• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 ITC-CSCC -3
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• pp.1740-1743
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• 2002

This paper presents the basic concept of a Solid Freeform Fabrication System using a rapid prototyping procedure. The system can fabricate a ceramic model by laser cutting, accumulating, laminating and sintering of each slice. The system is mainly equipped with a laser apparatus, an x-y table, a material transfer system, and an electric oven. The system could fabricate a small object with smooth surface within comparatively short period of time. The system has also shown its effectiveness in terms of the direct application of the object without the secondary mechanical process. The fabricated sample could directly be applied and used to fairly wide practical areas.

• 한국안전학회지
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• 제26권6호
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• pp.7-12
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• 2011

In recent years, environmental concerns have been raised on the use of poorly biodegradable fluids in electrical apparatus in regions where spills from leaks and equipment failure could contaminate the surroundings. The newly invented vegetable insulating oil is highly biodegradable and have negligible impact on the environment, human health and the ecosystem. For development of the environmental-friendly pole transformer using vegetable insulating oil, the dielectric constructions of the pole transformer were discussed in this paper. Depending on the dielectric constructions, the AC breakdown characteristics of the Nomex insulating papers and the vegetable insulating oil were studied by simulated electrode systems. Based on the experimental results, the maximum design stress($E_{max}$) for insulation design of the environmental-friendly pole transformer were suggested.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 C
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• pp.1757-1759
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• 2000

To make a inspection and maintenance of the high voltage equipment, electric machinery to transmit and distribute the electric power, the appearance of a simple and inexpensive indicator with which the charge condition of bare conductor parts could be read at a Stance has been needed. Liquid crystal has recently been expanding its application rapidly in appliances for everyday use. Since its display energy is extremely small, it is possible to obtain the working current with simple condenser voltage divider that makes use of stray capacity when it is applied to electric power equipment. Thus, an apparatus has finally appeared which is close to the one they have sought and indicates the existence of voltage impressions.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 A
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• pp.345-348
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• 1999

An arc model based on the N-S equations modified by adding an energy source term to take account of the arc is developed and solved using Taylor-Garlerkin FEM in the present paper. The numerical method is applied to the simulation of the opening procedure of a puffer type GCB. Moving boundary conditions of the arc chamber during operation is taken into account. Numerical predictions of the temperature profiles at different strokes are presented.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 C
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• pp.1593-1595
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• 2000

We present a new procedure to evaluate the degradation in a lCr-lMo-0.25V steel. The method is based on the existence of the peak of reversible permeability in the differential magnetization around the coercive field strength. The apparatus is based on the detection of the voltage induced in a surface type coil using a lock-in amplifier tuned to a frequency to the exciting one. Results obtained the reversible permeability and Vickers hardness on the annealed samples show the peak interval of reversible permeability and Vickers hardness decreased as ageing time increased. The correlation between Vickers hardness and the peak interval of reversible permeability could well be evaluated non destructively.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 B
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• pp.1067.1-1067.4
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• 2000

During the last three decades power electronics has gone through energetic technical evolution. The technical needs from wide area such as in industrial, commercial, consumer, aerospace and environmental applications have driven the environment favorably for the power electronics. In the future, two extreme technology-expansion trends are expected: one into low power, and the other into very high power. The former is based on the high frequency and the circuit miniature using VLSI circuit and surface mounting aiming for the system-on-chip (SOC) technology. The latter includes the application areas of power utility such as HVDC, FACTS and SVC and large science area of electrophsycal apparatus such as thermonuclear fusion, acclerators, and electric guns. This paper describes the technology status of some major elements which are available today and the key roles of the power electronics from view points of applications. The author would like to take this opportunity to raise discussions about the future technology development trend of power electronics in our country with the fellow power electronics engineers.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 전기설비
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• pp.91-93
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• 2005

본 논문에서는 전력기기의 온라인 진단을 위하여 개발된 모니터링 시스템에 대하여 소개하고자 한다. 개발된 진단 플랫폼은 전력기기의 온라인 진단을 위해 측정된 부분방전 신호를 이용하여 진단을 위한 파라미터를 추정하고 추정된 결과를 인터넷을 통해 실시간으로 모니터링 할 수 있도록 제작되었다. 개발된 진단 플랫폼은 연산처리를 위한 DSP 신호처리 부분과 웹서비스를 위한 VM부분으로 구성되어 있다. VM부분은 스트롱암 기반의 플랫폼을 적용하였으며 리눅스 환경에서 자바 가상머신을 이용하여 웹 서비스를 구현하였다. 본 논문에서 제시된 기술은 향후 산업용 장치들의 웹 기반 진단 및 모니터링 기술에 이용될 예정이며 또한 스마트 센서 모듈 및 분산 제어 시스템 모듈 개발에 응용될 수 있다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.28-30
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• 2005

This paper presents a scheme on the characteristics of voltage and current unbalance factor under the load variation at the three phase 4-wire system. The voltage unbalance factor of the three-phase 4-wire system is approved by the field measurement. This system is composed of three one-phase transformer with each other capacity. Current unbalance factor is measured by the power quality measurement apparatus and compared by the load unbalance factor. Each phase has an impedance each other by the unbalanced load operation pattern and give rise to voltage unbalance.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 추계학술대회 논문집 전기물성,응용부문
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• pp.182-183
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• 2006

It has been studied about the important consideration in designing and construction of the reliability assessment facilities including the combined testing system for simulating condition of acceleratedly deteriorated environment, which enable to test and evaluate the large-sized HV power apparatus without any disassembly up to transmission class in this paper. Also it is described simply about its ratings and main technical specifications and trial running of the system. To evaluate the performance characteristics against combined test condition for various power installation, especially for the polymer type insulators and kinds of bushings, brief investigation and an analysis of test objects and related international codes and standards have been conducted.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2007년도 동계학술발표대회 논문집
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• pp.640-645
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• 2007

An experimental apparatus to show the hot spot cooling of an IC chip using a thermoelectric cooler is developed. The spot heating in very small area is achieved by the applying CO$_2$ laser source and temperatures are measured using miniature thermocouples. The active effects of thermoelectric cooler on the hot spot cooling system such as rapid heat spreading in the chip and lowering the peak temperature around the hot spot region are investigated. The experimental results are simulated numerically using the TAS program, which the performance characteristics such as Seebeck coefficient, electrical resistance and thermal conductivity of the thermoelectric cooler are searched by trial and error. Good agreements are obtained between numerical and experimental results if the appropriate performance data of the thermoelectric cooler are given.