• Solar Energy
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• v.15 no.3
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• pp.59-73
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• 1995

The thermal analysis is accomplished with the route for the underground power transmission system which adopts the water pipe cooling with trough in tunnel. As a result, in case of a cooling system based on a refrigerator, the optimum condition for the flow rate of cooling water and the air velocity are calculated as the $2{\sim}3{\ell}/s/pipe$ and $1{\sim}2m/s/fan$, respectively. On the other hand, in case of cooling tower the optimum condition for them are calculated as the $2{\sim}3{\ell}/s/pipe$ and 6 m/s/fan, respectively. But the cooling system based on a cooling tower has the problem of enlarging the size of cooling fan and suppressing the labor of operator in tunnel. Therefore, to meet all the cooling conditions for a given cooling section, the cooling system based on a refrigerator is more acceptable.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.41 no.7
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• pp.703-711
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• 1992

As the underground area of the metropolitan becomes denser recently, an introduction of forced cooling system is under study to maximize the carrying capacity of existing cables in tunnels. Indirect water cooling system laid within trough will probably be adopted for the next 345KV class underground power cables in this country. The system covers a distance of 1.5-3.0Km for one water cooling interval and one water cooling interval is composed of several sub-sections that have different thermal analysis conditions. Thus the distribution of temperature in each sub-section is described by different conditions in general. In this paper a method that can accurately match the temperature of the coolant in the boundary between sub-sections has been suggested. An algorithm to find the temperature distributions effectively in the thermal system has also been presented. A computer program using this method has been tested in a smaple system and the results have shown the usefulness of this program.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.574-575
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• 2011

최근 도심지의 확대 및 경제발전에 따른 전력수요의 증대로 인해 지중송전선로 건설이 증가하고 있는 추세이나 전력구에 수용되어 있는 회선규모 및 운전기간에 따라 전력구 내부온도가 급격히 상승하여 그로 인한 송전용량 감소 및 순시원과 작업원의 안전에도 영향을 미치고 있다. 이러한 문제점을 해결하기 위해 국내 최초로 도입한 345kV 북부산-남부산 전력구 일부구간에 간접 수냉각 시스템을 설치하고 그 현황과 효과분석에 대해 기술하고자 한다.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.41 no.5
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• pp.445-458
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• 1992

As one of the forced cooling method of the underground power transmission system, external water cooled system with trough in tunnel was investigated. This study is performed on thermal analysis for a standard condition to determine the cable transmission current of the underground power transmission system about the cooling facility. A parametric study was performed for the inlet water temperatures, flow rates, the inlet air velocities, flow rates and the cooling spans. This study shows that the cable transmission current varies within the allowable limitation in compliance with the variation of inlet water temperatures and flow rates. It exhibits little variations for the most intervals in compliance with the variation of inlet air temperatures and flows. But, the cable transmission current fast reduces for a specified interval and consequently affects the underground transmission system. As a result, when the actual forced cooling system is designed, the design conditions of inlet air have to be considered as the most important parameters in determination of the cable transmission current.