• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.12
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• pp.2234-2237
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• 2008

Approximate equations for cylindrical breakdown voltages of planar pn junctions are proposed and verified. The equations show good agreement with the Baliga's results for $r_{j}/Wpp{\leqq}0.3$ and with numerical results for $r_{j}/Wpp{\geqq}0.3$ within 1% error. Sensitivity of the breakdown voltage with respect to the doping concentrations is successfully derived using the approximate equations. The sensitivity formula can be utilized in the area of tolerance design of power semiconductor devices.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.6
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• pp.821-826
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• 2012

The streaming electrification process of vegetable insulating oils occurring when the oils contacted with solid material in a high power transformer circulation system seems to cause electrical discharge incidents and may cause failures. We therefore measured the dielectric breakdown voltage tendency of vegetable insulating oils flowing on the surface of the charging device with various velocity and temperature. First, the relation between the velocity and breakdown voltage tendency of vegetable oils, can be explained by volume effect and v-t effect. Second, experimental results show that applied voltage have little effect on dielectric breakdown voltage, when vegetable insulating oils used for large power transformer.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.05a
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• pp.532-535
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• 1999

In power cable joints, the interfaces of two different dielectric materials are inevitable. In addition, the interfacial breakdown between two internal dielectric surfaces represents one of the major causes of failure for power cable joints. We chose epoxy/EPDM interface, one of the interface in cable joints, and investigate dielectric interfacial breakdown phenomenon. First, design specimen with Flux 2D. Second, find interface condition which has high dielectric strength. Third, investigate interfacial breakdown properties with variable temperature.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.45 no.3
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• pp.386-392
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• 1996

Zinc-Borosilicate is used as a side insulator wall to make high breakdown voltage with one Field Limiting Ring in a power p-n junction device in simulation. It is known that surface charge density can be yield at the interface of Zinc-Borosilicate glass / silicon system. When the glass is used as a side insulator wall, surface charge varied potential distribution and breakdown voltage is improved 1090 V under the same structure.The breakdown voltage under varying the surface charge density has a limit value. When the epitaxial thickness is varied, the position of FLR doesn't influence to the breakdown characteristic not only under non punch-through structure but also under punch-through structure. (author). 7 refs., 12 figs., 2 tabs.

• Progress in Superconductivity and Cryogenics
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• v.8 no.2
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• pp.37-42
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• 2006

A research on several characteristics such as volume breakdown and surface discharge of insulators for a termination of power transmission class HTS cable was performed. We investigated the surface discharge of glass fiber reinforced plastic (GFRP) under air, cryogenic nitrogen gas and nitrogen gas media. The breakdown characteristics of these media were studied. Experimental results revealed that flashover voltage greatly depends on pressure, temperature, the kinds of insulating media and voltages, but it is slightly affected by shape and material of electrode. The breakdown voltage of liquid nitrogen, cryogenic nitrogen gas and nitrogen gas deeply depends on the shape and dimension of electrode, kinds of voltages and pressure. Moreover, the breakdown voltage of cryogenic nitrogen gas and flashover voltage of GFRP in the cryogenic nitrogen gas is also influenced by temperature and vapour-mist density of the gas.

• KEPCO Journal on Electric Power and Energy
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• v.2 no.3
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• pp.421-424
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• 2016

In order to evaluate the insulation deterioration in the stator windings of air-cooled gas turbine generators(119.2 MVA, 13.8 kV) which has been operating for more than 15 years, diagnostic test and AC dielectric breakdown test were performed on phases A, B and C. Diagnostic test included measurements of AC current, dissipation factor, partial discharge (PD) magnitude and capacitance. ${\Delta}I$ and ${\Delta}tan{\delta}$ in all three phases (A, B, and C) of generator stator windings showed that they were in good condition but PD magnitude indicated marginally serviceable condition. After the diagnostic test, an AC overvoltage test was performed by gradually increasing the voltage applied to the generator stator windings until electrical insulation failure occurred, in order to determine the breakdown voltage. Although phase A of generator stator windings failed at breakdown voltage of 29.0 kV, phases B and C endured the 29.0 kV. The breakdown voltage in all three phases was higher than that expected for good-quality windings (28.6 kV) in a 13.8 kV class generator.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.25 no.4
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• pp.276-281
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• 2012

Power semiconductor devices are widely used as high voltage applications to inverters and motor drivers, etc. The blocking voltage is one of the most important parameters for power semiconductor devices. Generally most of field effect concentrations shows on the edge of power devices. Can be improve the breakdown characteristic using edge termination technology. In this paper, considering the variables that affect the breakdown voltage and optimization of parameters result for 600 V Super Junction MOSFET Field ring.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.28 no.9
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• pp.555-560
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• 2015

This paper was proposed 900 V Power MOSFET with ESD protection circuits using zener diodes. And we were carried out and analyzed its electrical characteristics. As a result of designing 900 V power MOSFET, we obtained 1,000 V breakdown voltage, 3.49 V threshold voltage and $0.249{\Omega}{\cdot}cm^2$. And we designed ESD circuits using 2 series zener diode and 4 series zener diodes. After analyzing electrical characteristics, we obtained 26 V forward voltage drop and 47 V breakdown voltage. Therefore, This devices can enoughly use power module, SMPS and Automotive.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.4
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• pp.85-92
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• 2008

Occurring forest fire or burning bushes beneath overhead transmission lines have caused breakdown disturbances of the system in many countries. In this study, experiments for flashover characteristics in the simulated condition of vertical power lines were conducted so as to investigate the reduction in insulation strength caused by combustion flame. As the results of an experimental investigation, it is demonstrated that flame can reduce breakdown voltages of the model lines according to height(h) of flame. The breakdown voltages were decreased with decreasing the height(h) of flame it can be seen that the average reduction of flashover levels, in comparison with the no-flame case, are 46.2[%] for h=9[cm] and 62.5[%] for h=3[cm] when ac voltage is applied.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.29 no.4
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• pp.199-204
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• 2016

This paper was proposed floating island power MOSFET for lowering on state resistance and the proposed device was maintained 600 V breakdown voltage. The electrical field distribution of floating island power MOSFET was dispersed to floating island between P-base and N-drift. Therefore, we designed higher doping concentration of drift region than doping concentration of planar type power MOSFET. And so we obtain the lower on resistance than on resistance of planar type power MOSFET. We needed the higher doping concentration of floating island than doping concentration of drift region and needed width and depth of floating island for formation of floating island region. We obtained the optimal parameters. The depth of floating island was $32{\mu}m$. The doping concentration of floating island was $5{\times}1,012cm^2$. And the width of floating island was $3{\mu}m$. As a result of designing the floating island power MOSFET, we obtained 723 V breakdown voltage and $0.108{\Omega}cm^2$ on resistance. When we compared to planar power MOSFET, the on resistance was lowered 24.5% than its of planar power MOSFET. The proposed device will be used to electrical vehicle and renewable industry.