• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2003.02a
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• pp.232-235
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• 2003

To realize the development of HTS power apparatus, various breakdown test of L$N_2$ should be carried out and the mechanism should be understood more. Moreover the dielectric design technology that the basic dielectric experimental data applied to the HTS power system should be developed. In this paper, the electric fields for the insulation design were calculated for example with the analysis of Weibull distribution. And V-t characteristics of L$N_2$ were discussed. Around the breakdown voltage the n values were less than 1.

• Proceedings of the KIEE Conference
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• 1999.07e
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• pp.2097-2100
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• 1999

Nondestructive and destructive tests were performed the stator windings of three high voltage motors prior to the rewind. Nondestructive tests included ac current increase rate($\Delta$I), dissipation factor(${\Delta}tan{\delta}$), and maximum partial discharge(Qm) The destructive tests included breakdown at three phases with ac voltage. Flashover occurred between the connected winding of endwinding and the stator flame. In two cases creeping discharge occurred between the individual phase windings and the wedges In the stator ends. The results of destructive tests could rarely be determined the breakdown voltage.

• Proceeding of EDISON Challenge
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• 2016.03a
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• pp.347-349
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• 2016

본 논문에서는 dopant density에 의존적인 pn junction의 breakdown 특성을 향상시키기 위하여, doping density와 doping profile에 대하여 분석했다. Doping density와 doping profile은 역방향 junction breakdown voltage를 결정하는 중요한 요소인 공핍영역의 두께와 공핍영역 내에 인가되는 electric field를 결정한다. Uniform doping profile과 Gaussian doping profile을 비교했고, 고전압 환경에서 사용할 수 있는 소자를 제작하는데 더욱 적절한 doping profile과 doping 농도에 대해 기술했다.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.9
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• pp.1511-1517
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• 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.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.29 no.11
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• pp.681-684
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• 2016

This research was carried out experiments of variety IGBTs for industrial inverter and electric vehicle. The devices for this paper were planar gate IGBT, trench gate IGBT and dual gate IGBT and we designed using same design and process parameters. As a result of experiments, the electrical characteristics of planar gate IGBT were 1,459 V of breakdown voltage, 4.04 V of threshold voltage and 4.7 V of on-state voltage drop. And the electrical characteristics of trench gate IGBT were 1,473 V of breakdown voltage, 4.11 V of threshold voltage and 3.17 V of on-state voltage drop. Lastly, the electrical characteristics of dual gate IGBT were 1,467 V of breakdown voltage, 4.14 V of threshold voltage and 3.08V of on-state voltage drop. We almost knew that the trench gate IGBT was superior to dual gate IGBT in terms of breakdown voltage. On the other hand, the dual gate IGBT was better than the trench gate IGBT in terms of on state voltage drop.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.48 no.1
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• pp.39-44
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• 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.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.04b
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• pp.8-9
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• 2008

In the procedure of the estimation, the short time breakdown characteristics for the epoxy composite specimens, which were made with the variation of hardener and/or filler, were tested firstly. Then the long time voltage-to-time test was implemented. Finally, the long time breakdown voltage of each specimen was estimated with the parameters obtained from the statistical treatment with Weibull distribution. Base on the results, it has been found that the optimal weight ratio of epoxy resin/hardener/filler that has the excellent long time breakdown characteristic was 100/100/65. It was due to the silane treatment which relieves the electric field at the interface between filler and epoxy.

• Transactions on Electrical and Electronic Materials
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• v.17 no.3
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• pp.155-158
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• 2016

The effect of microsilica content modified with silicone-modified epoxy on electrical and mechanical properties of cycloaliphatic epoxy/microsilica system was investigated. The cycloaliphatic epoxy resin was diglycidyl 1,2-cyclohexanedicarboxylate and curing agent was an anhydride. Surface of microsilica was modified with silicone-modified epoxy. Electrical breakdown strength, the most important property for electrical insulation materials was tested. Tensile and flexural tests were also performed using universal testing machine (UTM). The microcomposite with 60 wt% microsilica shows maximum values in electrical breakdown strength.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.2
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• pp.92-98
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• 2012

As the increasing of non-linear load, filter is coming to be high gradually in order to reduce the harmonic which occurs from the power conversion. The maintenance of passive filter is easier than active filter and it has been widely used in the industrial site. This passive filter is connected with condenser and reactor by series and parallel and it is installed at the front of nonlinear load. The breakdown of passive filter occurs frequently at the reactor side rather than capacitor. So the breakdown cause close examination is necessary. In this paper, we analyzed that the electric stress of reactor which is considered magnetization saturation at the passive filter. We confirm that the reduction of harmonics and the electric stress of reactor is influenced by the linear and non-linear element of reactor.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2007.11a
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• pp.39-43
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• 2007

In this paper the experiments of breakdown characteristics $SF_6$ liquid ($LSF_6$) in model GIS(Gas Insulated Switchgear) were described. From the experiments results, The ability of $LSF_6$ insulation is higher than high-pressurized $SF_6$ gas. The breakdown characteristics of $LSF_6$ were produced by bubble formed evaporation of $LSF_6$ and bubble caused by high electric emission. It is considered in this paper that the results are fundamental data for electric insulation design of superconductor and cryogenic equipments machinery which will be studied and developed in the future.