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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Progress in Superconductivity and Cryogenics
Journal Basic Information
Journal DOI :
The Korea Institute of Applied Superconductivity and Cryogenics
Editor in Chief :
Hyung-Seop Shin, Won-Nam Kang
Volume & Issues
Volume 8, Issue 4 - Nov 2006
Volume 8, Issue 3 - Sep 2006
Volume 8, Issue 2 - Apr 2006
Volume 8, Issue 1 - Mar 2006
Selecting the target year
A review of Magnetic Refrigeration Technology
Jeong S. ; Numazawa T. ; Rowe A. ;
Progress in Superconductivity and Cryogenics, volume 8, issue 2, 2006, Pages 1~10
This paper reviews the magnetic refrigeration technology that is a novel cooling method utilizing magnetic field to obtain low temperature. The key component of the refrigeration is a novel magnetic refrigerant which should possess sufficiently large magneto-caloric effect so that a pseudo-Carnot magnetic refrigeration cycle can cover reasonably large temperature span. Otherwise, a regenerative concept should be employed to expand the temperature span of the refrigeration cycle. There is a growing interest in magnetic refrigeration as a viable refrigeration technology not only for cryogenics as well as room temperature range. This paper covers historical developments, fundamental concepts, key components, application classification, and recent research trend of magnetic refrigerators.
Critical current densities of bicrystalline HTSC film under various magnetic fields
Lim S.M. ; Jung Y. ; Jang K. ; Lee S.M. ; Jung Y.H. ; Youm D. ;
Progress in Superconductivity and Cryogenics, volume 8, issue 2, 2006, Pages 11~16
Critical current densities were measured for a bicrystalline
film under various magnetic fields
. The fields were varied from -0.7KOe to +0.7KOe for various orientations with respect to the film surface. The curves of the critical current densities
showed the well known butterfly-like hysteretic curves. Our data could be analyzed for the two components of field, which are normal and parallel to the film surface, respectively. We combined the effect of
deduced from the data for the normal field
and the effect of
deduced from the data for the almost parallel field
. Our analyses indicate that
depends on the two components of flux density at the grain boundary. All the experimental data for various
fit well to this new formula which was obtained by multiplying the factors deduced from the field dependences of these two components.
A GHz-Level RSFQ Clock Distribution Technique with Bias Current Control in JTLs
Cho W. ; Lim J.H. ; Moon G. ;
Progress in Superconductivity and Cryogenics, volume 8, issue 2, 2006, Pages 17~19
A novel clock distribution technique for pipelined-RSFQ logics using variable Bias Currents of JTLs as delay-medium is newly proposed. RSFQ logics consist of several logic gates or blocks connected in a pipeline structure. And each block has variable delay difference. In the structure, this clock distribution method generates a set of clock signals for each logic blocks with suitable corresponding delays. These delays, in the order of few to tens of pS, can be adjusted through controlling bias current of JTL of delay medium. While delays with resistor value and JJ size are fixed at fabrication stage, delay through bias current can be controlled externally, and thus, is heavily investigated for its range as well as correct operation within current margin. Possible ways of a standard delay library with modular structure are sought for further modularizing Pipelined-RSFQ applications. Simulations and verifications are done through WRSpice with Hypres 3-um process parameters.
Analyzed Model of The Active Filter combined with SMES
Kim A-Rong ; Kim Jae-Ho ; Kim Hae-Jong ; Kim Seok-Ho ; Seong Ki-Chul ; Park Min-Won ; Yu In-Keun ;
Progress in Superconductivity and Cryogenics, volume 8, issue 2, 2006, Pages 20~24
Recently, utility network is becoming more and more complicated and huge due to IT and OA devices. In addition to, demands of power conversion devices which have non-linear switching devices are getting more and more increased. Consequently, because of the non-linear power semiconductor devices, current harmonics are unavoidable. Sometimes those current harmonics flow back to utility network and become one of the main reasons which can make the voltage distortion. Also, it makes noise and heat loss. On the other hands, voltage sag from sudden increasing loads is also one of the terrible problems inside of utility network. In order to compensate the current harmonics and voltage sag problem, AF(active filter) systems could be a good solution method. SMES is a very good promising source due to it's high response time of charge and discharge. Therefore, the combined AF and SMES system can be a wonderful device to compensate both harmonics current and voltage sag. However, SMES needs a superconducting magnetic coil. Because of using this superconducting magnetic coil, quench problem caused by unexpected reasons have always been unavoidable. Therefore, to solve out mentioned above, this paper presents a decisive method using shunt and series active filter system combined with SMES. Especially, authors analyzed the change of original energy capacity of SMES regarding to the size of resistance caused by quench of superconducting magnetic coil.
Development of the KSTAR Superconductor
Lim B.S. ; Choi J.Y. ; Lee S.I. ; Kim D.J. ; Park W.W. ; Woo I.S. ; Song Y.J. ; Song N.H. ; Kim C.S. ; Lee D.G. ; Kim K.P. ; Park H.T. ; Joo J.J. ;
Progress in Superconductivity and Cryogenics, volume 8, issue 2, 2006, Pages 25~28
The magnet system of KSTAR(korean Superconducting Tokamak Advanced Research) is consisted of 16 TF (Toroidal Field) coils and 14 PF (Poroidal Field) coils. Internal cooling CICC(Cable in Conduit Conductor) type conductor is used for both of TF and PF coil systems. The conduit material for
cable is Incoloy 908 and 316LN stainless-steel was used as conduit material for NbTi cable.
CICC is used for all TF coils and PF1-5 coils while NbTi CICC is used for PF6 and 7 coils.
and NbTi strands were made for KSTAR superconducting strand. They are satisfied with KSTAR superconducotr requirements. The
strands supplied from three companies; MELCO (Mitsubishi Electric Co.), OAS (Outokumpu Advanced Superconductor) and KAT (Kiswire Advanced Technology) were used. A special CICC jacketing system is developed for the KSTAR CICC fabrication which uses the tube-mill process consisted of forming, welding, sizing and squaring procedures. The. procedures for cabling and jacketing of CICC for TF and PF coils and their results including the geometrical specification and characteristics of strands are described.
Fault Current Limiting Characteristic of Non-inductively Wound HTS Magnets in Sub-cooled
Park Dong-Keun ; Ahn Min-Cheol ; Yang Seong-Eun ; Lee Chan-Joo ; Seok Bok-Yeol ; Yoon Yong-Soo ; Ko Tae-Kuk ;
Progress in Superconductivity and Cryogenics, volume 8, issue 2, 2006, Pages 29~32
An advanced superconducting fault current limiter (SFCL) using
superconducting (HTS) wire has been developed. The SFCL has a non-inductively wound magnet for reducing loss in normal state. Two types of non-inductively wound magnets, the solenoid type and the pancake type, were designed and manufactured by using Bi-2223 wire in this research. Short-circuit tests of the magnets were performed in sub-cooled
cooling system of 65 K. The magnets are thermally more stable and have a higher critical current in 65 K sub-cooled
cooling system than in 77 K saturated one. Because the resistivity of matrix at 65 K is lower than the resistivity at 77 K, the magnets generate a small resistance to reduce the fault current when the quench occurs. The magnets could limit the fault current to low current level with such a small resistance. The current limiting characteristic of the magnets was analyzed from the test result. The solenoid type was wound in parallel to make it non-inductive. The pancake type was also connected in parallel to be compared with the solenoid type in the same condition. The solenoid type was found to have a good thermal stability compared with the pancake type. It also had as large resistance as the pancake type to limit the fault current in sub-cooled
Comparison of Magnetization loss of YBCO wires and BSCCO Wires
Lim Hyoung-Woo ; Lee Hee-Joon ; Cha Guee-Soo ; Lee Ji-Kwang ;
Progress in Superconductivity and Cryogenics, volume 8, issue 2, 2006, Pages 33~36
Multi-stacked HTS wires are needed to conduct large current in the power application. In this paper, magnetization losses of the multi-stacked YBCO wire and the BSCCO wire have been measured and compared. 4 types of YBCO wires and BSCCO wires, that is, single, 2-stacked, 3-stacked and 4-stacked, have been tested. HTS multi-stacked wires were fabricated using face-to-face type stacking method. Measurements of magnetization loss were performed under various angles of external magnetic field to consider the anisotropic characteristics of HTS wires. The ratios of the magnetization loss by multiple stacking of superconducting wires were presented. Measurements results show that loss reduction ratios have three distinct regions due to the magnitude of external magnetic field, the material of HTS wire and number of stacks.
Breakdown Characteristics of Insulation Materials for a Termination of Power Transmission Class HTS Cable
Kwag Dong-Soon ; Cheon Hyeon-Gweon ; Choi Jae-Hyeong ; Kim Sang-Hyun ;
Progress in Superconductivity and Cryogenics, volume 8, issue 2, 2006, Pages 37~42
A research on several characteristics such as volume breakdown and surface discharge of insulators for a termination of power transmission class HTS cable was performed. We investigated the surface discharge of glass fiber reinforced plastic (GFRP) under air, cryogenic nitrogen gas and nitrogen gas media. The breakdown characteristics of these media were studied. Experimental results revealed that flashover voltage greatly depends on pressure, temperature, the kinds of insulating media and voltages, but it is slightly affected by shape and material of electrode. The breakdown voltage of liquid nitrogen, cryogenic nitrogen gas and nitrogen gas deeply depends on the shape and dimension of electrode, kinds of voltages and pressure. Moreover, the breakdown voltage of cryogenic nitrogen gas and flashover voltage of GFRP in the cryogenic nitrogen gas is also influenced by temperature and vapour-mist density of the gas.
Simultaneous Quench Characteristic of Resistive Superconducting Fault Current Limiting Modules by using BSCCO Tape
Yang Seong-Eun ; Ahn Min-Cheol ; Park Dong-Keun ; Youn Il-Goo ; Jang Dae-Hee ; Ko Tae-Kuk ;
Progress in Superconductivity and Cryogenics, volume 8, issue 2, 2006, Pages 43~45
Recently, the resistive Fault Current Limiter (SFCL) made with Coated Conductor (CC) has been researched with an advanced capability in CC. Current limiting elements must be connected in series in order to fabricate the resistive SFCL having large capacity. By the way, unless the applied voltage in the SFCL is distributed to the elements when the fault occurred, those elements will be critically damaged. Thus simultaneous quench of the elements is an important factor to design the resistive SFCL. In this paper, simultaneous quench characteristics of current limiting module by using BSCCO 2223 were researched before manufacturing the resistive SFCL by using CC. At the first fault stage, the elements generated the resistance at the same time. However, the unequal voltage is applied to the each element in process of time. The method is suggested to solve the problem of the unequal distribution. These experimental results will play an important part in developing for the resistive SFCL by using CC.
Design and Operational Test of 22.9kV, 30m, 3phase HTS Cable Cooling System
Kim Do-Hyung ; Kim Choon-Dong ; Park In-Son ; Jang Hyun-Man ; Lee Su-Kil ;
Progress in Superconductivity and Cryogenics, volume 8, issue 2, 2006, Pages 46~49
The 30m, 3phase, 22.9kV HTS (High Temperature Superconducting) power cable system was produced by LS Cable Ltd. The project aims for a commercial HTS cable. The designing, the manufacturing and the initial operating of HTS cable system were completed by 2004. Then, we have performed a long term operational test since February, 2005. This paper mainly reports the result of the HTS cable cooling operation.