• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 E
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• pp.1791-1793
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• 1997

Since Korea was initiated a industrialization, many transmission lines have been installed to meet the increasing demand for the electric power. In large city, underground transmission lines were widely installed because of the environmental issue. But there have been appeared many failures on the lines, such as the external scar of cable, a fire in the culvert, overheating of cable, and so on. There have been many studies to monitor them and improve the reliability of the power supply. As a method monitoring the lines, a DTS(Distributed Temperature Sensor) system is developed and applied. This system monitors the lines and predicts the failures, using a optical fiber sensor. This paper describes this DTS system and its application for the underground transmission lines.

• KEPCO Journal on Electric Power and Energy
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• 제4권2호
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• pp.63-66
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• 2018

Lattice towers and tubular steel poles have been commonly used for electrical power transmission in Korea as well as the other countries. They are durable, structurally stable, simple and can easily be constructed in limited spaces. However, residents are opposed to construct transmission lattice towers in their areas because they are not visually attractive, and electrical field occur at the transmission lines. Underground transmissions have been used instead of the traditional towers to resolve these problems, however they are not cost effective to construct and run. Therefore, we have developed compact towers that are more attractive, well blend into the surrounding environment and much more economical than underground transmissions. This paper shows the design of a compact towers with insulation arm, in order to reduce the height of tower and the separation between phases. The compact tower can be installed in a narrow right-of-way. Insulation arms are easily applied to lattice and steel tubular towers instead of steel arms. Compact towers with insulation arm are also considered as a solution to have public acceptance or to create a familiar atmosphere among towers and people. Compact tower compared with a conventional tower, insulation arms reduces the width and height of the tower by 20% and 15% respectively.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 E
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• pp.1620-1622
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• 1998

The failure occurs in the system of the underground transmission line, the time of restoration is very long, the damage from stopping power supply is very serious and the cost of restoration is very great. because of these problems, the system and equipment must be protected from every electrical failure by installing protection unit. This study is summarized and compared the effects of configuration method of cable protection device with respect to surges in EHV (Extra High Voltage) underground transmission system.

• 한국건설순환자원학회논문집
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• 제3권1호
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• pp.72-83
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• 2015

지중 송전선은 전기저항에 의한 발열현상이 늘 있으며, 그 주변의 되메움재를 통하여 열을 방출하게 된다. 따라서, 송전관로의 설계에는 발생하는 열을 주변 지반이 효과적으로 외부에 전달하여, 열적 안정성을 확보하는 것이 매우 중요한 설계 요소가 된다. 본 연구에서는 지중 송전관로 되메움재용 순환골재의 현장 적용성을 향상시키기 위하여, 순환골재의 품질기준 및 시공기준을 제시하고, 현장 실증시험을 통하여 송전관로의 열안정성을 분석하였다. 현장 실증시험에서는 순환골재 두 종류와 현재 되메움재로 사용하고 있는 모래의 열적 거동을 비교하였다. 시험 결과, 순환골재는 시간경과와 관로에서의 이격거리에 따라 온도와 함수비 변화가 모래와 유사하게 나타났다. 따라서 순환골재는 지중 송전관로 되메움재로서 일반 모래를 대체하여 적용 가능할 것으로 판단된다.

• 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.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 A
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• pp.718-720
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• 2005

This paper analyses the transient phenomena against lightning surge on underground power cable systems. For analysis, several actual underground power cable systems are modeled using ATP. 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.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 추계학술대회 논문집 전력기술부문
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• pp.405-407
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• 2006

The power system analysis based on the accurate impedance of the individual underground cable, which is the inter connected to a large power system, is required. A study on calculation method of impedance allowable current for underground cables. furthermore, various methods of bonding and earthing the sheath have been used for the purpose of eliminating or reducing the sheath losses. the effectes of bonding and earthing must be includied in impedances. therefore, the subject of predicting thermal performance of soil and cable systems has been received increasing attension. for these problems, this paper describes a general formulation of impedance that is based on the effect of crossbonding and earthing of the sheath on the 66kV, 132kV and 220kV underground cable systems. also the work is presented, for calculating the temperature rise of power cable and soil.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 추계학술대회 논문집 전기설비전문위원
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• pp.211-213
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• 2008

To detect partial discharge of 154kV joint box, we have made experiment by using the Al-foil electrode sensor. Generally the signals which are detected in partial discharge test of underground power transmission cable are accompanied with both noises of high voltage and noises of surrounding power cable. The most noise in near to end part of joint box is corona, beside other noises flowed from surrounding area. Partial discharge test is difficulty due to these noises. First, we had used Al-Foil sensor on middle joint box of 154[kV] underground transmission power cable, and then analysed reliability of calibration signal by using the Al-Foil electrode sensor of NJB. From above results, decrement properties measured highly. But incase of injecting calibration signal of 500[pC] after measuring signals in IJB, the S/N ratio had about 25[dB] acquisition.

• 한국초전도ㆍ저온공학회논문지
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• 제2권2호
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• pp.32-36
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• 2000

In this study, we performed the long-term expansion planning for the conceptual design of HTS power cable in Seoul area. In Korea, underground power cable has been required gradually with increasing demand of electric power transmission density and low loss characteristics in the comparison with a conventional power cables, so we assumed that the HTS power cable is applied between the downtown area and the outskirts of the city for the large power transmission capacity. This paper is to show the effects of HTS power cables in Seoul based on the power system analysis.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 A
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• pp.205-207
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• 2003

The line impedance is important data that is applied in all analysis fields of electric power system like power flow, fault current, stability and relay calculation etc. Usually, impedance can be accurately calculated in case of overhead line. However, in case of power cables or combined transmission lines, impedance can not be accurately calculated because cable systems have the sheath, grounding wires, and earth resistance. Therefore, if there is a fault in cable system, these terms will severely be caused much error to calculation of impedance. Therefore, the line impedance were measured for this study in an actual power system of underground cables, and were analyzed by a generalized circuit analysis program EMTP for comparison with the measured value. These analysis result is considered to become foundation of impedance calculation for underground cable.