• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 A
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• pp.98-100
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• 1998

This paper presents the fluid characteristics simulation and design guide line of the fluid path inside the rotor, which has an high-Tc superconducting field winding using Ag sheathed BSCCO-2223. The analysis was conducted with an equivalent model of the high-Tc superconducting synchronous motor under transition condition that occurs during the load varying from 250watt to 500watt. The results show that the designed fluid circulation system performs adequately in maintaining the superconducting state in the winding.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 B
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• pp.934-936
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• 2000

This paper presents the design of a double pancake winding type high $T_c$ superconducting power transformer In the design of the transformer. BSCCO-2223 tape was considered as the conductor. Double pan cake winding was adopted in order to easy the construction of the winding and to lessen the leakage reactance of the transformer. Numerical calculation was used to decide the arrangement of the double pan cake winding. Room temperature bore type cryostat has been constructed and its heat loss was estimation.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제49권1호
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• pp.27-31
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• 2000

This paper presents the performance evaluation of an HTS transformer. Numerical calculation by finite element method was used to evaluate the performance. BSCCO-2223 HTS tapes and double pancake winding were adopted in this design. Four double pancake windings were used in total. Among them two windings were connected in series for high voltage winding and two windings are connected in parallel for low voltage winding. Propertied of various type of the winding arrangement were examined. Characteristics of the transformer during the transient which was caused by sudden short were simulated. The current limiting effect, temperature rise and resistance growth of the superconducting winding were shown.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제52권9호
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• pp.442-447
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• 2003

Motors with HTS wires or bulks have been developing recently. Those are large synchronous motor with HTS wires at the field winding in the rotor, hysteresis and reluctance motors with HTS bulk in the rotor. This paper presents the fabrication and test results of an HTS induction motor. Conventional end rings and short bars were replaced with HTS wires in the motor. Stator of the conventional induction motor was used as the stator of the HTS motor. Rated capacity and rpm at full rotor of the conventional motor were 0.75[kW] and 1,710[rpm]. Two, HTS wires are used in parallel to make the end rings and bars. The critical current of the BSCCO-2223 HTS wire which was used in the bars and end rings were 115[A]. Electrodynamometer was coupled directly to the shaft of the rotor with HTS wires.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 추계학술대회 논문집 학회본부 B
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• pp.321-323
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• 2000

This paper describes the construction and test results of a 10kVA single phase HTS transformer. Double pancake windings with BSCCO-2223 HTS tape and GFRP cryostat with room temperature bore are used in the transformer. Two double pancake windings are connected in series to provide 184 turns and two double pancake windings are connected in parallel to conduct the secondary current of 45.4A. Coefficients of the constructed transformer are obtained using the fundamental tests of the transformer. According to the test results, larger leakage reactance than expected is observed due to the bulky core which surrounded the cryostat.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.24-26
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• 2001

The high temperature super-conductor transformer gains interests from the industries. This paper described construction and test results of a 10kVA HTS transformer. Three phase transformer with double pancake windings were constructed. BSCCO-2223 wire, silicon sheet steel core and FRP cryostats were used in that transformer After the test of basic properties of the 3 phase HTS transformer using no load test, short ciucuit test and full load test, continuous operation of 100 hours with pure resistive load has been carried out. Test proved over-load capability and reliability of the HTS transformer.

• 한국초전도ㆍ저온공학회논문지
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• 제5권1호
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• pp.48-51
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• 2003

A 1 MVA transformer with BSCCO-2223 high Tc superconducting (HTS) tapes was designed. The rated voltages of each sides of the transformer are 22.0 kV and 6.6 kV respectively. Double pancake HTS windings, which have advantages of insulations and distribution of high voltage, were adopted. Four HTS tapes were wound in parallel fer the windings of low voltage side. Each winding was composed of several double pancake windings made of four parallel conductors were transposed in order to distribute the currents equally in each conductor. A core of the transformer was designed as a shell type core made of laminated silicon steel plate and the core is separated with the windings by a cryostat with a room temperature bore. The operating temperature of HTS windings will be 65K with liquid nitrogen, and a cooling system using a cryocooler was proposed and designed conceptually. This HTS transformer is going to be manufactured in near future based on the design parameters presented in this paper.

• 한국초전도학회:학술대회논문집
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• 한국초전도학회 1999년도 High Temperature Superconductivity Vol.IX
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• pp.275-279
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• 1999

It is well known that HTS current lead minimizes helium vaporizations much less than the conventional current lead. To estimate the helium vaporizations in the design step, we need to compute the exact the temperature distributions on the lead. Unfortunately, the thermal parameters such as thermal conductivity and electrical resistivity depend strongly on the temperature. That is, heat equation itself has a nonlinear characteristics in the current lead. Furthermore, the uncertainties of helium vaporizations make it more difficult to estimate the boundary values. So far, numerical analyses using constant parameters in finite intervals have been used. In this paper, we calculate the temperature distribution in the current lead in considerations of temperature dependent parameters. The results showed self consistencies.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제52권3호
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• pp.101-106
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• 2003

The high temperature superconductor transformers gain interests from the industries. This paper described construction and test results of 10㎸A HTS transformer Three phase transformer with double pancake windings were constructed. To reduce the leakage magnetic field, secondary coil were placed between the two primary coils. BSCCO-2223 wire. silicon sheet steel core and FRP cryostats were used to construct the transformer. Three coils were stacked in one cryostat. Two double pancake coils were connected in series for the primary coil and one double pancake coil was used for the secondary coil. Total number of turns of the primary winding and the secondary winding were 112turns and 98urns, respectively, The rated voltages of each winding were 440/220V. The rated currents of each winding were 13.1/26.2A. After the tests of basic properties of the three phase HTS transformer using no-load test, short-circuit test and full-load test, continuous operation of 100 hours with pure resistive load has been carried out. Test results proved over-load capability and reliability of the HTS transformer.

• 한국초전도ㆍ저온공학회논문지
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• 제6권4호
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• pp.37-40
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• 2004

A 1 MV A single phase high temperature superconducting (HTS) transformer was manufactured and tested. The rated voltages of primary and secondary of the HTS transformer are 22.9 kV and 6.6 kV respectively. BSCCO-2223 HTS tape was used for HTS windings of 1 MV A HTS transformer. In order to reduce AC loss generated in the HTS winding, the type of concentric arrangement winding was adopted to a 1 MV A HTS transformer. Single HTS tape for primary windings and 4 parallel HTS tapes for secondary windings were used considering the each rated current of the HTS transformer. A core of HTS transformer was fabricated as a shell type core made of laminated silicon steel plate. And a GFRP cryostat with a room temperature bore was also manufactured. The characteristic tests of 1 MV A HTS transformer were performed such as no load test, short circuit test and several insulation tests at 65 K using sub-cooled liquid nitrogen. From the results of tests, the validity of design of HTS transformer was ascertained.