• Corrosion Science and Technology
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• 제6권2호
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• pp.77-81
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• 2007

Fault current can be discharged from power transmission tower due to lightning or inadvertent contact of crane, etc. Pipelines in proximity to either the source of the ground fault or the substation grounding grid may provide convenient conductive path for the fault current to travel. Inappropriate measures to the neighboring pipelines against the fault current may cause severe damages to the pipes such as coating breakdown, arc burn, puncture, loss in wall thickness, or brittle heat-affected zone. Like inductive and conductive AC coupling, steadily induced fault current right after the coating breakdown can lead to corrosion of the pipeline. In this work, some protection guidelines against fault currents used in the field have been validated through the simulation and analytical method.

• 대한전기학회논문지:전력기술부문A
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• 제49권8호
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• pp.405-411
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• 2000

When faults occur in transmission lines, the classification of faults is very important. If the fault is HIF(High Impedance Fault), it cannot be detected or removed by conventional overcurrent relays (OCRs), and results in fire hazards and causes damages in electrical equipment or personal threat. The fast discrimination of fault needs to effective protection and treatment and is important problem for power system protection. This paper propolsed the fault detection and discrimination algorithm for LIFs(Low Impedance Faults) and HIFs(High Impedance Faults). This algorithm uses artificial neural networks and variation of 3-phase maximum currents per period while faults. A double lines-to-ground and line-to-line faults can be detected using Neural Network. Also, the other faults can be detected using the value of variation of maximum current. Test results show that the proposed algorithms discriminate LIFs and HIFs accurately within a half cycle.

• Journal of Electrical Engineering and Technology
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• 제3권4호
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• pp.460-467
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• 2008

This paper presents a new numerical algorithm for the fault location estimation and arcing fault detection when a single-phase arcing ground fault occurs on a transmission line. The proposed algorithm derived in the spectrum domain is based on the synchronized voltage and current samples measured from the PMUs(Phasor Measurement Units) installed at both ends of the transmission lines. In this paper, the algorithm uses DFT(Discrete Fourier Transform) for estimation. The algorithm uses a short data window for real-time transmission line protection. Also, from the calculated arc voltage amplitude, a decision can be made whether the fault is permanent or transient. The proposed algorithm is tested through computer simulation to show its effectiveness.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2004년도 학술대회 논문집
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• pp.97-100
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• 2004

This paper introduced an artificial fault generator which was operated in the Go-Chang field-test center and explained the result of single line-to-ground fault by AFG. The AFG can basically experiment line-to-line and line-to-ground faults. This facility directly connected distribution transmission lines, so the test results are very useful for power system analysis and protection. Using the function of the AFG, we briefly said the test methods ud results for the 22.9[kV-v] and $6.6[kV-{\Delta}]$ system.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2000년도 추계학술대회 논문집
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• pp.704-711
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• 2000

This study is carried out using a circuit model approach. First, the self and shunt impedances of all the conductors in the rail system and the mutual impedances between different conductors are computed. Then, a circuit representing the both rail systems at interfaces including the rails, feeders, protection wires, contact wires, ground wires is built. Auto-transformers in the system are also represented in the circuit model. The circuit model is then 1]recessed using a circuit solver based on a double-elimination method. Several different scenarios are analyzed, including the load conditions and a few fault conditions with different fault locations. The effect of the buried ground wires is also analyzed by comparing the results with and without the presence of the ground wires. The analysis procedure presented in the paper demonstrated an accurate way of computing fault current distribution and EMC at interfaces between both systems. The results presented in the paper can be used as a reference for estimating interference levels in similar rail systems.

• 전기학회논문지
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• 제60권2호
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• pp.285-292
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• 2011

DC traction power system is operated ungrounded so that minimize the stray current. Because the stray current is still present, a rail potential is increased. The ground faults in the DC railway systems are usually detected by a potential relay(64P). Moreover, if the rail potential goes high in the ordinary operating state because of the traction load, the potential relay would be maloperated. A presented protective relaying algorithm that can identify exactly the faulted region and can distinguish a ground fault from the potential rising of the rail is presented in this paper. This paper presents simulation technique that is very similar to the real operation situation using PSCAD/EMTDC.

• 한국화재소방학회논문지
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• 제25권6호
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• pp.136-145
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• 2011

화재발생 원인 중 가장 많은 부분을 차지하는 것 중 하나가 전기적 요인이며 이 전기적 요인 중 일정 비율 이상을 차지하는 것이 누전 지락사고이다. 이러한 누전 지락사고를 줄이기 위해 최근 국제규격인 IEC 60364-4-41을 반영한 저압전로의 지락보호에 관한 기술지침(KECG 1091-2011)이 개정되었으며 설비의 상시사용 운용 및 고장 결함 등을 회복시켜 신뢰성을 향상시키는 보전방식이 대두되고 있다. 따라서 본 논문에서는 최근 10년간의 화재발생현황을 파악하여 전기화재의 위험성을 분석한 후 일정비율 이상 차지하고 있는 누전 지락사고를 개선시키기 위한 방법으로 KECG 1091-2011의 개정사항을 검토한 다음 누전 지락보호검출의 신뢰성을 향상시키기 위한 예방보전 방식을 적용하여 시간계획보전 방식으로 정기점검제도와 내용연수제도에 대한 문제점을 나열한 후 그 해결방안을 제시하고 상태감시보전 방식으로 누설전류 통합감시 장치와 디지털 누전경보기를 제안하고자 한다.

• 대한전기학회논문지:전력기술부문A
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• 제54권8호
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• pp.410-417
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• 2005

This paper analyses the transient phenomena against single line to ground fault and lightning surge on underground power cable systems. For analysis in various fault conditions, several actual underground power cable systems are modeled using ATP In ground fault, the transient characteristic of the conductor and the sheath according to the fault current and the installation types of CCPU are analysed. In lightning surge strokes, the various unbalanced conditions including the length of crossbonded lead, the breakdown of CCPU and distance unbalance are considered. This paper is expected to contribute the establishment of proper protection methods against transients on underground power cable systems.

• 한국화재소방학회논문지
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• 제2권1호
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• pp.21-28
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• 1988

This paper deals with the optimal use of the ELB (Electric Leakage circuit Breaks) for the protection of low voltage distribution system. Since the ELB is recently used together for grounding fault while only the ground resistance was used in the past, the analysis of ELB characteristics is indispensible. By the quantitative analysis and the setting of limit the ground resistance and the ELB is derived and then the optimal use of the ELB is expected to contribute to the system protection.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 춘계학술대회 논문집 전기설비전문위원
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• pp.51-53
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• 2005

Grounding systems are responsible rot the safe operation of a power system whetehr power system fault occures or not, their performance guarantees equipmet protection and personnel safety by limited the ground potential rise and touch voltages as well as step voltages under ground fault condition. therefore, it is necessary to measure the ground resistance frequently for checing the performance of grounding system. In order to verigy the designed grounding measurement system feasibility, two comparison verifications, which are the ground resistnace measurements using the designed system on power service and off power service, are carried out for the same substation.