• Proceedings of the KIEE Conference
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• 2008.10a
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• pp.85-86
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• 2008

케이블의 원가절감을 위해 절연체의 절연두께를 줄이거나 초초고압화가 되어 갈수록 절연성능의 신뢰성 향상이 한층 요구되고 있다. 이를 위해 케이블 및 접속함의 절연체 내에 각종의 결함이 어느 정도 절연성능을 떨어뜨리는지 정량적으로 파악하여 개선할 필요가 있다. 또한 완제품 내 잔족하고 있는 이물의 종류 및 위치를 알 수 있으면 생산공정 내에서 이물 유입 경로를 파악하여 이물이 유입되는 것을 차단할 수 있다. AC내전압 파괴시험을 수행할 때 설계치 보다 저전계에서 파괴될 경우 파괴공을 조사하여 원인을 규명하고자 하지만 국부적인 결함으로 인한 파괴는 결함부를 소실시키기 때문에 파괴공 및 주위의 절연체를 현미경으로 관찰하여도 찾기가 어렵다. 따라서, 전원을 고속으로 차단하여 결함부가 완전히 소손되는 것을 막고 PD발생 위치를 추정하여 결함을 확인하는 방법이 요구 되어진다. 이러한 시험 방법을 전구차단법 이라고 하며, 고도의 PD측정기술과 판정기술이 필요한 종합적인 기술이다. 본 논문에서는 PPD 기술의 핵심인 노이즈 제거 기술과 판별기술을 서술하고 실제 접속함(PMJ)에 적용하여 PPD 기술의 유효함을 증명하였다.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.54 no.3
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• pp.139-144
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• 2005

[ $SF_6$ ] gas circuit breakers are widely used short circuit current interruption in EHV or UHV power system. For a $SF_6$ gas circuit breaker development, the $SF_6$ gas velocity measurement is necessary during $SF_6$ circuit breaker's trip operation. Small-gap flashover characteristics are used for this measurement. So, small-gap measuring system which will be used to develope GCB should be developed. This study shows the characteristic analysis and experimental results of small-gap measuring system.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.48 no.2
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• pp.127-132
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• 1999

Both motion of free metallic particles from which most GIS internal failures are caused and partial discharges from the particles were examined using EHV GIS test chamber. Effects from particle length and gas pressure which are main factors to lead to breakdown failure were investigated theoretically and experimentally. Magnitude of both lift-off voltage and partial discharge inception voltage were measured respectively and, through these measurements, this paper showed the possibility of predicting breakdown fault and of taking action to prevent the fault in advance. The measurement of partial discharge when the particles began to move could be adopted to decide minimum sensitivity in developing predictive diagnostic equipments. Both the amount of apparent discharge and real discharge in GIS were examined theoretically and experimentally, then experimental results were analyzed on the basis of the theory.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.51 no.9
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• pp.460-466
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• 2002

A reliable fault phase selection algorithm plays a very important role in transmission line protection, Particularly in Extra High Voltage (EHV) networks. The conventional fault phase selection algorithm used the phase difference between positive and negative sequence current excluding load current. But, it is difficult to pick out only fault current since we can not know when a fault occurs and select the fault phase in weak-infeed conditions that dominate zero-sequence current in phase current. The proposed algorithm can select the accurately fault phase using the sum of unit vectors which are calculated by positive-sequence voltage and negative-sequence voltage.

• Proceedings of the KIEE Conference
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• 2000.07a
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• pp.458-460
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• 2000

In this paper, we analyze the inductive coupling between overhead power transmission lines and neighbouring gas pipelines or other conductors, when they parallel to a line section in a phase-to-earth fault is assumed on the transmission line. A numerical procedure employing the finite-element method(FEM) is used in conjunction with Faraday's law, in order to predict the current in a faulted transmission line as well as the induced voltages across points on a pipeline running parallel to the faulted line and remote earth. The results lead to conclusion that may be useful to power system engineers.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07b
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• pp.886-889
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• 2002

This paper describes the characteristic analyses and a new design of the bushing for the pole transformers. The mechanical breakdown of the upper part of the bushing was frequently occurred. This caused the leakage of mineral oil, resulted in the interruption of electric power. Therefore, the bushings were investigated by the material analytical method and Finite Element Method. The analyses were performed by the Induced Coupled Plasma(ICP), X-ray diffraction(XRD), Scanning Electron Microscopy(SEM), and Dielectric Thermal Analyzer(DETA). Also, the Von-Mises stress of the top part of bushing was determined by using ANSYS program. The Von-Mises stress of the newly designed bushing was reduced about 50%. Therefore, if we apply the newly designed bushing, the number of mechanical breakdown may be decreased.

• Proceedings of the KIEE Conference
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• 2005.07a
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• pp.99-101
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• 2005

전력수요의 지속저인 증가로 인해 초고압(EHV) 송전선로를 포함한 전력선비가 계속 건설됨에 따라 송전선로에서 발생하는 전자계에 관한 논란이 심화될것으로 예상된다. 본 논문에서는 이러한 문제를 해소하기 위해 효과적으로 전자계를 저감시킬 수 있는 저감 기법중 송전선로 주변에 수동 도체루프를 사용하여 자계를 저감시키는 방법을 검토하고 유전 알고리듬을 이용해 가공송전선로에서 발생하는 자계를 효과적으로 저감시키기 위한 최적의 도체루프 모델을 찾고자 하였다.

• Proceedings of the KIEE Conference
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• 2005.07a
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• pp.724-726
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• 2005

본 논문에서는 직렬보상된 430 km 길이의 초고압 선로를 EMTP를 이용하여 모델링하고 부하차단시에 직렬 보상량과 차단 부하크기에 따른 발생하는 과전압을 예측계산 하였다. 이러한 결과로부터 과전압발생을 허용범위 이내로 억제할 수 있는 조류한계와 직렬보상량을 산출하였다.

• Proceedings of the KIEE Conference
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• 2005.07a
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• pp.661-663
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• 2005

본 논문에서는 2회선 초고압 송전선로의 4.5 km 이격한 서로 다른 송전철탑에서 발생한 섬락사고의 원인을 규명하기 위한 연구결과를 소개하고자 한다. 섬락사고는 낙뢰가 원인을 제공한 것으로 추정되었으며 2회선중 각각 1개 상의 섬락고장을 동시에 유발하였다. 뇌고장은 낙뢰의 송전선 침입 위치에 따라 역섬락과 차폐실폐 고장으로 분류하고 각기 다른 대책을 적용한다. 연구에서는 고장유발 낙뢰의 크기를 모의계산을 통하여 추정하고 낙뢰에 의한 섬락 형태를 밝히고자 하였다.

• Proceedings of the KIEE Conference
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• 1989.11a
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• pp.197-200
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• 1989

The corona interference of extra high voltage (EHV) transmission lines has to be considered as an important design factor for establishing an electrical environmental countermeasure at a basic line design stage. This paper describes the conductor selection procedure through both corona performance test result in corona cage and its evaluation by the design criterion. It is known that three conductor configurations including $6{\times}810mm^2$ (spacing: 40 cm) are the suitable conductor bundle for the environmental preservation around both 2-circuits and 1-circuit T/L.