• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.234-234
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• 2009

This paper illustrates the use of electric field computation to optimize the design of high voltage composite bushing. In the bushing, a high electric stress occurred between field shaper and central conductor by the closely space. Also coaxial cylindrical shield has a great height along the axis to control an electric field. Consequently, all the potentials are raised axially along the field shaper and electric stress is concentrated on a part of the surface of the FRP tube near the upper end of the field shaper. Maxwell 2D simulator based on the boundary element method was also introduced in order to verify the reliability of the polymer bushing. The optimized design uses internal elements for electric stress grading at critical parts of the bushing.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.2173-2174
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• 2011

At the moment, the section insulators for different phases used for over head contact wire system has been all imported since its first application. However, because the section insulators need frequent maintenance and replacement due to the wear by the friction with pantograph and the contamination, which causes its life shorter than as expected, it is required to develop the insulation material with better wear-resistance characteristics and contamination-resistance characteristics. In this thesis, the author developed the section insulator which adopts Teflon tube insulation material which is composed of the Teflon material with the excellent electrical characteristics and wear-resistance characteristics for a longer expected life than that made of conventional FRP.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.566-567
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• 2011

본 논문에서는 500kV급 composite bushing에 사용되는 FRP tube 및 금구류에 대하여 풍하중에 대한 강도안전성을 평가하였다. 제품의 평가는 유한요소법을 이용한 구조해석을 진행하였으며, 해석 결과 풍하중에 대하여 충분한 강도 안전성 및 안전율을 가지고 제품이 설계된 것으로 나타났다. 따라서 본 연구에서 제시한 결과를 바탕으로 composite bushing은 강도안전성 측면에서 신뢰성 있는 제품으로 개발이 이루어지고 있음을 확인할 수 있으며, 향후 유한요소법을 이용한 해석을 통해 제품 개발 기간의 단축과 소비자에게 보다 향상된 품질을 보증하는데 기여할 수 있을 것으로 사료된다.

• 한국초전도학회:학술대회논문집
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• v.9
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• pp.291-291
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• 1999

Long 19-filamentary Bi-2223 tapes were prepared using the so called "powder-in-tube" method. In the preparation, two types of precursor powders and two different reduction rates during rolling were used. Also two rolling method, which resulted in different filament geometry, were used. The characteristics of the tapes will be presented. Also A coil was prepared using two 56 m-long 19-filament tape. It was consisted of two double pancake coils. Each pancake, which is separated by FRP spacer, was composed of 98 turns. The experimental results will be presented and compared to the simulation result.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.03b
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• pp.35-35
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• 2010

This paper illustrates the use of electric field computation to optimize the design of high voltage composite bushing. In the bushing, a high electric stress occurred between field shaper and central conductor by the closely space. Also coaxial cylindrical shield has a great height along the axis to control an electric field. Consequently, all the potentials are raised axially along the field shaper and electric stress is concentrated on a part of the surface of the FRP tube near the upper end of the field shaper. Maxwell 2D simulator based on the boundary element method was also introduced in order to verify the reliability of the polymer bushing. The optimized design uses internal elements for electric stress grading at critical parts of the bushing.

• Electrical & Electronic Materials
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• v.9 no.4
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• pp.410-414
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• 1996

기존의 초고압 옥외절연물은 세라믹을 소재로한 porcelain이었지만 최근 신소재기술의 발달로 내열성, 내후성, 내트래킹성 등이 우수한 고분자 재료들이 개발됨에 따라 구미 선진국을 중심으로 이들의 전기절연물분야 적용이 크게 증가하고 있다. 인발(pultrusion)공법으로 glass fiber와 수지를 결합시켜 고강도 무결점의 FRP절연봉이나 tube를 만들 수가 있다. 절연물에서 요구되는 구조재로서의 기계적 특성은 FRP복합재료가 충족시킬 수 있는데 이러한 봉을 core재로 하여 절연물의 표면전기특성을 만족하도록 고무로 된 shed를 씌우고 양쪽 끝에 금구류를 부착하여 composite insulator를 만들 수가 있다. composite insulator는 여러개의 shed를 한번에 진공사출하거나 shed를 금형에서 찍어 조립하여 제작할 수가 있는데 지금까지 검토되어 온 어떤 고분자 절연물보다 특성이 우수하고 장점이 많기 때문에 상업적 가치를 인정받고 있다. 본 고에서는 옥외용 절연물의 절연성능과 섬락사고기구를 요약하고 고분자신소재 절연물인 composite insulator의 장점, 국내외 개발현황, 평가방법등을 정리하였다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.489-490
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• 2008

This paper describes the analysis of electric field distribution of high voltage polymeric bushing with structure. The high voltage bushing consists of FRP tube and housing made of LSR. The field control can be achieved by means of the design of such internal field shaper and top corona ring as grading electrodes. In accordance, the optimized design uses both internal and external elements for electric stress grading at critical parts of the bushing. Maxwell 2D simulator based on the boundary element method was also introduced in order to verify the reliability of the polymeric bushing.

• Journal of Korean Society of Steel Construction
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• v.19 no.1
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• pp.43-52
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• 2007

There is a growing range of applications for concrete-filled steel tube (CFT) member because of its superior performance. But a CFT member may be uneconomical or has weight problems because it is fully filled with concrete. In this study, a new type of member, called internally confined hollow (ICH) CFT member, was developed to solve the high cost and weight problems of the CFT member. To determine stress-strain model of the concrete in an ICH CFT column, possible failure modes of an ICH CFT column were suggested and confining pressure was derived from equilibriums for each failure mode. From the derived equations, a computer program was coded and parametric studies were performed for some examples. Analytical results showed that internally confined concrete has enhanced strength and ductility compared with those of unconfined or biaxially confined concrete.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.11
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• pp.1633-1639
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• 2013

In a section of AC electric railway, a phase between the sections is different although voltage levels supplied from substations are the same. Therefore, section insulators have been installed to electrically divide between the sections. Two differenet types of section insulator, namely an overlap type and insulator type, are used. In Korean high-speed lines, overlap type section insulator has been adopted. And, insulator type is used in conventional line. The overlap type has the advantage of having no speed limit, but has the disadvantage of requiring long section length. However, the insulator type has the advantage of section length, but also has the disadvantage of having speed limit. In Korean conventional line, an insulator type one relies on the import and there is some problem with wear. In this study, we developed the insulator type section insulator which adopts Teflon tube insulation material. The Teflon material has advantage of the excellent electrical characteristics and wear-resistance characteristics for a longer expected life than that made of existing FRP. In order to compare wear characteristics between the materials, wear tests with reciprocal wear tester are performed. And dynamic behavior tests between the insulators and pantograph are also performed for showing its better dynamic characteristics.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.5
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• pp.436-442
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• 2009

This paper describes a study on the design of compact polymer bushing with inner control shield. In the bushing, a high electric stress occurred between field shaper and central conductor by the closely space. Also coaxial cylindrical shield has a great height along the axis to control an electric field. Consequently, all the potentials are raised axially along the field shaper and electric stress is concentrated on a part of the surface of the FRP tube near the upper end of the field shaper. In accordance, the field control can be achieved by means of the designs of such inner control shields. The floating and ring shield designs was decreased electric field concentration at critical parts of the bushing. The shield gaps is formed between field shaper and ring shield. Accordance equipotential lines extend through gaps. As a result, the resulting electrical stress are thus reduced in the range $17{\sim}23%$ in the bushing with floating and ring shield designs. Maxwell 2D simulator based on the boundary element method was also introduced in order to verify the reliability of the polymer bushing. The optimized design uses internal elements for electric stress grading at critical parts of the bushing.