An integrated joint topology suitable for high-temperature superconducting urban power cables
The integrated joint topology for high-temperature superconducting urban power cables addresses the challenge of reliable joint integration and refrigerant sealing, enabling efficient and cost-effective power transmission in urban environments.
Patent Information
- Application Number
- CN202111508405.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2021-12-10
- Publication Date
- 2024-12-17
- Estimated Expiration
- 2041-12-10
AI Technical Summary
Existing superconducting power cables face challenges in integrating reliable joints that maintain low-temperature environments and ensure efficient refrigerant sealing, particularly with liquid nitrogen, which is crucial for large-scale urban applications.
An integrated joint topology for high-temperature superconducting urban power cables, comprising high-temperature superconducting tapes spirally wound inside copper tubes, supported by brackets, wrapped with organic insulation and thermal insulation layers, and armored with stainless steel, using copper and VCR joints for electrical and mechanical connections.
The design ensures low-cost, reliable cable connections that maintain a low-temperature environment, facilitate easy assembly and disassembly, and enhance power transmission capacity, making it suitable for large-scale commercial application in urban settings.
Smart Images
Figure CN114171254B_ABST
Abstract
Description
Technical Field
[0001] The invention relates to an integrated joint topology used in the field of high-temperature superconducting cables and applicable to high-temperature superconducting urban power cables. Background Art
[0002] In recent years, second-generation high-temperature superconducting materials (REBCO coated conductors) have become a research hotspot in the field of power equipment due to their characteristics of no DC resistance loss and high conduction current density. Related applications have developed rapidly, such as superconducting cables, superconducting energy storage, superconducting transformers, superconducting current limiters, superconducting motors, etc. Due to their zero resistance characteristics, superconducting materials have great advantages in the application of power transmission and can save a lot of energy. The bundled cable is made of superconducting tapes wound spirally, and has the characteristics of high engineering current density. There is no insulation between layers, and the current can flow arbitrarily between layers. Therefore, it has high thermal stability and robustness, and has broad application prospects in power transmission systems. High-temperature superconducting power cables need to be in a low-temperature environment during power transmission. The refrigerants generally used for low-temperature refrigeration include liquid nitrogen, solid nitrogen, gas helium, liquid helium, supercritical helium, liquid hydrogen, etc., each with a different temperature range. The critical temperature of the second-generation high-temperature superconducting tape, which currently has the most promising commercial application prospects, is around 90K. Taking into account factors such as cost economy, the liquid nitrogen environment is an economical and applicable low-temperature environment. The temperature of liquid nitrogen under normal pressure is generally around 77K, which can meet the refrigeration needs of the second-generation high-temperature superconducting power cables.
[0003] At present, superconducting tapes have been prepared in kilometer-long strips. When used as power cables, joints are inevitably used. Common joints for superconducting power equipment use indium or tin to weld superconducting tapes to copper joints, and then press the copper joints to achieve electrical connection. When liquid nitrogen is used as a refrigerant, the sealing of liquid nitrogen must also be considered. In addition to conventional electrical connections, it is also necessary to ensure that the refrigerant in the refrigeration pipeline does not leak. At present, the most commonly used and mature technology for connecting liquid pipelines in the industry is to use VCR joints, which have good sealing and easy disassembly and assembly. As a mature product, VCR joints are available in a variety of different sizes. Therefore, how to integrate superconducting gas joints with VCR joints and form reliable superconducting cable connections is a key issue in the laying and application of superconducting power cables. Summary of the invention
[0004] The purpose of the present invention is to overcome the deficiencies of the prior art and to provide an integrated joint topology suitable for high-temperature superconducting urban power cables, which can meet the working environment of superconducting cables and realize large-scale application of superconducting cables.
[0005] A technical solution to achieve the above object is: an integrated joint topology suitable for high-temperature superconducting urban power cables, including high-temperature superconducting tapes and copper tubes;
[0006] The high-temperature superconducting tape is spirally wound inside the copper tube, a bracket for supporting the high-temperature superconducting tape is provided inside the copper tube, an organic insulating layer and a thermal insulation layer are wound on the outside of the copper tube, and a stainless steel tube armor layer is provided on the outside of the copper tube; electrical connectors are provided at both ends of the copper tube, and the electrical connectors are copper connectors, which are divided into male connectors and female connectors.
[0007] Furthermore, the material of the organic insulating layer is kapton organic material or asbestos.
[0008] Furthermore, the armor layer of the stainless steel tube is filled with thermal insulation material.
[0009] Furthermore, the inner diameter of the copper tube is 6 mm, and the incident angle of the spirally wound high-temperature superconducting tape is 35°-45°.
[0010] Furthermore, multiple layers of high-temperature superconducting tapes are wound on the inner side of the copper tube, and each layer of high-temperature superconducting tapes is wound together by a plurality of high-temperature superconducting tapes.
[0011] Furthermore, the end of the high-temperature superconducting tape and the electrical connector are welded together by tin or indium in an oil bath temperature-controlled manner.
[0012] Furthermore, for two adjacent sections of high-temperature superconducting cable integrated joints, they are interconnected through a male joint and a female joint to form an electrical connection, the copper tube is connected through a plug-in copper joint, the copper tube and the plug-in copper joint are welded and fixed, and the stainless steel tube armor layer is interconnected through a VCR joint, and the stainless steel tube armor layer is welded and fixed to the VCR joint.
[0013] The present invention is an integrated joint suitable for high-temperature superconducting urban power cables, and designs an integrated joint topology design for superconducting power cables at 77K. The advantages of the present invention are that a low-cost and feasible superconducting power cable joint topology design that matches liquid nitrogen refrigeration is proposed, and the low-temperature environment of the superconducting power cable is ensured by VCR joints and double-layer stainless steel pipes, and the purpose of refrigeration is achieved by the circulation of liquid nitrogen, and the purpose of convenient disassembly and assembly is achieved by the plug-in copper joint. The present invention is simple in design and can be used as a superconducting power cable design scheme for cities to promote the large-scale commercial application of superconducting power equipment, which can greatly reduce the energy consumption of power transmission and increase the power transmission capacity. BRIEF DESCRIPTION OF THE DRAWINGS
[0014] Figure 1 The present invention is a schematic structural diagram of an integrated joint topology suitable for high-temperature superconducting urban power cables. DETAILED DESCRIPTION
[0015] In order to better understand the technical solution of the present invention, the following is a detailed description through specific embodiments:
[0016] See also Figure 1 , the present invention is an integrated joint topology suitable for high-temperature superconducting urban power cables, the high-temperature superconducting tape 11 is spirally wound inside the copper tube 12, and the superconducting tape needs to be kept close to the copper tube, so a certain bracket needs to be filled inside to prevent the superconducting tape from loosening. Multiple layers of high-temperature superconducting tape layers can be wound on the inside of the copper tube, and each layer of high-temperature superconducting tape is wound together by several high-temperature superconducting tapes. In order to ensure that the cable has good mechanical bending characteristics and at the same time ensure that the critical current attenuation of the tape during the bending and winding process does not exceed 5%, the bundled cable preparation scheme adopts a copper tube 12 with an inner diameter of 6mm, and the incident angle of the spiral winding of the high-temperature superconducting tape 11 is in the range of 35-45 degrees, and each layer is wound together by 3 tapes. The inside of the copper tube is hollow, so that liquid nitrogen can flow freely in the tube to achieve better refrigeration effect. In order to ensure the insulation and heat preservation of the cable, an organic insulation layer 6 and a thermal insulation layer 7 are also wound on the copper tube. The organic insulation layer is generally a Kapton organic material or asbestos.
[0017] A stainless steel tube armor layer 2 is arranged outside the copper tube, and its inner diameter is larger than the outer diameter of the bundled cable and the thermal insulation layer and the insulating layer. The interior of the stainless steel tube is filled with thermal insulation material as much as possible to achieve a good thermal insulation effect.
[0018] Electrical connectors 5 are provided at both ends of the copper tube. The electrical connectors are copper connectors, which are divided into male connectors and female connectors. The ends of the high-temperature superconducting tape and the electrical connectors are welded together by tin or indium in an oil bath temperature control method. The difference in thermal expansion coefficients of different materials can be used to lock the female end of the copper connector on the male end at low temperature (in a liquid nitrogen environment).
[0019] For two adjacent sections of high-temperature superconducting cable integrated joints, an electrical connection is formed by interconnecting the male joint and the female joint, the copper tube is connected by a plug-in copper joint 3, the copper tube and the plug-in copper joint are welded and fixed, and the stainless steel tube armor layer is interconnected by a VCR joint 4, and the stainless steel tube armor layer is welded and fixed to the VCR joint.
[0020] At the outlet end of the cable, a ring-shaped copper terminal plus an insulating and heat-insulating sleeve is used for connection. The ring-shaped copper terminal is directly welded on the copper tube. It should be noted that there should be an insulating and heat-insulating cushion between the copper terminal and the double-layer stainless steel tube and the liquid nitrogen inlet to ensure that the entire cable is not electrically charged and is in a good low-temperature environment. At the liquid nitrogen inlet, a compressor is required to give the liquid nitrogen a certain pressure, forcing the liquid nitrogen to flow at a certain flow rate in the copper tube and flow out at the other end of the cable. At the same time, if there are two or more superconducting power cables installed in parallel (such as the positive and negative circuits of DC transmission and the three-phase circuit of AC transmission), the flow of liquid nitrogen can form a circulating cooling circuit by multiple compression pumps and refrigerators.
[0021] Those skilled in the art should recognize that the above embodiments are only used to illustrate the present invention, and are not intended to limit the present invention. As long as they are within the spirit of the present invention, any changes or modifications to the above embodiments will fall within the scope of the claims of the present invention.
Claims
1. An integrated joint topology suitable for high-temperature superconducting urban power cables, comprising a high-temperature superconducting tape and a copper tube, characterized in that: The high-temperature superconducting tape is spirally wound inside the copper tube, a bracket for supporting the high-temperature superconducting tape is arranged inside the copper tube, an organic insulating layer and a thermal insulation layer are wound outside the copper tube, and a stainless steel tube armor layer is arranged outside the copper tube; electrical connectors are arranged at both ends of the copper tube, the electrical connectors are copper connectors, and are divided into male connectors and female connectors, The inner diameter of the copper tube is 6 mm, the incident angle of the spirally wound high-temperature superconducting tape is 35° to 45°, The end of the high temperature superconducting tape and the electrical connector are welded together by tin or indium in an oil bath temperature control manner; For two adjacent sections of high-temperature superconducting cable integrated joints, an electrical connection is formed by interconnecting the male joint and the female joint, the copper tube is connected by a plug-in copper joint, the copper tube and the plug-in copper joint are welded and fixed, and the stainless steel tube armor layer is connected to each other through a VCR joint, and the stainless steel tube armor layer is welded and fixed to the VCR joint.
2. The integrated joint topology suitable for high-temperature superconducting urban power cables according to claim 1 is characterized in that: The material of the organic insulating layer is kapton organic material or asbestos.
3. The integrated joint topology suitable for high-temperature superconducting urban power cables according to claim 1 is characterized in that: The stainless steel pipe armor layer is filled with thermal insulation material.
4. The integrated joint topology suitable for high-temperature superconducting urban power cables according to claim 1 is characterized in that: Multiple layers of high-temperature superconducting tape are wound on the inner side of the copper tube, and each layer of high-temperature superconducting tape is wound together by a plurality of high-temperature superconducting tapes.