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SF<sub>6</sub>-N<sub>2</sub> 혼합가스 중 돌출 결함의 부분방전 특성
조향은,왕국명,김선재,박경수,길경석,Jo, Hyang-Eun,Wang, Guoming,Kim, Sun-Jae,Park, Kyoung-Soo,Kil, and Gyung-Suk 한국전기전자재료학회 2016 전기전자재료학회논문지 Vol.29 No.1
Studies on a $SF_6$-mixture and -alternative gas has been in progress to reduce the use of $SF_6$ gas as an insulation material of GIS (gas insulated switchgears). In this paper, we dealt with PD (partial discharge) characteristics in pure $SF_6$ and $N_2$, and their mixtures on aspects of insulation design and risk assessment for GIS. A POC (protrusion on conductor) and a POE (protrusion on enclosure) as the major defects were fabricated to simulate PD. We analyzed the DIV (discharge inception voltage), DEV (discharge extinction voltage), pulse magnitude, counts and phase distribution of PD pulse in $SF_6-N_2$ mixtures ($SF_6$ 100%, $SF_6$ 80%-$N_2$ 20%, $SF_6$ 50%-$N_2$ 50%, $SF_6$ 20%-$N_2$ 80%, and $N_2$ 100%) according to the IEC60270. The DIV, DEV as well as magnitude of PD pulse decreased on the POC as increase of $N_2$ ratio. For the POE, the DIV and DEV in $N_2$ ratio below 50% were the same voltages as those in $SF_6$ 100%. In this experiment, $SF_6$ 80%-$N_2$ 20% mixture could be considered with the equivalent insulation performance to a GIS.
가스절연 구조에서 단일 부분방전펄스 분석에 의한 결함 판별
조향은,김선재,정기우,길경석,Jo, Hyang-Eun,Kim, Sun-Jae,Jeong, Gi-Woo,Kil, Gyung-Suk 한국전기전자재료학회 2015 전기전자재료학회논문지 Vol.28 No.5
This paper dealt with a defect identification algorithm which is based on single partial discharge (PD) pulse analysis in gas insulated structure. Four types of electrode systems such as a needle-plane, a plane-needle, a free particle and a crack inside spacer were fabricated to simulate defects in gas insulated switchgear (GIS). We measured single PD pulse by an oscilloscope with a sampling rate of 5 GS/s and a frequency bandwidth of 1 GHz. Data aquisition and signal processing were controlled by a LabVIEW program. Physical shapes of PD pulses were compared with kurtosis, skewness and time-based parameters as rising time, falling time and pulse-width. These parameters were analysed by an algorithm with a back propagation algorithm (BPA). By applying the algorithm, the identification rate was 97% for the needle-plane electrode, 96% for the plane-needle electrode, 91% for the free particle and 93% for the crack inside spacer. The results verified that the algorithm could identify the type of defects in GIS.
Comparison of Partial Discharge Characteristics in SF6 Gas Under AC and DC
조향은,길경석,Guoming Wang,,김선재 한국전기전자재료학회 2015 Transactions on Electrical and Electronic Material Vol.16 No.6
In this paper, parameters related with partial discharge (PD) were analyzed in SF6 gas under AC and DC voltages. Three electrode systems (protrusion on conductor, protrusion on enclosure, and free particle) were fabricated to simulate PD defects in a gas-insulated switchgear (GIS). All electrode systems were filled with SF6 gas at 0.5 MPa. PD pulses were detected using an oscilloscope and a data acquisition (DAQ) based on IEC 60270. To analyze the PD characteristics under AC and DC voltages, parameters such as discharge inception voltage (DIV), discharge extinction voltage (DEV), pulse magnitude, repetition rate, and T-F map were compared. From the experimental results, PD was revealed to have different characteristics under AC and DC, and these results may be useful for diagnosis of power facilities operated under HVDC.
조향은,진창환,박대원,길경석,안창환,Jo, Hyang-Eun,Jin, Chang-Hwan,Park, Dae-Won,Kil, Gyung-Suk,Ahn, Chang-Hwan 한국전기전자재료학회 2012 전기전자재료학회논문지 Vol.25 No.2
This paper dealt with the frequency component analysis of acoustic signals produced by corona and series-arc discharges as a diagnostic technique for closed-switchboards. Corona and series-arc discharge were simulated by a needle-plane electrode and an arc generator specified in UL1699, respectively. Acoustic signal was detected by a wideband acoustic sensor with a frequency bandwidth of 4 Hz~100 kHz (-3 dB). We analyzed frequency spectrums of the acoustic signals detected in various discharge conditions. The results showed that acoustic signals mainly exist in ranges from 30 kHz to 60 kHz. From the experimental results, an acoustic detection system which consists of a constant current power supply (CCP), a low noise amplifier (LNA) and a band pass filter was designed and fabricated. The CCP separates the signal component from the DC source of acoustic sensor, and the LNA has a gain of 40 dB in ranges of 280 Hz~320 kHz. The high and the low cut-off frequency are 30 kHz and 60 kHz, respectively. We could detect corona and series-arc discharges without any interference by the acoustic detection system, and the best frequency is considered in ranges of 30 kHz~60 kHz.
조향은(Hyang-Eun Cho),차현규(Hyeon-Kyu Cha),정광석(Kwang-Seok Jung),박대원(Dae-Won Park),길경석(Gyung-Suk Kil),최용기(Yong-Ki Choi) 한국마린엔지니어링학회 2010 한국마린엔지니어링학회 학술대회 논문집 Vol.2010 No.4
We carried out a comparative analysis of electrical and optical characteristics for a low- and a medium-pressure ultra violet (UV) lamps to choose the best fitted lamp as a function of ballast water capacity. A 8 [W], a 10 [W], a 24 [W] (3×8 [W]), low- and a 3.5 [㎾] medium-pressure UV lamps were used in the experiment, and the UV intensity were measured as a function of distance from the lamp under sea-water. The UV intensity of lamp surface per unit were 32.3 [W/㎡] for 8 [W], 50.5 [W/㎡] for 10 [W], 158 [W/㎡] for 24 [W] and 107.8 [W/㎡] for 3.5 [㎾]. Also, the UV intensity per unit power were 35.61 [J] for 8 [W], 122.77 [J] for 10 [W], 224.69 [J] for 24 [W] and 1.47 [J] for 3.5 [㎾].
크리스타 볼프의『원전 사고』다시 읽기 - 비판적 고찰 -
조향 한국헤세학회 2017 헤세연구 Vol.38 No.-
Christa Wolfs Erzählung Störfall, die als literarische Reaktion auf das Reaktorunglück in Tschernobyl verfasst worden ist, handelt von drei Krisen: dem Atomunfall, der Hirnoperation des Bruders der Ich-Erzählerin, sowie ihrer weltanschaulichen und schöpferischen Krise als Schriftstellerin. Auf der Suche nach der Ursache der Katastrophe und beim Versuch, die drei Krisen zu bewältigen, klagt die Ich-Erzählerin zunächst die Wissenschaftler an, die für die Entwicklung und Durchführung von Kernkraftwerken und Atombomben zuständig sind. Sie erklärt sich die Technikversessenheit der männlichen Wissenschaftler damit, dass deren Gehirne durch einen Mangel an Liebe unterstimuliert sind, so dass sich die Wissenschaftler in Arbeit und Forschung stürzen. Ihre Kritik gründet dabei auf einem pessimistischen Menschenbild sowie einer Dichotomie von Natur und Kultur, die sie versucht, evolutionsgeschichtlich herzuleiten. Ihre dualistische Sicht auf Weiblichkeit und Männlichkeit einerseits, und auf Natur und Kultur andererseits, steht im Widerspruch zur Dialogizität, Polyphonie sowie Subversivität der Alltagspoetik und der intertextuellen Schreibweise von Christa Wolfs Erzählung. Mittels dieser Poetik und Schreibweise versucht die Autorin angesichts des unerhörten historischen Ereignisses die Probleme der von Zweckrationalität regierten Welt zu reflektieren und den “blinden Fleck” ihrer Kultur sichtbar zu machen, wobei die Literatur sich erneut als ein sinnvolles Medium für solche Reflexionen, Fragestellungen und die Bewältigung von Krisen erweist.