• Proceedings of the KIEE Conference
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• summer
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• pp.610-612
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• 2004

Because the overhead transmission lines are exposed to the outdoor weather, the faults of the transmission lines are due to natural conditions, and among these faults, the outage rate by lightning is about $50\%$. Therefore, the insulation design is important to decrease the damage of the facility and to increase the reliability of electric power system. This paper describes the protective method of substation equipments using the Underbuilt Ground Wire and the Guy Wire. This would not only reduce backflashover possibility but also minimize crest and duration of surges entering the substation. EMTP is used to analyze the efficiency of the proposed methods.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.54 no.6
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• pp.279-285
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• 2005

The lightning causes the damage of power system equipments as well as large power failure. Therefore, the insulation design should be established not only to decrease the damage of the facilities itself but also to increase the reliability of electric power system. This paper describes the useful way applying underbuilt ground wire and guy wire in transmission tower that safely protect the substation equipments. One or more shield wires under the phase conductor will not intercept lightning stroke, but they may improve reduce lightning voltages almost as effectively as if they were above the phase conductors. And the guy wires will mitigate the tower surge response. These would not only reduce backflashover possibility but also minimize crest and duration of surges entering the substation. EMTP is used to analyze the efficiency of the proposed methods.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.2226-2227
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• 2008

가공배전선로는 태풍과 같은 자연재해에 상시 노출되어 시설되므로 전기고장 및 설비피해가 발생할 우려가 매우 높다. 그러나 이와 관련한 실질적인 연구들이 부족하여 가공배전선로의 설계원들이 직선선로의 경간 결정시 단순히 저압부하밀도 및 전주강도만을 고려하고 있으며, 인류지선 및 종지선의 규격 선정방법을 잘 이해하지 못함에 따라 규격 선정의 오류가 발생되기도 한다. 따라서 본 고에서는 그 동안의 연구결과를 바탕으로 가공배전선로 설계시 수평선간이격거리를 고려한 경간 결정방법과 장경간 및 표준경간의 인류지선, 장경간개소 종지선 결정방법에 대하여 사례를 통해서 설명하였다. 본 고에서 제시한 방법에 따라 설계검토를 시행한다면 표준경간에서 선간단락고장을 예방할 수 있을 뿐만 아니라, 장경간 및 표준경간의 인류지선 및 종지선의 강도가 재해시에도 충분한 강도를 확보하여 설비피해 및 전기고장을 예방할 수 있을 것으로 기대된다.

• Journal of Korean Society of Forest Science
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• v.97 no.1
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• pp.61-70
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• 2008

This study was conducted to develop a mobile tower-yarder with tractor for agriculture and forestry that is the efficient yarder in steep terrains, thinning operation and small scale logging operation. It was designed and manufactured that the power source of tower-yarder is equiped three hydraulic pump connected to PTO of tractor, and three hydraulic pump is used to operate the four motor for drum, the cylinder for clutch of interlocker, the cylinder for tower expanding and the out-rigger cylinder. It was to adopt the running skyline system and the inter-lock function, and to equip the double capstan drum, the storage drum and the clutch for interlock in the development of tower-yarder. It was to develop the tower-yarder which the winch torque of double-capstan drum, the traction force of double-capstan drum, the number of rotation of double-capstan drum and the line speed is $191kg{\cdot}m$, 1,910 kgf, 220.5 rpm and 138.5 m/min, respectively. And it was known that the optimum flange diameter of the main and haulback storage drum is about 360 mm and about 460 mm in order to storage the main line length of 250m and the haulback line length of 450 m. The carriage was made to adopt the running skyline system and to equip the lock function in order to the convenience of chocking and the fall down preventing of tree. It was provided to develop the wire remote controller for the inter-lock function, the convenience of control and the efficiency of yarding. In development process, this tower-yarder was attached the 3-point linkage hitch equipment and the tire wheel for the traction and moving of tower-yarder. Also, it was equipped that the out-rigger and the guy line in order to raise the safety and efficiency of yarding of tower-yarder.