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불평등 전계에서 SF₆/CF₄ 혼합가스의 절연내력과 PD특성
黃靑虎(Cheong-Ho Hwang),成許慶(Heo-Gyung Sung),許昌洙(Chang-Su Huh) 대한전기학회 2008 전기학회논문지 Vol.57 No.4
New gas mixtures are now finding applications such as interrupting media for high-voltage circuit breakers. These mixtures consist of a high content of carbon tetrafluoride(CF₄) added to sulfur hexafluoride(SF?). Nowdays SF? has been established for the use in gas insulated substations due to its high insulation withstand level and good arc quenching capability. At this paper Breakdown characteristics were investigated for SF?/CF₄ mixtures when AC voltage and standard lightning impulse voltage(LI) was applied in a needle - plane electrodes. And partial discharge (PD)experiments were carried out in the test chamber which was made in needle - plane electrode. And Φ-Q-N distribution of partial discharge signals was analyzed. The total pressure of the SF?/CF₄ mixtures was varied within the range of 0.1 - 0.5 Mpa in the test chamber. The breakdown voltage in needle - plane electrode displayed N shape characteristics for increasing the content of SF? at positive impulse voltage and the PD inception voltage was increased slightly when pressure of SF?/CF₄ Mixtures was increased. Maximum PD inception voltage is showed in 80% SF6/20%CF₄..
불평등전계에서 SF₆/CF₄ 혼합 가스의 SLI, AC 절연내력 특성
黃靑虎(Cheong-Ho Hwang),成許慶(Heo-Gyung Sung),許昌洙(Chang-Su Huh) 대한전기학회 2008 전기학회논문지 Vol.57 No.2
Although many studies have been carried out about binary gas mixtures with SF?, few studies were presented about breakdown characteristics of SF?/CF₄ mixtures. At present study the breakdown characteristics of SF?/CF₄ mixtures in non-uniform field was performed. The experiments were carried out under AC voltage and standard lightning impulse (SLI) voltage. Breakdown characteristics were investigated for SF?/CF₄ mixtures when AC voltages and standard lighting impulse voltage was applied in a needle-plane. The needle-plane electrode whose gap distance was 3 ㎜ were used in a test chamber. SF?/CF₄ mixtures contained from 0 to 100% SF? and the experimental gas pressure ranged from 0.1 to 0.5 ㎫. The breakdown characteristics of SF?/CF₄ mixtures in non-uniform field may be influenced by defects like needle-shaped protrusions. In case of slowly rising SLI voltage and AC voltage it is enhanced by corona-stabilization. This phenomena caused by the ion drift during streamer development and the resulting space-charge is investigated. In non-uniform field under negative SLI voltage the breakdown voltage was increase linearly but under positive SLI voltage the breakdown voltage increase non-linearly. The breakdown voltage in needle-plane electrode displayed N shape characteristics for increasing the content of SF? at AC voltage. SF?/CF₄ mixture has good dielectric strength and arc-extinguishing properties than pure SF?. This paper presents experimental results on breakdown characteristics for various mixtures of SF?/CF₄ at practical pressures. We could make an environment friendly gas insulation material with maintaining dielectric strength by combing SF? and CF₄ which generates a lower lever of the global warming effect.
초고압,장갭의 불평등전계에서 SF?/N₂혼합가스의 절연내력 시뮬레이션 및 실험값와의 비교
이병택(Bying-Taek Lee),황청호(Cheong-Ho Hwang),허창수(Chang-Su Huh),이기택,장용무(Yong-Moo Chang) 대한전기학회 2010 대한전기학회 학술대회 논문집 Vol.2010 No.7
SF? is the most commonly used insulating gas in electrical systems. But In these days SF? mixtures and alternative gas has been studied because of global warming. so although many studies have been carried out about binary gas mixtures with SF?, few studies were presented about breakdown characteristics of SF6/N2 mixtures. At present study the breakdown characteristics of SF6/N2 mixtures in Non-uniform field was performed. In this paper, breakdown experiment values and breakdown simulation values are compared. Streamer theory was used for predicting breakdown voltage. For accurate simulation field factor, this simulation apply E field utilization using cst program AC breakdown experiments in non-uniform field was performed to compare with the breakdown simulation values. The pressure range of gas mixtures was 0.4 ㎫ to 0.7 ㎫. The rod-plane was used and mixture ratio is SF6 20% : N2 80%. The gap lengths is 10㎜ to 70㎜. As pressure increase, this simulation value do not correspond to the experiment value. So this simulation apply to utilization factor using CST program In the result, it was observed that breakdown voltage increase as pressure and gap lengths increase. But with gap lengths increasing, the breakdown voltage is saturated. So simulation need surface roughness factor.
초고압, 장갭의 불평등전계에서 SF?/N₂혼합가스의 절연내력 시뮬레이션
이병택(Bying-Taek Lee),황청호(Cheong-Ho Hwang),허창수(Chang-Su Huh),장용무(Yong-Moo Chang) 대한전기학회 2009 대한전기학회 학술대회 논문집 Vol.2009 No.11
SF? is the most commonly used insulating gas in electrical systems. But In these days SF? mixtures and alternative gas has been studied because of global warming. so although many studies have been carried out about binary gas mixtures with SF?, few studies were presented about breakdown characteristics of SF?/N₂ mixtures. At present study the breakdown characteristics of SF?/N₂ mixtures in Non-uniform field was performed. In this paper, breakdown experiment values and breakdown simulation value are compared. Streamer theory was used for predicting breakdown voltage. For accurate simulation field factor this simulation apply E field value using Finite Elements Method to field utilization. AC breakdown experiments in non-uniform field was performed to compare with the breakdown simulation values. The pressure range of gas mixtures was 0.4 MPa to 0.6 MPa. The rod-plane was used and mixture ratio is SF? 20% : N₂ 80%. The gap lengths is 10㎜ to 70㎜. In the result, it was observed that an increase in the dielectric strength is attained through the addition of pressure and gap lengths. But with gap lengths increasing, the breakdown voltage is saturated.
준평등전계에서 SF?/CF₄ 혼합가스의 절연 파괴 전압 및 임계전계 특성
이병택(Byung-Taek Lee),황청호(Cheong-Ho Hwang),안정식(Jung-Sik An),허창수(Chang-Su Huh) 대한전기학회 2009 대한전기학회 학술대회 논문집 Vol.2009 No.7
SF? is the most commonly used insulating gas in electrical systems. But In these days SF? mixtures and alternative gas has been studied because of global warming. so although many studies have been carried out about binary gas mixtures with SF?, few studies were presented about breakdown characteristics of SF?/CF₄ mixtures. At present study the breakdown characteristics of SF?/CF₄ mixtures in quasi-uniform field was performed. This experiments were carried out under AC voltages. The rod-rod electrode was used with 5 ㎜ gap distance. The mixture of SF?/CF4 containing 20%,50%,70% of SF? were compared with pure SF? and CF₄ gas and gas pressure ranged from 0.1 to 0.5 ㎫. The show that the breakdown voltages of gas were linearly increased according to the pressure in quasi-uniform field. For breakdown vlotage values of (E/P)<SUB>crit</SUB> are important. Because If values of (E/P) is a little more than (E/P)<SUB>crit</SUB>, electrons rapidly increase and streamer discharge gernerates. Through this experiments values of (E/P)<SUB>crit</SUB> are found to vary with the ratio of SF?/CF₄ mixture according to the following relationship.
인위적으로 발생된 전자파에 의한 반도체 소자의 파괴 효과
홍주일(Joo-Il Hong),황선묵(Sun-Mook Hwang),황청호(Cheong-Ho Hwang),박신우(Shin-Woo Park),허창수(Chang-Su Huh) 대한전기학회 2006 대한전기학회 학술대회 논문집 Vol.2006 No.7
이 논문은 인위적으로 전자파를 발생시켜 이 전자파에 의한 반도체 소자의 피해 효과를 조사한 것이다. 동작주파수가 2.45 ㎓인 마그네트론으로부터 발생되는 전자파는 끝단이 개방되어있는 도파관을 통해 자유공간으로 전파되고, 도파관 끝단으로부터 30㎝~50㎝인 지점에 반도체 소자들을 위치시켜 동작상태를 확인하였다. 시험에 사용된 피시험체인 반도체 소자로는 TTL과 CMOS 기반기술의 반도체를 사용하였고, LED 구동회로를 구성하여 LED의 점등 여부로 오동작 및 파괴 여부를 육안 식별 하였다. 또한 시험 전후의 반도체 소자 표면을 제거 후 칩 상태를 SEM 분석하였다. 시험 결과 도파관 끝단으로부터 50 ㎝, 40 ㎝ 떨어진 지점에 반도체 소자를 위치시키고 도파관 끝단에서 발생되는 전자파에 의한 반도체 소자의 피해는 전혀 없었다. 그러나 30 ㎝ 떨어진 지점에서 오동작 및 파괴가 일어났다. 오동작 및 파괴가 일어난 시료의 칩 상태를 SEM 분석한 결과 칩 내부의 onichipwire의 용융으로 인한 파괴와 bondingwire의 완전 파괴를 확인할 수 있었다. 위의 시험 결과는 인위적인 전자파 환경에서 반도체 소자의 결합 기구를 해석하는 기초 자료로 활용되며, 전자 장비들의 전자파 장해에 대한 이해에 도움이 되는 자료로 활용될 수 있을 것이다.
불평등 전계에서 표준 뇌 임펄스 전압의 SF. /CF₄ 혼합 가스의 절연 내력
허창수(Chang-Su Huh),성허경(Heo-Gyung Sung),박신우(Shin-Woo Park),황청호(Cheong-Ho Hwang),김남렬(Nam-Ryul Kim) 대한전기학회 2007 대한전기학회 학술대회 논문집 Vol.2007 No.11
In these days SF. mixtures and alternative gas have been studied because of global warming and liquefying at low temperature and high pressure. At present work the breakdown characteristics of SF. /CF₄ mixture in non-uniform field was performed. The experiments were carried out under positive and negative standard lightning impulse (SLI) voltages. The point-plane electrode was used with 3 ㎜ gap distance in the test chamber. The SF. /CF₄ mixture which contain 20% of SF. was compared with pure SF. and CF₄ gas. Experimental gas pressure ranged from 0.1 to 0.4 ㎫. The breakdown voltage under negative SLI is higher than the breakdown voltage under positive voltage. And the breakdown voltage of SF. 20%, CF₄ 80% mixture is similar to that of pure SF. .