High-voltage direct-current cable terminal electric field homogenization method based on nonlinear conductive material

Abstract

The invention relates to a high-voltage direct-current cable terminal electric field homogenization method based on a nonlinear conductive material, and the method employs the nonlinear conductive material to construct a specific interface structure, and achieves the effective homogenization of the electric field intensity at a cable terminal. In a high electric field environment, the specific interface structure can realize efficient dispersion of an electric field, the local electric field concentration phenomenon is remarkably reduced, and the safety and reliability of a cable system under extreme conditions are improved. The electric field homogenization method provided by the invention has the remarkable advantages of simplicity and convenience in operation, accurate result and high reliability, and is suitable for being widely used in various complex engineering applications. The method not only provides an innovative solution for electric field homogenization of the cable terminal, but also provides a feasible technical path for overall performance optimization of high-voltage electrical equipment.

Description

Technical Field

[0001] The invention belongs to the technical field of electric field equalization of high-voltage electrical equipment, in particular to a high-voltage direct current cable terminal electric field equalization method based on nonlinear conductive materials. Background Art

[0002] At the terminal where the high-voltage cable is connected to other electrical equipment, the lack of the shielding layer at the cable cutout leads to uneven electric field distribution and significantly enhanced electric field strength. This electric field enhancement phenomenon can easily cause local breakdown or flashover, which in turn causes equipment insulation failure, and is a weak link in the high-voltage power transmission system. In order to protect the safe operation of electrical equipment and the stability of the system, it is particularly important to achieve the homogenization of the electric field at the cable terminal. At present, one of the main challenges in controlling the electric field strength is how to effectively manage various factors related to material interfaces, electric field enhancement, and nonlinear conductivity characteristics. Therefore, it is urgent to propose an improved method based on nonlinear conductive materials and advanced interface engineering to achieve effective homogenization of the electric field at the cable terminal and precise control of the electric field strength. Summary of the invention

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

[0004] The present invention solves the technical problem by adopting the following technical solutions:

[0005] The electric field homogenization method of a high-voltage DC cable terminal based on nonlinear conductive materials comprises the following steps:

[0006] Step 1: construct a high-voltage DC cable terminal model based on nonlinear conductive materials;

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

[0008] Step 3: constructing a nonlinear conductive material interface structure according to 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 the 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: constructing a high-voltage DC cable terminal model based on nonlinear conductive materials, including a conductor, an insulating layer, a nonlinear layer, a stress cone and a semi-conductive screen, wherein a nonlinear layer and a semi-conductive screen are arranged below the stress cone, an insulating layer is connected below the nonlinear layer and the semi-conductive screen, and a conductor is connected below the insulating layer, wherein the interface structure of the nonlinear layer conductive material realizes nonlinear stress control of the material in terms of impedance, and a shrink tube or a 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] Moreover, the specific implementation method of step 2 is:

[0012]

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

[0014] Furthermore, the step 3 of constructing the nonlinear conductive material interface structure includes contact between particles and utilizing filler particles with nonlinear characteristics.

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

[0016] Moreover, the specific implementation method of utilizing filler particles with nonlinear characteristics is: selecting materials with nonlinear conductivity characteristics, introducing these nonlinear fillers into the substrate by mixing or blending to form an effective conductivity network; and affecting the electrical properties of the material through the interface interaction between the filler particles and the substrate.

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

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

[0019] The present invention constructs a high-voltage DC cable terminal model based on nonlinear conductive materials; calculates the conductivity of nonlinear conductive materials and constructs the interface structure of nonlinear conductive materials; forms an electric field of a high-voltage DC cable terminal model based on nonlinear conductive materials, and determines whether it is qualified by calculating the electric field machine. The present invention uses nonlinear conductive materials to construct a specific interface structure, and realizes effective homogenization of the electric field strength at the cable terminal. In a high electric field environment, this specific interface structure can achieve efficient dispersion of the electric field, significantly reduce the local electric field concentration phenomenon, and improve 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 the electric field homogenization of cable terminals, but also provides a feasible technical path for the overall performance optimization of high-voltage electrical equipment. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0021] Figure 2 The diagram is a schematic diagram of the relationship between the interface structure of the nonlinear conductive material of the present invention and the main insulation layer of the cable and the terminal stress cone. DETAILED DESCRIPTION

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

[0023] The electric field homogenization method of a high-voltage DC cable terminal based on nonlinear conductive materials comprises the following steps:

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

[0025] like Figure 1 and Figure 2 As shown, a high-voltage DC cable terminal model based on nonlinear conductive materials includes a conductor, an insulating layer, a nonlinear layer, a stress cone and a semi-conductive screen, wherein a nonlinear layer and a semi-conductive screen are arranged below the stress cone, an insulating layer is connected below the nonlinear layer and the semi-conductive screen, and a conductor is connected below the insulating layer, wherein the interface structure of the nonlinear layer conductive material realizes nonlinear stress control of the material in terms of impedance, and a shrink tube or a 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.

[0026] Step 2: Calculate the conductivity of the nonlinear conductive material according to 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, β E is the field coefficient and k is the Boltzmann constant.

[0029] Step 3: construct a nonlinear conductive material interface structure according to the constructed high-voltage DC cable terminal model based on nonlinear conductive materials.

[0030] The construction of nonlinear conductive material interface structure includes the contact between particles and the use of filler particles with nonlinear properties.

[0031] The method of constructing the interface structure of nonlinear conductive materials through contact between particles is: 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, and a conductive path is formed when the conductive particles are close enough, and the multiphase interface provided makes the material exhibit nonlinear conductive characteristics.

[0032] The method of constructing the interface structure of nonlinear conductive materials by nonlinear filler particles is as follows: selecting materials with nonlinear conductive properties including but not limited to silicon carbide, zinc oxide, BaTio3, TiO2, graphene, graphene oxide, carbon nanotubes, etc., and introducing these nonlinear fillers into the substrate by mixing or blending to form an effective conductive network; affecting the electrical properties of the material by the interface interaction between the filler particles and the substrate (chemical bonding, physical adsorption or electrostatic effect, etc.).

[0033] Step 4: Calculate the electric field of the high-voltage DC cable terminal formed based on the 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 of the high-voltage DC cable terminal formed based on nonlinear conductive materials is: using the electromagnetic module and the thermal module to perform bidirectional coupling through the electrothermal simulation interface to calculate the distribution of the electric field at the cable terminal.

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

Claims

1. A method for equalizing the electric field at a high-voltage DC cable terminal based on nonlinear conductive materials, characterized in that: The following steps are involved: Step 1: construct a high-voltage DC cable terminal model based on nonlinear conductive materials; Step 2: Calculate the conductivity of the nonlinear conductive material according to the constructed high-voltage DC cable terminal model based on the nonlinear conductive material; Step 3: constructing a nonlinear conductive material interface structure according to the constructed high-voltage DC cable terminal model based on the nonlinear conductive material; Step 4: Calculate the electric field of the high-voltage DC cable terminal formed based on the nonlinear conductive material. If the calculation is qualified, it can be used, otherwise return to step 1.

2. The method for electric field homogenization of a high-voltage DC cable terminal based on nonlinear conductive materials according to claim 1, characterized in that: The specific implementation method of step 1 is: constructing a high-voltage DC cable terminal model based on nonlinear conductive materials, including a conductor, an insulating layer, a nonlinear layer, a stress cone and a semi-conductive screen, wherein a nonlinear layer and a semi-conductive screen are arranged below the stress cone, an insulating layer is connected below the nonlinear layer and the semi-conductive screen, and a conductor is connected below the insulating layer, wherein the interface structure of the nonlinear layer conductive material realizes nonlinear stress control of the material in terms of impedance, and a shrink tube or a 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.

3. The method for electric field homogenization of a high-voltage DC cable terminal based on nonlinear conductive materials according to claim 1, characterized in that: The specific implementation method of step 2 is: Where T is temperature, E is electric field strength, A and α are constants, σ ​​is conductivity, Ea is activation energy, β E is the field coefficient and k is the Boltzmann constant.

4. The method for electric field homogenization of a high-voltage DC cable terminal based on nonlinear conductive materials according to claim 1, characterized in that: The step 3 of constructing the interface structure of the nonlinear conductive material includes contact between particles and using filler particles with nonlinear characteristics.

5. The method for electric field homogenization of a high-voltage DC cable terminal based on nonlinear conductive materials according to claim 4, characterized in that: The specific implementation method of the contact between particles is: the filler particles are uniformly dispersed in the polymer matrix by mechanical stirring, ultrasonic treatment or solvent method, and a conductive path is formed when the conductive particles are close enough, and the multiphase interface provided makes the material exhibit nonlinear conductivity characteristics.

6. The method for electric field homogenization of a high-voltage DC cable terminal based on nonlinear conductive materials according to claim 4, characterized in that: The specific implementation method of utilizing filler particles with nonlinear characteristics is: selecting materials with nonlinear conductivity characteristics and introducing these nonlinear fillers into the substrate through mixing or blending to form an effective conductivity network; and influencing the electrical properties of the material through the interface interaction between the filler particles and the substrate.

7. The method for electric field homogenization of a high-voltage DC cable terminal based on nonlinear conductive materials according to claim 1, characterized in that: The specific implementation method of step 4 is: using the electromagnetic module and the thermal module to perform bidirectional coupling calculation of the distribution of the electric field at the cable terminal through the electrothermal simulation interface.

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