• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.10
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• pp.14-20
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• 2009

It is very important for power stability to suppress the excessive fault current happened frequently in the real power grid The superconducting fault current limiter (SFCL) is one of the most effective ways to reduce the fault current among the facilities developed so far. In this paper, we have investigated the operating characteristics of the power grid with the SFCL according to three types such as the single, double and triple line-to-ground faults. In addition, we analyzed the consumption power of the superconducting units based on the working data of the SFCL. We confirmed that the fault current could be limited lower than its peak value to 85 percentage in initial fault condition and to 85 percentage after one cycle in the matrix-type SFCL. The consumption powers of the superconducting units were almost equal by reduction of the difference of the critical current between superconducting units element.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2004.11a
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• pp.297-299
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• 2004

In multi-ground distribution system, overhead ground wire and neutral wire are parallel connected to offer the electrical power energy and protect damage of lightning strokes. Therefore a case where the two wires become single wire, the power company can get the benefit such as installation cost saving and line fault protection by simplify of distribution line. In this paper we describe the result of impulse test in both system ; one is the present power system the other is unified power system parallel connected overhead ground wire and neutral wire. As a result of this impulse test, the present power system get lower impulse voltage than the unified power system.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.7
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• pp.9-19
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• 2010

Fuel cell (FC) distributed generation (DG) is gradually becoming more attractive to mainstream electricity users as capacity improves and costs decrease. New technologies including inverters are becoming available to provide a uniform standard interconnection of DGs with an electric power system. Some of the operating conflicts and the effect of DG on power quality are addressed and investigated through simulations on a real distribution network with an FC power plant. The results of these simulations have proved load tracking capability following the real and reactive power change of the load and have shown the flow of overcurrent from an FC power plant during the ground fault of a distribution line.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.10
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• pp.1418-1425
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• 2015

In this paper, an filtering method of FI(Fault Indication) information generated by FRTU(Feeder Remote Terminal Unit)s is proposed for the present DAS(Distribution Automation System). In order to find fault area, correct FI information should be generated. But when a single line-to-ground fault occurs, FI information is generated in downside of the fault in some circumstance because existing FI algorithm considers only magnitude. These wrong FI information can be removed by changing existing algorithm. An improved algorithm considers both the direction of zero-sequence current and the phase of three-phase current&voltage. But many FRTUs are distributed in DAS and Changing the algorithm all of FRTU will spend a lot of time and cost. On the other hand, an filtering algorithm proposed in this paper can substitute for it. The filtering algorithm also considers both the direction of zero-sequence current and the phase of three-phase current&voltage. In case study, the proposed method has been shown the reasonability in filtering the fault indication information.

• Proceedings of the KIEE Conference
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• 2003.07a
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• pp.494-496
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• 2003

This paper analyses the operation characteristic of distance relay when the single line to ground occurs in underground power cable systems that reduction device of sheath circulating current is installed. To apply that reduction device to actual system, the change of line impedance calculated at relay point is also analysed by the connection type of SVLs and fault location, fault inception angle with the installation of reduction device of reactor or not.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.384-385
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• 2007

The fault current through the earth originated from a power line ground fault might cause arcing through the soil to an adjacent pipeline, which might bring about not only a catastrophic accident such as gas explosion and oil leakage but also a hazard to the safety of workers responsible for the maintenance and repair of the pipeline. In this paper we experimented on the soil breakdown test using the fixture and outlined the standards for the separation distance of a buried pipeline adjacent to the power line tower.

• Journal of Advanced Marine Engineering and Technology
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• v.35 no.8
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• pp.1111-1116
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• 2011

Power distribution systems onboard vessels are typically configured without any live line connected to hulls for earthing purpose, where the line to hull voltages are affected and deformed depending on the impedances consisting of insulation resistances and distributed capacitances between power lines and hull. An insulation fault at power lines causes the line to hull voltages to increase to a higher level which brings more possibilities to electric shock and deterioration of insulation material. This study focuses on how to configure a module which enables to continuously monitor the voltages between power line and hull based on the vector diagram by analyzing the neutral point of 3 phase voltages and the algorithm for plotting method on the PC monitors.

• Proceedings of the KIEE Conference
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• 1998.07a
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• pp.346-348
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• 1998

The stability of Power system installed Hi-Tc Superconducting Fault Current Limiter(SFCL) is analyzed as a process of developing SFCL. In interpretation, simple mimic system(only one motor) is assumed and then the circuit with SFCL in system is solved. In case the SFCL is installed in Power system, it protected synchronization more effectively both in symmetrical 3-phase fault and single phase line to ground fault.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.355-356
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• 2009

In this paper, we investigated the fault current limiting characteristics according to the increase of voltage in the separates three-phase flux-lock type high-Tc superconducting fault current limiter using YBCO CC. The separated three-phase flux-lock type SFCL consists of single-phase flux-phase type SFCL in each phase. Superconductor was using the YBCO CC. To analyze the current limiting characteristics of a three-phase flux-lock type SFCL, the short circuit experiments were carded out fault such as the triple line-to-ground fault. The experimental result shows that fault current limiting characteristics was improved on the high voltage level.

• Proceedings of the KSR Conference
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• 2005.11a
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• pp.699-704
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• 2005

In the station of the railway and the subway various illumination equipment and a general power equipment for a passenger convenience, the signal equipment and the communication equipment which is necessary to the train operation provided. At the all of like this equipment from the electric room which is established in each station by changing from high voltage to low voltage and it supplies from the illumination transformer, the power transformer and the signal transformer. If it supplies to the equipment from the high voltage to the low voltage, it must be established to contact protection device in between the high voltage coil and the low voltage coil. Also it must do the grounding faulting device at the low voltage lines, the earthing devices at apparatus for the protection of an electric shock and an electric fire by the electric relation law. Compared the related regulations between the facilities which require protective functions such as grounding fault or earthing in public utilities like subway stations, and the facilities which do not require line earthing or protective functions such as electricity supplied for signalling the train. Also, will describe a countermeasure for the accident from a grounding fault.