• 한국농공학회지
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• 제32권3호
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• pp.39-46
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• 1990

This paper was analized the thermal conductivity of polystylene (TENSAR- GEOGRID) embeding into the subbase through frost penetration depth, frost heave, change of bearing capacity, and soil moisture movement due to freezing, thawing and icing actions, and their results were as follows : 1.The change of temperature into the sub-base was much increased by the Tensar-Geogrid insertion, and the frost penetration and frost heave were decreased as the thinner of the insulation thickness but the thawing velocity of melting period was appeared to be faster in case of non-insulated. 2.The frost heave had a close relationship with the thickness of insulations which was reasonably included anti-frost effects. 3.The moisture content during the freezing period of upper layer of the insulation insertion was increased by 15 per cent but it was returned to initial state of the thawing period, and at the down layer temporarily increased by 10 per cent and returned to the original state at once. 4.The insulation was acted as a function of distribution of surcharge, and the settlement of the sub-base was about 1.5 mm under 15 tonnage of load and which was included within the allowable limits. 5.The sliding resistance due to the icing which was induced by the insulation insertion into the sub-base was appeared as more 40 per cent than noninsulation area, so that the insulations should be restricted on the place such as mountains, curved and cross area which were required the braking power under the traffics.

• 조명전기설비학회논문지
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• 제30권1호
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• pp.72-78
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• 2016

In terms of power components which use environmentally-friendly dry air that can substitute SF6, there have been studies on the electrical properties of the solid insulation "spacer" for the purpose of securing dielectric strength as they become smaller. This study laminated solid insulation to keep the creeping distance the same in the dry air and investigated vertical surface discharge characteristics by shape. The three sheets of disk-type solid insulation(Bakelite) were laminated in a manner to keep the creeping distance the same. The lamination was categorized as follows: "Type A" in which the insulations with the same disk diameter were laminated; "Type B" in which the insulations whose middle disk diameter was large were laminated; and "Type C" in which the ones whose middle disk diameter was small were laminated. For a vertical surface discharge experiment, dry air was injected into the test chamber depending on the shape of the laminated solid insulation, and chamber pressure was adjusted in a range of 0.1-0.6MPa. As volume decreased, surface discharging voltage by unit volume increased. This was because of dielectric polarization according to the structural characteristics of the shape of lamination. The highest surface discharging voltage was found in "Type C."

• 한국화재소방학회논문지
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• 제20권4호
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• pp.26-32
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• 2006

국내에서는 현재 샌드위치패널의 화재성능 평가를 위하여 KS F 2271(건축물의 내장재료 및 구조의 난연성 시험방법)을 사용하고 있다. 그 중 연기 및 연소독성가스에 대한 시험인 가스유해성 시험은, 건축 재료 및 내장재의 연소시 발생하는 가스의 유해성을 마우스의 평균 행동정지시간으로 측정하는 방법으로, 정량적인 방법이 아니므로 마우스의 상태나 시험조건에 따라 시험결과가 달라질 수 있다. ISO 5659-2 연소챔버 시험방법은 광학밀도를 정량적으로 측정할 수 있으며, FTIR을 이용한 유독가스 분석이 가능하다. 본 연구에서는 ISO 5659-2 연소챔버 시험방법을 사용하여, 국내에서 일반적으로 사용되는 4종의 샌드위치패널 단열재의 광학밀도를 측정하여 각 시험체와 비교하였다. 또한, 시험체마다 3번의 시험 중 두 번째 시험시 FTIR 분석을 수행하여 HCl, $NO_2$ 등의 정량적 결과를 비교하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 C
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• pp.1832-1834
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• 2004

The degree of contamination on outdoor insulator is one of the most importance factors to determine the pollution level of outdoor insulations, and the sea salt is known as the most dangerous pollutant. As shown through the preceding study, the generation of salt pollutant and the pollution degree of outdoor insulator have a close relation with meteorological conditions, such as wind velocity, rainfall, and so on. So, in this paper, we have made database using the past meteorological data and ESDD(equivalent salt deposit density) and then we predicted the pollution degree in the future after analyzing currently meteorological data of database.

• KIEAE Journal
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• 제7권2호
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• pp.57-62
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• 2007

Recently Among indoor noises plumbing noise from supply and drain water pipe is being pointed out as a annoying noise following to floor impact noise, and it is increasing the rate to point the noise due to the following several reasons: water pressure, vibration by fabricated structures and direct noise propagation from upper floor through ceiling This study aims to analyse the characteristics of toilet stool plumbing noise in apartment bathroom which are generated by crossing plumbings and elbows. And it analyse the effect of noise reduction by soundproofing and insulations which are covered at crossing plumbings. And also analyse the characteristics of noise about a type of elbows, crossing plumbing and result of dB(A). At last it provide a fundamental data for the purpose of reduction of plumbing noise in apartment.

• 한국초전도ㆍ저온공학회논문지
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• 제3권1호
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• pp.29-34
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• 2001

A Bi-2223 tape has been developed for low-field Power applications such as Power cables or transformers working at liquid nitrogen temperature For such applications it is required to understand fault current characteristics of the Bi-2223 tape. In this paper we report fault current characteristics using two types of samples, straight sample and pancake coil sample. It was found that the fault current characteristics of the Bi-2223 tape are independent of external fields and frequencies . However they depend on electrical insulations and fault durations strong1y Also it was shown that the fault current characteristics in the insulated straight sample are similar to those in the pancake sample with a conductor insulation. Finally. it was shown that the Pancake sample with a layer insulation has better characteristics than that with a conductor insulation fur fault currents.

• Journal of Electrical Engineering and Technology
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• 제12권2호
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• pp.840-845
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• 2017

In this paper, in order to investigate the lifetime of oil-paper insulation, specimens were artificially aged with thermal and electrical multiple stresses. Accelerated ageing factors and equivalent operating years for each aging temperatures were derived from results of tensile strengths for the aged paper specimens. Also, the evaluation for the multi-stress aged specimens were carried out through the measurement of impulse breakdown voltage at high temperature of $85^{\circ}C$. The lifetimes of the oil-paper insulations were calculated with the value of 66.7 for 1.0 mm thickness specimens and 69.7 for 1.25 mm thickness specimens throughout the analysis of impulse BD voltages using equivalent operating years, which means that dielectric strengths would not be severely decreased until the mechanical lifetime limit. Therefore, for the lifetime evaluation of the oil-paper insulation, thermal aging would be considered as a dominant factor whereas electrical degradation would be less effective.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.2085-2086
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• 2011

전력설비의 절연물이 사용 환경 영향을 받아 열화되어 방전이 발생하게 되는데, 이 때 발생하는 방전의 크기 및 량은 절연물의 결함 형태와 환경에 영향을 받아 다양하게 나타난다. 절연물 결함에서 발생하는 신호는 열, 전자파, 초음파, 빛의 형태이며, 이들 신호가 복합적으로 방출된다. 결함을 갖는 절연물 종류에 따라 발생하는 이상 신호 패턴을 분석하여 절연성능 저하를 검출할 수 있고, 절연성능 저하 원인 규명에도 활용된다. 본 연구에서는 전력설비에 사용하고 있는 결함 또는 열화된 애자류의 이상신호 발생의 근본원인을 고찰하였으며, 이들의 신호를 검출하는 적절한 방법을 제시하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1992년도 하계학술대회 논문집 B
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• pp.969-972
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• 1992

It is shown that the ac breakdown strength, treeing phenomena, oxidation level, and crystallinity of unaged and aged distribution CV cables vary with XLPE insulations (characterizing anti-oxidation) and curing process. The maximum size of bow-tie tree in insulation influenced on the decrease of ac breakdown strength and the increase of oxidation level and crystallinity of XLPE according to aging time lead to increase the size and density of bow-tie trees.

• 전기학회논문지
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• 제60권10호
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• pp.1972-1977
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• 2011

The mechanical integrity of generator stator windings is one of the critical point because the electric power is generated and conducted to power system through these windings. To cool down the heat emitted from generator winding during its operation, a majority of generators use de-mineralized water characterized by high cooling efficiency. Contrary to such the excellent cooling efficiency, however, the damaged bar insulations attributed to the absorption of cooling water in the generator stator winding lead to highly time- and cost consuming efforts as well as to service deterioration due to unexpected forced outage of generator. It is described that the new design of water absorption sensor using cross capacitance for generator in power plant in order to increase the reliability of water absorption diagnostics for generator stator bar insulation.