• 한국수소및신에너지학회논문집
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• 제31권2호
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• pp.194-201
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• 2020

Recently, Type 2 high-pressure hydrogen storage tank is studied due to fast defect detection, easy manufacturing, and cost efficiency. Moreover, the dry winding a high-strength metal wire will make increased economic efficiency compare with the wet winding method and the carbon/glass fiber winding method. In this study, a theoretical study on the dry winding of a Type 2 high pressure hydrogen tank using a metal wire was done, and the equations of the total stress on the aligned and the staggered winding for the hoop winding were derived, and the following results were obtained by using these equations. As the diameter of the metal wire, the number of winding layers, and the outer diameter of the liner increase, the maximum stress decreases, but the difference between the maximum stress occurring in the aligned winding and the staggered winding increases. As the pressure increases, the thickness of the winding layer increases, but as the strength of the metal wire increases, the thickness of the winding layer decreases. In addition, regardless of the strength of the metal wire, the thickness of the winding layer of the staggered winding was about 13.4% thinner than that of the aligned winding.

• 한국초전도저온공학회:학술대회논문집
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• 한국초전도저온공학회 2003년도 학술대회 논문집
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• pp.58-61
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• 2003

A typical HTS power transmission cable has multi-layer conductor structure to increase the current capacity. The current distribution among the conductor tapes is controlled mainly by pitches and winding directions of the layers, because the inductance of the layer is determined by the pitch and the winding direction. However, usually the current is not evenly distributed among the layers. This paper describes a method to make the current distribution more uniform and hence reduce the AC loss. If we choose a good combination we can find the optimal pitches and make an even current distribution. We studied the effect of the winding direction on a 2-layer cable by a statistical way. Calculation results and discussions will be presented.

• Journal of Electrical Engineering and Technology
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• 제1권3호
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• pp.308-312
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• 2006

The inductance difference between conducting layers of high-Tc superconducting (HTSC) power transmission cable causes the current sharing of each conducting layer to be unequal, which decreases the current transmission capacity of HTSC power cable. Therefore, the design for even current sharing in HTSC power transmission cable is required. In this paper, we investigated the current distribution of HTSC power cable with a shield layer dependent on the pitch length and the winding direction of each layer. To analyze the effect of the shield layer on the current sharing of the conducting layers of HTSC power cable, the current distribution of HTSC power cable without a shield layer was compared with the case of HTSC power cable with a shield layer. It could be found through the analysis from the computer simulations that the shield layer of HTSC power cable could be contributed to the improvement of current distribution of conducting layers at the specific pitch length and the winding direction of conducting layer. The result and discussion for the current distribution calculated for HTSC power transmission cable with a shield layer were presented and compared with the cable without a shield layer.

• 한국초전도ㆍ저온공학회논문지
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• 제5권3호
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• pp.38-42
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• 2003

HTS transformer is promising one of HTS power applications to be commercialized in the near future. To realize the applications, insulation technology in the coolant, liquid nitrogen, should be established. So breakdown characteristics should be considered at insulation components; turn-to-turn, layer-to-layer, winding-to-winding, were investigated. Firstly breakdown strengths of Kapton films were compared with Kraft paper these are as turn insulator. And next the characteristics of surface flashover on FRP were measured and the influence on breakdown strength of bubble generated with joule heat was discussed with the shape of cooling channel between layers. Finally barrier effect at winding-to-winding was discussed.

• 한국초전도ㆍ저온공학회논문지
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• 제5권1호
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• pp.35-39
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• 2003

A typical HTS power transmission cable has multi-layer conductor structure to increase the current capacity. The tapes of the innermost layer are wound on a round former, and adjacent tapes of another layer are separated by a thin insulating film. However, usually the current is not evenly distributed among the layers because of inductance difference of each layer, and the inductance is provided by the winding pitch of each layer's tape. Consequently n method to make the current distribution more uniform is a adjusting the tape winding pitch, hence reduce the AC loss. This paper describes a current distribution by adjusting a tape winding pitch of each layer. Also, this paper shows recommendations for future cable conductor prototypes.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1993년도 하계학술대회 논문집 B
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• pp.584-587
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• 1993

Mica, which have a good thermal and electrical characteristics, while will cleave easily at these layers. In order to bond mica materials soldily, mica/epoxy composite insulation materials were developed for generator stator winding. There are lots of problems such as delamination and partial discharge of these insulation materials caused by mechanical, electrical and thermal aging. Several experiments have been conducted in order to find the useful diagnostic parameters from the partial discharge phenomena by applying a new measurement techniques. this paper deals with the partial discharge pulse characteristics, which may be a useful diagnostic concept in predicting insulation condition of generator stator insulation materials. Long term insulation aging test shows that partial discharge phase angle an magnitude are identified as one of the main key techniques for insulation diagnosis on generator stator winding.

• 한국화재소방학회논문지
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• 제21권4호
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• pp.59-64
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• 2007

본 논문은 전동기에 발생하는 화재에 대한 연구로서, 일반가전제품에 사용되고 있는 단상유도전동기에 과부하 및 외부화염을 가하여 그 변형 및 파손상태를 비교 분석하였다. 실험은 전동기의 구속을 통한 과부하 시험과 외부에서 화염을 가하는 실험으로 진행하였으며, 외부화염 시험의 경우 전압을 인가한 경우와 인가하지 않은 경우로 구분하였다. 실험결과 구속을 통한 과부하 시험의 경우 권선부분에서 층간 단락흔을 관찰할 수 있었고, 권선부분의 조직에서는 과부하에 의해 변형된 전선의 특징인 나무줄기 형상의 수지상 조직이 나타났다. 전압을 인가한 상태에서 외부화염을 가한 경우 고정자 권선부분의 코일이 원형을 유지하고 있는 것을 확인할 수 있었고, 권선주변의 색이 붉게 변색된 것을 볼 수 있었다. 전압을 인가하지 않고 외부화염을 가한 경우 고정자 권선부분의 코일이 원형에서 많이 변형된 것을 관찰할 수 있었고, 권선 주변의 색은 전압을 인가한 경우와 마찬가지로 붉게 변색된 것을 확인할 수 있었다.

• 대한토목학회논문집
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• 제28권6A호
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• pp.861-872
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• 2008

콘크리트충전 유리섬유 복합소재 튜브는 좋은 내구성과 심한 부식환경에서 견딜 수 있는 높은 화학적인 저항성으로 인해서 해양구조물에서 종종 사용된다. 이 연구는 원형 콘크리트충전 유리섬유 복합소재 튜브에 대한 다양한 실험을 수행하고 결과를 분석한다. 유리섬유 직포 수적층, 필라멘트 와인딩 적층을 압축을 받는 관의 바깥 튜브로 사용하는 경우에 고려해야 하는 몇 가지 측면을 실험 분석한다. 이 연구의 목적은 다음과 같다: (1) 유리섬유 층의 필라멘트 와인딩 각도의 효율성 검증 (2) GFRP 적층수가 강도 및 최고 변형률에 미치는 영향 평가 (3) 단부 재하조건이 구속효과 및 파괴양상에 미치는 영향 파악, 그리고 (4) 구속 상태에서 콘크리트의 응력-변형률 거동을 모사하는 해석적인 모델 제시이다. 세 가지 서로 다른 종류의 섬유 구성이 사용되었다: 직포층, ${\pm}45^{\circ}$ 필라멘트 와인딩 층, 그리고 ${\pm}85^{\circ}$ 필라멘트 와인딩 층. 각 층은 독립적으로 혹은 복합적으로 함께 사용되었다. 시편의 비 및 지름이 서로 다른 경우도 실험하였다. 총 27개의 GFRP 튜브 시편을 이용해서 인장 실험을 수행하였고, 66개의 콘크리트충전 GFRP튜브 시편을 이용해서 압축 실험을 수행하고 결과를 분석하였다. 구속상태의 콘크리트 응력-변형률 거동을 모사하는 해석적인 모델 및 영향계수를 제시하였다.

• 한국세라믹학회지
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• 제50권6호
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• pp.359-363
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• 2013

Silicon carbide and its composites are being considered as a nuclear fuel cladding material for LWR nuclear reactors because they have a low neutron absorption cross section, low hydrogen production under accident conditions, and high strength at high temperatures. The SiC composite cladding tube considered in this study consists of three layers, monolith CVD SiC - $SiC_f$/SiC composite -monolith CVD SiC. The volume fraction of SiC fiber and surface roughness of the composite layer affect mechanical and corrosion properties of the cladding tube. In this study, various types of SiC fiber preforms with tubular shapes were fabricated by a filament winding method using two types of Tyranno SA3 grade SiC fibers with 800 filaments/yarn and 1600 filaments/yarn. After chemical vapor infiltration of the SiC matrix, the surface roughness and fiber volume fraction were measured. As filament counts were changed from 800 to 1600, the surface roughness increased but the fiber volume fraction decreased. The $SiC_f$/SiC composite with a bamboo-like winding pattern has a smaller surface roughness and a higher fiber volume fraction than that with a zigzag winding pattern.

• 한국전기전자재료학회논문지
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• 제19권3호
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• pp.273-279
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• 2006

High-$T_c$ superconducting (HTSC) power cable is one of the interesting parts in power application using HTSC wire. However, its stacked structure makes the current distribution between conducting layers non-uniform due to difference between self inductances of conducting layers and mutual inductances between two conducting layers, which results in lower current transmission capacity of HTSC power cable. In this paper, the transport current distribution between conducting layers was investigated through the numerical analysis for the equivalent circuit of HTSC power cable with a shield layer, and compared with the case of without a shield layer. The transport current distribution due to the increase of the contact resistance in each layer was improved. However, its magnetization loss increased as the contact resistance increased. It was confirmed from the analysis that the shield layer was contributed to the improvement of the current distribution between conducting layers if the winding direction and the pitch length were properly chosen.