XLPE의 수트리에 의한 절연파괴 특성에 관한 연구

李聖一 충주대 2001 한국교통대학교 논문집 Vol.36 No.1

In order to investigate the water tree degradation behavior on XLPE cable, direct voltage of 200 to 800V has been applied to the material at 50℃∼100℃, and the water tree property has been correlated with voltage and temperature in this study.The leakage current was shown to increase as temperature increased and the Ohm's law was generally satisfied in this experiment though some experimental errors were found.The leakage current was shown to decrease and reach to the stable state with time.It was also shown that the time for the stabilization of leakage current was lessened as voltage increased.

電子線 照射에 따른 變壓器油의 誘電特性

李盛一 忠州大學校 1996 한국교통대학교 논문집 Vol.31 No.1

In this paper, the dielectric properties is made researches by the dose of in order to investigate the electrical properties for trans former oils due to the irradition of electron beam. The experimental condition of measuring the dielectric loss is performed 20~120[℃]in temperature range, 30~1.5X10??[㎐]in frequency, and 300~1500[㎷] in voltage. It is confirmed that carbonyl groups is increased according to increasing the dose of electron beam, and also that the nitric compounds are disappeared as a result of investigating the physical properties using infrared spectrum of specimen. In the experiment for the dielectric properties of specimen, the magnitude of dielectric dissipation factor appears maximun value by the contribution of dipoles and ions in the low temperature, low voltage region, and it is stable due to the saturation of carrier in the high temperature, high voltage region in the electric conduction characteristics.

충진제 변화에 의한 EPR의 열자격전류 특성에 관한 연구

李聖一 충주대 2000 한국교통대학교 논문집 Vol.35 No.1

This paper present the results of measured Thermally Stimulated Current of EPR(Ethylene Propylene Rubber) sheet material with variation of bias temperature range of -35~80[℃], the quality of the material of electrode, condition.The origins of these peaks are that, low temperature peak seems to result from dipole, and high temperature peak from the orientation electronic trap.

에폭시수지의 전기특성에 미치는 충전제 형상의 효과

李聖一 충주대 산업과학기술연구소 2001 産業科學論文集 Vol.9 No.-

Composite insulating materials used in outdoor high voltage equipments are required to have the high electric performance because of the miniaturization. The frequence dependence of the permittivity and the loss tangent have important information. In this paper we describe the frequency dependence of the permittivity and the loss tangent for epoxy resin filled with silica and the influence of filler shapes on the dielectric properties. The increment of tan δ in the low frequency region is caused by the increment of both the electrical conductivity and the polarization due to the shape of filler and the water sbsorbed in and near the interface between fillers and resins. The result of charge current and discharge measure, electric conduction is increased according to voltage.

EPR 케이블의 절연열화 진단에 관한 연구

이성일 충주대 산업과학기술연구소 1999 産業科學論文集 Vol.7 No.1

This paper describes the properties of between discharge current and the residual voltage for γ-irradiated in electric power cable using in nuclear power generating station. As these properties related with γ-irradiatiation dose, it is suggested that these properties can be utilized as a index of irradiation degradation. The discharge current is proportional to the cable length. From theory and experiment I found the residual voltage is not influenced by cable length and size. In the case of performing the insulation degradation diagnosis of cables, if the values which become the index of the degradation diagnosis differ depending on the length, it is necessary to make correction every time when the judgment of the diagnosis to be made and and so it is not desirable as diagnosis method. The discharge currents are almost the same regardless of ratio of degradation. As the ratio of degradation increases, the residual voltage in the initial time range increases and the peak moves to the shorter time. Therefore, I can know the degree of radiation degradation from the position of the peak.

現場監督者의 意識과 行動實態에 관한 比較硏究 : 韓國과 日本을 中心으로

李相道,宋瑞日,河正鎭 동아대학교 공과대학 부설 한국자원개발연구소 1981 硏究報告 Vol.5 No.2

This study is to show the way in which supervisors in this country will do after investigating how Korean and Japanese supervisors' consciousness and behavior have been changed under various environment condition of the company.

水晶體 β-Crystallin의 Carboxylmethylation에 關한 硏究

李康一,郭相太,林圭 충남대학교 의과대학 지역사회의학연구소 1988 충남의대잡지 Vol.15 No.2

Changes of protein patterns of nonmethylated and endogenous or exogenous methylated β-crystallin fractions have been investigated, and then the methyl-acceptor proteins identified by urea /polyacrylamide gel electrophoresis. 1. Nonmethylated β_H and β_L-crystallin were separated in ten, eleven fractions, respectively. In the endogenous methylated β_H-crystallin, subfraction No. 10 was disappeared and No.3 was increased when compared with that of nonmethylated. In the β_L-cryallin, subfraction No.8, 10, 11 were decreased and No.6, 7 was increased. 2. When native β-crystallins were electrophoresed, subfraction No. 7, 9 disappeared and No.8b, 10b were newly appeared and. No. 6 was increased in methylated β_H-crystallin, and subfraction No. 11 was disappeared, No.9 was decreased and No.8 was increased in meth ylated β_L-crystallin. But, subfraction profile of methylted a-crystallin was not changed. 3. Methyl-acceptor proteins in each crystallin were subfraction No. 1, 6, 8 in a-crystallin, 2, 3, 6, l0a in β_H-crystallin and 1, 6, 7, 8, 10 in β_L-crystallin, respectively. These results suggest that the effect of carboxylmethylation on the aggregation of β-crystallin is related to not only the interaction of a, r-crystallin subfractions, but also the interaction of β-crystallin subfractions. On the other hand, a-crystallin is only related to the interaction of the other crystallin subfractions.

SOFC의 산소극 특성에 관한 연구

이성일,김귀열 충주대 산업과학기술연구소 1996 産業科學論文集 Vol.4 No.-

In this paper, the cathode materials of solid oxide fuel cell were fabricated, and the analysis of TG/DTA, XRD, thermal expansion were investigated. As a result, thermal expansion coefficient of LSM was not quite different from that of electrolyte. And a performance of LSM(x=0.4) was better excellent than the others.

폴리에틸렌의 공간 전하와 절연 파괴 특성에 관한 연구

李聖一 충주대 2004 産業科學論文集 Vol.12 No.-

Polyethylene insulating materials are widely applied to power cables. Electric breakdown strength and space charge distribution are measured with the specimens which have various interfaces involved in insulating system of power cable. It is suggest that the increase in conduction current due to the generation or Injection lead to the breakdown.

저밀도 폴리에틸렌의 전기특성에 미치는 온도 및 주파수의 영향에 관한 연구

이성일 한국교통대학교 2019 한국교통대학교 논문집 Vol.54 No.-

In this study, an LDPE film specimen was wrapped in aluminum foil and heated for four hours in an anaerobic environment of 60°C to 80°C. This is the result of measuring dielectric loss tangent and capacitive properties by increasing voltage 1V and temperature from 60oC to 80oC by 5oC. As the temperature increases, the magnitude of the dielectric loss tangent increases with increasing frequency, which is thought to be due to dipole polarization. As the temperature increases, the capacitance decreases as the frequency increases, which is thought to be due to the rapid increase in the loss due to the vibration of the side chain hydrogen. FTIR(Fourier Transform Infred: FTIR) analysis of temperature degraded specimen for 4 hours at 60oC, 70°C and 80°C confirmed no change in molecular structure.