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한승학,남석호,이제열,송승현,전해룡,백건우,강형구,고태국 한국초전도.저온공학회 2017 한국초전도저온공학회논문지 Vol.19 No.3
Current lead is a device that connects the power supply and superconducting magnets. High temperature superconductor (HTS) has lower thermal conductivity and higher current density than normal metal. For these reasons, the heat load can be reduced by replacing the normal metal of the current lead with the HTS. Conventional HTS current lead has same cross-sectional area in the axial direction. However, this is over-designed at the cold-end (4.2 K) in terms of current. The heat load can be reduced by reducing this part because the heat load is proportional to the cross-sectional area. Therefore, in this paper, heat load was calculated from the heat diffusion equation of HTS current leads with uniform and non-uniform cross-sectional areas. The cross-sectional area of the warm-end (65K) is designed considering burnout time when cooling system failure occurs. In cold-end, Joule heat and heat load due to current conduction occurs at the same time, so the cross-sectional area where the sum of the two heat is minimum is obtained. As a result of simulation, current leads for KSTAR TF coils with uniform and non-uniform cross-sectional areas were designed, and it was confirmed that the non-uniform cross-sectional areas could further reduce the heat load.
Han, Seunghak,Nam, Seokho,Lee, Jeyull,Song, Seunghyun,Jeon, Haeryong,Baek, Geonwoo,Kang, Hyoungku,Ko, Tae Kuk The Korea Institute of Applied Superconductivity a 2017 한국초전도저온공학회논문지 Vol.19 No.3
Current lead is a device that connects the power supply and superconducting magnets. High temperature superconductor (HTS) has lower thermal conductivity and higher current density than normal metal. For these reasons, the heat load can be reduced by replacing the normal metal of the current lead with the HTS. Conventional HTS current lead has same cross-sectional area in the axial direction. However, this is over-designed at the cold-end (4.2 K) in terms of current. The heat load can be reduced by reducing this part because the heat load is proportional to the cross-sectional area. Therefore, in this paper, heat load was calculated from the heat diffusion equation of HTS current leads with uniform and non-uniform cross-sectional areas. The cross-sectional area of the warm-end (65K) is designed considering burnout time when cooling system failure occurs. In cold-end, Joule heat and heat load due to current conduction occurs at the same time, so the cross-sectional area where the sum of the two heat is minimum is obtained. As a result of simulation, current leads for KSTAR TF coils with uniform and non-uniform cross-sectional areas were designed, and it was confirmed that the non-uniform cross-sectional areas could further reduce the heat load.
Conceptual design of current lead for large scale high temperature superconducting rotating machine
Le, T.D.,Kim, J.H.,Park, S.I.,Kim, H.M. The Korea Institute of Applied Superconductivity a 2014 한국초전도저온공학회논문지 Vol.16 No.2
High-temperature superconducting (HTS) rotating machines always require an electric current of from several hundreds to several thousand amperes to be led from outside into cold region of the field coil. Heat losses through the current leads then assume tremendous importance. Consequently, it is necessary to acquire optimal design for the leads which would achieve minimum heat loss during operation of machines for a given electrical current. In this paper, conduction cooled current lead type of 10 MW-Class HTS rotating machine will be chosen, a conceptual design will be discussed and performed relied on the least heat lost estimation between conventional metal lead and partially HTS lead. In addition, steady-state thermal characteristic of each one also is considered and illustrated.
Conceptual design of cooling anchor for current lead on HTS field coils
Hyeon, C.J.,Kim, J.H.,Quach, H.L.,Chae, S.H.,Yoon, Y.S.,Lee, J.,Han, S.H.,Jeon, H.,Choi, Y.H.,Lee, H.G.,Kim, H.M. The Korea Institute of Applied Superconductivity a 2017 한국초전도저온공학회논문지 Vol.19 No.2
The role of current lead in high-temperature superconducting synchronous machine (HTSSM) is to function as a power supply by connecting the power supply unit at room temperature with the HTS field coils at cryogenic temperature. Such physical and electrical connection causes conduction and Joule-heating losses, which are major thermal losses of HTSSM rotors. To ensure definite stability and economic feasibility of HTS field coils, quickly and smoothly cooling down the current lead is a key design technology. Therefore, in this paper, we introduce a novel concept of a cooling anchor to enhance the cooling performance of a metal current lead. The technical concept of this technology is the simultaneously chilling and supporting the current lead. First, the structure of the current lead and cooling anchor were conceptually designed for field coils for a 1.5 MW-class HTSSM. Then, the effect of this installation on the thermal characteristics of HTS coils was investigated by 3D finite element analysis.
장현만,오상수,조전욱,조영식,하홍수,하동우,성기철,권영길,류강식,김상현,Jang, Hyeon-Man,O, Sang-Su,Jo, Jeon-Uk,Jo, Yeong-Sik,Ha, Hong-Su,Ha, Dong-U,Seong, Gi-Cheol,Gwon, Yeong-Gil,Ryu, Gang-Sik,Kim, Sang-Hyeon 한국초전도저온공학회 2000 한국초전도저온공학회논문지 Vol.2 No.2
1.5 kA class HTS current leads for a SMES magnet, which are connected to a conventional vapor cooled copper leads, were designed. The HTS leads are composed of Bi-2223/Ag-Au tapes and a stainless stell tube. The estimated critical current of the lead is about 1.6 kA at 77.3 K and in a self magnetic field, and the heat input to the liquid helium from the cold end of the 35 cm lead is 0.4 W/lead. It has been made clear that the heat input decreases with increase of the lead length and decrease of the warm end temperature and Ag-Au/SC ratio.
Oyunjargal Tuvdensuren,고병수,성해진,박민원 한국산업정보학회 2019 한국산업정보학회논문지 Vol.24 No.2
Many companies have tried to develop wind power generators with a larger capacity, smaller size and lighter weight. High temperature superconducting (HTS) generators are more suitable for wind power systems because they can reduce volume and weight compared with conventional generators. However, the HTS generator has problems such as huge vacuum vessel and the difficulty of repairing the HTS field coils. These problems can be overcome through the modularization of the HTS field coil. The HTS module coil require a current leads (CLs) for deliver DC current, which causes a large heat transfer load. Therefore, CLs should be designed optimally for reducing the conduction and Joule heat loads. This paper deals with a structural design and thermal analysis of a module coil for a 750 kW-class HTS generator. The conduction and radiation heat loads of the module coils were analysed using a 3D finite element method program. As a result, the total thermal load was less than the cooling capacity of the cryo-cooler. The design results can be effectively utilized to develop a superconducting generator for wind power generation systems.
Le, T.D.,Kim, J.H.,Park, S.I.,Kim, D.J.,Lee, H.G.,Yoon, Y.S.,Jo, Y.S.,Yoon, K.Y.,Kim, H.M. The Korea Institute of Applied Superconductivity a 2014 한국초전도저온공학회논문지 Vol.16 No.4
To minimize most heat loss of current lead for high-temperature superconducting (HTS) rotating machine, the choice of conductor properties and lead geometry - such as length, cross section, and cooling surface area - are one of the various significant factors must be selected. Therefore, an optimal lead for large scale of HTS rotating machine has presented before. Not let up with these trends, this paper continues to improve of diminishing heat loss for HTS part according to different model. It also determines the simplification conditions for an evaluation of the main flux flow loss and eddy current loss transient characteristics during charging and discharging period.