• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.2067-2068
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• 2008

해안지방의 염분 누적오손 특성을 분석하기 위하여 등가염분부착밀도(ESDD : Equivalent Salt Deposit Density) 측정장치를 국내 112 곳을 선정하여 설치하였다. 해안에서 500m 지점에 풍향, 풍속계를 설치하고, 실시간으로 측정하여 바람에 의한 영향을 분석하였다. 2005년 10월부터 2007년 9월까지 측정한 결과 고창은 해안에서 50m 떨어진 지점에서 최대 D 등급, 2,000m 지점은 B등급까지 오손되었으며, 포항 호미곳은 D등급까지 오손되었다. 분석결과 동해안의 오손특성은 타 지역보다 해안에 가까울수록 부착밀도가 급격히 증가하였으나, 서해안보다는 오손정도가 낮고 남해안보다는 높게 나타났다.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.1513-1514
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• 2015

전력설비가 열화, 서지에 의해 절연이 파괴되었을 경우 밀폐기기 경우 폭발, 화재를 일으킴으로써 일반인에게 피해를 입히거나 인근 설비로 파급이 확대될 가능성이 있다. 최근 전력설비는 대용량화 추세인 반면 콤팩트 사이즈를 요구하고 있어 절연문제로 인한 폭발 가능성은 더욱 커지고 있다. 이러한 전력설비의 폭발을 방지하고 피해확대를 줄이기 위해 방압변, 순간압력상승 방지장치 등이 설치되고 있으나, 예방에는 한계가 있다. 이에 최근, 국외를 중심으로 전력기기 특히, 지상설치기기의 안전성 확보를 위해 고속투입 접지스위치(Arc Eliminator)를 개발하여 설치 의무화를 고려하고 있다.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.1511-1512
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• 2015

자연재해의 특징은 설계불량이나 조작실수 등과 같이 다른 고장과 달리 위험요인을 인위적으로 저감하는 것이 불가능하다. 또한 자연재해는 규모나 양상에 있어서 매우 다양하며 뇌의 경우 위치와 장소에 따라 피해강도는 1,000배 정도 다른 결과를 초래할 수도 있다. 이와 같은 특징을 가진 자연재해를 완전히 예방하는 것은 비현실적이다. 자연재해에 따라 피해는 위험도와 전력시스템의 취약성이 교차하는 영역에서 발생한다. 피해를 저감하기 위해서는 취약성을 감소시키고, 이 교차 영역을 가능한 작게 하는 것이 기본개념이다.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.49 no.5
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• pp.665-670
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• 2016

A three-dimensional ecological model (EMT-3D) was used to simulate the behavior of PFOA in Gwangyang Bay, Korea. The results of sensitivity analysis showed that partition rate, adsorption rate, and settling rate were important factors in the variation in PFOA in particulate organic matter. Bioconcentration was the most significant factor for PFOA in phytoplankton, with the largest effect size. These parameters must therefore be carefully considered when modeling PFOA behavior. In simulations, 30% and 50% reductions in loads from land-based sources of PFOA resulted in concentrations of dissolved PFOA lower than 4 ng/L and 2 ng/L, respectively, in the central part of the bay.

• Proceedings of the KSME Conference
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• 2001.06a
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• pp.126-131
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• 2001

Materials property data are necessary to secure the reliability of failure prevention techniques such as inspection and remaining life assessment of civil infrastructure and industrial facilities. However, there is no properly collected data in Korea, and those foreign data are hard to use because of the scattering of the sources, the difference of standards, etc. In this paper, materials property database system which has been constructed at Korea Research Institute of Standards and Science is introduced. Constructed database contains 145,000 numeric data of materials property for 600 kinds of metals and can be retrieved on the internet. The database system provides graphical user interface-based information searching functions necessary for the life evaluation and safety analysis.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.05c
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• pp.7-10
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• 2002

In this study, polyolefin compounds were developed and evaluated for replacing a jacket material of URD power cables. The characteristics of compounds were investigated by water vapor transmission (WVT) test and mechanical test. In WVT test, all polyolefin compounds showed the superior water resistance to conventional PVC. The molecular structure and density of polyolefin play an important role in WVT. Also, polyolefin compounds showed the suitable characteristics in mechanical test. Especially, polyolefin compounds having linear molecules showed the superior characteristics to LDPE ones. From this study, it can be considered that polyolefin compounds may be suitable to jacket material for URD power cables.

• Proceedings of the KIPE Conference
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• 2010.07a
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• pp.347-348
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• 2010

본 논문에서는 기본적인 직류-직류 변환기 중 하나인 동기식 강압형 직류-직류 변화기를 디지털 제어로 구현함으로서 아날로그 제어기를 디지털 제어기로 변환 하는 과정에 관하여 설명한다. 먼저 전원단의 소신호 특성을 해석하여 제어대 출력전압의 전달함수를 찾아내고, 이것을 토대로 아날로그 제어기를 설계 하여 Simulink를 통하여 시뮬레이션을 수행하고, 설계된 아날로그 제어기를 바탕으로 Matlab을 이용한 Emulation 기법을 사용하여 디지털 제어기를 설계 한다. DSP(TMS320F28335)를 사용한 동기식 강압형 직류-직류 변환기에 설계된 디지털 제어기를 적용하여 안정도와 부하변동에 따른 응답 특성을 확인 한다.

• Proceedings of the KIEE Conference
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• 2002.07c
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• pp.1446-1448
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• 2002

The short-time permissible temperature of an overhead distribution line conductor is determined by the softening characteristics of ACSR-OC, ACSR AW/OC 160, typical conductors employed in the overhead distribution line. Transient heat transfer equation and Newton's cooling law were applied to analyze the heating and cooling effects of the insulating conductors, respectively, and the error of co-relation was calibrated after simulating the softening test to assess the short-time characteristic of the insulating conductor. In order to verify the softening characteristic, the conductors were tested with heat cycle. The test was totally carried out 200 cycles, and 1 cycle was to heat and cool at 1.1 times permissible current of the conductor, 1.15 times for 120 minutes, respectively. After heating, the tensile strength and surface of the conductor were observed. In case of ACSR-OC, as the result of 100 hour heating test, the tensile strength of the insulator was 0.8 times the initial value. This is equivalent to the value of the conductors which are used for 10 years at sites.

• Proceedings of the KIEE Conference
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• 2002.07c
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• pp.1896-1898
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• 2002

In this paper, to developing thermally and mechanically upgraded ones, we dismounted pole transformers used in the fields for over 13 years and conducted aged oil analysis. Also, when the cellulose and aramid papers in test cell were aging with oil at $130^{\circ}C$ for 3000 hours, with the testing period cellulose paper deteriorated more rapidly than the others. For example dielectric strength and dissipation factor of papers deteriorated with aging time. For evaluation of thermal aging characteristics, a mineral oil-immersed transformer was constructed with hybrid insulation system comprised of aramid paper and cellulose insulation. A Hybrid system has economic advantages. Cellulose materials are confined to cooler regions of the transformer winding. And aramid papers are served to insulate contact parts of hot conductors.

• Korean Journal of Pharmacognosy
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• v.40 no.1
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• pp.70-76
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• 2009

Thirty six essential oils from herb drugs entered in Korean official formulary, which are frequently used in oriental region, were tested for antibiotic resistance inhibition. When the oils were combined with ampicillin (Am) or amoxicillin (Amx) they showed significant inhibitory effects on the growth of multi-drug resistant Staphylococcus aureus SA2 in considerably low concentration. The most effective combinations were oils from Acanthopanacis Cortex ($0.49{\mu}g/mL$) with Am and Cnidii Rhizoma and Lonicerae Flos (2.77 and $2.79{\mu}g/mL$, respectively) with Amx as shown in minimum resistance inhibitory concentrations.