• Electrical & Electronic Materials
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• v.9 no.4
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• pp.344-350
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• 1996

Tracking is one of the biggist problems to be overcome in polymeric materials for outdoor insulators. But It can be decreased with the addition of filler such as alumina trihydrate (ATH). In this paper, the tracking of surface and evaluation of insulating ability at silicone rubber is investigated, using the salt fog test. At initial state, the peak leakage current and numbers by dry band arcing is increasing with increasing the filler level, but at aged state decreasing at high concentration filler samples. This is because the roughness of the surface may contribute to the increase in peak leakage cur-rent and numbers. As increasing the filler level, the insulating ability of materials is higher and weight loss is decreased. The mechanism of insulating failure is occurred by the erosion than the tracking and the erosion caused weight loss of 2 g.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.10
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• pp.1688-1693
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• 2016

In this study shall investigate the influence upon the electrical property of transformer oil due to the heat among accelerated heat degradation experiment for a constant hour in the typical insulation oils of mineral base oil, silicon base oil and vegetable oil. In addition, the electric insulation performance of insulation materials in transformer shall be evaluated through the electric property analysis according to the heat degradation of epoxy insulation material, which has been used for electric facilities such as a molded transformer.

• Proceedings of the KIEE Conference
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• 2001.07c
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• pp.1637-1639
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• 2001

Air arc interruption used in low rated voltage breaker, ACB and MCCB, have used the arc chamber composed of metal plates and insulating laminates which supposed these mechanically. and geometry and materials of arc chamber are very different by breaker manufacturer. These breakers have required to be smaller and to interrupt higher current by user. therefore the arc chamber geometry and material in breaker have been small, complex and various. The purpose of this study is to examine the effects of insulating laminates and contact materials on air arc interruption. Contacts were surrounded by a rectangle chamber of insulating laminates. Contact concoctions were composed of AgW, AgCdO that have used in low rated voltage breaker, and insulating laminates were polyester, epoxy. We found strong dependance of arc voltage on insulating material. The ablated vapor on polyester increased arc voltage that was useful in air arc interruption.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.04a
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• pp.111-115
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• 1997

There exists a interface among the different kinds of materials in the solid insulating ones, which effects on the insulating capability heavily. The insulating construction has been developed for each usages and take themselves into several sorts. The conjunction between CV cables have the electrical weakness of solidity and solid interface, so they were focused at the long distance-line. To this background, it is very important to get the information on the interface influencing on the insulating capability of cable and to observe its procedure. In this paper, the interface was made artificially to research the effect owing to the toughness of interface, which results in the aging and treeing proceeding was observed. The polyethylen, as is generally using for the cable, was taken in this research.

• Proceedings of the KIEE Conference
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• 1995.07c
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• pp.1235-1238
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• 1995

Electrical property of polymeric insulating plays a key role in the trend of making power apparatus high voltage, and reliability and safety of apparatus in the long term depend on it. There is a recent trend of applying polymeric material to insulating material for outdoor, and particularly it is expected that it may be used partly as a pin insulator. Using as an alternate of insulating material for outdoor, however, it has still many problems to be solved in the field of material such as resistances of environment and tracking. It has been given attention to that the silicon rubbers and the epoxy have recently been used. but the the reliability in the viewpoint of material property becomes an issue. The polymeric materials such as EPDM, Epoxy and PVC have also been used as an insulating materials for outdoor. In this point of view, we studied each tracking phenomenon with test material such as rubber for pin, PVC for powercable used as an insulating material for outdoor, and Epoxy etc. The characteristics of anti tracking shows EPDM>Epoxy>PVC in order in the results. We also know that there is an close relationship between properties of tracking and thermegravimetry.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.28 no.8
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• pp.508-512
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• 2015

Some insulating materials are tested and analyzed with variables to obtain the reliable pressboard which is located to core and coil of high voltage transformer. The high voltage transformer is used in electrical power system and operating reliability. Optimization possibility of pressboard shape including electrical insulation performance could be achieved by analysis simulation. Using insulating pressboard, which is made by mold applied eddy current loss, it could be measured the influences of moisture content for electrical properties. As a result, it is to contribute to improve the performance and ensure the reliability of the pressboard by investigating electrical strength according to the variation oil temperature. In addition pressboard thickness is important design factor to ensure electrical strength in high voltage transformer.

• Progress in Superconductivity and Cryogenics
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• v.13 no.4
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• pp.10-13
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• 2011

For the operation of high temperature superconducting (HTS) power equipments, it is necessary to develop insulating materials and high voltage (HV) insulation technology at cryogenic temperature of bushing. In this paper, the surface flashover characteristics of various insulating materials in $LN_2$ are studied. These results are studied at both AC and impulse voltage under a non-uniform field. The negative impulse breakdown voltage of GFRP is slightly higher than the positive impulse breakdown voltage. The use of glass fiber reinforced plastic (GFRP) and polytetrafluoroethylene (PTFE, Teflon) as insulation body for HTS bushing should be much desirable. Especially, GFRP is excellent material not only surface flashover characteristics but also mechanical characteristics at cryogenic temperature. The surface flashover is most serious problem for the shed design in $LN_2$ and operation of superconducting equipment.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.63 no.2
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• pp.119-123
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• 2014

In this study, four kinds of specimens of PE(polyethylene)-based insulating materials were prepared for selecting the optimum insulation materials in a wet environment. The specimens were tested by various methods, the anti tracking test, the transmittance test in the water vapor transmittance(WVT) and the abrasion resistive test, etc. The HDPE(high-density polyethylene) specimen was showed excellent property in the tracking resistance test and the lowest transmittance in water vapor transmittance test. In the abrasion resistive test, the LLDPE(linear low-density polyethylene) and MDPE(medium-density Polyethylene) were showed excellent mechanical properties. The value of cut-through resistance for MDPE and HDPE were superior to that for LLDPE and LDPE(low-density polyethylene).

• Electrical & Electronic Materials
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• v.10 no.9
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• pp.960-967
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• 1997

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.35 no.1
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• pp.93-97
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• 2022

We report highly efficient quantum dot light-emitting diodes (QLEDs) with TiO₂ nanoparticles (NPs) as an alternative electron transport layer (ETL) and poly (methyl methacrylate) (PMMA) as an insulating layer. TiO₂ NPs were applied as ETLs of inverted structured QLEDs and the effect of the addition of PMMA between ETL and emission layer (EML) on device characteristics was studied in detail. A thin PMMA layer supported to make the charge balance in the EML of QLEDs due to its insulating property, which limits electron injection effectively. Green QLEDs with a PMMA layer produced the maximum luminance of 112,488 cd/m² and a current efficiency of 25.92 cd/A. We expect the extended application of TiO₂ NPs as the electron transport layer in inverted structured QLEDs device in the near future.