• 플랜트 저널
• /
• 제16권3호
• /
• pp.42-46
• /
• 2020

FLNG 혹은 FSRU와 같이 대량의 LNG를 처리하는 공정에서의 LNG 누출 사고 시, 강재의 급격한 온도변화는 구조물의 취성파괴를 야기시킬 가능성이 있다. 본 논문에서는 극저온 유출 실험을 통해 극저온 유체가 강판에 형성되는 원리 및 과정을 알아보고, 노즐로부터의 거리 및 노출시간에 따른 강판의 온도변화의 상관관계를 분석하고자 한다. 극저온 유체는 LN2(비점 -192℃) 및 LNG(비점 -162℃) 두 가지 종류를 사용하였으며, 유출량은 LN2의 경우 1.6L/min 및 LNG 1.5L/min로 강판의 상부에서 분사하였다. 강재는 DH계열 이용하였으며, 총 10 지점에서 온도를 측정하였다. 실험 결과 극저온 유출 초기 강재표면에서 Leidenfrost 효과가 관찰 되었으며, 극저온 유체가 흐르는 경로 및 유체의 증발열에 차이에 따라 강재의 온도분포가 다르게 나타나는 것을 발견하였다.

• 한국조명전기설비학회:학술대회논문집
• /
• 한국조명전기설비학회 2007년도 추계학술대회 논문집
• /
• pp.39-43
• /
• 2007

In this paper the experiments of breakdown characteristics $SF_6$ liquid ($LSF_6$) in model GIS(Gas Insulated Switchgear) were described. From the experiments results, The ability of $LSF_6$ insulation is higher than high-pressurized $SF_6$ gas. The breakdown characteristics of $LSF_6$ were produced by bubble formed evaporation of $LSF_6$ and bubble caused by high electric emission. It is considered in this paper that the results are fundamental data for electric insulation design of superconductor and cryogenic equipments machinery which will be studied and developed in the future.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2007년도 제38회 하계학술대회
• /
• pp.252-253
• /
• 2007

In this paper the experiments of breakdown characteristics $SF_6$ liquid ($LSF_6$) in model GIS(Gas Insulated Switchgear) were described. From the experiments results, The ability of $LSF_6$ insulation is higher than high-pressurized $SF_6$ gas. The breakdown characteristics of $LSF_6$ were produced by bubble formed evaporation of $LSF_6$ and bubble caused by high electric emission. It is considered in this paper that the results are fundamental data for electric insulation design of superconductor and cryogenic equipments machinery which will be studied and developed in the future.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2005년도 제36회 하계학술대회 논문집 C
• /
• pp.2085-2087
• /
• 2005

In this paper the experiments of insulation characteristics by temperature change of $SF_6$ gas and liquid $SF_6$ in model GIS(Gas Insulated Switchgear) were described. From this results, the breakdown voltage was increased with a drop of temperature and an increase of the inner pressure in model GIS. The ability of insulation in liquid $SF_6$ was higher than that of the highly pressurized $SF_6$ gas. A liquid $SF_6$ discharge characteristics was caused by bubble formed evaporation of liquid $SF_6$ and bubble caused by high electric emission. It is considered that these result are fundamental data for electric insulation design of superconductor and cryogenic application machinery which will be studied and developed in the future.

• 한국조명전기설비학회:학술대회논문집
• /
• 한국조명전기설비학회 2008년도 추계학술대회 논문집
• /
• pp.261-264
• /
• 2008

In this paper the experiments of breakdown characteristics $SF_6$ liquid ($LSF_6$) in model GIS(Gas Insulated Switchgear) were described. From the experiments results, The ability of $LSF_6$ insulation is higher than high-pressurized $SF_6$ gas. The breakdown characteristics of $LSF_6$ were produced by bubble formed evaporation of $LSF_6$ and bubble caused by high electric emission. It is considered in this paper that the results are fundamental data for electric insulation design of superconductor and cryogenic equipments machinery which will be studied and developed in the future.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2006년도 추계학술대회 논문집 전기물성,응용부문
• /
• pp.178-179
• /
• 2006

In this paper the experiments of breakdown characteristics SF6 liquid ($LSF_6$) in model GIS(Gas Insulated Switchgear) were described. From the experiments results, The ability of $LSF_6$ insulation is higher than high-pressurized SF6 gas. The breakdown characteristics of $LSF_6$ were produced by bubble formed evaporation of $LSF_6$ and bubble caused by high electric emission. It is considered in this paper that the results are fundamental data for electric insulation design of superconductor and cryogenic equipments machinery which will be studied and developed in the future.

• 대한전기학회논문지:전기물성ㆍ응용부문C
• /
• 제54권8호
• /
• pp.355-360
• /
• 2005

In this paper the experiments of breakdown characteristics by temperature change of $SF_6$ gas, $SF_6$ liquid ($LSF_6$) and $N_2$ liquid ($LN_2$) in model GIS(Gas Insulated Switchgear) were described. From the experiments results, the breakdown voltage of $SF_6$ increases with the drop of temperature and the increase of the inner pressure in model GIS. The ability of $LSF_6$ insulation is higher than high-pressurized $SF_6$ gas and $LN_2$. The breakdown characteristics of $LSF_6$ were produced by bubble formed evaporation of $LSF_6$ and bubble caused by high electric emission. It is considered in this paper that the results are fundamental data for electric insulation design of superconductor and cryogenic equipments machine교 which will be studied and developed in the future.

• Journal of Electrical Engineering and Technology
• /
• 제2권2호
• /
• pp.257-262
• /
• 2007

In this paper the experiments of breakdown characteristics by temperature change of $SF_6$ gas($GSF_6$), and $SF_6$ liquid ($LSF_6$) in model GIS (Gas Insulated Switchgear) are described. From the experiment's results, the breakdown characteristics classify the vapor stage of $SF_6$ according to Paschen's law, in which the gas & liquid coexisted stage of voltage value increases, resulting in much deviation and the breakdown of voltage ($V_B$) low stage as the interior of the chamber gets filled with a mixture of $SF_6$ that is not liquefacted and remaining air that cannot be ventilated. The ability of $LSF_6$ insulation is higher than the high-pressurized $SF_6$ gas. The breakdown characteristics of $LSF_6$ were produced by bubble formed evaporation of $LSF_6$ and bubbles caused by high electric emission. It is considered in this paper that the results are fundamental data for electric insulation design of superconductor and cryogenic equipments machinery that will be studied and developed in the future.

• Journal of Electrical Engineering and Technology
• /
• 제7권5호
• /
• pp.765-771
• /
• 2012

$SF_6$ gas has been used as arc quenching and insulating medium for high and extra high voltage switching devices due to its high dielectric strength, its excellent arc-quenching capabilities, its high chemical stability and non toxicity. Despite of its significant contributions, the gas was classified as one of the greenhouse gas in the Kyoto Protocol. Thus, many researches are conducted to find out the replacement materials and to develop the $SF_6$ gas useless electrical equipment. This paper describes experiments on the temperature change-related breakdown characteristics of $SF_6$ gas ($SF_6$) and $SF_6$ liquid ($LSF_6$) in a model GIS(Gas-Insulated Switchgear) chamber in order to show the possibility of more stable and safe usages of $SF_6$ gas. The breakdown characteristics are classified into three stages, namely the gas stage of $SF_6$ according to Paschen's law, the coexisting stage of $SF_6$ gas with liquid in considerable deviation at lower temperature, and the stage of $LSF_6$ and remaining air. The result shows that the ability of the $LSF_6$ insulation is higher than the high-pressurized $SF_6$. Moreover, it reveals that the breakdown characteristics of $LSF_6$ are produced by bubble-formed $LSF_6$ evaporation and bubbles caused by high electric emission and the corona. In addition, the property of dielectric breakdown of $LSF_6$ is determined by electrode form, electrode arrangement, bubble formation and movement, arc extinguishing capacity of the media, difficulty in corona formation, and the distance between electrodes. The bubble formation and flow separation phenomena were identified for $LSF_6$. It provides fundamental data not only for $SF_6$ gas useless equipment but also for electric insulation design of high-temperature superconductor and cryogenic equipment machinery, which will be developed in future studies.

• Journal of Advanced Marine Engineering and Technology
• /
• 제39권9호
• /
• pp.876-880
• /
• 2015

IMO의 규제인 신조 선박에 대한 NOx 80% 감축의 2016년 발효를 앞두고, 청정에너지인 LNG연료 선박 및 벙커링 선박의 보급이 유럽 선진국들을 중심으로 추진되고 있다. LNG 저장탱크는 LNG 벙커링의 필수 설비로 현재의 액체질소 등을 저장하는 극저온 액체 저장탱크와 동일한 구조이며, IMO의 "C"형 가압탱크인 내외 용기로 구성된 2중 탱크에 진공펄라이트 단열재가 충전되는 형식이다. 그러나 이 단열방식은 진공작업이 어렵고 일 LNG 기화량이 2.0 % 내외가 되어 보다 고효율의 탱크가 요구되어 진다. 본 연구에서는 진공과 단열재를 분리하여 내외탱크에 고진공을 적용하고 외부 탱크에 우레탄폼을 가설시킨 탱크 단열 방식을 새로이 고안하여 열해석을 수행하였다. 해석결과 본 개발 탱크는 진공도가 $10^{-3}Torr$ 이하일 때 일 기화량이 0.03 % 이하로 매우 적게 유지될 수 있고, $10^{-4}Torr$ 이하가 되면 일 기화량이 0.11 %가 되었다. 진공이 파괴되는 경우에도 현재 진공펄라이트 단열은 일 4.9 %의 증발이 발생하나, 새 고안 탱크는 일 증발율이 4.12 %가 되는 매우 효율이 높고 안전한 LNG 탱크 단열방식이 되었다.