Method for homogenization of electric field in high voltage dc cable termination based on nonlinear conductive material

Abstract

The present application relates to a high-voltage direct-current cable terminal electric field homogenization method based on nonlinear conductive material, which uses nonlinear conductive material to construct a specific interface structure to effectively homogenize the electric field strength at the cable terminal. In a high electric field environment, this specific interface structure can effectively disperse the electric field and significantly reduce the local electric field concentration, improving the safety and reliability of the cable system under extreme conditions. The proposed electric field homogenization method has the significant advantages of simple operation, accurate results and high reliability, and is suitable for wide use in various complex engineering applications. This method not only provides an innovative solution for electric field homogenization of cable terminals, but also provides a feasible technical path for the overall performance optimization of high-voltage electrical equipment.

Description

Technical Field

[0001] This invention belongs to the field of electric field homogenization technology for high-voltage electrical equipment, and in particular to a method for electric field homogenization of high-voltage DC cable terminals based on nonlinear conductivity materials. Background Technology

[0002] At the terminals where high-voltage cables connect to other electrical equipment, the absence of a shielding layer at the cable cut leads to uneven electric field distribution and a significant increase in electric field strength. This enhanced electric field can easily cause local breakdown or flashover, resulting in equipment insulation failure and representing a weak link in high-voltage transmission systems. To protect the safe operation of electrical equipment and the stability of the system, homogenizing the electric field at cable terminals is crucial. Currently, a major challenge in controlling electric field strength is effectively managing various factors related to material interfaces, electric field enhancement, and nonlinear conductivity characteristics. Therefore, there is an urgent need to propose an improved method based on nonlinear conductive materials and advanced interface engineering to achieve effective homogenization of the electric field at cable terminals and precise control of the electric field strength. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the prior art and propose a method for equalizing the electric field at the terminal of a high-voltage DC cable based on nonlinear conductive materials. By adding a layer of nonlinear conductive material at the cable terminal, the electric field in a high electric field environment can be effectively dispersed, thereby effectively improving the insulation performance of electrical connection equipment.

[0004] The technical problem solved by this invention is achieved through the following technical solution:

[0005] A method for averaging the electric field at the termination of high-voltage DC cables based on nonlinear conductivity materials includes the following steps:

[0006] Step 1: Construct a high-voltage DC cable termination model based on nonlinear conductivity materials;

[0007] Step 2: Calculate the conductivity of the nonlinear conductive material based on the constructed high-voltage DC cable terminal model based on the nonlinear conductive material;

[0008] Step 3: Construct the interface structure of the nonlinear conductive material based on the constructed high-voltage DC cable terminal model based on the nonlinear conductive material;

[0009] Step 4: Calculate the electric field of the high-voltage DC cable terminal formed based on nonlinear conductive material. If the calculation is qualified, it can be used; otherwise, return to step 1.

[0010] Moreover, the specific implementation method of step 1 is as follows: construct a high-voltage DC cable terminal model based on nonlinear conductive material, including conductor, insulation layer, nonlinear layer, stress cone and semiconductive screen, wherein a nonlinear layer and semiconductive screen are provided below the stress cone, an insulation layer is connected below the nonlinear layer and semiconductive screen, and a conductor is connected below the insulation layer. The interface structure of the nonlinear conductive material realizes nonlinear stress control of the material in terms of impedance, and a shrink tube or patch is used to deposit the nonlinear conductive layer in the screen cutting and cable insulation area to homogenize the electric field strength of the cable terminal.

[0011] Furthermore, the specific implementation method of step 2 is as follows:

[0012]

[0013] Where T is temperature, E is electric field strength, A and α are constants, σ ​​is conductivity, Ea is activation energy, and β is... E is the field coefficient, and k is the Boltzmann constant.

[0014] Furthermore, step 3, which constructs a nonlinear conductive material interface structure, includes contact between particles and the use of filler particles with nonlinear properties.

[0015] Moreover, the specific method for achieving contact between particles is as follows: filler particles are uniformly dispersed in the polymer matrix by means of mechanical stirring, ultrasonic treatment or solvent method. When the conductive particles are close enough, an electrical conductivity path is formed. The provided multiphase interface makes the material exhibit nonlinear electrical conductivity characteristics.

[0016] Moreover, the specific implementation method of using filler particles with nonlinear characteristics is as follows: select materials with nonlinear electrical conductivity characteristics, and introduce these nonlinear fillers into the substrate by mixing or blending to form an effective electrical conductivity network; the electrical properties of the material are affected by the interfacial interaction between the filler particles and the substrate.

[0017] Moreover, the specific implementation method of step 4 is as follows: use the electromagnetic module and the thermal module to perform bidirectional coupling calculation of the electric field distribution of the cable terminal through the electrothermal simulation interface.

[0018] The advantages and positive effects of this invention are:

[0019] This invention constructs a high-voltage DC cable terminal model based on a nonlinear conductive material; calculates the conductivity of the nonlinear conductive material and constructs its interface structure; and forms an electric field in the high-voltage DC cable terminal model based on the nonlinear conductive material. The model's compliance is then determined by an electric field analyzer. This invention utilizes a nonlinear conductive material to construct a specific interface structure, achieving effective homogenization of the electric field intensity at the cable terminal. In high-electric-field environments, this specific interface structure enables efficient electric field dispersion, significantly reducing local electric field concentration and improving the safety and reliability of the cable system under extreme conditions. The proposed electric field homogenization method has significant advantages such as ease of operation, accurate results, and high reliability, making it suitable for widespread use in various complex engineering applications. This method not only provides an innovative solution for electric field homogenization at cable terminals but also offers a feasible technical path for optimizing the overall performance of high-voltage electrical equipment. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of a high-voltage DC cable terminal model based on nonlinear conductivity materials according to the present invention;

[0021] Figure 2 This is a schematic diagram showing the relationship between the interface structure of the nonlinear conductive material of the present invention and the terminal stress cone of the cable. Detailed Implementation

[0022] The present invention will be further described in detail below with reference to the accompanying drawings.

[0023] A method for averaging the electric field at the termination of high-voltage DC cables based on nonlinear conductivity materials includes the following steps:

[0024] Step 1: Construct a high-voltage DC cable terminal model based on nonlinear conductivity materials.

[0025] like Figure 1 and Figure 2 As shown, the high-voltage DC cable terminal model based on nonlinear conductive materials includes a conductor, an insulation layer, a nonlinear layer, a stress cone, and a semiconductive screen. The nonlinear layer and the semiconductive screen are located below the stress cone, and the insulation layer is connected below the nonlinear layer and the semiconductive screen. The conductor is connected below the insulation layer. The interface structure of the nonlinear conductive material enables nonlinear stress control of the material in terms of impedance. The nonlinear conductive layer is deposited in the screen cutting and cable insulation areas using shrink tubes or patches to homogenize the electric field strength of the cable terminal.

[0026] Step 2: Calculate the conductivity of the nonlinear conductive material based on the constructed high-voltage DC cable terminal model based on the nonlinear conductive material.

[0027]

[0028] Where T is temperature, E is electric field strength, A and α are constants, σ ​​is conductivity, Ea is activation energy, and β is... E is the field coefficient, and k is the Boltzmann constant.

[0029] Step 3: Construct the interface structure of the nonlinear conductive material based on the constructed high-voltage DC cable terminal model based on the nonlinear conductive material.

[0030] Constructing nonlinear conductive material interface structures involves particle-to-particle contact and the use of filler particles with nonlinear properties.

[0031] The method for constructing the interface structure of nonlinear conductive materials through particle-particle contact is as follows: filler particles (including but not limited to metal powder, carbon black, conductive polymers, etc.) are uniformly dispersed in a polymer matrix by means of mechanical stirring, ultrasonic treatment or solvent method. When the conductive particles are close enough, an electrical conduction path is formed. The provided multiphase interface enables the material to exhibit nonlinear electrical conduction characteristics.

[0032] The method for constructing the interface structure of nonlinear conductive materials using nonlinear filler particles is as follows: Select materials with nonlinear conductive properties, including but not limited to silicon carbide, zinc oxide, BaTiO3, TiO2, graphene, graphene oxide, carbon nanotubes, etc., and introduce these nonlinear fillers into the substrate by mixing or blending to form an effective conductive network; influence the electrical properties of the material through the interfacial interaction between the filler particles and the matrix (chemical bonding, physical adsorption, or electrostatic interaction, etc.).

[0033] Step 4: Calculate the electric field of the high-voltage DC cable terminal formed based on nonlinear conductive material. If the calculation is qualified, it can be used; otherwise, return to step 1.

[0034] The method for calculating the electric field at the terminal of a high-voltage DC cable based on nonlinear conductive materials is as follows: the distribution of the electric field at the cable terminal is calculated by bidirectional coupling of the electromagnetic module and the thermal module through the electrothermal simulation interface.

[0035] It should be emphasized that the embodiments described in this invention are illustrative rather than limiting. Therefore, this invention includes, but is not limited to, the embodiments described in the specific implementation. Any other implementations derived by those skilled in the art based on the technical solutions of this invention are also within the scope of protection of this invention.

Claims

1. A method for averaging the electric field at the termination of a high-voltage DC cable based on nonlinear conductivity materials, characterized in that: Includes the following steps: Step 1: Construct a high-voltage DC cable termination model based on nonlinear conductivity materials; A high-voltage DC cable terminal model based on nonlinear conductive materials is constructed, including a conductor, an insulation layer, a nonlinear layer, a stress cone, and a semiconductive screen. The nonlinear layer and the semiconductive screen are located below the stress cone, and the insulation layer is connected below the nonlinear layer and the semiconductive screen. The conductor is connected below the insulation layer. The interface structure of the nonlinear conductive material enables nonlinear stress control of the material in terms of impedance. The nonlinear conductive layer is deposited in the screen cutting and cable insulation areas using shrink tubes or patches to homogenize the electric field strength of the cable terminal. Step 2: Calculate the conductivity of the nonlinear conductive material based on the constructed high-voltage DC cable terminal model based on the nonlinear conductive material; Where T is temperature, E is electric field strength, and A and All are constants. Where E is the electrical conductivity and Ea is the activation energy. Here, k is the field coefficient, and k is the Boltzmann constant. Step 3: Construct the interface structure of the nonlinear conductive material based on the constructed high-voltage DC cable terminal model based on the nonlinear conductive material; Step 3 involves constructing a nonlinear conductive material interface structure, including contact between particles and the use of filler particles with nonlinear properties. The specific method to achieve contact between particles is as follows: filler particles are uniformly dispersed in the polymer matrix by means of mechanical stirring, ultrasonic treatment or solvent method. When the conductive particles are close enough, an electrical conductivity path is formed. The provided multiphase interface makes the material exhibit nonlinear electrical conductivity characteristics. The specific implementation method of using filler particles with nonlinear characteristics is as follows: Select materials with nonlinear electrical conductivity and introduce these nonlinear fillers into the matrix through mixing or blending to form an effective electrical conductivity network; influence the electrical properties of the material through the interfacial interaction between the filler particles and the matrix. Step 4: Calculate the electric field of the high-voltage DC cable terminal formed based on nonlinear conductivity material. If the calculation is qualified, it can be used; otherwise, return to step 1. The specific implementation method of step 4 is as follows: use the electromagnetic module and the thermal module to perform bidirectional coupling calculation of the electric field distribution of the cable terminal through the electrothermal simulation interface.

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