• Journal of Electrical Engineering and Technology
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• 제9권2호
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• pp.662-669
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• 2014

Mineral oil has been widely used as dielectric insulating fluid in transformers due to its excellent performance in-service. However, there are few issues with mineral oil such as it has poor biodegradability and could contaminate the environment if a spillage occurs. With the increasing tight regulation on safety and environment, alternative fluids for mineral oil are currently being investigated and among the suitable candidate is the vegetable oil. There are different types of vegetable oils and one of them is the palm based oil. At the moment, extensive research works are carried out to examine its feasibility to be applied in transformers. This paper will review the previous research works that were carried out to examine the suitability of palm based oil as dielectric insulating fluid in transformers. The physical and chemical properties of palm based oil are studied based on viscosity, acidity, oxidation stability and flash point. Next, the electrical characteristics of palm based oil are examined based on AC breakdown voltage, relative permittivity, dissipation factor and partial discharge.

• 대한건축학회논문집:구조계
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• 제35권6호
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• pp.121-128
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• 2019

There is a big move to build zero-energy buildings in the form of passive houses that reduce energy waste worldwide. Korea has set a goal of reducing its greenhouse gas emissions by 37% by 2030 through the activation of green buildings, such as strengthening the energy levels of new buildings and improving the energy efficiency of existing buildings. The use of insulation with high insulation performance is one of the key technologies to realize this, and vacuum insulation is the next generation insulation that blocks the energy flow of the building. In this study, we measured the bonding structure of dry and wet processing glass fiber core materials and compared the insulation performance of vacuum insulation panel. In addition, the insulation performance of vacuum insulation panel was measured according to the thickness of the laminated core. It can be confirmed that the lamination structure of the core and the lamination thickness are important factors for the heat insulating performance of the vacuum insulating panel.

• 설비공학논문집
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• 제29권1호
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• pp.21-28
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• 2017

Curtain-wall systems have been widely applied to buildings because of their lightweight and constructability characteristics. However, as curtain-wall systems include many building materials, vapor barriers can become damaged and condensation can occur. Due to the material properties of stone curtain-walls, the external appearance and structure of a building could be damaged and the insulating performance of the curtain-wall could be worse. Natural ventilation using an air cavity in a curtain-wall is expected to be effective for the prevention of condensation in inner walls and for the reduction of building cooling energy use in the summer. The purpose of this experimental study is to analyze the influence of a ventilated cavity on the insulating performance of a curtain-wall and the ventilated cavity depth and ratio of top opening needed to prevent condensation in a curtain-wall.

• 한국전기전자재료학회논문지
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• 제18권5호
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• pp.450-456
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• 2005

In this paper, the effect of adhesion properties of semiconductive-insulating interface layer of silicone rubber on electrical properties was investigated. The modifications produced on the silicone surface by oxygen plasma were accessed using ATR-FTIR, contact angle and Surface Roughness Tester. Adhesion was obtained from T-peel tests of semiconductive layer haying different treatment durations. In addition, ac breakdown test was carried out for elucidating the change of electrical property with duration of plasma treatment. From the results, the treatment in the oxygen plasma produced a noticeable increase in surface energy, which can be mainly ascribed to the creation of O-H and C=O. It is observed that adhesion performance was determined by surface energy and roughness level of silicone surface. It is found that at dielectric strength was increased with improving the adhesion between the semiconductive and insulating interface.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 C
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• pp.2026-2028
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• 2000

As the results of evaluation of its performance for 300 kN Ball and Socket type suspension insulators. There was electrically internal puncture of the solid insulating body of the insulating due to the steep front impulse voltage, which usually occurs puncture before external flash-over of insulators, moreover we have obtained satisfactory results in power arc test of 7.2kA cycle fatigue test with high qualify control index of 4.6, especially we have obtained more satisfactory results than that before improvement of its materials.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2003년도 추계학술대회 논문집(III)
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• pp.519-522
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• 2003

'KRS 6330-3256라' standard regulates performance test of insulating transformer for protecting the electronic interlock linkage equipment which is being done by test procedures and methods according to the standard. The balance/unbalance test evaluating the performance of transformer are applied by impulse voltage($l2/200{\mu}s$) but affected by many other factors. Therefore, the review about these is necessary to have the reliability and reappearance of test results. In this paper, we have simulated about several phenomenon appearing in real balance/unbalance test and compared simulated results with real ones. With the basis of these results, the influence to test result of inner and outer factors are investigated and analyzed and established the plan boosting the reliability and reappearance of test results.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 하계학술대회 논문집 Vol.6
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• pp.232-233
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• 2005

The Surface of semi-conductive silicone rubber was treated by oxygen plasma to improve adhesion and electric performance in joints between insulating and semi-conductive silicone materials. Surface characterizations were assessed using contact angle measurement and Fourier transform infrared spectroscope (FTIR). Adhesion level was understood from T-peel tests between plasma treated semi-conductive and insulating material. Electrical breakdown strength was measured to understand the charge of electrical performance. From the results, the oxygen plasma treatment produces a significant increase in function group of containing oxygen which can be mainly ascribed to the creation of carbonyl groups on the silicone surface from the strength were improved. Therefore it is concluded then plasma treatment leads to decrease voids originating form poor adhesive, and the improve the adhesion in silicone interface. So we could obtain higher electrical design level of silicone material used for electrical apparatus using oxygen plasma treatment.

• Transactions on Electrical and Electronic Materials
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• 제18권5호
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• pp.246-249
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• 2017

Pollution flashover of outdoor insulators is a common risk, which affects the safe operation of overhead transmission networks. Early electrical power systems, which feature insulators made from ceramic materials have been used all over the world with good performance. At present, non-ceramic insulators are in common use, as a result of their good electrical as well as mechanical properties. The aim of this paper is to discuss and compare the flashover performance of insulators typically used in power lines, such as, porcelain, ethylene-propylene-diene-monomer (EPDM) rubber, room temperature vulcanized (RTV) and high temperature vulcanized (HTV) coated silicone rubber. The effect of various parameters, including the severity of pollution, ice accumulation, and shade profile, are considered.. From the studies reviewed it was concluded that there is a distinct difference in the flashover voltages of different types of insulators, and the silicone provides the best flashover performance of all insulating materials.

• 콘크리트학회논문집
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• 제15권3호
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• pp.392-399
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• 2003

본 연구는 한중콘크리트 시공 시 초기보온 대책 중 가장 손쉽고 경제적일 것으로 사료되는 단열 보온양생을 대상으로 하였다. 실험은 한중콘크리트 시공조건을 상정하여 기존 거푸집과 각종 단열재 조합에 따른 단열거푸집간의 온도이력을 검토하여 효율적인 단열거푸집을 개발하고자 하였다. 실험결과 $-10^{\circ}C$ 일정인 외기온도 조건에서 벽용 거푸집의 경우, 일반 유로폼인 경우는 초기 24시간 이전에 급속한 온도저하에 의해 $0^{\circ}C$ 이하로 약 7시간 정도 지속되었고, PP＋스티로폼＋합판인 경우는 영상의 온도를 유지하고, 강도발현도 우수하며, 단열거푸집간 비교적 가격도 저렴하여 우수한 단열거푸집임이 밝혀졌다. 슬래브용 거푸집 실험의 경우, 하부는 단열거푸집으로 고정하고, 콘크리트 표면 양생방법을 달리하였을 때, 콘크리트의 온도이력을 측정한 결과, 노출시킨 경우 약 10시간 이후부터 영하로 저하하였고, 비닐+양생포의 경우 약 42시간 이후부터 영하로 저하하였다. 반면, 비닐＋스티로폼+양생포를 사용한 양생의 경우에는 약 55시간 이후부터 영하로 저하하여 노출이나 일반적으로 많이 사용되는 비닐＋양생포와 비교하여 우수한 단열효과임이 밝혀졌다. 7일 및 28일에 있어 슬래브의 코어 압축강도를 측정한 결과는 단열재를 사용하였을 때 크게 나타났다.

• 한국재료학회지
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• 제9권4호
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• pp.409-413
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• 1999

Recently, the polymeric insulators have been accepted in several countries for the outdoor high voltage applications. In comparison with the conventional porcelain, polymeric insulators offer various advantages such as light weight, superior vandal resistance and better contamination performance. The outdoor polymeric insulating materials such as silicone rubber, ethylene propylene diene monomer(EPDM), ethylene vinyl acetate(EVA) and epoxy are aged such as silicone rubber, ethylene propylene diene monomer(EPDM), ethylene vinyl acetate(EVA) and epoxy are aged under the various natural environment with the long-term performance in outdoor. In this paper, the effects of UV-under the various natural environment with the long-term performance in outdoor. In this paper, the effects of UV-ray on the surface of silicone rubber were investigated by using the weather-Ometer. The accelerated aging stresses were simulated by UV radiation, high temperature and humidity as well as water spray. These aging characteristics were examined through contact angle measurements, tracking resistance test, FT-IR and SEM/EDS analysis. The experimental results showed that tracking resistance decreases with increase in the UV-ray irradiation period. But the surface of silicone rubber kept hydrophobicity. It is found that the inorganic filler such as)$ Al(OH_3$ improves tracking resistance and the $Tio_2$is very effective in preventing degradation of silicone rubber surface from UV-ray.