• 대한전기학회논문지:전력기술부문A
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• 제51권2호
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• pp.102-108
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• 2002

This paper describes the overvoltage analysis and reduction methods of insulation joint boxes in underground transmission power cables when direct lightning surge strikes to overhead transmission line. An actual 154kV combined transmission line with underground Power cables was modelled in ATPDraw for simulation. Simulations were performed to analyze the overvoltage between insulation joint boxes, sheath-to-ground voltage according to the distance between cable conductors, cable lengths, burying types, CCPU connection types. The most effective method to reduce the induced overvoltage of Insulation joint boxes was proposed. It is evaluated that the proposed reduction method riven from the detailed simulations can be effectively applied to the actual underground power cable systems.

• 한국구조물진단유지관리공학회 논문집
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• 제18권4호
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• pp.59-66
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• 2014

건설구조물 상부의 단열은 에너지 절약 건설구조물에 있어서 중요한 요건 중 하나이다. 건설구조물 최상부는 단열성뿐만 아니라 방수성능도 중요하다. 이와 같은 이유로 단열성을 확보한 방수공법의 개발이 요구된다. 본 연구에서는 최근 일정 단열성능을 확보한 단열 보완형의 복합방수공법이 개발되어 해당 공법에 대한 단열성능을 평가하고자 하였다. 방수성 시험결과, 모든 시험체는 KS 표준 이상의 성능을 보여주었다. 단열성 시험결과, 스티로폼 박스가 가장 높은 온도인 $25.91^{\circ}C$, 버블시트 박스가 $17.28^{\circ}C$, 단열시트 박스가 $15.47^{\circ}C$, 단열보완형 방수시트가 $24.11^{\circ}C$로 확인되었다. 시트 접합부의 열교현상을 관찰한 결과 열교현상은 발생하지 않았다. 단열보완형 복합방수공법은 단열성능을 확보하고 있는 것으로 판단된다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 추계학술대회 논문집 전력기술부문
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• pp.380-382
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• 2001

This paper describes the protection of insulation joint box in combined transmission line which is connected with the 154kV underground power cables. An actual power cable system was selected to establish modeling and to analyze. Modeling was established in EMTP and ATPDraw. Simulation was carried out according to the buried method of cable and connection method of CCPU. Results presented in this paper will be applied to another power cable systems.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 E
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• pp.1614-1616
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• 1998

Insulation performance of major components of prefabricated joint such as epoxy insulation unit and premolded rubber cone are guaranteed by material selection design and proper manufacturing. On the other hand insulation performance of the interfaces between the premolded rubber cone and the epoxy insulation unit and the cable insulation is maintained by keeping the premolded rubber cone to close contact with such insulation by spring. Electric characteristics of a interface depend on the contact pressure, but the required characteristics are assured so far as a proper contact pressure is maintained. In this report, the interfacial pressure by pressure sensors both in the early stage and after heating cycle were measured and the simulation by FEM program were presented. The comparison of these two results show that interfacial pressure could be controlled optimally by changing the spring length and lubricant state of the interface.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.470-471
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• 2008

SVL is installed at underground transmission system to protect cables and insulation joint-box from overvoltages caused by lightning, switching, and line-to-ground fault. Domestic underground power system adopts cross bonding type to reduce the induced voltage at sheath, but single-point bonding is required depending the system installation configuration. SVL can be easily broken by overvoltages induced at joint-box because single-point bonding has uneffective system structure to extract fault current. ANSI/IEEE recommends Parallel Ground Continuity Conductor(PGCC) to prevent SVL breakdown. In this paper, EMTP simulation is performed to analyze effects on SVL under PGCC installation when single-line-to-ground fault occurs. The result shows that PGCC and short single-point bonding distance can reduce overvoltages at SVL.

• 전기학회논문지
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• 제64권2호
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• pp.247-253
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• 2015

Dielectric breakdown accidents have been mainly occurred in the vicinity of service entrance section in underground power transmission systems. One cause among them is due to the excessive component value of sheath located around service entrance of cable. In this paper, as one of the alternative to prevent these accidents, the change of cross bond grounding system and the location change of IJ(Insulation Joint) are suggested. Also, to evaluate effectiveness of this changing system, circulating current and induced voltage of sheath were analyzed in steady and transient state. By comparison of the analytical results for the several possible changing systems, a grounding system and location of IJ which has the smallest sheath component values is proposed. In this paper, analysis to evaluate the proposed system is carried out by EMTP/ATPDraw. It can be used as a valuable operational material to prevent accident of the service entrance section in underground power transmission system.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1993년도 춘계학술대회 논문집
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• pp.49-51
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• 1993

Recently, use of High Voltage cables with extruded insualtion is increasing. Generally this polymeric insuation contains residual stresses. The effect of internal residual stresses is the so-called shrink-back of the insulation. If not controlled, these stresses may lead to problems during installation and service of the cables. Therefore in this paper, the definition and cause of shrinkage are described and furthermore the influence due to shrink-back at cable joint-box.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2015년도 제46회 하계학술대회
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• pp.377-378
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• 2015

국내 지중송전선로의 포설형태는 시스유기전압과 시스순환전류를 저감하기 위해 케이블을 정삼각배열 및 접속함의 위치를 일정거리를 유지하여 시공하고 있다. 그러나 시공 형태에 따라 시스성분은 달라진다. 본 논문에서는 지중송전선로 접속함의 위치를 변경시켜 시스성분을 해석한 후 상호 비교하였고 그 결과를 통하여 절연접속함 위치변경의 효용성을 평가한 후 제안하였다. 모델링 및 해석은 EMTP를 이용하였다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 춘계학술대회 논문집 유기절연재료 전자세라믹 방전플라즈마 연구회
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• pp.72-75
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• 2001

전력케이블 선로에 가해지는 전압은 상시교류전압이외에 지락 등에 의한 사용주파과전압과 뇌써지와 같은 써지성 과전압이 있다. 써지성 과전압이 케이블 심선에 침입할 경우 종단접속부나 절연접속함의 접속점은 절연통 양단 및 시스와 대지간에 고전압이 발생하여 케이블심선-시스간 시스-대지간의 써지임피던스 비에 따라 과전압이 발생하며, 이와 같이 써지성 과전압이 방식층의 충격내전압치를 초과할 경우 방식층을 보호하기 위한 대책이 필요하며 그 보호장치로 절연통 보호장치를 사용하는 것이 일반적이다. 절연통에 대한 보호대책과, 설계 제작된 절연통 보호장치에 대한 주요시험항목을 실시하여 항목별 그 특성을 검토하고 절연통 보호장치의 지중송전선로에서 사용되는 조건인 열적내량을 검증하는 충격전류시험과 침수에 의한 기밀성능을 검증하는 내수성능시험을 실시함으로써 그 중요성을 인식할 수 있었다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.1422-1423
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• 2007

This study deals with various neural network algorithms for the on-site partial discharge pattern recognition. For the purpose, the pattern recognition has been carried out on partial discharge data for the typical artificial defect using 9 different neural network models. In order to enhance on-site applicability, artificial defects were installed in the insulation joint box of extra-high voltage xLPE cables and partial discharges were measured by use of the metal foil sensor and a HFCT as a sensor. As the result, it is found out that the accuracy of pattern recognition could be enhanced through the application of the Sigmoid function, the Momentum algorithm and the Genetic algorism on the artificial neural networks. Although Multilayer Perceptron (MLP) algorism showed the best result among 9 neural network algorisms, it is thought that more researches on others would be needed in consideration of on-site application.