• Journal of Electrical Engineering and Technology
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• 제10권3호
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• pp.1293-1297
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• 2015

This paper introduces the insulation coordination study results for UHV AC systems which was performed by CIGRE working group. The study results will be discussed within IEC technical committee in order to amend the IEC Insulation Coordination 60071-1 Ed. 8 2010 and 60071-2 Ed. 3, 1996. This paper includes the insulation coordination of transformer, gas insulated switchgear, metal oxide arresters and clearances of transmission towers. This article also illustrates the overvoltage specific to UHV systems such as TOV(temporary overvoltage), switching overvoltage, lightning overvoltage and VFTO(very fast transient overvoltage).

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 하계학술대회 논문집
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• pp.388-389
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• 2009

The use of arc tubes made of ceramic material further enhanced some of the metal halide lamp's properties. These properties translate into higher efficacy with better color rendering, stable color through lamp long life. Recently, due to an increase in the application of the ceramic metal-halide lamp, the study for the property etc. according to Ballast's driving scheme and the study for arc tube material, optimization of gas and so on are being proceeded to improve the property of the lamp. Especially, to control ceramic metal-halide lamp, the vigorous study and practical use with respect to Electronic Ballast, which has been improved in the disadvantages of the conventional Magnetic Ballast are made. In this paper, Electrical characteristics and gas insulation destroy time are analyzed by comparing magnetic ballast with electronic ballast.

• 한국표면공학회지
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• 제48권2호
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• pp.33-37
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• 2015

High efficiency LED device is being concerned due to its high heat loss, and such heat loss will cause a shorter lifespan and lower efficiency. Since there is a demand for the materials that can release heat quickly into the external air, the organic insulating layer was required to be replaced with high thermal conductive materials such as metal or ceramics. Through anodizing the upper layer of Al, the Breakdown Voltage of 3kV was obtained by using an uniform thickness of $60{\mu}M$ aluminum oxide($Al_2O_3$) and was carried out to determine the optimum process conditions when thermal cracking does not occur. Two Ni layers were formed above the layer of $Al_2O_3$ by sputtering deposition and electroplating process, and saccharin was added for the purpose of minimizing the remain stress in electroplating process. The results presented that the 3-layer film including the Ni layer has an adhesive force of 10N and the thermal conductivity for heat dissipation is achieved by 150W/mK level, and leads to improvement about 7 times or above in thermal conductivity, as opposed to the organic insulation layer.

• 한국산학기술학회논문지
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• 제17권6호
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• pp.166-172
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• 2016

원자력발전소 일차 냉각계통 주요 설비의 외부면에 열차폐를 위해 설치되는 반사형 금속단열재의 내진 성능을 확인하기 위한 연구가 수행되었다. 추후 실제 내진 시험 수행을 대비하기 위해서 국내 내진시험 시설에서 시험이 가능한 시편의 크기와 무게의 한도를 고려하여 원전 원자로압력용기의 실제 동특성과 근접한 진동 특성을 가지는 축소모델을 설계하였다. 또한 축소모델의 외곽에 금속단열재를 설치한 유한요소해석 모델을 작성하였으며, 등가정적해석법 및 응답스펙트럼해석법을 통해서 국내 원전의 안전정지지진 층 응답스펙트럼을 적용하여 내진해석을 수행하였다. 보수성을 확보하기 위하여 일차 냉각계통 주요 기기들의 층 응답스펙트럼들을 포괄하는 포괄 응답스펙트럼을 작성하여 가진 데이터로서 사용하였다. 해석 결과 최대응력이 금속단열재 재질의 항복응력보다 충분히 작게 나오는 것을 확인하였고, 따라서 국산화 개발 중인 반사형 금속단열재가 안전정지지진이 발생할 경우에도 구조적 건전성을 유지할 수 있음을 해석을 통해 확인하였다. 본 연구 결과는 추후 수행할 예정으로 있는 내진시험 결과와 비교할 예정이며 이를 통하여 국산화된 금속단열재의 내진 성능을 확보할 수 있고 내진해석과 내진시험을 비교 분석하여 내진검증방법을 체계적으로 구축할 수 있을 것이다.

• 한국자기학회:학술대회 개요집
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• 한국자기학회 2015년도 자성 및 자성재료 국제학술대회
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• pp.94-94
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• 2015

• 한국군사과학기술학회지
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• 제19권4호
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• pp.469-475
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• 2016

Thermal batteries are primary reserve power sources, which are activated upon the melting of eutectic electrolytes by the ignition of heat sources. Therefore, sufficient thermal insulation is absolutely needed for the stable operation of thermal batteries. Currently, excessive amount of heat sources is being used to compensate the heat loss in the cell stack along with the insertion of metal plates and thermal insulators to reserve heat at the both ends of cell stack. However, there is a possibility that the excessive heat flows into the cell stack, causing a thermal runaway at the early stage of discharge. At the same time, the internal temperature of thermal batteries cannot be maintained above the battery operating temperature at the later stage of discharge because of the insufficient insulation. Therefore, the effects of Phase Changing Material(PCM) plates were demonstrated in this study, which can replace the metal and insulating plates, to improve the thermal insulation performance and safety of thermal batteries.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제51권5호
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• pp.199-204
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• 2002

In order to recognize the deterioration of insulation system by partial discharge (PD), the characteristics of PD patterns which are occurring at the interface between epoxy and rubber materials in extra high voltage cable joints, have been investigated. The artificial defects such as voids, metal particles, insulation fiber and water impregnated insulation fiber are planted between the interfaces. A high frequency partial discharge detection system was used for measuring PD signals. An analysis of the PD patterns is focused on the shape of PD pattern, phase, width and time-dependence for each artificial defect. The PD Patterns in each defect show the different behaviors and it is suggested that the precise discrimination of PD patterns could be used for the diagnosis of deterioration in the insulation systems.

• 설비공학논문집
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• 제28권4호
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• pp.153-157
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• 2016

In case of metal insulation, which is produced by stacking stainless steel sheets and air layers in a multi-stack manner at a specific thickness, insulation performance will be evaluated based on thermal transmittance rather than the intrinsic physical properties of each material such as thermal conductivity. However, there is no standard for measuring thermal transmittance targeted for non-homogeneous insulation which is used in relatively high temperature conditions such as a power station. In this study, the thermal conductivity of homogeneous insulation acquired by the standardized guard hot plate method and the thermal conductivity of homogeneous insulation measured by the newly developed performance tester were compared to verify the confidence level of the tester. As a result, thermal conductivity acquired by the newly developed thermal transmittance tester was about 6% higher than the thermal conductivity measured by the existing guard hot plate method under the anticipated service temperature conditions.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 C
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• pp.1443-1445
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• 1997

This paper presents an analysing method to find out an optimum metal shape for insulation strength of SCI(Silicone Composite Insulator). Using finite element method, the interested parameters of the configuration such as a aspect of metal/silicone composite and a material properties are investigated and derived a thread of optimum design parameters.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 추계학술대회 논문집 전력기술부문
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• pp.403-405
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• 2001

This paper presents the detection method of partial discharge in metal clad switchgear(MCS) using electromagnetic technique. Two antennas are located in the inside and outside of the MCS, and electromagnetic waves detected by these antennas are analyzed and compared by FFT method in order to identify an insulation abnormality. As a result of the experiment by the proposed method, we show the detection possibility for partial discharge in the MCS. The proposed method is expected to apply to insulation condition observation and an accident prevention in the MCS effectively.