A lighting method of our county is ordinary center concentration form. Therefore, it is usally used the Five Point Method, Multiplicity Method of KS, and Four Point Method of IES to measure a space illuminance. We can use the Five Point Method of KS when we measure a uniformity ratio or activities that happen in space is more sensitive than whole illumination. In addition, we can use the Multiplicity Method of KS and Four Point Method of IES when we measure whole illuminance like mean illuminance. Such method of measurements should be used exactly according to the kinds of space and activities.

In this paper discusses single-phase DC-AC Inverter design of reversible power converter that driven by binary combination at different transformer winding ratio by BCD code level. It has a advantage that constructs a control system simply and obtain load current of good quality without filter circuit and free from noise or isolation for lower switching frequency. In this research, study on current type converter and inverter circuit that consist for possibility of AC-DC/DC-AC multi-level reversible converter.

It is important to select light sources and luminaires in the process of lighting design. Therefore, development of light sources has been constantly grown for a high efficacy and long life. And, the design of luminaires has been developed for the reflection of light mechanism. But it has been not enough to study for the refraction of light mechanism Therefore, the propose of this study is to study for the refraction of light mechanism. In addition, this study is modeling for the luminous intensity distribution of planar prism to use the results of photometric data that is able to obtain various luminous intensity distribution.

새로운 address-display 중첩 구동기술을 개발하고 실험용 PDP에 적용하였다. 이 구동방식은 priming 방전을 사용하지 않으며, 공간전하를 효과적으로 이용하기 위하여 sub-field의 addressing 순서를 제어하였다. 그 결과 20V의 전화면 address 구동마진을 확보하였고, 최대 1920개의 sustain 펄스를 인가할 수 있었으며, 최대 휘도 $720cd/m^2$와 절대 흑레벨의 배경휘도와 함께 명암비 무한대를 얻었다.

본 연구는 최근 서울시를 중심으로 진행되고 있는 도시 가로조명의 광원교체에 따른 조명환경 개선효과를 조사 분석하였다. 조사대상은 이미 기존의 나트륨램프를 고효율 메탈할라이드 램프로 교체한 서울시 종로구의 창경궁길로 선정하였다. 평가방법은 조사대상을 중심으로 야간의 교체 전, 후의 조명현황조사 및 물리량을 측정하였으며, 이를 토대로 개선효과를 분석하였다. 분석결과, 광원을 교체한 후 수평면 조도는 약 1.4배, 스칼라 조도는 약 1.3배 증가하였으며, 공간의 평균 휘도값은 $0.06cd/m^2$ 증가하였다. 색온도는 2,399[K]에서 3,632[K]로 증가하여 공간의 느낌이 따뜻한 느낌에서 차가운 느낌으로 변화되었는데, 이는 기존의 평온한 이미지에서 부드러운 이미지로 변화 된 것으로 분석된다. 색도는 주황색에 가까운 노란색에서 엷은 노란색을 띠는 백색으로 변화되었으며, 이는 램프의 연색성에 의하여 사물의 식별성에 대한 가시도가 증가한 것으로 분석된다. 또한, 에너지 절감형 친환경 메탈할라이드 램프의 교체에 의하여 앞으로 연간 에너지 절감효과도 클 것으로 기대된다.

태양광 채광시스템은 자연광의 유입이 어려운 공간에 주광을 유입하기 위하여 개발된 장치로써 에너지를 절약하고 인간의 쾌적성을 향상시키는 등 지속가능한 건축을 위해 도입 및 확대가 크게 기대 되는 장치이다. 이에 본 연구는 기존에 본 연구실에서 개발된 시스템의 문제점을 보완하고 개선하여 건축물 적용시의 채광성능을 평가하는데 연구목적이 있다. 본 시스템의 설치는 2004년 10월 25일 (주) 동아산전과의 공동작업으로 설치되었으며, 수원에 있는 K대학 공과대학 5층 옥상 파라펫에 설치하였다. 평가실험은 2005년 4월 5일 9시30분부터 15시30분까지 청천공 상태에서 실시하였고, 총32개의 측정점을 선정하여 주광조도비로 채광성능을 평가하였다. 실험결과, 반사거울을 설치 시 창이 있을 경우 실내의 주광조도비는 평균 20.3[%] 상승하였고 창을 제거할 경우 실내의 주광조도비는 평균 38.2[%]정도 상승하여 채광학적으로 유효한 것으로 분석되었다. 따라서 본 시스템은 건축물의 실내 및 옥외의 음영진 곳에서 유용하게 사용될 수 있음이 입증되었다.

IGBT를 이용한 형광등 백라이트 제어기를 설계 제작하여 특성 실험을 한 결과, 타 방식의 백라이트 제어기 비하여 고효율, 고역률, 고품질의 특성을 가지는 한편, 스위칭 시에 발생하는 피크 전류 및 노이즈로 인한 인접 전기전자기기에 영향을 미치지 않도록 함으로써 안정성이 뛰어나며, 또한 기존의 슬라이닥스를 이용한 전원장치를 대체하는 한편 원격제어를 손쉽게 구현할 수 있는 장점을 가지고 있다. 또한 본 제어기는 제로크로싱 동기를 채택하여 온 오프 시에 발생하는 피이크 전류를 방지함으로서 제품의 안전성을 극대화시킬 수 있는 장점을 가지고 있어 차후 산업용 전원 장치 및 각종 가변 전원을 필요로 하는 대상에도 광범위하게 응용될 수 있을 것이다.

열악한 환경과 점검이 곤란한 장소에 설치되는 전자식안정기용 원격 감시와 제어 시스템을 RF를 사용하여 설계 제작하였다. 본 연구에서는 시제품을 개발하여, 안정되게 동작함을 확인하였다.

In this paper, we investigate a filtering technique to reduce the adverse effect of long motor leads on H-bridge cascaded 7-level inverter fed ac motor drive. The switching surge voltage becomes the major cause to occur the insulation failure by serious voltage stress in the stator winding of high voltage induction motor. However, the effect of switching surge appears un seriousin high voltage induction motor than low voltage induction motor. Consequently, we demonstrated that the filter connected to the motor terminals greatly reduces the transient voltage stress and ringing, moreover we show lowers the dv/dt of the inverter switching pulse. The results of simulation show the suppression of dv/dt and the reduced peak voltage at the motor end of a long cable.

For a fire cause judgement this paper describes the short circuit characteristics of a electric wire through the cross section analysis under ac condition. The cower wires prepared for the experiment were 1.2mm, 1.6mm, and 2.0mm in diameter. Through the cross section analysis(CSA), it was confirmed that the dendrite structure grew at the angle of about $40^{\circ}\;or\;60^{\circ}$ when the fusing current was applied to the wires. The larger the fusing current is, the more decreased the growth angle of the dendrite structure is. It was confirmed that the dendrite structure was arranged like the columnar structure. In this paper, the characteristics analysis of short circuit was carried out in the range of transient duration and the correlation constant k was investigated by measuring the short circuit duration and the fusing current.

This paper describes the experimental results of the pre-breakdown phenomena in $SF_6/CO_2$ mixtures under non-uniform electric fields caused by positive and negative lightning negative voltages. $SF_6/CO_2$ mixtures have an advantage of an environmental aspect and cost reduction, and safety aspects. In order to analyze the pre-breakdown processes in $SF_6/CO_2$ mixtures stressed by impulse voltages, pre-breakdown current and luminous signals were measured by a shunt and a photo-multiplier tube, respectively. Dielectric strengthes of $SF_6/CO_2$ mixtures were investigated. Additionally, characteristics of discharge channels were observed by high speed cameras and the physical properties were discussed. The pre-breakdown propagates with a stepwise process. The in to breakdown from the corona onset point in positive polarity was shorter than that in negative polarity. The time intervals of positive leaders are shorter than those of negative leaders, and the path of positive leader channel is zigzag.

This paper describes the cut off time and the current characteristics of virgin RCDs and deteriorated ones in the seashore. The RCDs(Residual Current Protective Devices) are used for protecting the human body from electrical shock and for preventing facility accidents. According to the Korean standards, the RCDs are installed in panel boards. When RCDs are installed outside, they must be enclosed inside waterproof cases. In the case that RCDs are employed at temporary power sites and electrical facilities on the road they are exposed to the external environment. As a result, the RCDs deteriorated in the seashore for 3 months showed high failure rate, while the virgin RCDs all complied with Korean Standard. Considering that the RCDs are used under exposed condition outside, the reliance of RCDs must be ensured by modifying the related regulations and codes and by developing improved advanced in their performance.

This paper presents the reduction characteristics of penetrated electromagnetic fields through a narrow slot aperture in a planar conducting screen of infinite extent. When a plane wave is excited to the narrow slot, the aperture electric field is controlled by the parallel plate connected on the slot. The magnitude of penetrated electromagnetic fields through a narrow slot is controlled by electric field distributions on the slot aperture. An integral equation for the aperture electric field on narrow slots is derived and solved by applying Galerkin's method of moments. The results show that the magnitude of the penetrated electromagnetic field can be effectively reduced by installing the parallel plate on the slot aperture.

The arc dispersion and contacts characteristics were analyzed according to switching off Residual Current Protective Device(RCD) switch. Arc dispersion process was taken by high speed imaging system at a rate of 10,000 frames per second. When RCD was switched from on to off, art was observed and it took about 2.3[ms] from the generation of arc to the extinction of arc. When RCD was switched from off to on, arc was not observed. We repeated switching on and off 1000, 3000 and 6000 times. After repetition, the surface characteristics of contacts were taken by stereo microscope and Scanning Electron Microscope(SEM). From the scattering patterns analysis of arc and the analysis of deteriorated contacts, it could be applicable to the research of electric fire and arc suppression.

Most of the loads in industrial power distribution systems are balanced and connected to three power systems. However, voltage unbalance is generated at the user's 3-phase 4-wire distribution systems with single & three phase. Voltage unbalance is mainly affected by load system rather than power system. Unbalanced voltage will draws a highly unbalanced current and results in the temperature rise and the low output characteristics at the machine. It is necessary to analyse correct voltage unbalance factor for reduction of side effects in the industrial sites. Voltage unbalance is usually defined by the maximum percent deviation of voltages from their average value, by the method of symmetrical components or by the expression in a more user-friendly form which requires only the three line voltage readings. If the neutral point is moved at the 3-phase 4-wire system by the unbalanced load, by the conventional analytical method, line and phase voltage unbalance leads to different results due to zero-sequence component. This paper presents a new analytical method for phase and line voltage unbalance factor in 4-wire systems. Two methods indicate exact results.

This article suggests an improved method for more accurate load forecast for the power system. The authors propose an improved load forecast expert system based on expert's know-how. A field manual for the load forecast can be made using proposed method. The authors expect this article could give a guidance to those who wish to be load forecast expert.

A study to assess and show applications of the easy lighting constructions of the new technics has presented in this paper. we have taken the present men-power to determine the optimum levels of the selected labour cost and analysis of the unit prices on the new developed lighting device for modularized to unit length, named Lite-way.

In this paper, when electric train is in dead-section the effect on electric train system was dealt. The feeding system of electrical railway is AC or DC. When the electric train is passed AC feeding system to DC, vice versa or phase is changed in between AC feeding systems, there is a dead section. A dead section usually makes the electrical system complex md may have an adverse effect on the electrical system inside the train. Accordingly, it is important to analyze the effect on trains in dead-section. Modeling an electric train and simulation using PSCAD/EMTDC was accomplished to analyze how power quality problem such as inverter switching surge is propagated to electric train through the feeding line, railway, pantograph.

조명기술의 발전에 따라 현대의 박물관에서는 조명에 의한 다양한 연출 효과를 얻기 위해 같은 전시공간 내에서도 여러 종류의 광원들을 사용한다. 이는 역으로 각각의 유물들이 다양한 환경의 빛에 노출되어 전시되고 있다는 것을 말해준다. 유물의 전시를 위한 최적의 조명환경 조건과 보존을 위한 최적의 조명환경 조건이 서로 다른 측면이 있다. 본 연구에서는 신 국립중앙박물관의 전시실 및 진열장에 조사되는 광복사량, 복사분포 등을 측정하였으며, 측정 데이터를 바탕으로 국립중앙박물관의 조명환경을 비교, 분석하여 보았다.

형광램프의 절전화에 있어서 기본적으로 고려해야 할 점은 램프측의 절전은 램프전력을 감소시키고, 안정기측의 절전은 램프전류를 감소시킴으로써 이루어진다. 형광램프의 절전화에 있어 핵심요소는 봉입기체의 변경, 관경의 세관화 그리고 형광체의 개량에 있다. 즉, 램프 전력을 절감하기 위해 최적의 봉입기체를 선택하도록 하고, 램프전류를 억제하기 위해 관경을 줄이는 한편, 관경의 축소에 따른 형광체의 열화를 막기 위해 3파장 형광체와 같은 새로운 형광체를 사용해야 한다. 본 논문에서는 FPL36W에 대해 전기적 특성시험과 안정기수명시험 및 램프수명말기시험, 저온에서의 온 오프 시험 등을 실시하여 전자식 안정기 성능을 향상시키는 방안을 모색하였다.

In this paper, LED traffic signal lamp's operating circuit using Flyback converter and PFC IC has been presented. Most power conversion circuits use PFC IC for Power Factor Correction. The design parameter's value of Flyback converter has been proposed and the error amplifier which regulates the output voltage has been designed Besides, the under voltage protection circuit and the over voltage protection circuit for protecting the operating circuit kin unbalance of common electric power source and the temperature compensation circuit for fixed optical output power have been proposed.

This study examined the luminance and light appearance about 14 flood lighting established bridges of 26 Han River bridges and then analyzed the result through questionnaire and so on. Through this result, we looked out for new direction of analysis research for flood lighting that consider the problem of optimum brightness and light appearance harmony at flood lighting presentation, proposed to be utilized concretely in lighting design guideline for Han River bridge.

최근 에너지 절약에 대한 관심이 고조되면서 기존 광원보다 효율이 좋은 광원개발이 계속되고 있으며 그 대표적 것이 고출력(high-power) LED이다. 고효율 LED의 개발로 인해 일부에서는 일반 조명용으로 사용하려는 연구가 진행 중이며 풍력과 태양광 발전을 이용한 야간 조명용 전원으로 사용하려는 연구도 진행되고 있다. 이에 본 논문에서는 조명용 광원으로 직류 전원을 이용한 고출력 LED의 사용 가능성을 확인하고자 하며 기존 방식에 비하여 보다 안정적이고 효율이 좋은 새로운 LED 전원구동장치를 제안한다. 제안된 방식은 기존의 방식에 리액터의 크기를 줄일 수 있었으며 효율이 개선됨을 확인하였다.

This study purposes to increase the energy-saving effects by reducing excessive intensity of radiation of artificial lighting through analyzing daylight incident A photosensor sends amounts of detected luminous flux to digital control unit(DCU) as a signal and then, it can decide dimming ratios, received a proper dimming signal from DCU. Generally it Is effective to control artificial lighting with the different control ratio of each row by setting a photosensor as same numbers and rows as artificial lighting. However, it is ineffective to do in initial costs of systems aspect in offices. As a result of grasping the distribution of daylight previously, we can dim different dimming ratios to each row of artificial lighting by a single photosensor.

Outdoor lighting is an important factor of urban scape. As a night image of the city, outdoor lighting acts important roles. Cities of developed countries have already had night images of their cites. About this, government is encouraging outdoor lighting of building by various ways. However, in present, outdoor lighting of headquarter buildings was not activated more than that of public buildings in our country. From this point of view, this paper presents a method to measure outdoor lighting effects as quantitative aspects for outdoor lighting activation. Presented the method of outdoor lighting effects is difficult to apply all buildings. Therefore, this paper limits the target to the headquarter buildings.

Recently, a drain of energy resources is issued seriously. The daylight responsive dimming systems can reduce electric energy uses. But, we cannot predict amounts of energy-saving and accuracy of system performance. Therefore, the purpose of this study is a development of software for the system performance of daylight responsive dimming systems. The principle of this software based on luminous flux transfer method and finite elements method. The control algorithm of this software and daylight responsive dimming systems use the same algorithm. In addition the advantages of this software are use to same algorithm of daylight responsive dimming systems, electric power-luminous flux data and rates of frequency of sky conditions. Therefore, this software can predict more correct calculation about illuminance and amounts of energy-saving of daylight responsive dimming systems.

유전자 알고리즘은 전체 탐색 공간을 통해 전역 해를 찾는 최적화 알고리즘으로서 복잡한 상태 공간에서 최적 해를 찾기 위해 전통적인 최적화 기법과는 달리 유향성 임의 탐색을 행한다. 또한, 유전적 탐색과 국부 탐색을 결합시킨 복합 유전자 알고리즘은 최적해로의 수렵 속도를 향상시킬 수 있다. 이 논문에서는 함수 최적화를 위해 학습 속도를 개선한 복합 유전자 알고리즘(C-AGA)을 제안한다. 제안한 최적화 알고리즘의 효율을 기존의 복합 유전자 알고리즘 기법(라마키안 진화 및 볼드윈 효과)과 비교 평가하였다. 다양한 함수 최적화 문제에 대하여 제안한 알고리즘이 기존의 방법보다 더 빨리 전역 최적 해를 찾을 수 있음을 증명하였다.

We present the method to obtain four speckle patterns with relative phase shift of ${\pi}/2$ passive devices such as wave plate and polarizer, and calculate the phase at each point of the speckle pattern in shearographic system using Wollaston pin And, we analyzed the phase error caused by wave plates used in the proposed method by Jones matrix.

In this paper the experiments of insulation characteristics by temperature change of $SF_6$ gas and liquid $SF_6$ in model GIS(Gas Insulated Switchgear) were described. From this results, the breakdown voltage was increased with a drop of temperature and an increase of the inner pressure in model GIS. The ability of insulation in liquid $SF_6$ was higher than that of the highly pressurized $SF_6$ gas. A liquid $SF_6$ discharge characteristics was caused by bubble formed evaporation of liquid $SF_6$ and bubble caused by high electric emission. It is considered that these result are fundamental data for electric insulation design of superconductor and cryogenic application machinery which will be studied and developed in the future.

산업현장에서 많이 사용되고 있는 전력기기에 결함이 발생하면 치명적인 사고로 진전되어 경제적, 인적 손실이 발생될 수가 있다. 본 논문은 GIS에 사용되는 절연가스인 $SF_6$의 압력 변화에 따른 부분 방전을 모의하고, 발생되는 부분방전 신호를 절연 진단 방법 중 하나인 UHF법을 이용하여 부분방전 시 방사되는 방사전자파의 스펙트럼을 분석해 금속이물질이 $SF_6$가스 부분방전에 미치는 영향을 측정하였다. 이러한 연구는 현장 GIS 및 $SF_6$ 가스절연 전력설비에서 내부압력 변화 시 금속이물질에 의해 발생되는 절연파괴 사고의 방지에 중요한 역할을 할 것으로 사료된다.

본 연구는 한국 조명전기설비학회에 게재된 학술논문 및 DBPIA에서 검색된 조명관련 학술논문을 대상으로 조명 분야의 연구동향을 살펴본 것이다. 그 결과, 한국 조명전기설비학회지에 발표된 전체 논문 수는 꾸준히 상승하고 있었으나 조명분야의 논문 수와 저자 수는 매우 열악함을 알 수 있었다. 또한 다른 학회에서 조명분야를 연구하는 동향을 살펴본 결과, 건축분야에서 가장 많은 연구가 이루어짐을 알 수 있었으며, 우리나라 조명학 연구자 Pool은 2004년 기준 276명으로 파악되었다.

Colors are in the inseparable relation ia the all parts of human life. The color influences not only our psychological and physiological aspects, but also our way of behavior. The purpose of this study was to investigate the color preference and the personal color of 100 university students. As results of researching current university students color preference when we compare it with pre-studied results, it shows some differences. In pre-studied, the blue and black marked high degree, but for recent students, it has appeared that warm color is highly preferred. Also warm color has shown as the personal color. There were significant differences in the relation between the blood type and color preference. It appears that the blood type A and B were preferred to cold color while the blood type of B and AB were preferred to warm color.

생활체육(life-time sports)은 태어나서 죽을 때까지 평생에 걸친 체육 스포츠 활동을 일상생활 내용으로 하는 것이다. 생활체육의 주목적은 신체활동의 부족, 자기표현의 기회상실, 인간관계 등과 관련하여 신체활동을 통해 체력을 단련하고 생황에 활력을 가져 보다 밝고 풍요한 생활을 영위하는 데 있으며 국내 생활수준의 향상에 힘입어 향후 생활체육시설은 급증 할 것으로 예측된다. 이러한 이유로 본 논문에서는 생활체육시설이 주로 옥외에 설치되어 있어 야간에 시설을 이용 할 경우 필수적 시설인 조명설비에 대한 실제 설계의 예(춘천 공지천 공원)를 들고 이를 통하여 타 지역의 생활체육시설의 조명계획과 설계에 도움이 되도록 제시하였다.

본 논문에서는 E급 영전압 스위칭(zero-voltage-switching) 인버터 방식의 타려식 형광램프용 전자식 안정기를 설계하였다. 이론을 통하여 각 파라미터 값을 산출하고, PSpice를 이용한 시뮬레이션을 통하여 램프 출력을 예측하였으며, 실제 안정기를 제작하여 전기적 특성을 살펴보았다.

Offline switching power supplies have high voltage and high current switching waveforms that generate Electromagnetic Interference(EMI) in the form of both conducted and radiated emissions. Consequently, all off-line power supplies must be designed to attenuate or suppress EMI emissions below commonly acceptable limits. Electrodeless fluorescent lamp's ballasts have AC/DC flyback converter, so we must control the EMI emissions.

본 논문에서는 65 [W] 저압나트륨램프용 전자식 안정기를 제작하여 전기, 광학적 특성을 측정하였다. 개발한 전자식 안정기는 구동주파수가 200 [kHz]로, 기존의 25 [kHz] 전자식 안정기에 비하여 20% 이상의 효율향상을 달성하였다.

본 논문에서는 말굽형과 장방형 터널의 기본부의 노면과 벽면의 조도를 Lightscape를 사용하여 계산하였으며, 계산된 결과를 분석하여 보면 노면의 평균조도와 평균균제도는 두 가지 터널 사이에 큰 차이가 없었으며, 벽면조도는 노면에서 높아질수록 두 가지 터널에서 차이가 커지는 것으로 나타났다.

형광램프는 일정전력을 소비하는 경우, 전원주파수 1[kHz]부근에서 전류는 최대 값을 램프전압은 최소값을 갖는 현상을 나타낸다. 본 논문에서는 원자레벨의 방전 모델식을 만들어 입자밀도와 전자온도의 변화를 수치해석을 이용하여 계산하고, 이를 이용하여 전원주파수에 따라 형광램프의 전류와 램프전압이 변화하는 현상을 이론적으로 설명하였다.

본 논문에서는 수동소자와 능동소자를 이용한 형광램프용 전자식 안정기의 보호회로를 PSpice 시뮬레이션을 사용하여 설계 제작하여 32W형광램프용 전자식 안정기에 적용하였다.

도시에서의 빛의 연출은 도시의 축을 부각시키고, 가로의 아이덴티티를 연출함으로서 도시의 인지도를 향상시킬 수 있다. 또한 야간의 경관은 인공조명을 이용한 빛의 연출로 주간과는 다른 빛환경 경관을 연출할 수 있다. 이에 본 연구는 도시 가로 중에서 상업가로와 주거가로를 대상으로 주 야간의 빛환경 특성을 분석하여, 가로의 용도에 따른 주야간의 빛환경 차이를 고찰하였다. 이를 위하여 두 가로의 일정길이에 대하여 수평면조도, 스칼라 조도, 휘도 및 색온도를 측정하였으며 측정결과를 용도별, 주 야별로 비교하여 분석하였다. 측정한 결과를 정리하면 다음과 같다. (1)수평면조도의 측정 결과, 주간의 주거가로에 비하여 상업가로가 28.8[%] 높게 나타났으며 야간의 경우 87.2[%] 높게 나타났다. (2) 스칼라조도의 측정결과, 스칼라조도의 특성상 전반적으로 균일한 분포를 보이며, 수평면 조도와 마찬가지로 주간에 비하여 야간에 84[%] 높은 값이 측정되었다. (3) 휘도의 측정 결과, 주간 배경에 대한 대상의 휘도비는 상업과 주거가로가 1:2이하로 나타나 조화로운 가로경관을 연출하며, 야간배경에 대한 대상의 휘도비는 상업가로는 1:17로 활기 있는 경관을 연출하고 주거가로는 1:5로 가로경관 이미지에 적당한 강조효과가 나타났다. (4) 색온도의 측정 결과, 주간의 배경은 맑은 하늘의 색온도를 나타냈으며 대상은 상쾌하고 활동적인 이미지의 색온도를 나타내었다. 또한 야간의 경우 상업가로와 주거가로 모두 나트륨 등의 영향을 받아 전반적으로 따뜻한 느낌의 색온도가 연출되었다.

조명설계시 조명의 양을 결정하는데 있어서 유효공간반사율(Effective Cavity Reflectance)을 사용하는 계산이 널리 사용된다. 그러나 유효공간반사율은 광원의 형태를 고려하지 않고 광속만을 고려하기 때문에 조명설계시 설계값과 실측값 사이에는 오차가 있다. 이에 본 논문에서는 가상의 공간을 모델링하고 이 공간에 대해서 유효공간반사율을 이용한 작업면 평균조도값 계산과 시뮬레이션을 통하여 광원의 형태가 작업면 평균조도값에 미치는 영향에 대하여 고찰하였다. 검토 결과 유효공간반사율을 사용하여 계산된 평균조도값과 시뮬레이션을 사용하여 계산된 평균조도값 사이에는 최대 15%의 오차가 있다. 또한, 광원이 형태에 따라 평균조도값이 달라지기 때문에 유효공간반사율을 사용한 조명설계시 광원의 형태를 고려해야 함을 확인하였다.

태양 전지를 이용하여 정원등의 시스템을 구성하면 환경 친화적이면서도 에너지 절감의 큰 효과를 얻을 수 있다. 또한 기존의 정원등은 수은등을 사용하기 때문에 전력 소비가 많은 반면, 고휘도 LED를 사용한 정원등은 전력소비를 줄일 수 있는 큰 장점을 가지고 있다. 본 논문에서는 간단한 회로 구성과 CDS센서를 이용하여 실제적인 회로 설계를 하였다.

To enhance the reliability of distribution transformers in service and to reduce the cost of maintaining and replaceing these, the condition and life of those insulating system should be evaluated accurately and the time to replace should be determined economically. Since the transformer failures related to insulation failure indicates that the primary cause is normally mechanical failure of integrity due to loss of mechanical strength as a result of degradation, the tensile strength characteristics of paper during ageing under accelerated conditions in insulating oil and research trends for assessing the life of insulating paper were investigated.

To improve the safety of facilities and human beings when the ground fault occurs, public power utility prescribes the reasonable ground resistances, measures and controls the ground resistance of all the ground electrodes biennially. Concerning the safety of human, there are two safety criteria widely accepted, i.e. the IEEE Std 80-2000 and the IEC 479-1:1994. The IEEE Std 80-2000 is based on a simplified electric shock model usually translated into permissible touch and step voltages. The IEC 479-1:1994 is less specific than IEEE Std 80-2000 for analysis purpose. The IEC 479-1:1994 provides values of permissible body current against electric shock duration. This paper provides a technical study of these two standards to analyze the safety of human beings of ground electrodes developed recently for distribution power system.

Grounding electrodes as discharge paths to the earth are normally used to ensure the safety of human body and facilities from the over-voltages in distribution power system, and each grounding mode has a prescribed ground resistance value respectively which is applied by the utilities. As the various electrodes for distribution power system are recently developing to improve the performance of them and resolve the problem of space restriction, it is necessary to measure and investigate the safety of human body of developed electrodes. Therefore, in this paper, we provide briefly a technical comparison of two standards, i.e. IEEE Std 80 and the IEC 479-1, and describe the configuration of safety measurement system which can measure the step voltage and the touch voltage of grounding electrodes based on IEEE Std 80.

This paper presents study on the electric potential distribution when have a short in skeet lamp. In order to measure electric potential testing ground is built in. A experiment is conducted to simulate dry and submerged situation of street lamp. The street lamp is leaked by artificial means. And electric potential is measured in grounded street lamp and street lamp alone. The results show that touch voltage of grounded street lamp is possible to more high than street lamp alone. And the electric shock hazard is high because high electric potential is distributed near submerged street lamp. Also if street lamp is submerged ground is not useful to decrease electric shock hazard.

Magnetic field has been used to hold plasma at high temperature for a long time. Reverse field has shown unstable process. Using ratio frequency, the author could control the instability of the process and formed a stable erversed field.

본 논문에서는 화재 감지 센서(UV TRON R2868)와 센서 구동 회로를 이용하여 일반 교류 전원을 스위칭할 수 있는 장치를 제안하고 이를 구현하였다. 구성된 전원 구동 회로의 해석을 위해서 OrCAD 프로그램을 사용하였고, 이를 실제 구동 회로 세트에 부가하여 구성한 후 실험하였다. 실험 결과 주어진 환경에서 불꽃이나 화염만을 감지하여 경보해 주는 특성을 비교적 안정적으로 수행하였으며, 그 결과는 불꽃이나 화염을 감지 후 경보를 필요로 하는 실제적인 활용 분야에 적용할 경우 회로설계의 자료에 참조 할 수 있으리라 사료된다. 이 결과를 바탕으로 화재 감지 센서와 구동 회로를 이용한 전원 개폐 장치의 동작이 실제로 활용 가능함을 검증할 수 있었다.

This paper gives a field-test method and result of PQM(Power Quality Meter) and PQMS(Power Quality Management System). The field-test was carried out as our own method. So, the test method has several kinds of improvement in this paper because it is first time to try the field-test of the equipment. However, we expect that the test result of PQM & PQMS has been used as a reference data which makes a scheme of evaluating performance of the equipment that has been used or is developed.

This paper presents the transient behaviors of grounding system impedance against lighting impulse currents. The dynamic characteristics of the deeply driven ground rod and grounding grid subjected to the impulse current with various rise time were investigated. It was found that the transient ground impedance strongly depends on the configuration and size of grounding electrodes and the shapes of impulse currents, and the inductance of grounding electrodes has a significant affect on the transient ground impedance of grounding system in the short time domain.

본 논문은 최근 2년간 25.8kV 가스 절연 부하개폐기에서 발생한 고장을 전력연구원에서 분석하여 고장 원인별 현황을 나타내었다. 고장 주요원인인 절연불량, 기계적 손상, 외부 손상 등이 발생하는 원인을 분석하였다. 가스절연개폐기의 고장모드 및 성능평가 방법을 나타내었다. 개폐기의 장기신뢰성 확보를 위해서는 제조업체 및 한전의 품질개선을 위한 노력이 필요하며 특히, 경년특성을 검증할 수 있는 효율적인 방법의 제시가 필요하다.

Although DC ground resistance is a good index of grounding performance for grounding electrodes, it does not reflect the grounding performance during transient state. Besides, impulse ground impedance, which is defined by a ratio of the peak value of transient ground potential rise to the peak value of impulse current, cannot be an absolute index due to its dependence on impulse current shape. In this paper, ground impedance of various rod-type ground electrodes has been measured in frequency domain ranging from 1 Hz to hundreds of kHz. Equivalent circuit models of the ground rod have been identified from the measured values of ground impedance in frequency domain.

Big fire such as mountain fire my cause the prevention of the functions of the overhead cables and insulators, which may affect the operation of the transmission lines. Therefore, in order to understand the effect of the mountain fire on the polymeric insulator for transmission lines, the author observed the deformation of the sheds of the polymeric insulators and the change of the discs of the porcelain insulators under fire, and investigated the electrical and mechanical characteristics of the insulators after the ignition test. As the result the following conclusions were obtained. First, the porcelain insulator was degraded in electrical characteristics when the insulator was subjected to the fire for approximately 5 minutes; whereas, the polymeric insulator was not degraded though there were some damage on its sheds. Second, after 20 minute exposure to the fire, the polymeric insulator lost a lot of parts of sheds, but the electrical characteristics was lowered by around 20%, but the porcelain insulators were electrically degraded by more than 80%.

This paper gives a basic information of live line maintenance technique of UHV T/L and introduce a technical background and trends of domestic and abroad. The importance of live line maintenance technology getting increased because the change of power system environment and maintenance conditions in korea. this paper explain the present state of the development of live line maintenance technique in korea and show a difference with advanced countries.

본 논문에서는 최대 견인력 제어를 위해서 최소 차원 부하 토크 외란 관측기를 이용하여 점착력 계수를 추정하고 추정한 점착력 계수의 미분치를 PI 토크 제어하는 Anti-slip제어를 제안한다. 최소차원 부하 토크 외란 관측기는 회전자의 위치 정보와 토크 전류의 정보를 이용하여 부하 외란토크를 추정하고, 부하 외란 토크에 철도차량 상수를 이용하여 점착력 계수를 추정한다. 또한 부하토크외란 관측기는 구조가 간단하며, 시스템의 외란 및 각종 제어이득, 시스템의 상수 변화에 대해서도 견실한 견인력 제어 특성을 가지고 있다. 이와 같은 시스템의 모델링과 전동기 토크에 대한 회전자의 위치 정보를 이용하여 최소차원 부하 토크 외란 관측기의 상태변수인 점착력 계수를 추정하고, 추정한 점착력 계수의 미분치를 PI토크 Anti-Slip제어하여, 최대 견인력 제어가 되도록 하였다.

The human beings have increased concern about Energy saving and alternative energy. The power demand has increased the growth of industry and the improvement of life. We have to explore alternate energy sources and utilize effectively domestic resources. The lighting equipments developed Energy saving by using an electric ballast. The load installation should be promoted to rational power management, according to the network, inteligent, and high-function. Therefore, this paper has studied the method of energy saving and consulting.

본 논문에서는 유원시설 내의 유기기구에 대하여 운전실태를 분석하여 유기기구의 수용률을 산정하는 방식을 제시하였다. 유기기구별로 기계적구동방식과 전기구동방식으로 나누어 설비용량에 대한 실제 부하특성을 측정하였으며 그 결과를 토대로 유원시설에서 유기기구에 대한 전원변압기의 용량을 산정하는데 필요한 유기기구의 구동방식별 수용률의 참고치를 제시하였다. 본 논문의 산정방식을 참고할 경우 유원시설에서 좀더 효율적이고 경제적인 전원설비 운용에 기여할 수 있을 것이다.

Morden electronic equipments are becoming very important in information oriented society, but they are vulnerable to lightning surges. Soil resistivity in the vicinity of grounding electrodes my be affected by the current flowing from the grounding electrodes into the surrounding soil. Electrical conduction in soils depends on the grain size, compactness, and variability of the grain sizes. When a high current is injected into the soil, and the breakdown phenomenon occur. In the present work, Electrical behaviors related to discharge in soils were investigated. The breakdown voltages in soil were lower than that sparkover voltage in air. The breakdown voltage in the gravel layer is relatively low, and the breakdown was caused by the flashover through the surface of gravels

In this paper, one general approach is proposed for the design of power system that can be applicable for next generation LEO satellite application. The power system consists of solar panels, battery, and power control and distribution unit(PCDU). The PCDU contains solar array modules, battery interface modules, low-voltage power distribution modules, high-voltage distribution modules, heater power distribution modules, on-board computer interface modules, and internal DC/DC converter modules. The PCDU plays roles of protection of battery against overcharge by active control of solar array generated power, distribution of unregulated electrical power via controlled outlets to bus and instrument units, distribution of regulated electrical power to selected bus and instrument units, and provision of status monitoring and telecommand interface allowing the system and ground operate the power system, evaluate its performance and initiate appropriate countermeasures in case of abnormal conditions. We review the functional schemes of the main constitutes of the PCDU such as the battery interface module, the auxiliary supply module, solar array regulators with maximum power point tracking(MPPT) technology, heater power distribution modules, spacecraft unit power distribution modules, and instrument power distribution module.

This paper is aimed at presenting a proton exchange membrane (PEM) fuel cell stack. The fuel cell electrical output voltage and current (V-I) characteristic is described for the first time by a simplified closed form suitable. The characteristics obtained from the simulation are compared with the experimental results on a Ballard commercial fuel cell stack as well as to the manufacturer given data.

This paper proposes a simple MPPT control scheme of a Current-Control-Loop Error system Based that can be obtains a lot of advantage to compare with another digital control method, P&O and IncCond algorithm, that is applied mostly a PV system. An existent method is needed an expensive processor such as DSP that calculated to change the measure power of a using current and voltage sensor at the once. Therefore, it is applied a small home power generation system that required many expenses. But, a proposed method is easy to solve the cost reduction and power unbalance problems that it is used by control scheme to limit error of a current control of common sensor. This proposed algorithm had verified through a simulation and an experiment on battery charger using PIC that is the microprocessor of a low price.

This paper presents the protection effect of SPDs according to installation conditions. To develop the effective protection countermeasures of information and communication equipments against lightning surges, actual-sized experiments in relation to the protection effects on the installation positions of surge protective devices(SPDs), the length of branch circuit the materials and long of conduit were conducted. The best method for protecting the electronic equipments from surges is to install the SPD at the front point of the devices to be protected. The installation method of the metal conduit bonded with common ground conductor were more effective than that of the PVC conduit.

This paper presents the frequency-dependent characteristics of leakage currents flowing through ZnO surge arrester block. The leakage current-voltage (I-V) characteristic curves of the commercial ZnO surge arrester blocks were measured. The resistive leakage current was found to increase with increasing frequency in the low conduction region. The capacitance of ZnO block was independent of the magnitude and frequency of the applied voltage. The power losses of ZnO block increase as the frequency of applied voltage increases, because of the dielectric loss related to the frequency of the test voltage.

Most of the electric power in the power system of South Korea is flowing from the south area to the north area, Seoul, in the capital of South Korea. Almost of the needs of the electric power in the capital area are about 43% of the total loads and generation plants are mainly located in the south area of South Korea. As mentioned the earlier characteristic, transmission congestion is one of the important research issues. Because of the limits of the power flows from the south to the north which are anticipated to be increased more and more in the future, these congestion situations may cause a serious voltage stability problem in emergency of the power system. Accordingly, we are interested in an interruptible load control program so as to solve this problem in emergency. This problem can be solved by an interruptible load management in emergency, however, the systematic and effective mechanism has not been presented yet. In this paper, the algorithm of interruptible load management plan using the line sensitivity to the loads for the transmission congestion management in emergency is presented. The proposed method is applied to 6-Bus sample system and their results are presented.

이 논문은 다른 종류의 유도전동기 구름베어링 손상을 유도전동기 고정자 전류신호해석을 통하여 검출하고 실시간으로 손상을 진단하는 알고리즘을 개발하였다. 유도전동기 구름베어링의 손상을 검출하기 위하여 정상적인 베어링을 갖는 유도전동기, 축정열에 불량을 가지고 있는 전동기와 베어링 외륜에 구멍을 가지고 있는 2가지 종류의 비정상 베어링을 갖는 유도전동기 3set를 실험시스템을 구축하였다. 또한 유도전동기의 구름베어링시스템의 비정상적인 상태에서 고정자전류을 검출하기 위하여 TMS320F2407 DSP 칩을 이용하여 데이터 획득보드를 개발하였다. 이 고정자전류신호를 해석을 통하여 베어링 손상을 검출하기 위한 방법으로 FPT, 웨이브렛 분석 및 내적에 의한 평균신호패던에 의한 분석결과를 제시하였다. 특히 내적에 의한 신호분석을 통하여 베어링 손상 여부를 실시간으로 진단할 수 있는 새로운 알고리즘과 분석방법을 제시하였다.

The interface between host processor and the ShortStack Micro Server may be a Serial Communication Interface(SCI). The LonWorks control module with a high performance is developed, which is composed of the 8 bit PIC Microprocessor for host processor and the smart neuron chip for the ShoretStack Micro Server. This intelligent control board is verified as proceeding the various function tests from experimental system with an boost pump and inverter driving systems. It is also confirmed that the developed control module provides stably 0-10VDC linear signal to the input signal of inverter driving system for varying the induction motor speed. Thus, the experimental results show that the fabricating intelligent board carried out very well the various functions in the wide operating ranges of boost pump system. This developed control module expect to apply to industrial fields to require the comparatively exact control and monitoring such as multi-motor driving system with inverter, variable air volume system and the boost pump water supply systems.

최근 제어설비 계통은 전력변환장치와 센서의 사용이 증가하여 많은 노이즈가 발생되고 있다. 이 노이즈로 인해 설비의 오동작과 제어 회로의 메모리 손실이 발생된다. 따라서, 본 논문에서는 제어설비 계통의 노이즈 발생량을 계측 분석하였고, 이에 따라 NCT, 등전위 접지, PNR, 노이즈필터와 같이 노이즈 감소를 위한 효과적인 보호설비를 적용하였고 계측 결과를 제시하였다.

It is increased electrical energy consumption with the development of intelligence society in the office buildings and thus an energy conservation through efficient use of electricity became more important. This paper shows a reasonable design demand factor in office buildings, that was made by the systematic and statistical way considering actual conditions, such as investigated electric equipment capacity, peak power consumption, demand factor, etc., for 54 office buildings and 34 electrical design offices. In this dissertation, it is necessary to analyse the key features and general trend from the investigated data. It made an analysis of the feature parameters, such as average, standard deviation, median, maximum, minimun and thus it was carried linear and nonlinear regression analysis.

Most utiltity systems are subject to frequent changes, often due to increased loads and demand to up-grade quality of service provided. Urban renewal, expressway construction and suburban growth have also caused significant changes in urban utility distribution systems. Recently, it is required that a guideline for planning of a complete system, the reasonable design and construction methods for the efficient installation common utility tunnels must be estabilished. It prompts drastic measures to guard cities and their inhabitants against the horror of massive fires in the future. Preparedness holds the key to safety.

This paper describes the electron energy distribution function characteristics in $SF_6-He$ gas calculated for range of E/N values from $50{\sim}700[Td]$ by the Monte Carlo simulation(MCS) and Boltzmann equation(BE) method using a set of electron collision cross sections determined by the authors and the values of electron swarm parameters are obtained by time of flight(TOF) method. The results gained that the values of the electron swarm parameters such as the electron drift velocity, the electron ionization or attachment coefficients, longitudinal and transverse diffusion coefficients agree with the experimental and theoretical for a range of E/N. The results of Boltzmann equation and Monte carlo simulation have been compared with experimental data by Pollock, Ohmori, cottrell and Walker.

This paper presented problems occurred in design and construction of LPS(Lightning Protection System) based on the new KS(Korea Standard), and proposed various solution for those. Imperfect KS, poor data on lightning characters in Korea lack of train for engineer, immature SPD engineering and absence of LPS design sample for various buildings are main problems. We suggested that comprehensive measures attending every persons and organizations relevant LPS are needed to solve the problems.

Recently, there are many equipment of electricity, electronics, and communication which need to grounding in the building. When the electric current flows into a certain grounding system in the same building, the potential rise of other grounding system is possible to be affected by its potential rise. This potential interference was affected by the surface potential, it is deeply related whit the electrode shape. In this paper, basic formula is deduced on the basis of both electrodes surface potential of grounding electrode in a source of the potential interference and groundidng electrode which receive the potential interference. Therefore the degree of potential interference as multiple groundidng electrode can be verified the simulated results by means of the simple model in advance. This is for investigating the grounding resistance of grounding electrodes, the experiment was performed with model-scale of the grounding system and the scaled model grounding system was to this experiment using a water tank of a stainless steel-hemisphere shape. since mesh electrodes have been widely in the general building, we're tried to analyze that this water tank model and it's simulation as well.

The electrical characteristics for applying the foundation of the house to the substitutional earth electrode was reviewed fundamentally. In order to measure the earth resistance in the foundation of the house, it was performed to investigate the effect of the electrode arrangements and configurations concerning to grounding methods, and tried to the adequate simulation for comparing those experimental data. The number of steel rods and the ground resistivity were affected to change the earth resistance, but the latter caused the large variation in its resistance compared to the former in this experiment. Since the large surface area in the foundation of the house have contacted the ground usually, it is possible to use the earth electrode substitutionally.

본 논문에서는 도로시설물의 감전 위험성의 실태를 파악하기 위하여 신호등, 공중전화, 입간판, 에어콘 실외기를 현장 조사하였다. 취득된 자료에 의거하여 도로시설물의 실태를 감전 위험성 측면에서 정밀하게 분석하였다. 조사결과, 규정이 미비하여 많은 시설물들이 올바르게 설치되어 있지 않기 때문에 감전의 위험성이 있는 것으로 밝혀졌다. 따라서 감전 예방의 관점에서 도로시설물의 설치 및 관리에 대한 구체적인 규정을 설정하는 것이 필요하다.

WPAN 시스템 개발의 중요한 목표는 다양한 대역폭의 멀티미디어 서비스를 효율적으로 언제, 어디서나, 누구와도 자연스럽고 현실감 있게 정보를 교환할 수 있도록 제공하는 것이다. 멀티미디어 서비스 품질을 보장하기 위해서는 Ad hoc 네트워크에서 한정된 자원과 물리적인 한계에 의해서 가장 취약한 부분인 무선접속 구간에서의 트래픽 특성에 따른 채널할당이 가장 중요시 고려되어야 한다. 본 논문에서는 WPAN을 응용을 지원하기 위한 대역폭 요구사항에 대해 알아보고, 응용 서비스별 트래픽 종류에 따라 WPAN MAC 계층에서의 채널 시간 할당방안에 대해 살펴본다.

In this paper, a small band pass filter is designed using new probe type for wireless communication system. In order to provide a band pass filter which can be reduced in dimension, can be reduced in height, and can be surface-mounted. The filter was fabricated using $TE_{01{\delta}}$ mode dielectric resonator. The input/output probes are attached to coner portion of the rectangular metal cavity. Results of the manufactured filter$(12{\times}12{\times}8mm)$ show that the center frequency is 9.953GHz, the insertion loss is -2.98 dB, the 3dB-bandwidth is 15 MHz, and the lode Q is 663.

EMC(Electromagnetic Compatibility) is the ability of an electronic device that operates properly in its intended electromagnetic environment and not be a source of pollution to that environment. The designer anticipates EMC problems at beginning of the process and finds remaining problems in early prototype stages, and tests the final prototypes for EMC as thoroughly as possible. This is a more cost-effective method. In this paper, it analyzes EMC problems that were appeared in actual measurement of electric power control device and presents reduction technique of these problems.

This paper presents the prospects of today's situation of Korea Electric Power Industry and future's development direction at the sudden chin international environment Several paradigm,-Deregulated electric market Energy shortage, Green house effect due to $CO_2$, TBT(Technical Barrier to Trade), Digital society-will facilitate the glove to develope new technology based Power Industry. With respect to this change, Korea Power Industry needs to find new technology solutions for the smarter operation, higher efficiency and lower carbon consuming power system based on mid-long term plan.

This paper provided a counter measures against the troubles and accidents that are likely to take place in the power plant using hydrogen gas as a coolant for the cooling system of the generator. Because of the extremely wide flammability limits of hydrogen in comparison to the other flammable gases, the safety measures against the hydrogen accidents is very important to ensure the normal operation of electric-power facility. This study's purpose was a presentation of standard model of safety management of hydrogen equipments in the coal firing power plant such as following items: 1) providing the technical prevention manual of the hydrogen explosions and hydrogen fires occurring in the cooling system of power generator; 2) the selection of explosion-proof equipments in terms of the risk level of operating environment; 3) the establishment of regulations and counter measures, such as the incorporation of gas leakage alarm device, for preventing the accidents from arising; 4) the establishment of safety management system to ensure the normal operation of the power plant.

This paper studies flicker evaluation considering power quality disturbance. A flicker problem with light device irritates human's eyes. Also, the flicker problem has an influence on adverse effect such as rolling device and rotating device. However, a study of flicker evaluation is not complete. A flicker is measured and evaluated at monitoring point. But we consider power quality disturbances such as voltage sag and transient that cause fault and inverter/breaker switching. Power quality disturbances affects flicker evaluation. A flicker evaluation index increases. Therefore, we consider power quality disturbances. We detect voltage sag and transient using wavelet and evaluate flicker without flicker index including power quality disturbances.

In korea, the power consumption is increasing every year because of economic growth, requiring of convenience and delightfulness condition. As increasing power consumption, Private Use is steadily increasing and the rate of electrical accident is increasing. Therefore we research the electrical safety culture of our people by the survey of electrical safety. The subject to investigation is possessor, occupier of Private Use and electrical safety manager. This paper will be used to base data for the protection of electrical accident and facility accident at Private Use

This paper presents a user-friendly application for voltage sag analysis and effective visualization for analysis date. This developed tool provides basic functions for voltage sag analysis such as load flow analysis, short circuit analysis and determination of vulnerability of sensitive equipments. Particularly it has the ability to visualize analysis results effectively using computer graphic and animation. In order to give the real sense, analysis results are displayed with geographical information in an intuitive and rapid manner. The developed voltage sag simulator is applied to the Jeju-Island power system in order to show its capabilities.

부양용해 기술은 티타늄등 용해 및 주조에 어려움이 있는 기능성 금속의 용해 시 소재의 오염이나 고가의 도가니 없이 용해할 수 있는 기술로써 기계 부품 경량화 및 고강도를 위한 기술 및 신수요 창출을 위한 기반을 제공할 수 있다. 본 논문은 실기용 부양용해 cold crucible의 설계 및 제작에 앞서 실기 제작할 cold crucible에 대한 기초 자료를 바탕으로 컴퓨터 시뮬레이션을 위한 부양체를 포함한 3차원 전자기장 해석 model을 구축하여, 실제 cold crucible 설계 제작 시 다양한 형태로 활용될 수 있는 기본자료를 확보하는데 그 목적이 있다.

In this literature, when the utility line is normal, the Off-Line UPS operates as an active power filter to compensate the reactive power from a load, and when the utility line is in outage, the On-Line UPS opuates as in single phase inverter to supply an active and reactive power to the load. An additional static switch in UPS was used to decrease an transient state during these mode changes. And the result shows that the transient state disappeared.

In this literature, we mose the design method of a proportional pressure control valve using valve system analysis and finite element method. And it is shown that a manufactured proportional pressure control valve character is well matched to tile theoretical analysis results. Also it is verified that the proposed valve has excellent performance compared to the other foreign products.

In this paper, we present a method of fuzzy controller design for the power plant superheater in the form of bilinear system. For the steam temperature control, the input variables are constructed by the area of difference between the profiles estimated from bilinear observer and reference profiles, and the time rate of change. We estimate the control rules by T. Takagi and M. Sugeno's fuzzy model. The feasibilities of the suggested method are illustrated via the computer simulation result.

In this paper, we propose a intelligent controller design method for the water level control of the power plant drum in the form of nonminimum phase system. The proposed method is based on T. Takagi and M. Sugeno's fuzzy model. And we illustrate the improved characteristics as the simulation results, comparing with the conventional the PID and LQ controller design method

Recently, sectionalizing switches have been coming to be operated by remote control through the distribution SCADA system. However, the problem of determining the optimal switching sequence is a combinatorial optimization problem, and is quite difficult In solve. Hence, it is imperative to develop practically applicable solution algorithms create a new arbitral distribution system configuration from an initial configuration and some of these algorithms do not show a load transfer sequence to reach the objective system.

A distributed FBG temperature sensor system was constructed for the use in protection of electric power system. A F-P wavelength tunable filter is used converting temperature-induced wavelength variations to temporal peak locations. We used Gaussian line-fitted algorithm to alleviate the error caused by quantization and electrical noises. The experimental results showed much better accuracy than the raw peak-detection scheme.

The fiber-optic interferometer which is a powerful application for nondestructive measurement techniques has many advantages such as capability of making portable system, easy optical arrangement, low optical loss. In spite of these advantages, this system has an environmental sensitivity of thermal drifts and vibrations. Against environmental perturbations and nonlinear characteristic of phase modulator, the accurate and fast ${\pi}/2$ phase stepping has been achieved by using zero-crossing detection. CCD camera trigger signal is generated at the 4 zero-crossing points. Our System has achieved up to 100 Hz of image capture speed and 0.6 mrad of accuracy of phase stepping, accuracy.

In this paper, We proposed the stereo image modeling using 2-dimensional images captured by the high resolution cameras to inspect the ball defects of BGA(Ball Grid Array) device. The proposed algorithm consists of the package/ball area extraction part, the FOV(Field of View) calibration part, the top point matching part, and ball height measurement part, In the package/ ball area extraction part, the package and ball areas are separately extracted in a left and right image by the extraction algerian. Through the experiment, we draw out the result.

In this paper, we proposed the 2-dimensional inspection algorithm for micro-BGA(Ball Grid Array) device using a vision system. The proposed method uses the subpixel algorithm for high precision. The proposed algorithm preferentially extracts the package area of device in the input image. After the extraction of package area, each ball areas are extracted by ball search window method. The parameters for inspection are calculated for the extracted ball area. In the simulation results, we have the average error within $17{\mu}m$.

This paper proposed a regeneration inverter system, which can regenerate the excessive power form dc bus line to ac source for traction system. The proposed regeneration inverter system for dc traction can reduce harmonics which are include to ac current source. The regenerative inverter is operated as two modes. As a regeneration inverter mode, it can recycle regenerative energy caused by decelerating tractions and as an active power filter mode, it can compensate for harmonic distortion produced by the rectifier substation. In the paper, a regeneration inverter used PWM DC/AC converter algorithm. And an active power filter used p-q theory. The simulation was composed as a prototype model[3kW]. Simulation results show that two algorithm can be used to real model[100kW]. Finally, the inverter was successfully operated as regeneration mode.

Brushless DC Motor(PM BLDCM) is widely used in industrial applications due to its high efficiency and power density. In order to increase reliability and reduce system cost, this paper studies particularly applicable method for sensorless PM BLDCM drive system. The resulting third harmonic signal keeps a constant phase relationship with the rotor flux for any motor speed and load condition, and is practically free of noise that can be introduced by the inverter switching, making this a robust sensing method. As a result, the method described here is not sensitive to filtering delays, allowing the motor to achieve a good performance over a wide speed range. In addition, a simple starting method and a speed estimation approach are also proposed.

Preventive diagnostic system for power transformer prevents the sudden power failure through monitoring of abnormal symptoms. KEPCO has adopted the preventive diagnostic system at nine 345kV substations since 1997. Application techniques of the diagnostic sensors were settled, but diagnostic algorithm and practical use of accumulated data are not yet established. To build up the diagnostic algorithm and effective use of the preventive diagnostic system, the reliability of the data accumulated in a server computer is very important. Therefore, this paper describes problem when apply system to substation and solution way to improve reliability of the system

This paper presents a new speed control scheme of the spindle induction motor (IM) using fuzzy-logic control in fold weakening region. The implementation of the proposed FLC-based spindle IM are investigated and compared to those obtained from the conventional PI controller based drive system, we have confirmed good simulation and experimental results at different dynamic operating conditions such as sudden change in command speed, step change, etc.

In this paper, design and control of the novel SEPIC-Flyback converter(SF converter) is developed as a possible converter for fuel cell system. This output characteristic of SF converter is similar to Buck-Boost converter in that it can step-up or step-down the voltage. With the small signal equivalent circuit modeling of SF converter, control-to-output transfer function is obtained. SF converter couples up the inductive type converter to capacitive type converter with one transformer, which has less ripple current than its respective one does. To verify the validity of the proposed converter, 500W, 100kHz converter is designed and tested. ZVS switching and active clamping are also tested in practice.

In home appliances, electric energy is optimally controlled by using power electronics technology, creating a comfortable environment in terms of energy saving, low sound generation, and reduced time consumption. Usually simplicity and robustness make the three phase induction motor attractive for use in domestic appliance, including washing machines. Two main fpes of domestic washing machine have evolved. We focus on the front loading machine favored in Europe, which has a horizontal drum axis. With the advent of electronic control, universal motor, with a phase controller operating directly from the ac source, has become popular in washing machine. The efficiency improvement in home appliances is very important for customers. Induction motor efficiency can be improved by means of loss reduction, which can be realized by motor selection and design, improvement of the waveforms supplied by power inverter, utilizing a suitable control method. So this paper describes the architecture and feature of washing machine fed induction motor drive under minimizing losses vector control.