• Progress in Superconductivity
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• v.5 no.1
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• pp.61-64
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• 2003

In HTS transformer with double pancake windings, the perpendicular component of leakage magnetic flux density ($B_{r}$ ) applied to HTS tapes of double pancake windings of HTS transformer acts as a cause to decrease the critical current in HTS tape. So, in this paper, HTS transformer with reciprocal arrangement winding is designed. And in order to investigate the$ B_{r}$ applied to HTS windings, the 2-D non-linear electromagnetic analysis of HTS transformer is performed by using the OPERA 2D. The maximum $B_{r}$ applied to winding of HTS transformer is 0.112 T and the characteristics of HTS transformer were also obtained. But in this type of winding arrangement, reciprocal arrangement, the generated ac-loss to the HTS windings is very high because of the applied $B_{r}$ to HTS windings. Therefore, in order to reduce the generated ac-loss to the HTS windings, the new design of HTS transformer with concentric winding arrangement is presented in this paper and the 2-D non-linear electromagnetic analysis and the ac-loss for HTS transformer with the concentric winding arrangement is also carried out.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.05e
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• pp.61-64
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• 2003

In the response to an increasing demand for electrical energy, much effort aimed to develop and commercialise HTS power equipments is going on around the world. For the development, it is necessary to establish the dielectric technology in $LN_2$. Hence many types of dielectric tests should be carried out to understand the dielectric phenomena at cryogenic temperature and to gather various dielectric data. Among the many types dielectric tests, the barrier effect were conducted with the simulated electrode after analysing the insulating configuration of the pancake coil type HTS transformer. The influence of a barrier on the dielectric strength was measured according to the size and the position of the barrier. It was shown that the effectiveness, the ratio of the breakdown voltage in presence of barrier to the voltage without barrier, is highest when the barrier is placed at the needle electrode side. And the barrier effect was not depend on the electrode array. The life time to breakdown with decreasing the applied voltage was increased remarkably having wide error band but the shape parameter in Weibull distribution was almost constant.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.30 no.2
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• pp.106-110
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• 2017

This paper compared current limiting characteristics of superconducting fault current limiter (SFCL) using E-I core due to the location of windings. Since E-I core has three legs and two magnetic paths, the current limiting characteristics of SFCL were expected to be affected by the installation location of windings, either center leg or right/left leg. To analyze its characteristics, the electrical equivalent circuit of the SFCL were derived and the electromagnetic analysis for the SFCL with the designed structure were performed. From the short-circuit tests, the hysteresis curve and the voltage-current trajectory of the SFCL due to the installation location of windings were extracted and compared each other. The SFCL with windings in the center leg of E-I core was shown to be larger magnetizing inductance compared to the one with windings in the right or left leg of E-I, which was analyzed from the hysteresis curve. In addition, larger decreased fault current right after the fault occurrence in the SFCL with windings in the center leg of E-I core was confirmed than the SFCL with windings in the right or left leg of E-I.