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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 :
Volume & Issues
Volume 11, Issue 4 - Nov 2009
Volume 11, Issue 3 - Sep 2009
Volume 11, Issue 2 - May 2009
Volume 11, Issue 1 - Mar 2009
Selecting the target year
Analysis of Coupling Loss with Size and Material in the KSTAR PF Superconducting Coils
Lee, H.J. ; Chu, Y. ; Lee, S. ; Park, Y.M. ; Park, H.T. ; Oh, Y.K. ;
Progress in Superconductivity and Cryogenics, volume 11, issue 3, 2009, Pages 1~5
It is important to predict AC loss in
and NbTi cable-in-conduit-conductor (CICC) reliably for the design and operation of large superconducting coils. The hysteresis loss in the superconducting filaments and coupling loss within strands and among strands in a cable or composite are dominant ac losses in superconducting magnets. The coupling loss in a superconductor can be characterized by identifying the coupling constant time
. To reduce the coupling loss, all the strands (superconductor and Cu) in KSTAR (Korea Superconducting Tokamak Advance Research) are chromium plated with thickness of
. The ac losses of PF1, PF5 and PF6 coils has been measured by calorimetric method while applying trapezoidal current pulses with various ramp rate from 0.5 kA/s to 2 kA/s. The coupling time constants for
ms and the values are not co-related with the coil size, the time constants for NbTi coil is 30 ms.
Quench Analysis in HTS Pancake Coil
Park, C.S. ; Ahn, T.K. ; Park, K.W. ; Kim, D.H. ; Cha, G.S. ; Seo, J.S. ;
Progress in Superconductivity and Cryogenics, volume 11, issue 3, 2009, Pages 6~9
The thermal characteristics of quench propagation is a crucial problem for the stability of the superconductor. The objective of this study is to simulate the quench propagation with the variation of disturbance energy in Bi-2223/Ag HTS pancake coil. In this analysis, the temperature-time trace of a point away from heater was calculated under conditions of different quench energy. The critical disturbance energy between quench propagation and quench recovering was calculated, In addition, the minimum quench energy with different transport currents was obtained through the present simulation. These results are significant to the application of HTS.
Quench/recovery test results of the YBCO coated conductors(CCs) having various stabilizer thicknesses
Kwon, N.Y. ; Kim, H.S. ; Kim, K.L. ; Kim, K.J. ; Yim, S.W. ; Kim, H.R. ; Hyun, O.B. ; Lee, H.G. ;
Progress in Superconductivity and Cryogenics, volume 11, issue 3, 2009, Pages 10~14
Since a stabilizer of YBCO coated conductor (CC) plays a very important role of bypassing over-current and transferring heat generated in the moment of fault, it is one of big issues to determine the material of the stabilizer and its dimension for the high performance of the HTS power application system. Especially, in the case of a superconducting fault current limiter (SFCL), which requires it to react immediately to the occurrence of fault, characteristics of stabilizer are decisive in limiting fault current and recovering superconducting properties during and after quenching. In this paper, the quench / recovery characteristics of YBCO CCs with various thickness of stabilizer were analyzed. The quench/recovery test carried out at 20
, 5 cycles (60 Hz) and results showed that as the thickness of the stabilizer decreased, both the final approach temperature and the recovery time decreased.
Reduction Characteristics on Perpendicular Magnetization Loss in Transposed Stacking Conductor of Striated YBCO CC
Lee, J.K. ; Byun, S.B. ; Han, B.W. ; Park, S.H. ; Choi, S.J. ; Kim, W.S. ; Park, C. ; Choi, K.D. ;
Progress in Superconductivity and Cryogenics, volume 11, issue 3, 2009, Pages 15~19
Recently, it is proposed to make striations on the YBCO coated conductor and to transpose each other as one of the solutions to decrease the perpendicular magnetization loss. For large power application using HTS, the stacked conductor packing the YBCO coated conductors should be used because single conductor is limited in flowing of demanded large current. In this paper, we research the affect of the striation and continuously transposed stacking geometry on the magnetization loss in perpendicularly exposed magnetic field. Several short samples having different number of striation and continuously transposed stack are prepared and tested in perpendicularly exposed magnetic field for the magnetization loss characteristics. The magnetization loss of striated sample was lower than sample without striation. The reduction effect on magnetization loss by the striation is obviously appeared in higher field and lower number of stack and decreased as increasing the transposed stacking number. Also, the reduction effect by transposed stack is obviously appeared in lower field at lower number of striation and isn't appeared at higher striation number and higher magnetic field.
Quench Analysis and Operational Characteristics of the Quench Detection System for the KSTAR PF Superconducting Coils
Chu, Y. ; Yonekawa, H. ; Kim, Y.O. ; Park, K.R. ; Lee, H.J. ; Oh, Y.K. ;
Progress in Superconductivity and Cryogenics, volume 11, issue 3, 2009, Pages 20~25
The quench detection system of the KSTAR (Korea Superconducting Tokamak Advanced Research) primarily uses the resistive voltage measurement due to a quench. This method is to detect the resistive voltage generated by a quench, which is continuously maintained above the preset voltage threshold for a given holding time. As the KSTAR PF (Poloidal Field) coils are operated in the pulse current mode, the large inductive voltages are generated. Therefore the voltage threshold and the quench holding time should be determined by considering both the inductive voltages measured during the operation, and the maximum conductor temperature rise through the quench analysis. In this paper, the compensation methods for minimizing the inductive voltages are presented for the KSTAR PF coils. The quench hot spot analysis of the PF coils was carried out by the analytical and numerical methods for determining the proper values of the quench voltage threshold and the allowable quench protection delay time.
Operation result of the Cryogenic and Mechanical Measurement System for KSTAR
Kim, Y.O. ; Chu, Y. ; Yonekawa, H. ; Bang, E.N. ; Lee, T.G. ; Baek, S.H. ; Hong, J.S. ; Lee, S.I. ; Park, K.R. ; Oh, Y.K. ;
Progress in Superconductivity and Cryogenics, volume 11, issue 3, 2009, Pages 26~30
Korea Superconducting Tokamak Advanced Research(KSTAR) device is composed of 30 superconducting magnets, magnet structure, vacuum vessel, cryostat, current feeder system, and etc. KSTAR device is operated in the cryogenic temperature and high magnetic field. We install about 800 sensors - temperature sensors, stain gages, displacement gages, hall sensors - to monitor the thermal, mechanical, electrical status of KSTAR during operation. As a tremendous numbers of sensors should be installed for monitoring the KSTAR device, the method of effective installation was developed. The sensor test was successfully carried out to check its reliability and its reproduction in the cryogenic temperature. The sensor signal is processed by PXI-based DAQ system and communicated with central control system via machine network and is shown by Operator Interface(OPI) display in the main control room. In order to safely operate the device, any violations of mechanical & superconductive characteristic of the device components were informed to its operation system & operator. If the monitored values exceed the pre-set values, the protective action should be taken against the possible damage. In this paper, the system composition, operation criteria, operation result were presented.
The AC loss of 22.9kV/50MVA High-Tc Superconducting Power Cable
Choi, Suk-Jin ; Lee, Sang-Jin ; Sim, Ki-Deok ; Cho, Jeon-Wook ; Lee, Soo-Gil ; Yang, Byeong-Mo ; Yoon, Hyung-Hee ;
Progress in Superconductivity and Cryogenics, volume 11, issue 3, 2009, Pages 31~34
An HTS power cable is generally composed of 2 layers for conducting and 1 layer for shielding. For the analysis of AC loss of an HTS power cable, 2-dimensional magnetic field analysis is carried out. The magnetization loss in HTS cable core was calculated, and the transport current loss was obtained from the monoblock equation and the elliptical Norris Equation. And the total AC loss of the cable was expected by the sum of magnetization loss and transport current loss. The variation of ac loss with respect to the gap and uncertain factor between the superconducting tapes was investigated, and the ac loss of 22.9kV/50MVA high-Tc superconducting power cable was calculated. These results well agree with those of experiment.
A basic study on protective relay testing using RTDS in power system applying SFCL
Lee, Seung-Ryul ; Yoon, Jae-Young ; Kim, Jae-Ho ; Lee, Byong-Jun ;
Progress in Superconductivity and Cryogenics, volume 11, issue 3, 2009, Pages 35~39
The study for a protective relay system is one of the important technical issues on the power system application of Superconducting Fault Current Limiter (SFCL). We used Real Time Digital Simulator(RTDS) to study the true interaction of the protection system with the power system. RTDS modeling of SFCL is necessary to the detailed protective relay tests. In this paper, we developed an analysis model using RTDS for studying the transient behavior of 22.9kV SFCL and carried out closed-loop testing of protective relays in distribution power system with the developed SFCL model. The SFCL model has the operation mechanism of 22.9kV hybrid SFCL being developed by LSIS and KEPRI in Korea. The parameters of the model are based on the test data of the real SFCL. Power system planners and operators can solve the expected problems in power system application of SFCL using protective relay testing results.
Characteristic analysis of components of a high temperature superconducting power supply using YBCO coated conductor
Yoon, Yong-Soo ; Cho, Dae-Ho ; Park, Dong-Kuen ; Yang, Seong-Eun ; Kim, Ho-Min ; Chung, Yoon-Do ; Bae, Duck-Kwon ; Ko, Tae-Kuk ;
Progress in Superconductivity and Cryogenics, volume 11, issue 3, 2009, Pages 40~45
Many superconductor applications such as MRI and SMES must be operated in persistent current mode to eliminate the electrical ohmic loss. This paper presents the characteristic analysis of the high temperature superconducting (HTS) power supply made of YBCO coated conductor (CC). In this research, we have manufactured the HTS power supply to charge the 0.73 mH HTS double-pancake magnet made of YBCO CC. Among the all design parameters, the heater triggerring time and magnet applying time were the most important factors for the best performance of the HTS power supply. In this paper, three-dimensional simulation through finite element method (FEM) was used to study the heat transfer in YBCO CC and the magnetic field of the magnetic circuit. Based upon these results, the final operational sequence could be determined to generate the pumping current. In the experiment, the maximum pumping current reached about 16 A.
A Study on the DC Critical Current Test Method for 22.9kV/50MV A Superconducting Power Cable Considering the Uncertainty
Choi, S.J. ; Lee, S.J. ; Sim, K.D. ; Cho, J.W. ; Lee, S.K. ; Yang, B.M. ; Ko, T.K. ;
Progress in Superconductivity and Cryogenics, volume 11, issue 3, 2009, Pages 46~49
A 3-phase 100m long, 22.9kV class HTS power transmission cable system was developed by Korea Electrotechnology Research Institute (KERI) and LS cable Ltd. those are participated in the 21st Century Frontier project R&D Program of Korea. It is important to test the DC critical current related with its power capacity before applying to the real power grid. In 1995, several international standards organizations including International Electrotechnical Commission (IEC), decided to unify the use of statistical terms related with 'accuracy' or 'precision' in their standards. It was decided to use the word 'uncertainty' for all quantitative (associated with a number) statistical expressions. In this paper, we measured DC critical current of 22.9kV/50MVA superconducting power cable with several voltage tap and analyzed the uncertainty with these results.
Specifications of 22.9kV HTS cables and FCLs considering protection systems in Korean power distribution system
Lee, Seung-Ryul ; Park, Jong-Young ; Yoon, Jae-Young ; Lee, Byong-Jun ; Yang, Byeong-Mo ;
Progress in Superconductivity and Cryogenics, volume 11, issue 3, 2009, Pages 50~54
In Korea, 22.9kV 50MVA HTS (High Temperature Superconducting) cables and 630A/3kA hybrid SFCLs (Superconducting Fault Current Limiters) have been or are being developed by LS Cable, LS Industrial System, and Korea Electric Power Research Institute. They will be installed at Icheon 154kV Substation for real-power-distribution-system operation in 2010. This paper proposes specification of current limiting resistor/reactor for the SFCL and fault current condition of the HTS cable for applying the superconducting devices to Korean power distribution system, from the viewpoint of power system protection.
Determination of a Substation and Installation Site for applying Superconducting Cable/FCL to Real Power Grid
Yang, B.M. ; Won, Y.J. ; Kim, B.H. ; Kang, J.W. ; Yoon, J.Y. ; Lee, S.R. ; Moon, Y.H. ;
Progress in Superconductivity and Cryogenics, volume 11, issue 3, 2009, Pages 55~59
In attempts to closely study the effect of high efficiency, friendly environment HTS(High Temperature Superconducting) cable and SFCL(Superconducting Fault Current Limiters) on power system, several projects were carried out around the world. Promising results have been achieved in terms of cable capacity and reliability. commercial HTS cable and SFCL, however, must not only be only be feasible, but meet practical requirements as well. To facilitate the transition of HTS cable technology from the Lab. to the Real Grid, a New project for applying 22.9kV HTS cables and SFCL to the commercial Power Grid supported by Government has just started in KEPCO. Target of this project is to operate two 22.9kV, 50MVA, 150MVA HTS cables and two 22.9kV 630A, 3000A SFCL in a KEPCO Grid in order to demonstrate its reliability and stable operation. This paper will present the technology for selecting appropriate site and its plan for installation & operating of 22.9kV HTS cables & SFCL in KEPCO Grid.
Magnetic Field Distribution Analysis of Superconducting Niobium Foil of Linear Type Magnetic Flux Pump using Simulation
Lee, Eung-Ro ; Chung, Yoon-Do ; Bae, Duck-Kweon ; Yoon, Yong-Soo ; Ko, Tae-Kuk ;
Progress in Superconductivity and Cryogenics, volume 11, issue 3, 2009, Pages 60~64
We investigated an operating characteristic of linear-type magnetic flux pump (LTMFP) as a current compensator under the various conditions. In order to explain the mechanism of the LTMFP, the magnetic behavior of superconducting Nb foil according to pumping actions should be understood. In this paper, the magnetic field analysis of superconducting Nb foil installed in LTMFP has been performed based on the three-dimensional finite element method (3D FEM). Through the simulation analysis, the normal spot region on the superconducting Nb foil is found to be enhanced swiftly over about 20 Hz. The simulated finding agreed with an analytical estimation based on the phenomenon of magnetic diffusion.
Effects of the environmental temperature on the performance of the Stirling cryocooler
Hong, Yong-Ju ; Kim, Hyo-Bong ; Park, Seong-Je ;
Progress in Superconductivity and Cryogenics, volume 11, issue 3, 2009, Pages 65~68
The Stirling cryocoolers have been widely used for the cooling of the infrared detector(InSb, HgCdTe, and etc,) and HTS(High Temperature Superconductor) to the cryogenic temperature. The monobloc Stirling cryocoolers with the rotary compressor are applicable to the cooling device for the compact mobile thermal imaging system, because the cryocoolers have the compact structure and light weight. The typical performance factors of the Stirling cryocooler are the cool-down time, cooling capacity at the desired temperature (80 K), the electric input power and COP. The above performance factors depend on the operating conditions such as the charging pressure of the helium gas, the thermal environment and etc.. In this study, the effects of the thermal environment (temperature of 241, 293, and 333 K) on the performance of the cryocooler were investigated by experiments. The results show the effects of the temperature of the thermal environment on the cooling capacity and input power.