• Title, Summary, Keyword: Volume electrical resistivities

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Effects of Freshwater Flooding on Properties of CSPE with Number of Dried-Days (건조일수에 따른 CSPE의 특성에 미치는 담수침지의 영향)

  • Kang, Myeong-Kyun;Lee, Jung-Hoon;Lee, Seung-Hoon;Jeon, Jun-Soo;Park, Young;Park, Ki-Yub;Jeong, Kyu-Won;Shin, Yong-Deok
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.26 no.8
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    • pp.597-601
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    • 2013
  • The accelerated thermal aging of a CSPE were carried out for 0, 80.82, 161.63 days at $100^{\circ}C$, which are equal to 0, 40 and 80 years of aging at $50^{\circ}C$, respectively. The volume electrical resistivities of the seawater and freshwater flooding were measured through 3-terminal circuit diagram. The volume electrical resistivities of the 0y, 40y and 80y were $2.454{\times}10^{13}{\sim}1.377{\times}10^{14}{\Omega}{\cdot}cm$, $1.121{\times}10^{13}{\sim}7.529{\times}10^{13}{\Omega}{\cdot}cm$ and $1.284{\times}10^{13}{\sim}8.974{\times}10^{13}{\Omega}{\cdot}cm$ at room temperature, respectively. The dielectric constant of the 0y, 40y and 80y were 2.922~3.431, 2.613~3.285 and 2.921~3.332 at room temperature, respectively. It is certain that the ionic ($Na^+$, $Cl^-$, $Mg^{2+}$, ${SO_4}^{2-}$, $Ca^{2+}$, $K^+$) conduction current was formed by the salinity of the seawater. The volume electrical resistivity of the cleaned CSPE via freshwater trends slightly upward with the number of dried days at room temperature. As a result, the $CH_2$ component of thermally accelerated aged CSPE decreased after seawater and freshwater flooding for 5 days respectively, whereas the atoms such as Cl, O, Pb, Al, Si, Sb, S related with the conducting ion ($Na^+$, $Cl^-$, $Mg^{2+}$, ${SO_4}^{2-}$, $Ca^{2+}$, $K^+$) component increased relatively.

Effects of Freshwater Flooding on the Properties of the Accelerated Thermally Aged CSPE (가속열화 된 CSPE의 특성에 미치는 담수침지의 영향)

  • Kang, Myeong-Gyun;Lee, Jung-Hoon;Lee, Seung-Hoon;Jeon, Jun-Soo;Kim, In-Yong;Shin, Yong-Deok
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.63 no.3
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    • pp.367-370
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    • 2014
  • The accelerated thermal aging of a CSPE were carried out for 0, 80.82, 161.63 days at $100^{\circ}C$, which are equal to 0, 40 and 80 years, respectively. The volume electrical resistivities of the non-accelerated thermally aged CSPE and the accelerated thermally aged CSPE for 40y and 80y were $9.620{\times}10^{12}{\sim}1.246{\times}10^{13}{\Omega}{\cdot}cm$, $5.066{\times}10^{12}{\sim}7.576{\times}10^{12}{\Omega}{\cdot}cm$ and $7.195{\times}10^{12}{\sim}9.208{\times}10^{12}{\Omega}{\cdot}cm$ at room temperature, respectively. The dielectric constant of the non-accelerated thermally aged CSPE and the accelerated thermally aged CSPE for 40y and 80y were 3.355~4.030, 2.996~3.963 and 3.020~4.776 at room temperature, respectively. After seawater and freshwater flooding, the volume electrical resistivity of the CSPE trend slightly upward according to drying day at room temperature. After seawater flooding, the dielectric constant of the accelerated thermally aged CSPE were not measured. After seawater flooding, bright open pores of the accelerated thermally aged CSPE were partly transferred to dark close pores due to salinity. After freshwater flooding, dark close pores of the accelerated thermally aged CSPE were partly transferred to bright open pores because salinity of them is decreased. An insulation property of a cable in NPPs was decreased because of the seawater flooding, and an insulation property of them was recovered through the freshwater flooding. As a result, it is considered that an insulation property of a contaminated cable through Tsunami can be recovered if it is cleaned quickly.

Geophysical Surveys for Investigating the Groundwater Environment of the Chojeong, Chungbuk (충북 초정지역의 지하수환경 조사를 위한 지표지구물리탐사)

  • 김지수;한수형;김경호;신재우
    • Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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    • pp.103-106
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    • 2000
  • Geophysical data sets from the Chojeong area in the Chungbuk-Do are compositely studied in terms of multi-attribute interpretation for the subsurface mapping of shallow fracture zones, associated with groundwater reservoir. Utilizing a GIS software, the attribute data are implemented to a database; a lineament from the satellite image, electrical resistivities and its standard deviation, radioactivity, seismic velocity, bedrock depth from exploration data. In an attempt to interpret 1-D electrical sounding data in 2-D and 3-D views, 2-D resistivities structures are firstly made by interpolating 1-D plots. Reconstruction of a resistivity volume is found to be an effective scheme for subsurface mapping of shallow fracture zones. Shallow fracture zones in the southeastern part of the study area are commonly correlated in the various exploration data.

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The Analysis of HVDC Cable Oil Swelling Characteristics on the Silicone Rubber (HVDC 절연유 중에서 Silicone Rubber의 팽윤특성 분석)

  • Lee, T.H.;Kim, N.Y.;Kim, J.N.;Jeon, S.I.
    • Proceedings of the KIEE Conference
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    • pp.623-624
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    • 2007
  • This work examines the effects of swelling MI type HVDC cable oil on the semiconductive silicone rubber and silicone rubber as used in accessories for application on outdoor termination (EBA) slip on sleeve. The behavior of volume resistivity is monitored as a function of the amount of cable oil diffused into the material. Resistivities of semiconductive silicone samples up to the typical insulator range (${\sim}10^{10}{\Omega}-cm$) are observed as a consequence of swelling due to the presence of the diffused oil. The measured volume resistivities of the oil-impregnated semiconductive silicone rubber are compared to desired value as function of stress relief cone.

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Humidity effects on surface resistivities in PE and PP mixtures (PE 및 PP혼합 재료의 표면저항에 미치는 습도효과)

  • 강전홍;유황민;김한준;한상옥;김종석
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.424-426
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    • 2002
  • The surface and volume resistivity in the polymers, PE(polyethylene) and PP(polypropylene) mixtures are tested and measured by the ASTM D257(KS M3015) standard. Humidity effects on surface and volume resistivity in two polymers have been studied qualitatively at room temperature. The results of resistivity in these polymers show that the values of surface resistivity (and volume resistivity) at the humidity of 90% are remarkably small compared with those at the humidity of 50%, independing on applied voltage. When we varied the humidity in two polymers, it was found to takes many hours to recover into original surface resistivity (and volume resistivity) of these polymers.

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Electrical Properties of Organic/lnorganic Hybrid Composites for Insulation materials (유기/무기 복합 절연재료의 전기적 특성)

  • 깅상철;김현석;옥정빈;안명진;박도현;이건주
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.78-83
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    • 2001
  • In this work, the surface of inorganic fillers were modified with some functional groups such as stearic acid, aliphatic long chain, vinylsilane and aminosilane to control the interaction between inorganic fillers and polymer matrix. Ethylene-vinyl acetate copolymers (EVA) with various amount of vinyl-acetate content and copolyether-ester elastomer were used as polymer matrix. The addition of inorganic fillers increases flame retardancy, but results in steep drop of electrical and mechanical properties, which may be caused by the defect in the interface between organic/inorganic hybrid composites. The hybrid composites are found to show better mechanical properties and higher volume resistivities as inorganic fillers are well dispersed and have good adhesion with polymer matrix. Also, the most effective type of functional group coated on fillers depends on the chemical structure of polymer.

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Electrical Properties of Organic/Inorganic Hybrid Composites for Insulation Materials

  • Kim, Sang-Cheol;Ok, Jeong-Bin;Aho, Myeong-Jin;Park, Do-Hyun;Lee, Gun-Joo
    • Transactions on Electrical and Electronic Materials
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    • v.3 no.1
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    • pp.9-13
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    • 2002
  • In this work, the surface of inorganic fillers were modified with some functional groups such as stearic acid, aliphatic long chain, vinylsilane and aminosilane to control the interaction between inorganic fillers and polymer matrix. Ethylene-vinyl acetate copolymers (EVA) with various amount of vinyl-acetate and copolyether-ester elastomer were used as polymer matrix. The addition of inorganic fillers increases flame retardancy, but results in steep drop of electrical and mechanical properties, which may be caused by the defects in the interface between organic/inorganic hybrid composites. The hybrid composites are found to show better mechanical properties and higher volume resistivities as inorganic fillers are well dispersed and have good adhesion with polymer matrix. Also, the most effective type of functional group coated on fillers depends on the chemical structure of polymer.

Analysis of dielectric and insulation characteristics of elastic epoxy resin according to elastomer contents for power machines (전력용 탄성형 에폭시의 유전 및 절연 특성 해석)

  • Kim, Seok-Jae;Park, Seong-Hee;Lim, Kee-Joe;Lee, Ki-Tae;Kang, Seong-Hwa;Park, Dea-Hee
    • Proceedings of the KIEE Conference
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    • pp.230-232
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    • 2004
  • In this paper, we investigated dielectric and insulation characteristics of epoxy resin which includes elastomers to improve mechanical property, as varied additive elastomer contents with 5[phr], 10[phr], 15[phr], and 20[phr]. We measured permittivity and tan $\delta$ at 1kHz of signal frequency and room temperature. And we also measured BVD(break-down voltage) and volume resistivities. According to the experimental results, it is appeared that when the additive elastomer contents are increasing, permittivity, volume resistivity, BVD and volume resistance are decreasing because elastomer remains inferior to epoxy resin on electrical properties.

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Electrical Transport and Joule Heating of ZrB2 Network in SiC Matrix

  • Kim, Jung-Hun;Kim, Chang-Yeoul;Choi, Sung-Churl
    • Journal of the Korean Ceramic Society
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    • v.55 no.5
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    • pp.440-445
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    • 2018
  • To control the electrical properties of a SiC heating element, we sintered $SiC-ZrB_2$composites by using the spark plasma sintering method. The addition of $ZrB_2$ particles with lower electrical conductivity to the SiC matrices with comparatively higher electrical resistivity lowers the electrical resistivities of the composite material. The $ZrB_2$ particles aggregate to form large particles and 3-1, 3-2, and 3-3 networks, i.e., conduction paths. In our study, about $1-{\mu}m$-sized $ZrB_2$ powders start to form the conduction path at about 10 vol.% of addition, namely the threshold volume. The Joule heating experiment shows that 20 vol.% $ZrB_2$-added SiC heating element has outstanding heating efficiency.

The Analysis of Characteristics of Silicone Rubber in Insulating Oil (절연유에 의한 Silicone Rubber의 특성 변화 분석)

  • Kim, H.J.;Kim, H.J.;Lee, C.M.;Han, J.H.
    • Proceedings of the KIEE Conference
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    • pp.1216-1217
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    • 2008
  • A description is given of impregnated silicone rubber used in accessories for application on outdoor termination (EB-A). We examines the effects of swelling and mechanical/electrical characteristics for impregnated silicone rubber to develop slip on type sleeve of silicone material. There are semi-conductive silicone rubber and insulation silicone rubber. This examination is monitored as a function of the viscosity and temperature of oil during 30hr. We measure elongation at breakdown and AC breakdown strength and volume resistivities of the oil-impregnated silicone rubbers. The measured values are compared to initial value as function of stress relief cone.

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