• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2010년도 춘계학술대회 논문집
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• pp.8-8
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• 2010

In this paper, the limiting characteristics of the fault current in a power system with a superconducting fault current limiter(SFCL) applied into neutral line of main transformer in a distribution power line were analyzed. The SFCL applied into the neutral line of main transformer power system can limit the unsymmetrical fault current from the single-line ground fault or the double-line ground fault. In addition, it could be decreased a number of SFCL and a load. This method could be expected to reduction of a power loss in the neutral line, because of a neutral line current is zero in ordinary times.

• 한국전기전자재료학회논문지
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• 제23권2호
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• pp.148-152
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• 2010

The superconducting fault current limiter (SFCL) applied into the neural line of a power system, which can limit the unsymmetrical fault current from the single-line ground fault or the double-line ground fault, was reported to be the effective application location of the SFCL in a power system. However, the limiting operation for the symmetrical fault current like the triple line-ground fault is not effective because of properties of the balanced three-phase system. In this paper, the limiting method of the symmetrical fault current in a power system with a SFCL applied into neutral line was suggested. Through the short-circuit experiments of the three-phase fault types for the suggested method, the fault current limiting and recovery characteristics of the SFCL in the neutral line were analyzed and the effectiveness of the suggested method was described.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2006년도 전력전자학술대회 논문집
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• pp.492-494
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• 2006

Neutral line current is analyzed by the neutral line CF in nonlinear load balanced and unbalanced conditions. The worst nonlinear load condition is nonlinear balanced load condition, and It is below CFNL=1.194 that a neutral line current could not excess the rated value

• 전기학회논문지
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• 제56권3호
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• pp.465-471
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• 2007

The one step type pole and two step type pole are used in KEPCO's distribution system. The neutral current increases in three-phase four-wire distribution system due to unbalanced load. Usually, power line and communication line are installed at contiguity by effect of topography in Korea. To this end, the damages such as electrostatic induction, electromagnetic induction and harmonic induction generated by induced voltage and current are occured in power line and communication line. This paper calculates the neutral current in KEPCO's distribution system using EMTP by composing various simulated conditions. Also, these results are verified by vector analysis.

• 한국초전도ㆍ저온공학회논문지
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• 제15권4호
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• pp.34-38
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• 2013

According to the increase of electric consumption nowadays, power system becomes complicated. Due to this, the size of single line-to-ground fault from power system also increases to have many problems. In order to resolve these problems effectively, an Superconducting Fault Current Limiter(SFCL) was proposed and continuous study has been done. In this paper, an SFCL was combined to the neutral line of a transformer. An superconductivity has the characteristics of zero resistance below critical temperature. because of this, SFCL has nearly zero resistance. so we connecting SFCL to neutral line will not only have any loss in the normal operation but also have the less burden of electric power because of only limiting the initial fault current. We analyzed the characteristics of current, voltage according to the changes of turn ratio of 3 phase system in case of combinations of an SFCL to the neutral line. It was confirmed that the limiting rate of initial fault current by the increase of turn ratio was reduced.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.1459-1467
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• 2011

본 논문은 낙뢰 Surge 방호를 위하여 독립접지를 공통접지로 개선하는 효율적인 방법을 제안하였다. 낙뢰 Surge 방호를 위해서는 등전위 이론에 근거하는 공통접지방식이 적합하고, 중성선이 있는 전원계통에서는 공통접지방식을 사용하는 것이 국제적으로 통용되는 기술규격이다. 따라서 낙뢰 Surge에 취약한 문제점을 갖고 있는 기존의 중성선이 없는 전원계통과 독립접지방식을 중성선이 있는 전원계통과 공통접지방식으로 개선을 하고, 정전압소자를 이용하여 낙뢰 Surge를 방호하는 효율적인 등전위 시스템 구축 방법을 제안한다.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2013년도 추계학술대회
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• pp.215-218
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• 2013

본 논문은 낙뢰 Surge 방호를 위하여 독립접지를 공통접지로 개선하는 효율적인 방법을 제안하였다. 낙뢰 Surge 방호를 위해서는 등전위 이론에 근거하는 공통접지방식이 적합하고, 중성선이 있는 전원계통에서는 공통접지방식을 사용하는 것이 국제적으로 통용되는 기술규격이다. 따라서 낙뢰 Surge에 취약한 문제점을 갖고 있는 기존의 중성선이 없는 전원계통의 독립접지방식을 중성선이 있는 전원계통의 공통접지방식으로 개선을 하고, 정전압소자를 이용하여 낙뢰 Surge를 방호하는 효율적인 등전위 시스템 구축 방법을 제안한다.

• 전기학회논문지
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• 제58권11호
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• pp.2089-2094
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• 2009

The fault current has increased due to growth of distributed generations for the large power demand in power distribution system. To solve some problem such as excess of the circuit breaker's cut-off ratings, the superconducting fault current limiter(SFCL) has been progressed. However, the operational characteristics of the relay is changed by SFCL. Therefore, the proper impedance for the SFCL should be selected to keep protective coordination with the SFCL when SFCL is introduced on the neutral line of main transformer in distribution system. In this paper, the proper normal conducting resistance was suggested to solve the problem in case of the protection coordination with SFCL.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.155-157
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• 2005

This paper analyzed the adoption possibility of a low cost single phase active power filter as the neutral current reduction device in three-phase four-wire power system with the balanced or/and unbalnaced nonlinear load conditions. Proposed system can make neutral line current to within rated vale without the phase current THD change of the installed phase line.

• 조명전기설비학회논문지
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• 제27권7호
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• pp.37-44
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• 2013

Phase to ground faults are possibly one of the maximum number of faults in power distribution system. During a ground fault the maximum fault current and neutral to ground voltage will appear at the pole nearest to the fault. Distribution lines are consisted of three phase conductors, an overhead ground wire and a multigrounded neutral line. In this paper phase to neutral faults were staged at the specified concrete pole along the distribution line and measured the ground fault current distribution in the ground fault current, three poles nearest to the fault point, overhead ground wire and neutral line. A simplified equivalent circuit model for the distribution system under case study calculated by using MATLAB gives results very close to the ground fault current distribution yielded by field tests.