• 한국초전도학회:학술대회논문집
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• v.9
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• pp.373-377
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• 1999

HTS magnet operated at 20${\sim}$40 K was fabricated using three pieces of 100 m Bi-2223 high temperature superconductors fabricated by powder-in-tube process. It was composed of 6 double pancakes with 75 ID. and 113 OD. connected by lab splice. Coil I$_c$ of each DP.(double pancake) obtained for a 140 turn, fabricated using react and wind procedure was 6${\sim}$8 A at 77 K, self field. The maximum field was measured 0.06 T at lop = 5 A, 77 K. The joint resistance due to lap splice of HTS tapes affect badly to operate HTS magnet with persistent current mode, total effective magnet resistance included lap splice was 55 ${\mu}$ ${\omega}$ at 77 K.

• Proceedings of the KIEE Conference
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• 2002.07b
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• pp.831-834
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• 2002

Several companies in the world are marketing superconducting wires, films and bulks. High-Tc superconducting systems using these superconductors are begun to commercialize. For the successful realization or commercialization of superconducting system used Bi-2223 wires, the database on the degradation of critical current is essentially needed. In this paper, the electrical degradation of a Bi-2223 wires is measured. The electrical degradation rate was measured after the certain time of continuous current transportation. Specimens have the length of 190cm and double-pancakes coil have the length of 10m were tested. Tested Bi-2223 wires are commercialized product has 115A of Ic. When the transportation current was 95% of Ie, the degradation of Ic was appeared after 5 hours of transportation time. When the transferred current is enough larger than Ic, Bi-2223 double pancake is damaged seriously.

• Proceedings of the KIEE Conference
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• 2003.07b
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• pp.723-725
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• 2003

The result of design and Partial fabrication of a 1 MVA single phase high temperature superconducting(HTS) transformer for power distributions are presented in this paper. The HTS windings are wound as double pancake windings which have advantages of uniform distribution of high voltage over the windings. the rated primary and secondary voltages are 22.9 kV and 6.6 kV respectively. Four HTS tapes are wound in parallel for secondary windings considering the rated currents of the transformer. The HTS windings will be cooled down to 65 K by natural convection of sub-cooled liquid nitrogen using a single-staged GM-cryocooler in order to make the stability of the HTS windings better. The iron core is designed as shell type and isolated from the liquid nitrogen by an FRP cryostat which have a room temperature bore. After the complete fabrication of the total HTS transformer system, performance test of the transformer will be carried out.

• Proceedings of the KIEE Conference
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• 2002.07b
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• pp.932-934
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• 2002

In this paper, we proposed a method to shield perpendicular magnetic fields in high Tc superconductor(HTS) tape of a shell-type HTS transformer with double pancake windings. A diamagnetism of characteristics of superconductor is used to shield magnetic field. For a shielding experiment, a proper shielding model is chosen, and several kinds of HTS are used such as a monofilament HTS tape, two kinds of multifilament HTS tapes and YBCO film disk. The effect of shielding for the perpendicular magnetic field is measured with HTSs for shielding and their utility for shielding is proved.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2002.02a
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• pp.233-236
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• 2002

A conceptual design of single phase high Tc superconducting (HTS) 1MVA transformer was presented in this paper. The rated voltages of each sides of the transformer are 22.9kV /6.6kV respectively. Double pancake windings of BSCCO-2223 HTS tape and the room temperature shell type core are adopted. The HTS tapes of windings are going to be cooled down to 65K by sub-cooled liquid nitrogen. A cryostat made of nonmagnetic and nonconducting material with a bore is going to be used in order to locate the core out of the cryostat. This conceptual design will be modified and a fabrication of the machine is going to be based on the presented design in this paper.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2002.02a
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• pp.225-228
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• 2002

This paper presents electro-magnetic analysis of IMVA High T$_{c}$ Superconductivity transformer designed conceptually. A winding type of this transformer is a double pancake type, and a transformer of solenoidal winding type is selected to be compared with it. Both transformers have the same sizes and the same turns. Results of the analysis are compared with results of solenoidal winding. And, in this paper, leakage inductances are calculated too. There are a lot of methods to calculate inductance including Neumann Formula, Energy conservation and so on. In this paper, Energy conservation method are selected.d.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07a
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• pp.420-423
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• 2002

In this paper the characteristics of surface flashover for high temperature superconducting transformer(HTS) was discussed. The transformer, will be developed in the shell type with double pancake coil, isn't developed yet in the world. We conducted experiment of surface flashover that could occur in the windings of the transformer. First, we distinguished the surface flashover with electrode alignment into two type, such as parallel and vertical, and then compared with each characteristics of surface flashover. And the surface flashover with metallic particle was tested, it was also affected by the particle position. .

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.1114-1115
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• 2015

This paper describes the design of toroid-type HTS DC reactor magnet. Target operating current and inductance of the HTS DC reactor are 1,500 A and 400 mH, respectively. The HTS DC reactors were designed through electromagnetic analysis and 3D CAD program. And, we analyze the operating performance of the Double Pancake Coil module for the 1,500 A, 400 mH HTS DC reactor magnet under the liquid nitrogen condition.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2003.02a
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• pp.196-199
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• 2003

Characteristics of a heater-triggered switch has been analyzed through the simulations and experiments. It was for the charging of Bi-2223 double pancake load with 1.7 mH and two heaters were used. The timing of the sequential control and the heating current with two heaters are important factors to generate pumping-current. The thermal analysis of the switch considering the heater input and time was carried out. Based on the analysis just mentioned. heater-triggered switch was fabricated. Characteristic analysis was carried out through two modes having different sequential timing controls. Maximum pumping-current reached 18 A and the pumping rate was 113 mA/s at that time.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2003.02a
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• pp.220-223
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• 2003

High-Tc superconducting(HT S) systems are commercialized by many study on high-Tc superconductor. For the successful commercialization of superconducting systems using Bi-2223 wires, the database on the degradation of critical current is essentially needed. In this paper, critical current variation of Bi-2223 wires according to the transport time was investigated. The degradation rate of critical current was also calculated. Solenoid type specimens have the length of 190cm Bi-2223 wire and double-pancake type specimens have the length of l0m wire were tested. Tested Bi-2223 wires are commercialized products of AMSC (American Superconductor) and Innost. When the transportation current was 95% of critical current, the degradation of critical current was appeared after 5 hours of transport time.