• Title, Summary, Keyword: Superconducting element

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A Study on Combination Technology of a Transformer and a Superconducting Fault Current Limiter (변압기와 초전도한류기의 결합기술 연구)

  • Choi, Hyo-Sang
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.59 no.3
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    • pp.330-334
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    • 2010
  • We tried to combine a transformer with a superconducting element and investigated the current limiting characteristics. When a superconducting element was connected to third winding of the transformer, the fault current was limited to about 90 % effectively. The fault current and consumption power were able to be controlled by the turn's ratio of secondary and third windings. It gives flexibility of the rating of a transformer in the power grid. As a result, power burden of a superconducting element was reduced by the decrease of turn's ratio in third winding of a transformer. It was because the voltage behavior of a superconducting element was dependent on turn's ratio of a transformer while the current characteristic was independent.

3-D Magnetostatic Finite Element Simulation of a Low-Tc Superconducting Power Supply with Respect to the Excitation Current (여자전류에 따른 저온초전도전원장치의 3차원 정자계 유한요소 시뮬레이션)

  • Bae, Deok-Gwon;Kim, Ho-Min;Lee, Chan-Ju;Yun, Yeong-Su;Lee, Sang-Jin
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.51 no.7
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    • pp.364-369
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    • 2002
  • In this paper, 3-D magnetostatic finite element simulation of a rotux type Low-Tc superconducing (LTS) superconducting power supply, finite element method, cryogenic system, superconducting foil by generated magnetic flux from the rotating pole. The magnetic flux density on the superconducting foil caused by two exciters is therefore sufficiently greater than its critical magnetic flux density and it is an essential point in LTS power supply design. To establish the sufficient flux path of this machine, ferromagnetic materials is used in this power supply. When ferromagnetic materials is used at extremely low temperature, its characteristic of magnetization differs to that at room temperature. For this reason, special consideration is needed in the magnetic analysis of cryogenic systems. When the excitation current is 10A, the normal spot appears on superconducting foil. The results of this analysis are calculated and compared with the experimental results. The linkage flux due to the excitation current of 10, 20, 30, 40 and 50A are respectively $1.30{\times}10-4$, $2.67{\times}10-4$, $5.08{\times}10-4$ and $6.15{\times}10-4Wb$.

Transient Characteristic Analysis of Quick Response Extraction Type Superconducting Generator by Finite Element Method (유한 요소법에 의한 속응 여자 초전도 발전기의 과도 특성 해석)

  • Kim, Jeong-Cheol;Hahn, Sung-Chin
    • Progress in Superconductivity and Cryogenics
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    • v.2 no.2
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    • pp.26-31
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    • 2000
  • This paper deals with finite element analysis of 2GVA superconducting generator which has slitted electrothermal shield in d-axis (SES). Three phase fault is considered torque of the S.C.G. Using the result, generator parameters are calculated by F.E.M. The results are compared with superconducting generator having conventional electrothermal shield (CES). The result shows that quick response excitation could be applied to superconducting generator with slitted electrothermal shield.

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Operational Characteristics of the FCL Using the Mechanical Contact in the Power System (기계적 접점을 이용한 FCL의 동작 특성)

  • Jung, Byung-Ik;Choi, Hyo-Sang
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.65 no.5
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    • pp.878-882
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    • 2016
  • These days, SFCLs are being developed in order to limit fault current. However, the superconducting elements that limit the fault current have such problems as capacity increase and require auxiliary devices including cooling device. If devices that comprise the current power network can withstand fault current for at least one cycle, it is possible to limit the fault current with current limiting elements by bypassing it on the fault line. In this study, the fault current limiter was configured with current transformer, vacuum interrupter, and current limiting element. Through the experience, it was confirmed that the fault current was limited within one cycle. The superconducting element, as a current limiting element, limited the fault current by 80 % within one cycle from fault occurrence, and the passive element limited it more than 95 %. Also, through the comparison between resistance curve and power consumption curve, it was confirmed that the current limiting element using a passive element was more stable than the superconducting element that required capacity increase and other auxiliary devices. It was considered that the FCL proposed in this study could limit fault current stably within one cycle from fault occurrence by using the existing power technologies such as fault current detection and solenoid valve operating circuit.

Study on Transient Current Limiting Operational Characteristics of Transformer Type SFCL with Two Peak Current Limiting Function (두 번의 피크전류제한 기능을 갖는 변압기형 초전도한류기의 과도전류제한 동작 특성 연구)

  • Han, Tae-Hee;Lim, Sung-Hun
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.29 no.8
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    • pp.499-504
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    • 2016
  • In this paper, we analyzed the operational characteristics of the fault current limiting according to the amplitude of the fault current for the transformer type superconducting fault current limiter (SFCL). If the fault current happens, the superconducting element connected to the secondary coil is occurred quench and the fault current is limited. When the larger fault current occurs, the superconducting element connected to the third coil is occurred additional quench and the peak fault current is limited. We found that the fault current can be more effectively controlled through the analysis of the fault current limiting and the short-circuit tests.

Analysis of Magnetic Field Application Effect on Fault Current Limiting Characteristics of a Flux-lock Type SFCL

  • Lim, Sung-Hun
    • Transactions on Electrical and Electronic Materials
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    • v.9 no.6
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    • pp.255-259
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    • 2008
  • The magnetic field application effect on resistance of a high-$T_c$ superconducting (HTSC) element comprising a flux-lock type superconducting fault current limiter (SFCL) was investigated. The YBCO thin film, which was etched into a meander line using a lithography, was used as a current limiting element of the flux-lock type SFCL. To increase the magnetic field applied into HTSC element, the capacitor was connected in series with a solenoid-type magnetic field coil installed in the third winding of the flux-lock type SFCL. There was no magnetic field application effect on the resistance of HTSC element despite the application of larger magnetic field into the HTSC element when a fault happened. The resistance of HTSC element, on the contrary, started to decrease at the point of four periods from a fault instant although the amplitude of the applied magnetic field increased.

Analysis on Fault Current limiting and Recovery Characteristics of Flux-Lock Type Superconducting Fault Current Limiter According to Increase of Applied Voltage (전압증가에 따른 자속구속형 초전도 한류기의 전류제한 및 회복특성 분석)

  • Oh, Kum-Gon;Han, Tae-Hee;Cho, Yong-Sun;Cho, Hyo-Sang;Choi, Myoung-Ho;Han, Young-Hee;Sung, Tae-Hyun
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.21 no.8
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    • pp.107-112
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    • 2007
  • The flux-lock type SFCL consists of transformer with primary and secondary windings connected to a superconducting element in serial. It can be divided into the subtractive and the additive polarity windings according to the winding direction. It could change the fault current limiting characteristics according to the inductance ratio between the coil 1 and coil 2. We investigated the voltage-current characteristics of the flux-lock type SFCL according to the increment of applied voltage. When the applied voltage of the SFCL with the subtractive and the additive polarity windings was increased a initial limiting current ($I_{ini}$) and the quench time of the superconducting element were increased. The recovery time of the superconducting element was increased by increment of applied voltage. Therefore, it was confirmed that recovery characteristics in the flux-lock type SFCL were largely dependent on the consumed energy of a superconducting element because of increment of the consumption power into the superconducting element.

Operation characteristics of a fault current limiter by high speed interrupter and a superconducting element

  • Im, I.G.;Jung, I.S.;Choi, H.S.
    • Progress in Superconductivity and Cryogenics
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    • v.16 no.3
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    • pp.10-14
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    • 2014
  • Due to continuous increase of electric power consumption, couple of resolutions for improving accuracy in power system like line separation are being studied. The increase of the power demand can cause problems such as supply difficulties of the electricity and broadband outages, failure, etc. When a fault occurs in the power system, a fault current also increases. Fault current creates problems like reduction of lifespan and failure on the power system. In order to resolve these problems, the reduction of initial fault current using the characteristics of superconducting element was applied to fault current limiter. We applied the system to high speed fault current limiter. We found that the superconducting element effectively reduced initial fault current and the fault current was limited by changing operation of high speed interrupter.

Analysis on Power Consumption and Accumulated Energy According to Resistance of Superconducting Element and Winding Current of Transformer Type SFCL Using Double Quench (이중 ?치를 이용한 변압기형 초전도 한류기의 권선전류와 초전도소자 저항에 따른 전력소모 및 누적에너지 분석)

  • Han, Tae-Hee;Lim, Sung-Hun
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.29 no.10
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    • pp.630-634
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    • 2016
  • In this paper, we analyzed the power consumption and the accumulated energy in HTSC (high-TC superconducting elements) according to the resistance of HTSC element and the winding current of transformer type SFCL (superconducting fault current limiter) using double quench. For the analysis, two different inductances of the one secondary winding among two secondary windings comprising the transformer type SFCL were selected and the short-circuit tests were carried out. The consumed power and the accumulated energy in HTSC element connected into the secondary winding with larger inductance were analyzed to be larger compared to the one connected into the secondary winding with lower inductance.

Preliminary Design of Current Lead for 21T Superconducting Magnet (21T 초전도자석을 위한 전류도입선 예비설계)

  • Choi, Y.S.;Kim, D.L.;Yang, H.S.;Lee, B.S.;Painter, Thomas A.
    • Progress in Superconductivity and Cryogenics
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    • v.10 no.3
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    • pp.43-46
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    • 2008
  • Design of current lead for 21T superconducting magnets is presented. The current lead is composed of a normal metal element, conducting the current from room temperature to intermediate temperature, and an HTS element, conducting the current down to liquid helium temperature. The metal element is disengaged from the HTS element without breaking vacuum after excitation. The optimization of the lead is performed to minimize the thermal heat load when carrying operational current with some margin. In order to confirm the feasibility of our new design, the intermediate joint between a normal metal and HTS element is fabricated and the reliability is tested during engage and disengage performance. The effects of vacuum level and performance cycle on the electrical contact resistance are also investigated.