AE기법을 이용한 자기애자의 손상 분석

최인혁,신구용,임윤석,구자빈,손주암,임대연,오태근,윤영근,Choi, In-Hyuk,Shin, Koo-Yong,Lim, Yun-seog,Koo, Ja-Bin,Son, Ju-Am,Lim, Dae-Yeon,Oh, Tae-Keun,Yoon, Young-Geun 한국전기전자재료학회 2020 전기전자재료학회논문지 Vol.33 No.3

This paper investigates the soundness of porcelain insulators associated with the acoustic emission (AE) technique. The AE technique is a popular non-destructive method that measures and analyzes the burst energy that occurs mainly when a crack occurs in a high-frequency region. Typical AE methods require continuous monitoring with frequent sensor calibration. However, in this study, the AE technique excites a porcelain insulator using only an impact hammer, and it applies a high-pass filter to the signal frequency range measured only in the AE sensor by comparing the AE and the acceleration sensors. Next, the extracted time-domain signal is analyzed for the damage assessment. In normal signals, the duration is about 2ms, the area of the envelope is about 1,000, and the number of counts is about 20. In the damage signal, the duration exceeds 5ms, the area of the envelope is about 2,000, and the number of counts exceeds 40. In addition, various characteristics in the time and frequency domain for normal and damage cases are analyzed using the short-time Fourier transform (STFT). Based on the results of the STFT analysis, the maximum energy of a normal specimen is less than 0.02, while in the case of the damage specimen, it exceeds 0.02. The extracted high-frequency components can present dynamic behavior of crack regions and eigenmodes of the isolated insulator parts, but the presence, size, and distribution of cracks can be predicted indirectly. In this regard, the characteristics of the surface crack region were derived in this study.

산불영향에 따른 송전용 폴리머애자의 특성

최인혁,이동일,정용운,유근양 대한전기학회 2005 전기학회논문지C Vol.54 No.3(C)

Big fire such as mountain fire may cause the prevention of the functions of the overhead cables and insulators, which may affect the operation of the transmission lines. In the worst case, this kind of disaster may have a huge effect on the whole industry of a country. However, the study on the effect of the mountain fire on the transmission line is very rare. 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, varying the ignition time using the artificial ignition testing equipment which simulates the mountain fire, and investigated the electrical and mechanical characteristics of the insulators after the ignition test. For the test, the miniature insulators made of polymeric material and porcelain have been utilized. 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%.

송전용 애자(Insulator) 기술현황

최인혁,박준영,강동훈,Choe, In-Hyeok,Park, Jun-Yeong,Gang, Dong-Hun 한국전력공사 2016 KEPCO Journal on electric power and energy Vol.2 No.3

송전용 실리콘 폴리머애자의 산불영향 신뢰성 평가( I )

최인혁,이동일,정용운,유근양,Choi, In-Hyuk,Lee, Dong-Il,Chung, Yong-Woon,Yu, Kun-Yang 한국전기전자재료학회 2004 전기전자재료학회논문지 Vol.17 No.11

Most overhead transmission lines in Korea run over the mountain; however, only little study has been made for the effect of mountain fire on polymeric insulator for transmission lines, though the study is significantly required, Therefore, in this study, the authors observed the deformation of the sheds of the insulator under fire, varying the ignition time using artificial ignition testing equipment, and investigated electrical and mechanical characteristics of the insulator through dry withstand voltage test, impulse flashover test and tensile load test. As the results of the tests, the following conclusions were obtained, First, when the insulator was subjected to the fire, the electrical characteristics were slightly reduced, but there was no change on the mechanical characteristics, Secondly, the sheds and sheath of the insulator were not non-flammable but less-flammable. These two results show the high mechanical stability and durability of the insulator under severe fire condition, though the electrical characteristics can be deteriorated as the time that the insulator is subjected to fire, goes by.

송전용 폴리머 애자에 대한 산불 영향 평가

최인혁,이동일,이철호,강병규,이원교,박준호,Choi, In-Hyuk,Lee, Dong-Il,Lee, Chul-Ho,Kang, Byoung-Kyu,Lee, Won-Kyo,Park, Jun-Ho 한국전기전자재료학회 2007 전기전자재료학회논문지 Vol.20 No.9

To understand the effects of forest fires on polymer insulators for transmission lines, the forest fire simulation tests were performed with polymer and porcelain insulators at Gochang testing center. These tests consisted of energizing 90 kV at line-to-ground voltage of 154 kV lines and open flame rising up to $600-630^{\circ}C$ as being measured at insulator surface. Mechanical and electrical characteristics such as specific mechanical load, leakage current, low frequency dry flashover voltage and impulse flashover voltage were analyzed for the polymer insulators before, during and after simulation tests compared with porcelain insulators. At the end of fire simulation tests, there was no detrimental deterioration of any insulators. All insulators passed the criteria of KEPCO specification. This study showed that forest fire simulation had no impact on polymer insulators.

영재학생들을 위한 교육 서비스 지원과 영재 통합교육 과제에 관한 연구

최인혁 한국통합교육학회 2006 통합교육연구 Vol.1 No.2

This study has a goal that shows the direction of the inclusive education for gifted students. Gifted students have higher intelligence and faster learning ability than the general students. What is more they have more emotional and recognizable reaction level for learning. Furthermore they have abstract and challenging attitudes and require very unique needs. Therefore we must think over their personal inclination. This study provides service supports, educational approaches and progresses, service delivery, and the choice of the vocational training which should be offered from childhood to adolescence(1997, Joan). And this study presents combined process that introduces not only program development for gifted students who have handicap but also educational arrangement and problems in teaching and training gift experts. Of course this study is under discussion about suggestion of inclusive environment which general education and particularity education as special education can provide proper education services for all students in cooperation and administrative supports of raising the gifted. Although inclusive education doesn't have simple concept and meaning, it is variously discussed and debated qualitative and quantitative. Generally, educators are positive about the concept of the inclusiveness, but there are a lot of varieties in order to practice inclusiveness in school. According to Andrews and Lupart(1999), inclusive education means that all children have a duty of being educated in public school and teachers have a responsibility and positive authority in educating them. The best way to combine formal education with special education is to emphasize professional collegiality, to allow proper and advanced education, and to make a inclusive circumstance for advanced technique and gifted students. We need the school which can provide a suitable education about inclusive education system combined general education with special education for all students. That will include gifted students and gifted students who have handicap. In fact, successful effort in this field will make an important contribution to inclusive education as a future education 본 내용에서는 영재아동에게 제공되어져야 하는 유년초기, 취학 전, 아동/ 청소년기 까지의 서비스 지원인 교육상의 접근, 교육과정을 서비스 전달과 직업교육을 제시하였다. 또한 장애영재를 비롯한 통합의 과제로, 프로그램 개발과 함께 해야 할 교육적 배치, 교사 및 영재전문가 육성에 따른 문제들을 소개하여 통합과정의 방향을 제시하고 있다. 또한 일반 교육과 영재교육인 특수교육이 협력적으로 모든 학생의 적절한 교육을 제공 할 수 있는 통합 환경의 제안과 영재육성의 행정상 지원을 논의하였다.

고순도 양극동의 전해정련 및 글로방전질량분석법에 의한 극미량불순물 분석

최인혁,임재원,김민석,박경호,조훈,권혁천,최국선 한국자원공학회 2010 한국자원공학회지 Vol.47 No.2

Purification of a high-purity anode copper by electrorefining process was carried out using 30 g/L of Cu with 1 mol/L H2SO4 solution at 40℃. Detailed impurity analysis of the electrorefined copper was performed using GDMS (Glow Discharge Mass Spectrometry). The purity level of electrorefined copper indicated 5N6 (99.9996%) from 4N8 (99.9988%) anode copper and there was small impurity variation of <1 ppm in range of 5~20 mA/cm2 current density. It was found that some impurities like Al, Si, Zn and Sn, which show lower electrode potential value than copper, were increased more than original anode copper. Further studies are needed to investigate contamination route of these impurities. 4N8의 순도를 갖는 양극동을 사용한 전해정련 연구가 글로방전질량분석법(GDMS)에 의한 극미량 불순물 분석을 기반으로 수행되었다. 황산용액 1 mol/L에 Cu 30 g/L로 제조한 전해액의 온도는 40℃로 일정하게 유지시키고 전류밀도만 5, 10, 20 mA/cm2으로 달리하였다. 전해정련 후 얻은 동 시편에 대한 GDMS 분석에 의하면 4N8(99.9988%) 양극동으로부터 5N6(99.9996%) 이상의 고순도 음극동이 얻어졌으며, 전해정련 효과에 미치는 전류밀도의 영향에 따른 순도 차이는 1 ppm 미만으로 나타났다. 또한 전기화학적 원리에 의해 동 보다 낮은 전극전위를 갖는 Al, Si, Zn 및 Sn의 경우, 음극동 내에서의 농도가 감소되어야 함에도 불구하고 실제 실험에서는 오히려 증가하는 현상이 발견되었다. 이는 전해정련 시 오염에 의한 것으로 사료되며, 상세한 오염기구는 추가 연구에 의하여 검증되어야 할 것이다.

Mixed steam and carbon dioxide reforming of methane on Ni CeO2/MgAl2O3 catalyst: the performance of pelletized catalyst

최인혁,전기원,이윤조,백승찬,박해구 한국공업화학회 2014 한국공업화학회 연구논문 초록집 Vol.2014 No.0

전해정련을 통한 동의 초고순도화 (초)

최인혁,김민석,최국선,임재원 대한금속ㆍ재료학회 2009 대한금속재료학회 학술대회 개요집 Vol.2009 No.-

이득 포화 SOA 와 반사형 SOA 변조기를 이용한 data rewriter 특성 연구

최인혁,권혁춘,김태영,한상국 한국통신학회 2004 한국통신학회 기타 간행물 Vol.2004 No.11