• Wind and Structures
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• v.11 no.4
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• pp.303-321
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• 2008

When first commissioned, the 1.6 km span 275kV Severn Crossing Conductor experienced large amplitude vibrations in certain wind conditions, but without ice or rain, leading to flashover between the conductor phases. Wind tunnel tests undertaken at the time identified a major factor was the lift generated in the critical Reynolds number range in skew winds. Despite this insight, and although a practical solution was found by wrapping the cable to change the aerodynamic profile, there remained some uncertainty as to the detailed excitation mechanism. Recent work to address the problem of dry inclined cable galloping on cable-stayed bridges has led to a generalised quasi-steady galloping formulation, including effects of the 3D geometry and changes in the static force coefficients in the critical Reynolds number range. This generalised formulation has been applied to the case of the Severn Crossing Conductor, using data of the static drag and lift coefficients on a section of the stranded cable, from the original wind tunnel tests. Time history analysis has then been used to calculate the amplitudes of steady state vibrations for comparison with the full scale observations. Good agreement has been obtained between the analysis and the site observations, giving increased confidence in the applicability of the generalised galloping formulation and providing insight into the mechanism of galloping of yawed and stranded cables. Application to other cable geometries is also discussed.

• Proceedings of the KIEE Conference
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• 2000.07c
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• pp.2020-2022
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• 2000

The cross-linked polyethylene(herein after XLPE) insulated power cable emit the methane($CH_4$)gas in the course of chemical cross-linking process. The general stranded conductor easily discharge this methane gas through the gap of each stranded wires. But the special stranded conductor that filled with semi-conducting rubber compound to prevent water penetration which is applied to water proof type of cable(22.9kV CN/CV-W), disturb the methane gas emission. The pre-mold type cable joint shall be expanded gradually by emit of gas left in XLPE insulation. For example, sometimes the corona problem outbreak on a new power distribution line, resulted from the gap between the sleeve and semi-conductive layer of cable joint. If above mentioned problem especially happened on the way of operating. We have to shut down the line and try to discharge the methane gas in cable joint. In this point, we would like to explain the mechanism of methane gas & cable joint and our test result briefly. At last, we are pleased to introduce the solution for preventing reoccurrence of this problem.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1428-1429
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• 2011

This paper variation of stranded cable conductor with CIP(Cold Isostatic Press) technology. Conductor as cable material takes majority costs. Thus many experiments have been done on conductor compaction. The core technology is to maintain the resistance of circular stranded conductor after compaction process, while reducing the weight of conductor diameter, but by increasing filling factor. Testing by varying the compaction ratio using 300SQ conductor, conductor after CIP process shows lower resistance rather than conductor before CIP process.

• Proceedings of the KIEE Conference
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• 1993.11a
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• pp.76-78
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• 1993

When an alternating current is supplied to a super-conducting multi-stranded cable, the quench current value of the cable was observed to be less than the simple summation of individual quench current value of each strand. One of the causes for such a degradation was attributed to the nonuniform of the current distribution in multi-stranded cable due to magnetic mutual coupling among the strands. The degradation of the superconducting cable is evaluated theoretically by taking into account the magnetic coupling among the strands.

• Proceedings of the KIEE Conference
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• 1999.07a
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• pp.95-97
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• 1999

It is becoming demand of OPGW required high reliability of the characteristics of earthing and tight transmission. This paper study the mechanical and electrical characteristics of the OPGW stranded stainless tubes lied optical fiber and aluminum alloy wire to grasp their performance and to approach to design suitable for various environment.

• Proceedings of the KIEE Conference
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• 1995.07c
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• pp.1296-1298
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• 1995

This paper presents the power cable with the concentric neutral wires of S-Z stranding. This type Cables, 22.9KV CN/CV Cables used in the distribution systems have been developed in order to improve bend, bend after torsion and tension charateristics. We have designed and made S-Z stranding machine, testing equipment etc., and have established the manufacturing technology of the equipment and the testing technology.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.28 no.3
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• pp.191-195
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• 2015

Inside the existing superconducting cables, the superconducting wire carries a loss-free current, and the cable former (the stranded copper wire) bypasses the fault current to prevent damage and loss of the superconducting cable when the fault current is applied. The fault-current-limiting-type superconducting cable proposed in this paper usually carries a steady current; but in a fault state, the cable generates self-resistance that makes the fault current lower than a certain width. That is, the superconducting cable that transmitted only a low voltage and a large capacity power repetitively limits the fault current, as does a superconducting current limiter. To complete this structure, it is essential to investigate the mutual resistance relationship between the superconducting wires after applying a fault current. Therefore, in this paper, one kinds of superconducting wires (a wire without a stabilization layer) were connected parallel 4 tapes, respectively; and after applying a fault current, the current, voltage, resistance and thermal stability of the HTS thin-film wires were examined.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.276_277
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• 2009

풍력 케이블의 nacelle부와 Tower 사이에 포설되는 케이블은 사용 환경의 특성상 장력+비틀림의 스트레스를 받는다. 이러한 사용 환경 때문에 케이블은 전기적인 특성 뿐 아니라 반복 운동을 하는 환경에 대해 구조적인 특성에 대해서도 검토가 요구되어진다. 본 논문에서는 풍력 케이블의 핵심 검토 요소로 도체의 구조적 위험 요소를 줄이기 위한 연구 대상으로 도체의 (*)피치 변화의 특성을 분석하였으며, 피치가 길어지면 도체에 발생되어지는 응력(스트레스)이 작아질 것이고 피치가 짧아지면 도체에 발생되어지는 응력(스트레스)이 커질 것이라는 일반적인 상식을 벗어나 각 피치별 응력(스트레스)의 최저점들을 찾게 되었고 그 중 유연성을 함께 고려하여 품질의 향상을 기여하는 최적 피치를 선정하였다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.227-228
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• 2005

사용중인 OC의 사고가 외물접촉, 자연현상, 일반인 과실 등으로 인하여 전체 배전선로 일시고장의 대부분을 차지하고 있음으로, 피복의 트래킹 성능을 개선하여 수목 및 조류와의 접촉으로 인한 접촉부 전개 집중 시 또는 지지금구의 바인더부에 고전계 인가 시 트래킹에 의한 절연물의 탄화, 침식 등에 의하여 발생할 수 있는 절연파괴 등의 사고 위험을 줄이기 위하여 개발된 제품으로 산악지역 등에서 내트래킹, 내부식성, 수밀성 및 전기적인 특성이 우수하다. 본 평가기술에서는 알루미늄 묘|복강선, 연선 및 절연체의 일반적인 특성과 트래킹성, 도체수밀, 내후성, 밀착도, 교류파괴전압 등의 주요한 평가시험에 대한 방법을 검토하여 평가시험에 적용하여 평가시험시 문제점을 도출하고 평가시험방법을 정립하고자 한다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.12
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• pp.150-156
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• 2017

This study examined the stress recovery length due to the local damage of a 7-wire strand, which is applied widely to PSC (Post Tensioned Concrete) bridges and cable-stayed bridges. The 7-wire strand is a multiple stranded steel of PC prestressing strand. Owing to the nature of the material, it is damaged continuously after completion with corrosion being the main cause of damage. On the other hand, due to its structural characteristics, it is difficult to grasp the degree of damage inside the cable and the pattern of stress variation. In the case of cables applied to bridges, the parts that are susceptible to corrosion are generated depending on the water supply and installation shape, which may cause local damage. This study analyzed the tendency of performance degradation and stress recovery length according to local damage of a 7-wire strand, which is applied mainly to bridge post-tensioning or stay cables. This study developed a computer-based simulation model that was validated with experimental results. The model developed in this study can be used to evaluate the safety level and estimate the remaining life span of P SC bridges or cable-stayed bridges.