• Title/Summary/Keyword: Breakdown strength

Search Result 522, Processing Time 0.035 seconds

Analysis of Electrical Degradation in Epoxy Composites by Dielectric Breakdown Properties (절연파괴 특성을 이용한 Epoxy 복합체의 전기적 열화 분석)

  • 최철호;박용필;임중관
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
    • /
    • 2002.07a
    • /
    • pp.414-419
    • /
    • 2002
  • The dielectric breakdown of epoxy composites used for transformers was experimented and then its data were simulated by Weibull distribution probability. First of all, speaking of dielectric breakdown properties, the more hardener increased the stronger breakdown strength at low temperature because of cross-linked density by the virtue of ester radical. The breakdown strength of specimens with filler was lower than it of non-filler specimens because it is believed that the adding filler forms interface and charge is accumulated in it, therefore the molecular motility is raised and the electric field is concentrated. In the case of (idled specimens with treating silane, the breakdown strength become much higher Finally, from the analysis of weibull distribution, it was confirmed that as the allowed breakdown probability was given by 0.1[%], the applied field value needed to be under 21.5 MV/cm.

  • PDF

Evaluation of Electrical Degradation in Epoxy Composites by Dielectric Breakdown Properties (절연파괴 특성을 이용한 Epoxy 복합체의 전기적 열화 평가)

  • Lim, Jung-Kwan;Park, Yong-Pil
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
    • /
    • 2002.05c
    • /
    • pp.212-217
    • /
    • 2002
  • The dielectric breakdown of epoxy composites used for transformers was experimented and then its data were simulated by Weibull distribution probability. First of all, speaking of dielectric breakdown properties, the more hardener increased the stronger breakdown strength at low temperature because of cross-linked density by the virtue of ester radical. The breakdown strength of specimens with filler was lower than it of non-filler specimens because it is believed that the adding filler forms interface and charge is accumulated in it, therefore the molecular motility is raised and the electric field is concentrated. In the case of filled specimens with treating silane, the breakdown strength become much higher Finally, from the analysis of weibull distribution, it was confirmed that as the allowed breakdown probability was given by 0.1[%], the applied field value needed to be under 21.5 MV/cm.

  • PDF

Prediction of Insulation Reliability and Breakdown Life in Epoxy Composites (에폭시 복합체의 절연신뢰도 및 파괴수명 예측)

  • 신철기;박건호;왕종배;김성역;이준웅
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
    • /
    • 1996.11a
    • /
    • pp.260-264
    • /
    • 1996
  • In this study, the dieiectric breakdown of epoxy composites used for transformers was experimented and then its data were simulated by Weibull distribution probability . As a result. first of all, speaking of dielectric breakdown properties, the more hardener increased the stronger breakdown strength at low temperature, and the breakdown strength of specimens because it is believed that the adding filler farms interface and charge is accumulated in it, therefore the molecular motility is raised, the electric field is concentrated, and the acceleration of electron and the growth of electron avalanche are early accomplished. In the case of filled specimens with treating silane, the breakdown strength become much higher since the suggests that silane coupling agent improves interfacial combination and relays electric field concentration. Finally, from the analysis 7f weibull distribution. it was confirmed that as the allowed breakdown probability was given by 0.11[%].

  • PDF

A Study on Electrical Insulation Breakdown and Tensile Strength for Epoxy/Spherical Silica Composites (에폭시/구상실리카 콤포지트의 전기적 절연파괴 및 인장 강도 특성 연구)

  • Lee, Seung-Hun
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
    • /
    • v.26 no.10
    • /
    • pp.726-730
    • /
    • 2013
  • In order to develop a high voltage insulation material, spherical silicas with two average particle sizes of 5 ${\mu}m$ and 20 ${\mu}m$ were mixed in different mixing ratios (1:0, 0.7:0.3, 0.5:0.5, 0.3:0.7, 0:1) and their total filling content was fixed at 65 wt%. In order to observe the dispersion of the spherical silicas and the interfacial morphology between silica and epoxy matrix, field emission scanning electron microscope (FE-SEM) was used. The electrical insulation breakdown strength was estimated in sphere-plate electrodes with different insulation thicknesses of 1, 2, and 3 mm. Electrical insulation breakdown strength decreased with increasing mixing ratio of 5/20 ${\mu}m$ and the thickness dependence of the breakdown strength was also observed. The tensile strength of the neat epoxy was 82.8 MPa as average value and its increased with decreasing particles size and that of epoxy/silica (2 ${\mu}m$) was 107 MPa, which was 130.8% higher value.

Dielectric and Breakdown Characteristics of MDPE included Semiconductor layer (반도전층을 갖는 MDPE의 운전 및 절연파괴 특성)

  • Yoo, Sung-Soo;Lee, Jong-Chan;Park, Dae-Hee
    • Proceedings of the KIEE Conference
    • /
    • 1999.07d
    • /
    • pp.1633-1635
    • /
    • 1999
  • In this study, we evaluated the dependence of thickness and temperature in the breakdown strength of MDPE and effect of semiconductor. As the result, breakdown strength trend to decrease according to the increase of thickness and temperature. We obtained the result that the breakdown strength was a little lower in the structure of Semi/MDPE than Semi/MDPE/Semi, but breakdown strength of MDPE was greater both of all. The dependency of permittivity, tan ${\delta}$ and conductance on frequency and temperature were investigated. Both of the specimans showed the trend of decreased in permittivity as the temperature increased but increase as the frequency increased.

  • PDF

A study on the improvement of thermostability and dielectric breakdown strength for packaging and impregnating epoxy composite materials for electrical machines and apparatus (전기 기기용 봉지 및 함침 에폭시 복합 재료의 내열성 및 절연파괴 특성 개선에 관한 연구)

  • 김명호;김재환
    • Electrical & Electronic Materials
    • /
    • v.7 no.6
    • /
    • pp.527-533
    • /
    • 1994
  • In this study, it was studied on dielectric breakdown strength and thennostability properties due to the structure variation of matrix resin and treatment of coupling agent of epoxy insulating materials. The interpenetrating network structure was formed by simultaneous heating curing the epoxy resin with single network structure and the methacrylic acid resin. Also inner structure was observed and the glass transition temperature was measured on these three type specimens. Dielectric breakdown properties were investigated by applying DC, AC and impulse voltage. As a result, the glass transition temperature and the dielectric breakdown strength of specimen with interpenetrating network structure was more higher than another two type specimens.

  • PDF

Electrical Breakdown Properties of Insulating Oils for oil-immersed transformer (유입변압기용 절연유의 절연파괴특성)

  • 이인성;신현택;이종필;이수원;홍진웅
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
    • /
    • 2001.11a
    • /
    • pp.605-608
    • /
    • 2001
  • With the intention of investigating the breakdown properties of oil-immersed transformer oils in temperature range of 20∼100[$^{\circ}C$], we are made researches AC breakdown in the gap of 500∼2,500[$\mu\textrm{m}$]. The classification for the physical properties of oil for oil-immersed transformer by FTH and $^1$H-NMR experiments was confirmed to type of mineral oils. As the dependance of breakdown properties due to electrode gap length variation, breakdown voltage was found increasing according to the increase of gap, while dielectric strength was decreasing. As a result the characteristics for AC breakdown, It goes to prove that the breakdown voltage was increased to 90[$^{\circ}C$] but decreased over 90[$^{\circ}C$] in the temperature range. Also, breakdown voltage was found increasing in the increase of gap and the rising of temperature according to Weibull distribution.

  • PDF

A Study on Thickness and Temperature Dependence of Dielectric Breakdown in Polyethylene (폴리에틸렌의 절연파괴와 그의 온도 및 두께의존성)

  • Kim, Jeom-Sik;Lee, Jong-Bum;Jung, Woo-Kyo;Kim, Mi-Hang;Park, Dae-Hee
    • Proceedings of the KIEE Conference
    • /
    • 1995.07c
    • /
    • pp.1388-1390
    • /
    • 1995
  • The characteristic of dielectric breakdown in solid insulating material dominates the reliability and safety of power equipment and affects directly to its life. In this point of view, the thickness and temperature dependence of dielectric breakdown strength and mechanism of dielectric breakdown in low density polyethylene which has been employed widely as insulating material have been technically reviewed by examinations of thermal property. The dielectric breakdown strength depending on its thickness was measured 2.6[MV/cm] at the thickness of 20[${\mu}m$] and 1.9[MV/cm] at the thickness of 75[${\mu}m$] based on ambient temperature of 30[$^{\circ}C$]. It is shown the temperature dependence that dielectric breakdown strength decreases in linear as the thickness increases. The dielectric breakdown strength depending on temperature was measured 2.6[MV/cm] at the temperature of 30[$^{\circ}C$], 1.6[MV/cm] at 60[$^{\circ}C$] and 1.3[MV/cm] at 90[$^{\circ}C$] based on the thickness of 20[${\mu}m$]. As the ambient temperature increases, the temperature dependence is shown that a very large drop is occurred up to temperature of 60[$^{\circ}C$] and a very small drop is discovered over 60[$^{\circ}C$].

  • PDF

Analysis of DC dielectric breakdown strength of Nano-composite insulation material for HVDC Cable (HVDC용 나노복합 절연재료의 DC절연파괴 분석)

  • Cho, Sung-Hoon;Jung, Eui-Hwan;Lee, Han-Ju;Lim, Kee-Joe;Jeong, Su-Hyun
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
    • /
    • 2010.06a
    • /
    • pp.104-104
    • /
    • 2010
  • With the advent of nano-particle fillers in insulating materials, the insulating materials of superior quality have come to fore. In the recent past, nanocomposite LDPE/XLPE (Low Density Polyethylene/Cross Linked Polyethylene) power cable dielectrics have been synthesized. A preliminary evaluation of these new class of materials seem to show that, addition of small amounts of sub-micron inorganic fillers improved the dielectric properties of the composite, in particular, the volume resistivity, and the DC breakdown strength. The thermal behaviour, for example, the stability of composites against decomposition and ensuing electrical failure, do not seem to have been addressed. In a conventional XLPE insulated cable, the average thermal breakdown strength and maximum temperature at the onset of breakdown were seen to be markedly lower than the corresponding intrinsic breakdown strength and decomposition temperature. In this page, analysis of DC Breakdown of nano-composite insulating material for HVDC Cable is introduced.

  • PDF

The Estimation of the Dielectric Strength Decrease of the Solid-solid Interfaces by using the Applied Voltage to Breakdown Time Characteristics

  • Shin, Cheol-Gi;Bae, Duck-Kweon
    • Transactions on Electrical and Electronic Materials
    • /
    • v.8 no.6
    • /
    • pp.278-282
    • /
    • 2007
  • In the complex insulation system that is used in extra high voltage(EHV) devices, according to the trend for electric power equipment of high capacity and reduction of its size, macro interfaces between two different bulk materials which affect the stability of insulation system exist inevitably. In this paper, the dielectric strength decrease of the macro interfaces between epoxy and ethylene propylene diene terpolymer(EPDM) was estimated by using the applied voltage to breakdown time characteristics. Firstly, the AC short time dielectric strength of specimens was measured at room temperature. Then, the breakdown time was measured under the applied constant voltage which is 70% of short time breakdown voltage. With these processes, the life exponent n was determined by inverse power law, and the long time breakdown voltage can be evaluated. The best condition of the interface was LOS(low viscosity(350 cSt) silicone oil spread specimen). When 30 years last on the specimens, the breakdown voltage was estimated 44% of the short time breakdown voltage.