CN-121983383-A - Compact stress cone terminal structure for high-temperature superconducting cable

CN121983383ACN 121983383 ACN121983383 ACN 121983383ACN-121983383-A

Abstract

The invention provides a compact stress cone terminal structure for a high-temperature superconducting cable, which belongs to the technical field of power cable terminals and comprises a stress cone main body, a central insulating cylinder and a semiconductive stress control layer, wherein the stress cone main body is sleeved outside a conductor channel assembly, the semiconductive stress control layer is arranged on the inner surface of the stress cone main body, the central insulating cylinder is axially arranged, an upper compression structure and an upper conductor connecting piece are sequentially arranged above the central insulating cylinder, a lower supporting structure is arranged below the central insulating cylinder, the top of the central insulating cylinder is fixedly connected with the upper compression structure, and the bottom of the central insulating cylinder supports the stress cone main body through the lower supporting structure. The compact stress cone terminal structure for the high-temperature superconducting cable solves the problems of insufficient insulation reliability, unreasonable electric field distribution, poor laminating stability, short service life and overlarge volume of the existing stress cone under a low-temperature environment.

Inventors

FANG JIN
LIU HUAXIANG
DAI JUNFEI
FANG XINYU

Assignees

天津北交智通超导电气科技有限公司

Dates

Publication Date: 20260505
Application Date: 20260311

Claims (7)

1. The utility model provides a compact stress cone terminal structure for high temperature superconducting cable, a serial communication port, terminal structure includes stress cone main part, central insulating cylinder, semiconductive stress control layer, stress cone main part cover is established in the conductor channel subassembly outside, semiconductive stress control layer sets up in stress cone main part internal surface, central insulating cylinder sets up along the axial, central insulating cylinder top has set gradually and has pressed structure, upper portion conductor connecting piece, central insulating cylinder below is provided with lower part bearing structure, central insulating cylinder top and last pressing structure are fixed to link to each other, central insulating cylinder bottom supports stress cone main part through lower part bearing structure.
2. The compact stress cone terminal structure for the high-temperature superconducting cable according to claim 1, wherein the terminal structure further comprises a conductor channel assembly and a superconducting cable conductor, the conductor channel assembly comprises a conductive transition piece and a conductor terminal, the conductor channel assembly is arranged in the central insulating cylinder in a penetrating mode, the upper end and the lower end of the conductive transition piece are fixedly connected with the conductor terminal and the superconducting cable conductor respectively, and the conductive transition piece is electrically connected with the conductor terminal and the superconducting cable conductor respectively.
3. The compact stress cone terminal structure for the high-temperature superconducting cable according to claim 1, wherein the stress cone main body is made of a composite insulating material, the composite insulating material is made of a low-temperature-resistant silicon rubber substrate and ceramic fiber reinforced phase composite material, an axial guide hole is formed in the stress cone main body, the stress cone main body is sleeved outside a superconducting cable conductor through the axial guide hole, a gradual cone structure is formed in the stress cone main body, the gradual cone structure is integrally designed as a front-section slow cone, a middle-section groove and a rear-section steep cone, and the middle-section grooves are uniformly distributed along the circumferential direction of the cone.
4. The compact stress cone terminal structure for the high-temperature superconducting cable of claim 3, wherein the stress cone main body further comprises an elastic positioning mechanism and a heat conducting buffer layer, the elastic positioning mechanism comprises an annular elastic clamp and a positioning guide groove, the positioning guide groove is arranged on the inner side wall of the stress cone main body and extends along the axial direction, the annular elastic clamp is embedded in the positioning guide groove, the heat conducting buffer layer is attached to the inner side of the stress cone main body, and the heat conducting buffer layer is fixedly connected with the stress cone main body through a low-temperature compatible adhesive.
5. The compact stress cone termination structure for high temperature superconducting cables of claim 4, wherein the annular spring clip is in interference fit with the positioning guide groove to tightly attach the stress cone body to the outer insulation layer of the superconducting cable.
6. The compact type stress cone terminal structure for the high-temperature superconducting cable according to claim 1, wherein a gradual change type conical surface structure is arranged in the stress cone main body, and the gradual change type conical surface structure adopts a sectional type variable cone angle design and is suitable for superconducting cables with different voltage levels.
7. The compact stress cone termination structure for high temperature superconducting cables according to claim 1, wherein the stress cone body is made of composite insulating material, and the composite insulating material is made of composite material of low temperature epoxy resin and glass fiber, so as to adapt to the requirement of higher mechanical strength.

Description

Compact stress cone terminal structure for high-temperature superconducting cable Technical Field The invention relates to the technical field of power cable terminals, in particular to a compact stress cone terminal structure for a high-temperature superconducting cable. Background The high-temperature superconducting cable has a wide application prospect in the fields of long-distance power transmission, urban power grid upgrading and the like by virtue of the advantages of extremely low transmission loss and extremely large transmission capacity, and has become one of core transmission equipment of an intelligent power system in the future. The stress cone is used as a key core accessory of a terminal and an intermediate joint of the high-temperature superconducting cable, the performance of the stress cone directly determines the insulation safety, the electric field distribution rationality and the long-term operation reliability of a cable system, and the stress cone is an important link for guaranteeing the stable service of the superconducting cable. The operation environment of the high-temperature superconducting cable has remarkable specificity, the high-temperature superconducting cable usually works in a liquid nitrogen temperature region, the terminal structure needs to realize reliable electrical transition between the low-temperature conductor and the normal-temperature air environment, and strict requirements are provided for the material suitability and structural design rationality of the matched stress cone. However, at present, the stress cone for the high-temperature superconducting cable in the industry mostly uses the design thought of the traditional high-voltage cable, and special optimization is not performed on the low-temperature operation characteristic and the electric field distribution rule of the superconducting cable, so that a plurality of outstanding problems are exposed in practical application, and the performance exertion and the service life of the high-temperature superconducting cable system are seriously restricted. The existing stress cone is made of single silicon rubber insulating materials, embrittlement phenomenon is easy to occur in a 77K liquid nitrogen temperature zone, elasticity is remarkably attenuated, bonding gaps between the stress cone and a superconducting cable insulating layer are increased, and then local electric field concentration is caused, so that the risk of insulation breakdown is greatly improved, and insulation reliability in a low-temperature environment cannot be guaranteed. The traditional stress cone adopts a linear gradual change cone structure, and is not optimally designed aiming at the low-temperature electric field characteristic of a conductor-insulating layer interface of a superconducting cable, so that the electric field concentration coefficient is as high as 2.8-3.2, insulation aging is extremely easy to cause in the long-term operation process, and the service life of the stress cone is shortened. Meanwhile, the interface design of the conductor current path and the stress control structure in the partial structure is complex, assembly errors are easy to generate, electric field distribution is further disturbed, a new electric field concentration area is formed near the conductor terminal, and the hidden danger of partial discharge is increased. Moreover, the existing stress cone lacks a special positioning mechanism adapting to a low-temperature environment, cone surface deflection is easy to occur in the installation process, the problem of stress concentration is aggravated, and the thermal shrinkage effect of materials in the low-temperature environment can further expand gaps among components, so that the attaching stability of the stress cone and a cable insulating layer is reduced. In addition, partial structures have the condition that stress control layer and load-carrying structure are mixed and use, and the atress route is unclear, leads to the life of stress cone only to be 5-8 years, is far below the design life of superconducting cable body 30 years, has seriously influenced the long-term operational reliability of whole cable system. The conventional stress cone structure is adopted in the existing high-voltage cable terminal, so that the overall size is large, the miniaturization and the compact arrangement of the superconducting cable terminal are not facilitated, and the severe requirements of scenes such as urban substations and dense power grids on equipment space occupation are difficult to meet. The material selection and the structural design of the existing stress cone do not break through the technical framework of the traditional cable accessories, and the low-temperature operation environment, the special electric field distribution rule and the miniaturized application requirements of the superconducting cable cannot be fully considered, so that the existing stress cone cannot adapt to the us