation model of a first object, and analyzing the spatial distribution of characteristic parameters of the first object in a first operating state; Comparing the measured characteristic parameters of the first object, correcting the input of the simulation model, and obtaining a first simulation of the simulation model; Obtaining a second simulation of the simulation model by analyzing the first object in a second operating state; According to the first simulation and the second simulation, combined with the measured values ​​of the first object, the model parameters are corrected to achieve the simulation reproduction and defect simulation inversion of the first object in different states.

2. The cable GIS terminal operation status inversion method according to claim 1, characterized in that: The simulation model includes determining a multi-physics simulation model of the first object in the first operating state according to actual structural parameters; Determine a local multi-physics field simulation model of the first object in the second operating state according to the actual structural parameters; The simulation model is meshed.

3. The cable GIS terminal operation status inversion method according to claim 2, characterized in that: The first operating state includes, but is not limited to, a normal operating state of the first object; The second operating state includes an operating state of the first object under a local defect.

4. The cable GIS terminal operation status inversion method according to claim 3, characterized in that: The spatial distribution includes solving a simulation model in the first operating state by a simulation tool to obtain a distribution of characteristic parameters.

5. The cable GIS terminal operation status inversion method according to claim 4, characterized in that: Modifying the input of the simulation model includes obtaining a change in the characteristic parameter by changing the input of the first object, thereby obtaining a functional relationship between the input of the first object and the characteristic parameter; The obtained functional relationship is applied to the simulation model to correct the input quantity corresponding to each group of characteristic parameters.

6. The cable GIS terminal operation status inversion method according to claim 5, characterized in that: The second operation state further includes performing electromagnetic thermal multi-physics field simulation of epoxy resin casing defects and electromagnetic thermal multi-physics field simulation of bolt loosening defects respectively; The influence of heating and partial discharge of cable GIS terminals caused by loose bolts between the conductive rod and the cable terminal is analyzed, and the key characteristic quantities near the terminal under different defect states are obtained; The correction model parameters include correcting the initial conditions of the simulation model based on the multi-physics field coupling simulation of the cable GIS terminal and the local simulation of the cable defects, combined with the measured values ​​of the cable line state parameters, to maximize the fit to the characteristic parameters of the actual cable GIS terminal; The correction process includes: establishing an iterative optimization algorithm, taking the difference between the simulation results and the actual values ​​as the objective function, continuously reducing the objective function by correcting the initial condition parameters, and finally reaching the set stop threshold to stop the calculation.

7. The cable GIS terminal operation status inversion method according to claim 6, characterized in that: The simulation reproduction and defect simulation inversion include inputting physical quantities into the simulation model of the first object, obtaining characteristic parameters of the model, and inferring the internal state or defect characteristics of the device.

8. A cable GIS terminal operation status inversion system using the method according to any one of claims 1 to 7, characterized in that: A model building unit, which builds a simulation model of a first object and analyzes the spatial distribution of characteristic parameters of the first object in a first operating state; a first simulation unit, which compares the measured characteristic parameters of the first object, corrects the input of the simulation model, and obtains a first simulation of the simulation model; a second simulation unit, which obtains a second simulation of the simulation model by analyzing the first object in a second operating state; The inversion unit corrects the model parameters according to the first simulation and the second simulation in combination with the measured values ​​of the first object, so as to realize the simulation reproduction and defect simulation inversion of the first object in different states.

9. A computer device comprising: A memory and a processor; the memory stores a computer program, wherein the processor implements the steps of any method as claimed in claim 1 when executing the computer program.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 7 are implemented.

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