Cable insulation degradation analysis method, electronic equipment and storage medium

Abstract

The invention discloses a cable insulation degradation analysis method, electronic equipment and a storage medium. The method comprises the following steps: acquiring electrical, thermal and mechanical performance parameters of an insulating material of a cable; according to the electrical, thermal and mechanical performance parameters of the insulating material, determining strain energy and electrostatic energy of a corresponding area of the insulating material; establishing a phase field variable associated with the damage degree and the dielectric parameter of the insulating material; according to the damage degree of the insulating material and the relation between the dielectric parameters and the phase field variables, the phase field variables are updated through strain energy and electrostatic energy, and the damage evolution state and the degradation breakdown path of the insulating material are obtained; wherein the change of the phase field variable is driven by the strain energy and the electrostatic energy of the corresponding region of the insulating material. According to the technical scheme, the insulation degradation process of the cable can be reproduced through numerical calculation and theoretical analysis according to actual operation and maintenance conditions and performance parameters of the power cable, and a technical means is provided for cable construction, maintenance and insulation state evaluation.

Description

Technical Field

[0001] The present invention relates to the field of insulation of high-voltage electrical equipment, and particularly to a method for analyzing cable insulation deterioration, an electronic device, and a storage medium. Background Art

[0002] In a power cable system, the performance of the insulating material is directly related to the reliability and safety of the equipment. With the continuous increase in the current-carrying capacity and operation years of power cables, the influence of factors such as electricity, heat, and mechanical stress on cable insulation during operation becomes increasingly complex, and the problem of insulation deterioration becomes increasingly prominent. Insulation deterioration not only leads to the premature failure of power cables but may also cause faults or even accidents in the power system, resulting in huge economic losses and social impacts. Electrical tree deterioration is an early phenomenon of insulation breakdown. Studying the growth characteristics of electrical trees and then evaluating and reproducing the deterioration process of cable insulation under complex working conditions is of great significance for evaluating the operating state of cables.

[0003] The growth of electrical trees is jointly coupled by factors such as internal mechanical stress, thermal effects, and electrical stress in the insulating material. At present, some studies have revealed the key factors affecting electrical tree deterioration from an experimental perspective, such as temperature, stress, voltage form, etc. However, the existing studies are all qualitative theoretical analyses, and the results obtained also stay at the qualitative description based on the analysis of experimental phenomena, which has obvious limitations for accurately evaluating and reproducing the actual power cable breakdown process. Summary of the Invention

[0004] The present invention provides a method for analyzing cable insulation deterioration, an electronic device, and a storage medium to analyze the insulation deterioration process of power cables and provide technical support and theoretical guidance for cable insulation design, laying construction, operation and maintenance.

[0005] According to one aspect of the present invention, there is provided a method for analyzing cable insulation deterioration, characterized by comprising:

[0006] Obtaining the electrical, thermal, and mechanical property parameters of the insulating material of the cable;

[0007] Determining the strain energy and electrostatic energy of the corresponding region of the insulating material according to the electrical, thermal, and mechanical property parameters of the insulating material;

[0008] Establishing a phase-field variable associated with the damage degree and dielectric parameters of the insulating material;

[0009] Updating the phase-field variable by using the strain energy and the electrostatic energy according to the damage degree of the insulating material and the relationship between the dielectric parameter and the phase-field variable to obtain the damage evolution state and deterioration breakdown path of the insulating material; wherein, the change of the phase-field variable is driven by the strain energy and the electrostatic energy of the corresponding region of the insulating material.

[0010] Optionally, obtain the electrical, thermal, and mechanical property parameters of the insulating material of the cable, including:

[0011] Query the cable technical parameter manual to obtain the electrical and mechanical property parameters of the insulating material of the cable; or,

[0012] Sample and test the same batch of cable samples to obtain the electrical and mechanical property parameters of the insulating material of the cable; or,

[0013] Conduct experimental tests on the failed and retired cables to obtain the electrical and mechanical property parameters of the insulating material of the cable.

[0014] Optionally, determine the strain energy and electrostatic energy of the corresponding region of the insulating material according to the electrical, thermal, and mechanical property parameters of the insulating material, including:

[0015] Calculate the strain energy and the electrostatic energy through the following formula,

[0016]

[0017] where W mec is the strain energy, W elec is the electrostatic energy, ε0 is the vacuum permittivity, ε r is the relative permittivity, E is the electric field strength, σ is the stress magnitude, including mechanical stress and thermal stress, Y r is the Young's modulus of the insulating material.

[0018] Optionally, the phase field variable and the damage degree of the insulating material satisfy a double-well function relationship, and respectively correspond to the breakdown phase and the non-breakdown phase at two extreme points, that is, satisfy:

[0019] W sep = W c η 2 (1 - η) 2 ;

[0020] where W sep is the free energy density, W c is the energy barrier between the breakdown stage and the non-breakdown stage, is the critical energy causing electrical and mechanical damage to the insulating material, and η is the phase field variable.

[0021] Optionally, the critical energy is jointly determined by the elongation at break and the breakdown field strength of the insulating material, and is expressed as:

[0022]

[0023] where W c ' is the corrected critical energy, T k = 60 is a normal constant, u 11and u 22 is the second-order strain tensor in the two-dimensional model, and u max (T) is the maximum tensile strain of the insulating material at different temperatures.

[0024] Optionally, updating the phase field variable according to the strain energy and the electrostatic energy includes:

[0025] Based on the Allen-Cahn equation, comparing the sum of the electrostatic energy and the strain energy with the critical energy density, updating the phase field variable in real time, and correspondingly changing the dielectric parameter of the insulating material, iteratively calculating the electrical, thermal, and stress distributions of the insulating material, and obtaining the damage evolution state and the degradation breakdown path of the insulating material.

[0026] Optionally, the relationship between the phase field variable and the dielectric parameter of the insulating material satisfies the following formula:

[0027] M = (M i ·η 3 (10 - 15η + 6η 2 )) + M b (1 - η 3 ·(10 - 15η + 6η 2 ));

[0028] where M i is the dielectric parameter of the insulating material before breakdown, M b is the dielectric parameter of the insulating material after breakdown, and η is the phase field variable.

[0029] Optionally, comparing the sum of the electrostatic energy and the strain energy with the critical energy, and updating the phase field variable in real time, includes:

[0030] Updating the phase field variable using the following formula:

[0031]

[0032] where η(r, t) characterizes the spatial and temporal evolution of the breakdown phase, η(r, t) = 0 and η(r, t) = 1 represent the breakdown and non-breakdown states respectively, L0 is the kinetic coefficient, with a value of 1.0 m 2 s -1 N -1 . H(W elec +W mec -W c ') is the unit step function, H(W elec +W mec -W c ' > 0) = 1, H(W elec +W mec -W c ' < 0) = 0.

[0033] According to another aspect of the present invention, there is provided an electronic device, the electronic device comprising:

[0034] at least one processor; and

[0035] a memory communicatively connected to the at least one processor; wherein,

[0036] the memory stores a computer program executable by the at least one processor, and the computer program is executed by the at least one processor so that the at least one processor can execute the cable insulation degradation analysis method according to any embodiment of the present invention.

[0037] According to another aspect of the present invention, there is provided a computer-readable storage medium storing computer instructions for causing a processor to implement the cable insulation degradation analysis method according to any embodiment of the present invention when executed.

[0038] The technical solution of the embodiment of the present invention can obtain potential fault problems of the cable by acquiring the electrical, thermal and mechanical performance parameters of the insulating material of the cable and determining the strain energy and electrostatic energy of the corresponding region of the insulating material according to the electrical, thermal and mechanical performance parameters of the insulating material. A phase field variable associated with the damage degree and dielectric parameter of the insulating material is established, and according to the damage degree of the insulating material and the relationship between the dielectric parameter and the phase field variable, the phase field variable is updated by using the strain energy and electrostatic energy, and the damage evolution state and degradation breakdown path of the insulating material are obtained, so that the damage degree, dielectric parameter change and degradation breakdown path of the insulating material under different conditions can be predicted. The technical solution of the present invention can reproduce the cable insulation fault process through numerical calculation and theoretical analysis according to the actual operation and maintenance conditions and performance parameters of the power cable, and provide technical means for cable construction, maintenance and insulation state assessment.

[0039] It should be understood that the content described in this part is not intended to identify the key or important features of the embodiments of the present invention, nor is it used to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention, and those of ordinary skill in the art can also obtain other drawings without creative efforts based on these drawings.

[0041] Figure 1 is a flowchart of a cable insulation degradation analysis method according to an embodiment of the present invention;

[0042] Figure 2 It is a double-well function relationship diagram between the phase field variable and the damage degree of the insulating material under different working conditions provided by the embodiments of the present invention;

[0043] Figure 3 It is a dynamic simulation result diagram of the deterioration process under the superposition of mechanical stress and low temperature provided by the embodiments of the present invention;

[0044] Figure 4 It is a schematic structural diagram of an electronic device for implementing the cable insulation deterioration analysis method of the embodiments of the present invention. Detailed implementation manners

[0045] In order to enable those skilled in the art to better understand the solution of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0046] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above drawings are used to distinguish similar objects, and do not have to be used to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and their variations are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device including a series of steps or units does not have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0047] Figure 1 The embodiments of the present invention provide a flowchart of a cable insulation deterioration analysis method. This embodiment is applicable to the situation of cable insulation deterioration analysis. This method can be executed by a cable insulation deterioration analysis device, which can be implemented in the form of hardware and / or software, and the device can be configured in a power system. As Figure 1 shown, this method includes:

[0048] S101. Obtain the electrical, thermal, and mechanical property parameters of the insulating material of the cable.

[0049] Among them, the electrical, thermal, and mechanical property parameters of the insulating material of the cable are the key indicators for evaluating its performance. The electrical property parameters may include insulation resistance, breakdown strength, leakage current, and dielectric parameters, etc. The thermal property parameters may include heat resistance, thermal conductivity, and thermal stability, etc. The mechanical property parameters may include mechanical strength and elasticity, etc. These parameters can be obtained by sampling and testing the cable, or by querying the cable technical parameter manual.

[0050] S102. Determine the strain energy and electrostatic energy of the corresponding region of the insulating material according to the electrical, thermal, and mechanical property parameters of the insulating material.

[0051] Among them, the strain energy refers to the energy stored in the insulating material when it is subjected to mechanical stress. When the insulating material is subjected to external forces such as tension, compression, or bending, the internal molecular structure will change, thereby storing a certain amount of energy, and this energy is the strain energy. The magnitude of the strain energy is related to mechanical parameters such as the elastic modulus and Poisson's ratio of the material, and is also related to the magnitude of the applied stress and strain. The electrostatic energy refers to the energy stored in the insulating material in an electric field. When the insulating material is placed in an electric field, the charges inside it will be redistributed due to the action of the electric field, resulting in a polarization phenomenon inside the material. This polarization phenomenon will cause the rearrangement of bound charges and free charges inside the material, thereby storing electrostatic energy inside the material. The magnitude of the electrostatic energy is related to electrical parameters such as the dielectric constant and conductivity of the material, and is also related to the applied electric field strength. The strain energy and electrostatic energy of the insulating material can be determined by using material mechanics tests and electrical property tests, as well as numerical simulation methods. The numerical simulation methods can be one or several of methods such as the finite element method, finite volume method, boundary element method, and phase field model. Exemplarily, the strain energy and electrostatic energy of the insulating material can be determined by the finite element method with a transient model. It is realized through finite element simulation, and the modules involved include but are not limited to the electrostatic field module, heat transfer module, stress-strain analysis module, current field module, etc.

[0052] S103. Establish a phase field variable associated with the damage degree and dielectric parameters of the insulating material.

[0053] Among them, the damage degree of the insulating material mainly includes mechanical damage, electrical damage, and damage caused by environmental factors. The dielectric parameters are used to describe the ability of the material to store electrostatic energy in an electric field, and mainly include the dielectric constant and dielectric loss factor. Based on finite element simulation, calculate the electrical, thermal, and stress distribution characteristics of the insulation of power equipment under different operating conditions with a transient model, and conduct damage degree determination, and establish a phase field variable associated with the damage degree and dielectric parameters of the insulating material.

[0054] S104. According to the damage degree of the insulating material and the relationship between the dielectric parameters and the phase field variables, update the phase field variables using the strain energy and the electrostatic energy to obtain the damage evolution state and the degradation breakdown path of the insulating material; wherein, the change of the phase field variables is driven by the strain energy and the electrostatic energy in the corresponding area of the insulating material.

[0055] Among them, during the long-term operation of the insulating material, due to the influence of factors such as electric field, temperature, and mechanical stress, aging and damage will occur. These damages will lead to a decline in the electrical, thermal, and dielectric properties of the insulating material. The degradation breakdown path of the insulating material involves the phenomenon of electrical tree degradation. Electrical tree degradation refers to the fact that during the long-term operation of the insulating material, due to the influence of factors such as electric field, temperature, and mechanical stress, it gradually ages and is damaged, ultimately resulting in a decline in insulation performance and forming a dendritic degradation path. The phase field simulation method can be used to study the evolution of internal insulation damage of the insulating material. By calculating the insulation degradation driving energy at different positions and determining the damage degree, and on this basis, performing cyclic iterative calculations of the electric, thermal, and stress fields, and updating the phase field variables through the strain energy and the electrostatic energy, the damage evolution state and the degradation breakdown path of the insulating material can be obtained. The insulation degradation driving energy is composed of the strain energy and the electrostatic energy in the corresponding area of the insulating material.

[0056] Specifically, introduce a phase field variable related to space and time and associate it with the damage degree and dielectric parameters of the insulating material. The change of the phase field variables is driven by the strain energy and the electrostatic energy in the corresponding area of the insulating material. The electrostatic energy and the strain energy are calculated according to the electric field and the magnitude of the mechanical stress at the corresponding position of the insulating material. Compare the sum of the electrostatic energy and the strain energy with the critical energy density, update the parameter value of the phase field variable in real time, and correspondingly change the dielectric parameters of the material. Thus, iterate and calculate the electric, thermal, and stress distributions of the insulating material, iterate and calculate the damage evolution state of the material, and obtain the material degradation breakdown path.

[0057] The technical solution of the embodiment of the present invention, by obtaining the electrical, thermal, and mechanical performance parameters of the insulating material of the cable, and determining the strain energy and the electrostatic energy in the corresponding area of the insulating material according to the electrical, thermal, and mechanical performance parameters of the insulating material, potential fault problems of the cable can be obtained. Establish a phase field variable associated with the damage degree and dielectric parameters of the insulating material. According to the damage degree of the insulating material and the relationship between the dielectric parameters and the phase field variables, update the phase field variables using the strain energy and the electrostatic energy to obtain the damage evolution state and the degradation breakdown path of the insulating material, and the damage degree, dielectric parameter change, and degradation breakdown path of the insulating material under different conditions can be predicted. The technical solution of the present invention can reproduce the cable insulation fault process through numerical calculation and theoretical analysis according to the actual operation and maintenance conditions and performance parameters of the power cable, and provide technical means for cable construction, maintenance, and insulation state evaluation.

[0058] In some alternative embodiments of the present invention, the electrical, thermal, and mechanical property parameters of the insulating material of the cable are obtained, including:

[0059] Querying the cable technical parameter manual to obtain the electrical and mechanical property parameters of the insulating material of the cable; or,

[0060] Sampling and testing the same batch of cable samples to obtain the electrical and mechanical property parameters of the insulating material of the cable; or,

[0061] Conducting experimental tests on the faulty retired cables to obtain the electrical and mechanical property parameters of the insulating material of the cable.

[0062] Among them, the cable technical parameter manual usually contains detailed information on cable design, laying, performance requirements, etc. The electrical and mechanical property parameters of the insulating material of the cable can be obtained by querying the cable technical parameter manual, or can also be obtained by sampling and testing the same batch of cable samples or faulty retired cables.

[0063] In some alternative embodiments of the present invention, according to the electrical, thermal, and mechanical property parameters of the insulating material, the strain energy and electrostatic energy of the corresponding region of the insulating material are determined, including:

[0064] Calculating the strain energy and electrostatic energy through the following formula,

[0065]

[0066]

[0067] Among them, W mec is the strain energy, W elec is the electrostatic energy, ε0 is the vacuum permittivity, ε r is the relative permittivity, E is the electric field strength, σ is the stress magnitude, including mechanical stress and thermal stress, Y r is the Young's modulus of the insulating material.

[0068] In some alternative embodiments of the present invention, the phase field variable and the damage degree of the insulating material satisfy a double-well function relationship, and respectively correspond to the breakdown phase and the non-breakdown phase at the two extreme points, that is, satisfy:

[0069] W sep = W c η 2 (1 - η) 2 ;

[0070] Among them, W sep is the free energy density, W c is the energy barrier between the breakdown stage and the non-breakdown stage, which is the critical energy causing electrical and mechanical damage to the insulating material, and η is the phase field variable.

[0071] Specifically, the double-well potential function is usually used to simulate a system with two stable states, and there is an energy barrier that prevents particles from moving from one potential well to another. The energy barrier between the breakdown stage and the non-breakdown stage refers to the energy obstacle that needs to be overcome in an insulating material during the process from the normal working state to breakdown (i.e., losing the insulating property).

[0072] In some alternative embodiments of the present invention, the critical energy is jointly determined by the elongation at break and the breakdown field strength of the insulating material, and is expressed as:

[0073]

[0074] where W c ' is the critical energy after correcting for the electrical and mechanical operating conditions of the material, T k = 60 is a positive constant, u 11 and u 22 are the second-order strain tensors in the two-dimensional model, and u max (T) is the maximum tensile strain of the insulating material at different temperatures.

[0075] Specifically, the changes in the electrical and mechanical property parameters of the insulating material under different operating conditions will change the critical failure barrier of the material, thereby affecting its failure process. If damage occurs to the insulating material, i.e., the value of η changes, the corresponding electrical and mechanical parameters of the material need to be iteratively updated according to the degree of damage.

[0076] In some alternative embodiments of the present invention, updating the phase field variables according to the strain energy and the electrostatic energy includes:

[0077] Based on the Allen-Cahn equation, comparing the sum of the electrostatic energy and the strain energy with the critical energy density, updating the phase field variables in real time, and accordingly changing the dielectric parameters of the insulating material, and iteratively calculating the electrical, thermal, and stress distributions of the insulating material to obtain the damage evolution state and the degradation breakdown path of the insulating material.

[0078] Among them, the Allen-Cahn equation is used to study the phase transition phenomenon of materials, and its numerical solution method is of great significance for understanding and predicting the behavior of materials. The critical energy density refers to the threshold energy for the material to undergo phase transition or damage. Based on the Allen-Cahn equation, calculating the insulation degradation driving energy at different positions and comparing it with the critical energy density to determine the degree of damage to obtain the numerical value of the phase field variable. The insulation degradation driving energy is the sum of the strain energy and the electrostatic energy.

[0079] The relationship between the phase field variable and the dielectric parameter of the insulating material satisfies the following formula:

[0080] M = (M i ·η 3 (10 - 15η + 6η2 ) + M b (1 - η 3 ·(10 - 15η + 6η 2 ));

[0081] Among them, M i is the dielectric parameter of the insulating material before breakdown, M b is the dielectric parameter of the insulating material after breakdown, and η is the phase field variable. M is the dielectric parameter of the updated insulating material.

[0082] In some alternative embodiments of the present invention, the sum of the electrostatic energy and the strain energy is compared with the critical energy, and the phase field variable is updated in real time, including:

[0083] The phase field variable is updated using the following formula:

[0084]

[0085] Among them, η(r, t) is the spatial and temporal evolution of the breakdown phase, η(r, t) = 0 and η(r, t) = 1 represent the breakdown and non-breakdown states respectively, L0 is the kinetic coefficient, and its value is 1.0 m 2 s -1 N -1 . H(W elec +W mec -W c ') = 0 is the unit step function, H(W elec +W mec -W c ' > 0) = 1, H(W elec +W mec -W c ' < 0) = 0.

[0086] Figure 2 is the double-well function relationship diagram between the phase field variable and the damage degree of the insulating material under different working conditions provided by the embodiments of the present invention. Figure 3 is the dynamic simulation result diagram of the degradation process under the combined action of mechanical stress and low temperature provided by the embodiments of the present invention. The technical solution of the present invention can reproduce the damage evolution state and degradation breakdown path of the insulating material as shown in Figure 3 , thus providing an important technical means for the construction, operation and maintenance of cables and the evaluation of insulation status.

[0087] Figure 4FIG. 0 shows a schematic structural diagram of an electronic device 10 that can be used to implement an embodiment of the present invention. The electronic device is intended to represent various forms of digital computers, such as laptop computers, desktop computers, workstations, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. The electronic device can also represent various forms of mobile devices, such as personal digital processors, cellular phones, smart phones, wearable devices (such as helmets, glasses, watches, etc.) and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely examples and are not intended to limit the implementation of the present invention described and / or claimed herein.

[0088] As Figure 4 shown, the electronic device 10 includes at least one processor 11, and a memory communicatively connected to the at least one processor 11, such as a read-only memory (ROM) 12, a random access memory (RAM) 13, etc. The memory stores a computer program executable by the at least one processor. The processor 11 can perform various appropriate actions and processes according to the computer program stored in the read-only memory (ROM) 12 or the computer program loaded from the storage unit 18 into the random access memory (RAM) 13. In the RAM 13, various programs and data required for the operation of the electronic device 10 can also be stored. The processor 11, the ROM 12, and the RAM 13 are connected to each other through a bus 14. An input / output (I / O) interface 15 is also connected to the bus 14.

[0089] Multiple components in the electronic device 10 are connected to the I / O interface 15, including: an input unit 16, such as a keyboard, a mouse, etc.; an output unit 17, such as various types of displays, speakers, etc.; a storage unit 18, such as a magnetic disk, an optical disk, etc.; and a communication unit 19, such as a network card, a modem, a wireless communication transceiver, etc. The communication unit 19 allows the electronic device 10 to exchange information / data with other devices through a computer network such as the Internet and / or various telecommunication networks.

[0090] The processor 11 can be various general-purpose and / or special-purpose processing components with processing and computing capabilities. Some examples of the processor 11 include, but are not limited to, a central processing unit (CPU), a graphics processing unit (GPU), various dedicated artificial intelligence (AI) computing chips, various processors running machine learning model algorithms, a digital signal processor (DSP), and any suitable processor, controller, microcontroller, etc. The processor 11 executes the various methods and processes described above, such as the cable insulation deterioration analysis method.

[0091] In some embodiments, the cable insulation degradation analysis method can be implemented as a computer program tangibly embodied in a computer-readable storage medium, such as storage unit 18. In some embodiments, part or all of the computer program can be loaded and / or installed onto the electronic device 10 via the ROM 12 and / or the communication unit 19. When the computer program is loaded into the RAM 13 and executed by the processor 11, one or more steps of the cable insulation degradation analysis method described above can be performed. Alternatively, in other embodiments, the processor 11 can be configured to execute the cable insulation degradation analysis method by any other suitable means (e.g., by means of firmware).

[0092] The various embodiments of the systems and techniques described above in this document can be implemented in digital electronic circuitry, integrated circuit systems, field programmable gate arrays (FPGA), application specific integrated circuits (ASIC), application specific standard products (ASSP), systems on a chip (SOC), complex programmable logic devices (CPLD), computer hardware, firmware, software, and / or combinations thereof. These various embodiments can include: being implemented in one or more computer programs that can be executed and / or interpreted on a programmable system including at least one programmable processor, which can be a special-purpose or general-purpose programmable processor that receives data and instructions from a storage system, at least one input device, and at least one output device, and transmits the data and instructions to the storage system, the at least one input device, and the at least one output device.

[0093] The computer programs for implementing the methods of the present invention can be written in any combination of one or more programming languages. These computer programs can be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing apparatus, such that when the computer programs are executed by the processor, the functions / operations specified in the flowcharts and / or block diagrams are implemented. The computer programs can be executed entirely on the machine, partially on the machine, as a stand-alone software package partially on the machine and partially on a remote machine, or entirely on a remote machine or server.

[0094] In the context of the present invention, a computer-readable storage medium can be a tangible medium that can contain or store a computer program for use by or in connection with an instruction execution system, apparatus, or device. The computer-readable storage medium can include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus, or devices, or any suitable combination of the foregoing. Alternatively, the computer-readable storage medium can be a machine-readable signal medium. More specific examples of the machine-readable storage medium would include an electrical connection based on one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0095] To provide for interaction with a user, the systems and techniques described herein can be implemented on an electronic device having: a display device (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor) for displaying information to the user; and a keyboard and a pointing device (e.g., a mouse or a trackball) by which the user can provide input to the electronic device. Other kinds of devices can also be used to provide for interaction with the user; for example, feedback provided to the user can be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user can be received in any form (including acoustic input, voice input, or tactile input).

[0096] The systems and techniques described herein can be implemented in a computing system that includes backend components (such as, for example, a data server), or a computing system that includes middleware components (such as, for example, an application server), or a computing system that includes frontend components (such as, for example, a user computer having a graphical user interface or a web browser through which the user can interact with an implementation of the systems and techniques described herein), or a computing system that includes any combination of such backend components, middleware components, or frontend components. The components of the system can be interconnected by any form or medium of digital data communication (such as, for example, a communication network). Examples of communication networks include: a local area network (LAN), a wide area network (WAN), a blockchain network, and the Internet.

[0097] A computing system may include a client and a server. The client and the server are generally far from each other and usually interact via a communication network. The client-server relationship is created by computer programs running on respective computers and having a client-server relationship with each other. The server may be a cloud server, also known as a cloud computing server or a cloud host, which is a host product in the cloud computing service system, and solves the defects of difficult management and weak business scalability existing in traditional physical hosts and VPS services.

[0098] It should be understood that various forms of processes shown above can be used, steps can be reordered, added or deleted. For example, the steps described in the present invention can be executed in parallel, sequentially or in a different order, as long as the desired results of the technical solution of the present invention can be achieved, and no limitation is made herein.

[0099] The above specific embodiments do not constitute a limitation to the protection scope of the present invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A cable insulation degradation analysis method, characterized in that: include: Obtain the electrical, thermal and mechanical performance parameters of the cable insulation material; Determine the strain energy and electrostatic energy of the corresponding area of ​​the insulating material according to the electrical, thermal and mechanical performance parameters of the insulating material; Establishing phase field variables related to the damage degree and dielectric parameters of insulating materials; According to the damage degree of the insulating material and the relationship between the dielectric parameters and the phase field variables, the strain energy and the electrostatic energy are used to update the phase field variables to obtain the damage evolution state and degradation breakdown path of the insulating material; wherein the change of the phase field variables is driven by the strain energy and the electrostatic energy of the corresponding area of ​​the insulating material.

2. The method according to claim 1, characterized in that: Obtain the electrical, thermal and mechanical performance parameters of the cable insulation material, including: Consult the cable technical parameter manual to obtain the electrical and mechanical performance parameters of the cable insulation material; or, Conduct sampling tests on cable samples from the same batch to obtain the electrical and mechanical performance parameters of the cable insulation materials; or, Experimental tests are carried out on faulty retired cables to obtain the electrical and mechanical performance parameters of the cable's insulation materials.

3. The method according to claim 1, characterized in that According to the electrical, thermal and mechanical properties of the insulating material, the strain energy and electrostatic energy of the corresponding area of ​​the insulating material are determined, including: The strain energy and the electrostatic energy are calculated by the following formula, Among them, W mec is the strain energy, W elec is the electrostatic energy, ε0 ​​is the vacuum dielectric constant, ε r is the relative dielectric constant, E is the electric field strength, σ is the stress magnitude, including mechanical stress and thermal stress, Y r is the Young's modulus of the insulating material.

4. The method according to claim 1, characterized in that: The phase field variable and the damage degree of the insulating material satisfy a double potential well function relationship, and the two extreme points correspond to the breakdown phase and the non-breakdown phase, respectively, that is, satisfying: W sep =W c or 2 (1st) 2 ; Where W sep is the free energy density, W c is the energy barrier between the breakdown stage and the non-breakdown stage, which is the critical energy causing electrical and mechanical damage to the insulating material, and η is the phase field variable.

5. The method according to claim 4, characterized in that The critical energy is determined by the elongation at break and the breakdown field strength of the insulating material and is expressed as: Where W c ' is the corrected critical energy, T k =60 is a normal number, u 11 and u 22 is the second-order strain tensor in the two-dimensional model, u max (T) is the maximum tensile strain of the insulating material at different temperatures.

6. The method according to claim 1, characterized in that Updating the phase field variable according to the strain energy and the electrostatic energy includes: Based on the Allen-Cahn equation, the sum of the electrostatic energy and the strain energy is compared with the critical energy density, the phase field variables are updated in real time, and the dielectric parameters of the insulating material are changed accordingly. The electrical, thermal and stress distributions of the insulating material are iteratively calculated to obtain the damage evolution state and degradation breakdown path of the insulating material.

7. The method according to claim 6, characterized in that The relationship between the phase field variable and the dielectric parameter of the insulating material satisfies the following formula: M=(M i ·or 3 (10-15th+6th 2 )+M b (1st) 3 ·(10-15th+6th 2 )); Among them, M i M is the dielectric parameter of the insulating material when not broken down. b is the dielectric parameter of the insulating material after breakdown, and η is the phase field variable.

8. The method according to claim 6, characterized in that Comparing the sum of the electrostatic energy and the strain energy with the critical energy, and updating the phase field variables in real time, including: The phase field variables are updated using the following formula: Among them, η(r, t) represents the spatial and temporal evolution of the breakdown phase, η(r, t) = 0 and η(r, t) = 1 represent the breakdown and non-breakdown states, respectively, and L0 is the kinetic coefficient, which is 1.0 m 2 s -1 N -1 ; H(W elec +W mec -W c ')=0 is the unit step function, H(W elec +W mec -W c '>0)=1,H(W elec +W mec -W c '<0)=0.

9. An electronic device, characterized in that: The electronic device comprises: at least one processor; and a memory communicatively connected to the at least one processor; wherein, The memory stores a computer program executable by the at least one processor, and the computer program is executed by the at least one processor so that the at least one processor can perform the cable insulation degradation analysis method according to any one of claims 1 to 8.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer instructions, and the computer instructions are used to enable a processor to implement the cable insulation degradation analysis method according to any one of claims 1 to 8 when executed.

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