• Transactions on Electrical and Electronic Materials
• /
• 제11권4호
• /
• pp.149-154
• /
• 2010

With soaring public concerns of environmental issues, many researchers have started to carry out research on various related topics in many areas of science and engineering. This paper describes a brief outline of typical recent research results obtained in the author's laboratory on electrical and optical properties of dielectric materials, done aiming at contributing to green power technology.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1997년도 하계학술대회 논문집 C
• /
• pp.1402-1404
• /
• 1997

To evaluate the effects of impurities on insulating properties of polymeric insulator in high electric power distribution cable, OIT and OMT were measured. By using Eyring plot, the thermodynamic parameters of ${\Delta}H$ and ${\Delta}S$ could be obtained.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2006년도 추계학술대회 논문집 전기물성,응용부문
• /
• pp.190-191
• /
• 2006

In this paper, a method to assess the reliability of an insulating spacer used in gas insulated switchgear by electrical accelerated lifetime test is represented. And a test plan to assure the expected lifetime with 90 % confidence level is also included.

• 대한전기학회논문지
• /
• 제34권12호
• /
• pp.457-463
• /
• 1985

This paper studies on the tracking phenamena by the IEC recommended method with various polymeric insulating materials which are used in industrial fields. Under the same experimental condition, according to the materials it is observed that there are the type of tracking breakdown and the type of tracking erosion. In the tracking breakdown type materials, the tracking breakdown is occurred at a small number of drops increasing of test voltage and solution density. In the tracking erosion type materials, the erosion depth is saturated or proportioned as increasing of test voltage and solution density.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 1990년도 추계학술대회 논문집
• /
• pp.1-16
• /
• 1990

In this paper, a system to measure treeing degradation phenomena in organic insulating materials, using an image sensor, is discussed. Using an image processing technique, tree features immediately after tree initiation as well as changes in the configuration of the tree were measured. which up to now have been extremely difficult to observe by conventional visual methods. As a result, it was possible to record the image of tree propagation immediately after its first appearance, and to describe the specific characteristics of tree growth in terms of the length, the degraded area and the sequential images.

• 한국전기전자재료학회논문지
• /
• 제30권9호
• /
• pp.558-565
• /
• 2017

Hybrid insulators that have the advantages of both porcelain (high mechanical strength and chemical stability) as well as polymer (light weight and high resistance to pollution) insulators, can be used in place of individual porcelain and polymer insulators that are used for both mechanical support as well as electrical insulation of overhead power transmission lines. The most significant feature of hybrid insulators is the presence of porcelain/polymer interfaces where the porcelain and polymer are physically bonded. Individual porcelain and polymer insulators do not have such porcelain/polymer interfaces. Although the interface is expected to affect the mechanical/electrical properties of the hybrid insulator, systematic studies of the adhesion properties at the porcelain/polymer interface and the effect of the interface on the insulation characteristics and electric field distribution of the hybrid insulator have not been reported. In this study, we fabricated small hybrid insulator specimens with various types of interfaces and investigated the effect of the porcelain/polymer interface on the microstructure, insulating characteristics, and electric field distribution of the hybrid insulators. It was observed that the porcelain/polymer interface of the hybrid insulator does not have a significant effect on the insulating characteristics and electric field distribution, and the hybrid insulator can exhibit electrical insulating properties that are similar or superior to those of individual porcelain and polymer insulators.

• International Journal of Safety
• /
• 제1권1호
• /
• pp.36-42
• /
• 2002

This paper is aimed at predicting the life of rubber insulating gloves under normal operating stresses from relatively rapid test performed at higher stresses. Specimens of rubber insulating gloves are subject to multiple stress conditions, i.e. combined electrical and thermal stresses. Two modes of electrical stress, step voltage stress and constant voltage stress are used in specimen aging. There are two types of test for electrical stress in this experiment: the one is Breakdown Voltage (BDV) test under step voltage stress and thermal stress and the other is lifetime test under constant voltage stress and temperature stress. The ac breakdown voltage defined as the break-down point of insulation that leakage current excesses a limit value, l0mA in this experiment, is determined. Because the very high variability of aging data requires the application of statistical model, Weibull distribution is used to represent the failure times as the straight line on Weibull probability paper. Weibull parameters are deter-mined by three statistical methods i.e. maximum likelihood method, graphical method and least squares method, which employ SAS package, Weibull probability paper and FORTRAN, respectively. Two chosen models for predicting the life under simultaneous electrical and thermal stresses are inverse power model and exponential model. And the constants of life equation for multistress aging are calculated using numerical method, such as Gauss Jordan method etc.. The completion of life equation enables to estimate the life at normal stress based on the data collected from accelerated aging test. Also the comparison of the calculated lifetimes between the inverse power model and the exponential model is carried out. And the lifetimes calculated by three statistical methods with lower voltage than test voltage are compared. The results obtained from the suggested experimental method are presented and discussed.

• Journal of Electrical Engineering and Technology
• /
• 제13권6호
• /
• pp.2392-2401
• /
• 2018

Creepage discharge faults in air on solid insulating material play a vital role in degradation and ageing of material which ultimately leads to breakdown of power equipment. And electric discharge decompose air in to its by-products such as Ozone and $NO_x$ gases. By analyzing air decomposition gases is a potential method for fault diagnostic in air. In this paper, experimental research has been conducted to study the effect of creepage discharge on rate of generation of air decomposition by-products using different insulating materials such as RTV, epoxy and fiberglass laminated sheet. Moreover XRF analysis has been done to analyze creepage discharge effect on these insulating materials. All experiments have been done in an open air test cell under constant temperature and pressure conditions. While analysis has been made for low and high humidity conditions. The results show that the overall concentration of air decomposition by-products under creepage discharge in low humidity is 4% higher than concentration measured in high humidity. Based on this study a mathematical relationship is also proposed for the rate of generation of air decomposition by-products under creepage discharge fault. This study leads to indirect way for diagnostic of creepage discharge propagation in air.

• 대한전자공학회논문지
• /
• 제25권11호
• /
• pp.1294-1303
• /
• 1988

광 유도 전류 천이 (photo-induced current transient)방법으로 측정한 SI GaAs의 전자와 정공 trap이 갖을 수 있는 activation energy({\Delta}E_r)의 범위는 0.16$\pm$ 0.01eV에서 0.98$\pm$ 0.01eV까지 분포되어 있다. SI Undoped GaAs가 SI GaAs : Cr 보다 깊은 준위의 수가 적음을 확인 하였다. Trap의 열적인 capture cross section과 농도를 평가 하였고, 약간의 trap은 SI GaAs 성장시에 발생될 수 있는 결함과 관련되어 있음을 확인하였다. 특히 SI GaAs에서 보상 level로 작용하는 Cr과 “0” level를 좀 더 정확하게 측정하기 위하여 서로 다른 측정방법을 사용하여 측정한 결과를 각기 비교 검토 하였다. 즉, PICT측정, 상온 이상의 온도에서 측정한 Hall data 및 광전류 spectra data 등을 비교 검토 하였으며, 보상 level은 격자 결합이 매우 약함을 확인할 수 있었다. Hall data를 computer로 분석한 결과 중성 불순물 scattering이 측정 온도 범위에서 매우 중요한 역할을 하고 있음을 알 수 있었다.

• 한국건축시공학회지
• /
• 제16권6호
• /
• pp.595-601
• /
• 2016

현재 건축구조물에 사용되는 단열재의 단열성능은 초기성능을 기준으로 설계 시에만 반영하고 있으며, 장기 내구성 저하에 따른 단열성능 감소는 반영되고 있지 않다. 본 연구에서는 가속내구성 시험을 통해 단열재의 내구성 저하에 따른 단열성능 저하를 검토하였다. 연구결과, 발포폴리스티렌 단열재 비드법의 경우 표준환경 조건 및 실험실 가속 시험 조건에서는 경시변화에 따른 성능저하가 나타나지 않았으나, 동결 융해 시험 조건에는 성능이 저하하는 것으로 나타났다. 반면, 압출법의 경우 동결 융해 시험 조건에서는 단열성능 저하가 작았지만, 경시변화 초기에 내부 가스의 방출로 급격한 성능저하를 나타내었다. 또한, 경질 폴리우레탄 폼 단열재의 경우 다른 단열재에 비해 초기 단열성능이 매우 뛰어났으나, 실험실 가속 시험조건 및 동결 융해 시험 조건에서는 성능이 다소 저하하는 것으로 나타났다.