• 전기학회논문지
• /
• 제67권11호
• /
• pp.1463-1470
• /
• 2018

In this study, 20 types of samples were prepared by mixing different kinds of inorganic materials to develop insulation materials for epoxy - based GIS substation equipment used under high voltage environmentally friendly insulation gas. One of the electrical characteristics, AC insulation breakdown experiment was performed. As mixing ratio of mixed heterogeneous inorganic materials, the dielectric breakdown strength was increased with increasing filler ratio of micro silica, micro silica : micro Alumina, 1:9, 3:7, 5:5, 7:3, 9:1, and decreased as the filling amount of micro alumina increased. The AC insulation breakdown characteristics were the best when the composition ratio was 9:1. The higher the content of silica, the better the interfacial properties, and the larger the alumina content ratio, the worse the interfacial properties.

• Transactions on Electrical and Electronic Materials
• /
• 제13권3호
• /
• pp.149-152
• /
• 2012

The effects of amino silane coupling agent on the AC electrical treeing and breakdown behaviors in an epoxy/layered silicate (1 wt%) were examined in needle-plate electrode geometry. A layered silicate was exfoliated in an epoxy base resin by using our AC electric field apparatus. To measure the tree initiation and propagation and the breakdown rate, an alternating current (AC) of 10 kV (60 Hz) was applied to the specimen in needle-plate electrode arrangement with a $30^{\circ}C$ insulating oil bath. In the epoxy/amino silane system, the tree initiation time was 11.5 times higher and the breakdown time was 17.9 times higher than those of the neat epoxy resin. The tree initiation time in the epoxy/layered silicate (1 wt%) system with the amino silane was 2.0 times higher, and the breakdown time was 1.5 times higher than those of the epoxy/layered silicate (1 wt%) system.

• 대한전기학회논문지:전기물성ㆍ응용부문C
• /
• 제48권1호
• /
• pp.39-44
• /
• 1999

The dielectric layers in AC plasma display panel(PDP) are essential to the discharge cell structure, because they protect metal electrodes from sputtering by positive ion bombarding in discharge plasma and form a sheath of wall charges which are essential to memory function of AC PDP. This layer should have high dielectric breakdown voltage, and also be transparent because the luminance of PDP is strongly correlated this layer. In this paper, we discussed the dielectric breakdown voltage and transparency of the dielectric layer under various conditions. As a result, on the $15\mum$ thickness, the minimum dielectric breakdown voltage was 435V and the transmission coefficient was about 80% after $570^{\circ}C$ firing process. It can be proposed that the resonable dielectric thickness in AC PDP is $15\mum$ because it has about 75V margin on the maximum applied voltage.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2004년도 춘계학술대회 논문집 방전 플라즈마 유기절연재료 초전도 자성체연구회
• /
• pp.87-93
• /
• 2004

Laminated Polypropylene Paper (LPP) and Kraft paper were used as ac power insulation for conventional cable as well as high temperature superconducting (HTS) cable because of its prominent insulating characteristics. However, researches on the use of LPP/Kraft paper in HTS cables are thinly scattered. In this paper, the effect of laminate polypropylene paper on the breakdown strength of LPP/Kraft multi-layer sample impregnated with liquid nitrogen (LN2)under ac and impulse applied voltage was studied. In addition, the breakdown strength characteristics of LPP and Kraft multi-layer sample were also investigated. It was found from the experimental data that the LPP has higher breakdown strength value than Kraft paper in ac and impulse. Especially in the ac case, the breakdown strength increases as the component ratio of LPP in the LPP/Kraftsample increases and slightly affected by the inserting position of LPP but in impulse case, the breakdown strength strongly depends on the number of LPP and the relative position of LPP.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2001년도 추계학술대회 논문집 Vol.14 No.1
• /
• pp.605-608
• /
• 2001

With the intention of investigating the breakdown properties of oil-immersed transformer oils in temperature range of $20\sim100[^{\circ}C]$, we are made researches AC breakdown in the gap of $500\sim2500[{\mu}m]$. The classification for the physical properties of oil for oil-immersed transformer by FTIR and 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.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2001년도 추계학술대회 논문집 Vol.14 No.1
• /
• pp.597-600
• /
• 2001

In order to investigate the electrical properties of X-ray tube oils for insulating and cooling, the breakdown characteristics in temperature range of $20\sim100[^{\circ}C]$, that of AC breakdown in 0.5~2.5[mm] of gap length, we are made researches. The classification for the physical properties of oil for X-ray tube by FTIR and H-NMR experiments was confirmed to type of mineral oils. As for the dependance of breakdown characteristics due to electrode gap length, breakdown voltage was found nearly uniform by impurity effect according to the increase of gap. As a result the characteristics for AC breakdown, the dielectric strength was increased to $90[^{\circ}C]$ but decreased over $90[^{\circ}C]$ in the temperature range.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2001년도 추계학술대회 논문집
• /
• pp.597-600
• /
• 2001

In order to investigate the electrical properties of X-ray tube oils for insulating and cooling, the breakdown characteristics in temperature range of 20∼100[$^{\circ}C$], that of AC breakdown in 0.5∼2.5(mm) of gap length, we are made researches. The classification for the physical properties of oil for X-ray tube by FTIR and $^1$H-NMR experiments was confirmed to type of mineral oils. As for the dependance of breakdown characteristics due to electrode gap length, breakdown voltage was found nearly uniform by impurity effect according to the increase of gap. As a result the characteristics for AC breakdown, the dielectric strength was increased to 90[$^{\circ}C$] but decreased over 90[$^{\circ}C$] in the temperature range.

• 전기학회논문지
• /
• 제65권9호
• /
• pp.1511-1517
• /
• 2016

The aim of this study is to improve of properties for electrical AC insulation breakdown strength using epoxy/micro-nano alumina composites with adding glycerol diglycidyl ether (GDE:1,3,5g). This paper deals with the effects of GDE addition for epoxy/micro alumina contents (40,50,60wt%)+surface modified nano alumina(1_phr) composites. 14 kinds specimen were prepared with containing epoxy resins, epoxy micro composites and epoxy nano-micro alumina mixture composites. Average particle size of nano and micro alumina used were 30nm and $1{\sim}2{\mu}m$, respectively. The micro alumina used were alpha phase with Heterogeneous and nano alumina were gamma phase particles of spherical shape. The electrical AC insulation breakdown strength was evaluated by sphere to sphere electrode system and raising velocity 1kV/s. The AC breakdown strength decreased insulation properties of multi-composites according to increasing micro alumina and GDE addition contents.

• Transactions on Electrical and Electronic Materials
• /
• 제13권6호
• /
• pp.301-304
• /
• 2012

Epoxy/microsilica (65 phr)/nanosilica (0~5 phr) composites (EMNC) were prepared in order to develop a high-voltage insulation material, where phr means parts per hundred relative to the epoxy oligomer. Tensile and flexural tests of the composites were carried out, and the AC electrical breakdown strength was measured, after which all the data were estimated by Weibull statistical analysis. As the nanosilica content increased, the tensile strength increased, and the highest value was 117.7 MPa in the EMNC system with 3 phr nanosilica, which was ca. 10% higher than that of the system without nanosilica. The value then decreased after 3 phr. The flexural strength and AC electrical breakdown strength showed the same tendencies as the tensile strength. The highest value of the flexural strength was 184.6 MPa in the EMNC system with 3 phr of nanosilica, which was ca. 15% higher than that of the system without nanosilica. The strongest value of the AC electrical breakdown strength was 79.0 kV/0.5 mm in the EMNC system with 3 phr of nanosilica, which was ca. 34% higher than that of the system without nanosilica.

• Journal of Electrical Engineering and Technology
• /
• 제12권2호
• /
• pp.865-873
• /
• 2017

Converter transformer is the key equipment of high voltage direct current transmission system. The solid suspending particles originating from the process of installation and operation of converter transformer have significant influence on the insulation performance of transformer oil, especially in presence of DC component in applied voltage. Under high electric field, the particles easily lead to partial discharge and breakdown of insulating oil. This paper investigated copper particle effect on the breakdown voltage of transformer oil at combined AC and DC voltage. A simulation model with single copper particle was established to interpret the particle effect on the breakdown strength of insulating oil. The experimental and simulation results showed that the particles distort the electric field. The breakdown voltage of insulating oil contaminated with copper particle decreases with the increase of particle number, and the breakdown voltage and the logarithm of particle number approximately satisfy the linear relationship. With the increase of the DC component in applied voltage, the breakdown voltage of contaminated insulating oil decreases. The simulation results show that the particle collides with the electrode more frequently with more DC component contained in the applied voltage, which will trigger more discharge and decrease the breakdown voltage of insulating oil.