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고압배전반의 전기적 안정성 향상을 위한 버스바의 배치기법에 따른 전자기 특성에 관한 연구
남석호,허정일,홍종기,강형구,Nam, Seokho,Heo, Jeong Il,Hong, Jonggi,Kang, Hyoungku 한국전기전자재료학회 2013 전기전자재료학회논문지 Vol.26 No.3
The rated voltage has been rising in order to minimize the losses in power transmission. The high voltage electric machines should be minimized due to the constraints of space. Therefore, the temperature of high voltage electric apparatuses easily exceeds the temperature limits. In this paper, it is investigated that how to minimize the internal temperature rising of a high voltage switchgear by adjusting the arrangement of bus bars. High voltage switchgears consist of a circuit breaker, a CT, a PT, a earthing switches, bus bars, and so on. It is very difficult to estimate the electromagnetic properties of a high voltage switchgear due to these various environments and structures. In this paper, analyses are focused on the electromagnetic characteristics of bus bars according to the arrangement method and the enclosures to simplify the electromagnetic characteristics of a switchgear. It is found that the characteristics of electric field intensity and electromagnetic losses in bus bars are influenced by the arrangement method of bus bars. However, it is confirmed that the electromagnetic characteristics of enclosures are not affected by the arrangement of bus bars. In this paper, the arrangement methods of bus bars to minimize the electric field intensity and electromagnetic losses are suggested. It is expected that the research results are helpful to design and develop an electrically reliable high voltage switchgear.
에너지하베스팅 소자용 PZW-PMN-PZT 세라믹의 압전특성
정영호(Yeongho Jeong),남석호(Seokho Nam),김승래(Seungrae Kim),정주현(Juhyun Jung),류주현(Juhyun Yoo),이갑수(Kabsu Lee),이유형(Yuhyong Lee) 한국조명·전기설비학회 2009 한국조명·전기설비학회 학술대회논문집 Vol.2009 No.5월
In this study, in order to develop the composition of ceramics capable of being sintered at low temperature with high piezoelectric properties, PZW-PMN-PZT system ceramics for piezoelectric energy harvesting application were manufactured according to the amount of PZW addition. And also, their microstructural, dielectric and piezoelectric properties were investigated. At the sintering temperature of 930℃, a 5 ㏖% PZW substituted specimen showed a maximum value of density = 7.905g/㎤, kp = 0.585, d₃₃= 351 pC/N and Qm = 1,254, respectively.
비용 효율이 높은 24kV급 고압배전반 개발을 위한 Bus Bar 사이즈에 따른 전·자기 손실 특성 분석
홍종기(Jonggi Hong),허정일(Jeong Il Heo),남석호(Seokho Nam),강형구(Hyoungku Kang) 대한전기학회 2012 전기학회논문지 P Vol.61 No.4
The analysis on the bus bar effect is conducted to develop a cost effective 24kV/2,000A switchgear. The temperature enclosures and bus bars could rise due to several heat sources such as eddy current losses and copper losses. Therefore, a study on the characteristics of the electric field intensity and electromagnetic loss according to the bus bar size in a bus bar compartment is essential to design a electrically reliable high voltage switchgear. It is investigated that the electromagnetic influence to the temperature rising and the dielectric stability according to various bus bar sizes by using finite element method(FEM). The electric field intensity and electromagnetic loss according to various bus bar sizes are calculated to design a reliable and a high voltage switchgear. As results, it is found that the electromagnetic loss and the dielectric stability of bus bar could be determined by a bus bar size. It means that a cost effective 24kV/2,000A high voltage switchgear could be developed by selecting the proper size of a bus bar. Also, it is recognized that the electromagnetic characteristics according to various bus bar sizes in order to design an electrically stable high voltage switchgear when the enclosure size is determined as a fixed value. Futhermore, studies on the various nominal voltage class and bus bar sizes will be conducted to develop a cost effective high voltage switchgear.
액체질소 내에서 뇌 임펄스전압에 대한 압력별 GFRP의 절연파괴 특성 분석
홍종기(Jonggi Hong),허정일(Jeong Il Heo),남석호(Seokho Nam),강형구(Hyoungkul Kang) 대한전기학회 2012 전기학회논문지 Vol.61 No.10
A study on the dielectric characteristics of the Glass Fiber Reinforced Plastic (GFRP) is important for designing a reliable high voltage superconducting machines such as transmission superconducting fault current limiters, superconducting cables, and superconducting transformers. In this paper, dielectric experiments of the GFRP under lightning impulse voltage are conducted in liquid nitrogen(LN₂) according to various experimental conditions such as the thicknesses of the GFRP, the diameters of electrode systems and the pressures. The dielectric characteristics of the GFRP are analyzed by using a Finite Elements Method(FEM) according to various field utilization factors. It has been reported that the electrical insulation design of the GFRP would be conducted by considering the mean electric field intensity(Emean) distributed inside the GFRP. In this study, it is found that the dielectric performance of the GFRP could be explained by not only Emean but also the maximum electric field intensity (Emax). Finally, the empirical formulae of the GFRP to estimate an electrical breakdown voltage at sparkover under the lightning impulse condition are deduced. It is expected that the presented experimental results in this paper are helpful to design electrically reliable high voltage superconducting machines using the GFRP as an insulation material.