• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.25 no.1
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• pp.18-29
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• 2011

Light emitting diode(LED) technology has been increasingly developed and larger color gamut by LED illuminations can be reproduced; therefore more efficient LED lighting design can be accomplished under a consideration of color emotion. Fifty-two LED colors which are uniformly distributed on the uniform chromaticity space are evaluated in terms of fatigueness and preference and their relation to three color-appearance attributes(lightness, chroma and hue) are investigated. As a result, 23 human observers likely to prefer and feel comfortable, when lightness of a given LED color stimulus increases as well as its chroma decreases. The highest fatigueness score is observed in red color series and the most preferred LED color is found in green color series. In addition, fatigueness and preference show a strong negative linear relation and their Pearson correlation is higher than -0.8.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.194-197
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• 2001

Traction motors driven by high speed switching inverters is demanded higher operating temperature, severe duty cycles, higher starting current, frequent voltage transients and finally severe environmental exposure. For applications to inverter duty, traction motors needs a special insulation system, which has characteristics of increased bond strength, lower operating temperature and higher turn-to-turn insulation. In this paper, design considerations and manufacturing procedure of 200 Class insulation system with polyimde(Kapton) main insulation and silicone resin VPI process on the traction motor for EMU will be reviewed. And performance test and long life evaluation test which prove stability and long life evaluation test which prove stability and reliability of insulation system for traction motor will be introduced.

• Proceedings of the KIEE Conference
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• 2005.07a
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• pp.899-901
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• 2005

EMTP 프로그램으로 뇌써지 발생시 가공송전선로 등가모델 구현을 위한 필수적인 요소들과 비선형 요소들을 시간영역에서 해석이 가능하다. 따라서 이번 연구에서는 EMTP를 이용하여 전력전송이 이루어지는 가공 송전 선로 등가모델을 구현하고 전송선로의 길이와 굵기, 뇌격전류의 크기를 변화시켜가면서 시뮬레이션을 통해 자료를 얻는다. 이 과정으로 얻어진 결과는 송전계통의 설계에 사용되어 안정적인 전력 전송에 적용될 수 있을 것이다.

• Proceedings of the KIEE Conference
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• 2006.07a
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• pp.494-495
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• 2006

개폐기, 차단기와 같은 스위치기어들은 지중케이블이나 가공선로, 콘덴서 뱅크에 흐르는 진상 전류의 개폐를 많이 하게 된다. 이때 진상전류의 크기는 정격 차단전류나 부하전류보다 그 크기가 매우 작다. 그러나 스위치기어 측면에서는 전압을 고려하였을 때 가혹한 시험이며, 이는 차단 후 극간에 걸리는 과도한 회복전압에 기인한다. 본 논문에서는 국제규격에서 요구하는 진상전류 시험의 회로조건들을, 회복전압 측면에 바탕을 두고 고찰해 보았다.

• Proceedings of the KIEE Conference
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• 2005.07d
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• pp.3111-3113
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• 2005

EMTP 프로그램으로 뇌써지 발생시 가공송전선로 등가모델 구현을 위한 필수적인 요소들과 비선형 요소들을 시간영역에서 해석이 가능하다. 따라서 이번 연구에서는 EMTP를 이용하여 전력전송이 이루어지는 가공 송전 선로 등가모델을 구현하고 전송선로의 길이와 굵기, 뇌격전류의 크기를 변화시켜가면서 시뮬레이션을 통해 자료를 얻는다. 이 과정으로 얻어진 결과는 송전계통의 설계에 사용되어 안정적인 전력 전송에 적용될 수 있을 것이다.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.14 no.1
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• pp.51-56
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• 2015

This paper presents an investigation of abnormal wear of a contact jig between a nail and a nail fixture in electric resistance welding. To perform an analysis on the abnormal wear phenomenon, several methods are provided. Based on the theory of electric resistance welding, are analyzed. Using microscopic analysis, surface craters are observed. In the measurement of the electric current flow in the nail fixture, the current flow distribution is measured. From several analyses, the cause of abnormal wear in the contact jig is measured using the electric discharge of high current density at the inflow point of the electric supply to the nail fixture. An alternative shape for normal wear is proposed.

• Proceedings of the KIEE Conference
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• 1999.07c
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• pp.1155-1157
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• 1999

The UPFC is known to have the ability to control both the real power flow and the reactive power flow. [1],[2] The power flow in the system is heavily related with the system security. [4] This paper deals with the operation of the UPFC to increase the power system security. The concept of the power system security is verified and the index to indicate the power system security level is suggested. And the algorithm to find the optimum operation point of the UPFC improving the system security level is presented.

• Proceedings of the KIEE Conference
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• 1999.07c
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• pp.1287-1289
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• 1999

The UPFC(Unified Power Flow Controller) controls the magnitude and phase of the series injected voltage to exchange the real and reactive power with transmission line. The UPFC consists of two inverters connected together through the DC link capacitor. This paper describes the detailed UPFC switching-level model. PWM (Pulse Width Modulation) method is chosen to operate the inverters. Automatic voltage control mode and automatic power flow control mode is selected to control the UPFC. EMTP simulation is offered to obtain the basic operation characteristics of the UPFC and the dynamic characteristics of the UPFC is studied in detail.

• Proceedings of the KIEE Conference
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• 1999.07c
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• pp.1039-1041
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• 1999

Recently Advanced Static Var Compensators(ASVC) or STATic Synchronous COMpesator(STATCOM) has been considered as a next generation reactive power controller. [2] STATCOM is a voltage source inverter(VSI) based static VAr compensator with only small capacitors on the do side. The main function of the STATCOM is to keep the bus voltage magnitude at the desired value. [1] This paper compares the PAM STATCOM with PWM STATCOM. The characteristics and the control method of each model is analyzed. And the simulation of STATCOMs based on the above two methods was presented.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07b
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• pp.1139-1142
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• 2003

NOx, Soot and other exhausted components already became a dangerous state as principal materials of the air pollution. Therefore, the exhausted regulations are getting strict in the many countries. In this paper, reduction characteristic of NOx, Soot and CO from diesel engine are investigated, when MF plasma-EGR hybride system is put to the diesel engine. NOx is decreased in all measured load and applied voltage to plasma renter However Soot is increased as increasing EGR rate and it is decreased as increasing applied voltage.