• Progress in Superconductivity and Cryogenics
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• v.19 no.2
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• pp.44-47
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• 2017

In this paper, the current limiting characteristics of the transformer type superconducting fault current limiter (SFCL) with the two coupled secondary windings due to its winding direction were analyzed. To analyze the dependence of transient fault current limiting characteristics on the winding direction of the additional secondary winding, the fault current limiting tests of the SFCL with an additional secondary winding, wound as subtractive polarity winding and additive polarity winding, were carried out. The time interval of quench occurrence between two superconducting elements comprising the transformer type SFCL with the additional secondary winding was confirmed to be affected by the winding direction of the additional secondary winding. In case of the subtractive polarity winding of the additional secondary winding, the time interval of the quench occurrence in two superconducting elements was shorter than the case of the additive polarity winding.

• Transactions on Electrical and Electronic Materials
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• v.18 no.1
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• pp.42-45
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• 2017

In this paper, a transformer type SFCL (superconducting fault current limiter) using an additional magnetically coupled circuit was suggested. Its transient fault current limiting characteristics, due to the winding direction of additional coupled circuit, were analyzed through fault current limiting tests. The suggested transformer type SFCL was composed of the primary winding, and one secondary winding wound on the same iron core together with an additional magnetically coupled circuit. That circuit consists of the other secondary winding together with the other SC (superconducting) element connected in parallel with its other secondary winding. As one of the effective design parameters to affect the transient fault current of the SFCL, the fault current limiting tests of the suggested SFCL were carried out considering the winding direction of its additional coupled circuit. It was confirmed that, through the analysis on the fault current tests of the SFCL, the quench sequence of two SC elements comprising the suggested SFCL could be adjusted by the winding direction of the additional coupled circuit.

• 한국초전도학회:학술대회논문집
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• v.13
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• pp.82-82
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• 2003

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.1
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• pp.113-117
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• 2008

We investigated the current limiting and the recovery characteristics of a flux-lock type superconducting fault current limiter(SFCL) according to the winding directions. The flux-lock type SFCL consists of two coils. The primary coil was wound in parallel to the secondary coil through an Iron core, and the secondary coil was connected with the superconducting element in series. We have changed the winding direction of coils to compare the resistive type SFCL with the flux-lock type SFCL. The current limiting and the recovery characteristics were dependent on the winding direction. The quenching time in the additive polarity winding was faster than that of the subtractive polarity winding or the resistivity type. A consumed energy in a superconducting element was represented as $W= VIt=I^2Rt$. We found that there was a difference in the consumed energies in accordance with winding types because of differences in voltages imposed on a superconducting element in accordance with a winding direction.

• 전기의세계
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• v.22 no.3
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• pp.13-24
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• 1973

In this report, as a method to solve the problems on impulse insulation coordination in ribbon core transformer owing to it's BIL stepping up, new design to alter winding distribution of multiple-layer concentric winding to Convex type winding is proposed. The main focus of this method is to settle the weakness of axial direction insulation strength and as a result of theoretical analysis through experiment of model transformers, the following conclusions are obtained; (a) As the electric loadings in a design which increases by strengthenning axial direction insulation endurance in presently avarilable transformers owing to it's BIL stepping up can be restricted in Convex type winding, reasonable design will be suited to the transformer with higher BIL. (b) Convex type winding is a very improved insulation design in respect of insulation coordination because it has shield plate effect to even impulse oscillation. (c) There is a disadvantage to cause leakage flux to increase in Convex type winding, however, the constancy of electric loadings in a design in spite of BIL stepping up restricts the increase of leakage flux to some extent.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.9
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• pp.812-815
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• 2007

To apply the superconducting fault current limiter(SFCL) into a power system, the analysis for its recovery characteristics as well as the consideration for its cooperation with other protecting machine such as a circuit breaker is required. The recovery characteristics of the flux-lock type SFCL like its current limiting characteristics are dependent on the winding direction of two coils. In this paper, the experiments of the current limiting and the recovery characteristics of the flux-lock type SFCL with YBCO thin film were performed. From the analysis on the experimental results due to the winding direction of two coils, the limited fault current in case of the additive polarity winding was observed to be lower than that for the case of the subtractive polarity winding. In addition, the recovery time was found to be faster in case of the additive polarity winding compared to the subtractive polarity winding.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.8
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• pp.694-697
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• 2009

The separated three-phase flux-coupling type superconducting fault current limiter(SFCL) is composed of a series transformer and superconducting unit of the YBCO coated conductor. The primary and secondary coils in the transformer were wound in series each other through an iron core and the YBCO coated conductor was connected with secondary coil in parallel. In this paper, we investigated the current limiting characteristics through winding number of coil 2 and winding direction in the flux-coupling type SFCL. Through the analysis, it was shown that additive polarity condition and lower winding number of coil 2 have advantaged from the point of view of fault current limiting and burned of YBCO coated conductor.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2003.02a
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• pp.58-61
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• 2003

A typical HTS power transmission cable has multi-layer conductor structure to increase the current capacity. The current distribution among the conductor tapes is controlled mainly by pitches and winding directions of the layers, because the inductance of the layer is determined by the pitch and the winding direction. However, usually the current is not evenly distributed among the layers. This paper describes a method to make the current distribution more uniform and hence reduce the AC loss. If we choose a good combination we can find the optimal pitches and make an even current distribution. We studied the effect of the winding direction on a 2-layer cable by a statistical way. Calculation results and discussions will be presented.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.2
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• pp.159-163
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• 2010

The superconducting fault current limiter (SFCL) plays a role in compensating the voltage sag of the sound feeder adjacent to the fault feeder as well as the fault current limiting operation of the fault feeder. Especially, the SFCL using magnetic coupling of two coils with parallel connection has different voltage sag compensating and current limiting characteristics due to the winding direction and the inductance ratio of two coils. In this paper, the current limiting and the voltage sag compensating characteristics of a SFCL using magnetic coupling of parallel connected two coils were analyzed. Through the analysis on the experimental results considering the winding direction of two coils, the SFCL designed with the additive polarity winding was shown to have the higher limited fault current than the SFCL designed with the subtractive polarity winding. In addition, it could be confirmed that the higher fault current limitation of the SFCL could be contributed to the higher load voltage sag compensation.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.25 no.12
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• pp.1000-1003
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• 2012

The superconducting fault current limiter (SFCL) can quickly limit the fault current shortly after the short circuit occurs and recover the superconducting state after the fault removes and plays a role in compensating the voltage sag of the sound feeder adjacent to the fault feeder as well as the fault current limiting operation of the fault feeder. Especially, the flux-lock type SFCL with an isolated transformer, which consists of two parallel connected coils on an iron core and the isolated transformer connected in series with one of two coils, has different voltage sag compensating and current limiting characteristics due to the winding direction and the inductance ratio of two coils. The current limiting and the voltage sag compensating characteristics of a SFCL using a transformer winding were analyzed. Through the analysis on the short-circuit tests results considering the winding direction of two coils, the SFCL designed with the additive polarity winding has shown the higher limited fault current than the SFCL designed with the subtractive polarity winding. It could be confirmed that the higher fault current limitation of the SFCL could be contributed to the higher load voltage sag compensation.