• 한국초전도ㆍ저온공학회논문지
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• 제7권4호
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• pp.28-31
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• 2005

To verify the feasibility of bifilar winding type superconducting fault current limiter (SFCL) using BSCCO tape, two types of magnets were fabricated and tested by short-circuit in this research. Even if the FCL using high Tc superconducting (HTS) tape has zero resistance in normal state, it needs to be wound as a bifilar winding for zero inductance. Solenoid type and pancake type bifilar winding magnets are designed and fabricated with the same length of BSCCO tape. The test system consists of AC power supply, transformer, fault switch, load and bifilar winding magnet. The applied AC voltages during fault duration, 0.1s, were from 0.5V to 20V. The test results without bifilar winding magnet were compared with those with each type magnets. The test results include voltage against magnet, transport current and generated resistance curve. Thermal stability, the recovery time, was studied from the results of two type magnets. The pancake type was the most effective to limit fault current but the solenoid type was thermally the most stable. From this research, short-circuit characteristics of the two types were obtained.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.83-85
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• 2004

We proposed the bridge type fault current limiter(FCL) using switching operation of high-Tc superconducting(HTSC) thin film. The proposed bridge type FCL consists of HTSC thin film, a diode bridge and a dc reactor. The controller for the operation of an interrupter is required in the conventional bridge type FCL to prevent the continuous increase of fault current after a fault happens. On the other hand, the proposed bridge type FCL can limit the fault current without the interrupter and the controller for its operation by the resistance generated when the gradually increased fault current exceeds HTSC thin film's critical current. We calculated the time when the gradually increased fault current started to be limited by the resistance generated in HTSC thin film after a fault happened and confirmed that it could be dependent on the amplitude of source voltage. The experimental results well agreed with the calculated ones from simulation.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 춘계학술대회 논문집 초전도 자성체 연구회
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• pp.65-68
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• 2003

Interconnected power system operation has given rise to the problem of increased fault levels and leads to over stressing of all the components. Use have been made of recently developed high Tc superconductor in devising a superconducting fault current limiter (SFCL) that promises optimum performance in terms of capital cost, size, auto sensing, operational losses, response time and reliability. Recently, research about the application of the SFCL is actively progressing in Korea. To be applied for SFCL practically, the electrical insulation design of SFCL must be developed. Therefore, this paper presents the result of an investigation of the dielectric characteristics of turn-to-turn insulation for SFCL in liquid nitrogen. The dielectric characteristics of turn-to-turn insulation models of SFCL were investigated. We obtained following results. The breakdown voltages increased as the spacer thickness and length increased. And the breakdown voltages of turn-to-turn model without spacer were higher than the breakdown voltages of turn-to-turn model with spacer under impulse as well as AC voltages. The information gathered in this test series should be helpful in the design of liquid nitrogen filled SFCL.

• Progress in Superconductivity
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• 제7권2호
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• pp.179-183
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• 2006

As a material for SFCL(Superconducting Fault Current Limiter), BSCCO tube with metal stabilizer is a promising candidate, assuring the stability and large power capacity, For the application, the proper soldering technique, which overcome the difficulties of the joining between BSCCO and metal stabilizer, is required. In this study, after soldering In-Bi solder and In-Sn solder with BSCCO superconductor, welding properties between BSCCO and solders were investigated. Because ceramic materials is difficult to weld, Ag electro-plating on BSCCO 2212 is used for intermetallic layer. To find out the best welding condition for superconductor, soldering is tested in the maximum temperature from $155^{\circ}C\;to\;165^{\circ}C$ in the reflow oven. By investigating the composition and thickness of IMC (lntermetallic Compound) created in the reaction of Ag with solder, we analyzed the welding properties of High-Tc superconductor from a micro point of view.