• The Transactions of the Korean Institute of Electrical Engineers P
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• v.66 no.3
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• pp.139-143
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• 2017

In this paper, we propose a separation method of the dielectric particles in the liquid flow. Since particles are dielectric in most cases, they experience dielectrophoretic(DEP) force under non-uniform electric field. The field characteristics in the electromagnetic and fluid dynamic systems are solved by using the finite element method. The motional equation of the particles is calculated by the Runge-Kutta method. The field analysis shows the feasibility of the proposed method. The particle separation model with large DEP force exerting on particles is designed by analyzing field characteristics.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.11
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• pp.1008-1013
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• 2003

We have studied the effect of black matrix (BM) according to the dielectric anisotropy of liquid crystals (LCs) for a homogeneously aligned LC cell driven by fringe-electric field. The results show that for a LC with positive dielectric anisotropy (+LC) there is a large transmittance change when using a conductive BM, whereas the transmittance change is low for a LC with negative dielectric anisotropy (-LC). The conductive BM existing on top substrate produces vertical electric field, which makes the LC molecules be tilt upward from the substrate and have small twist angle for the +LC. However, for the -LC the conductive BM affects the LC distribution only slightly due to characteristic of the -LC orienting perpendicular to the field. Therefore, for the +LC the electro-optic characteristics are strongly dependent on conductivity of the BM on top substrate in a homogeneous liquid crystal cell driven by fringe-electric field.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.9
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• pp.801-807
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• 2008

Recently, CV, CN-CV and CNCV-W cable are used for HVDC transmission and distribution cable. However, XLPE which is used as insulation layer of power cable has thermosetting properties. It is very difficult to recycling. In this paper, we prepared HDPE/EVA film, which the blending ratio are 80:20, 70:30, 60:40, 50;50 respectively for the purpose of recycling. Main factor such as electric field distribution and its resistivity in insulation system affected on insulation performance and reliability for HVDC applications. Therefore, electric field distribution formed by space charge and characteristics of volume resistivity was currently investigated. We suggest the possibility of utilization for HVDC insulation layer from the results.

• Journal of the Optical Society of Korea
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• v.11 no.4
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• pp.177-182
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• 2007

This paper discusses the errors associated with electric field cross talk for optical voltage sensors in a three-phase electric system and provides a solution to compensate the errors. For many practical conductor configurations, the electric field cross talk may cause errors unacceptable for the accuracy requirements of the sensors. We devised a real time compensation method for the cross talk and built an electronic circuits based on it. The mechanism of the compensation and the corresponding error reduction were discussed.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.11a
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• pp.603-606
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• 2004

Aspects of PD occurrence from PD sources are different with their physical and structural appearances which cause the variation of electric field distributions of them. This paper have investigated electric field distributions of some kinds of electrode structure by FEM applied analysis program. Numeric analysis is a good method to investigate Ihe electric and magnetic field distribution of partial discharge source. The analysis results were confirmed by real PD occurring situation in the laboratory.

• Transactions on Electrical and Electronic Materials
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• v.10 no.6
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• pp.196-199
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• 2009

The practical applications of piezoelectric ceramics are applied not only under low electric field environment. Therefore, an examination for characteristics of PZT ceramics under the high electric field condition can contribute to reducing the susceptibility of multifarious applications and to facilitating production of control circuits. These contributions can lead to the expansion of industrial applications. In this research, we fabricated disk-type PZT ceramic samples using conventional methods, measured the resonance characteristics of these samples under from low to high voltage conditions and calculated the PZT constants.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.11a
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• pp.333-335
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• 2005

The simulation of electric field distribution of discharge tube with globular $ZrO_2$ and the removal characteristic of Escherichia coli by the discharge tube with globular $ZrO_2$ were estimated. The removal characteristic of Escherichia coli was related to the input voltage because the electric field is increased according to input voltage. As the particle size of $ZrO_2$ beads increased, the removal time of Escherichia coli was shortened due to the dielectric polarization of $ZrO_2$ beads.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.207-208
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• 2007

Epoxy resin insulators show a lot of advantages for electrical power apparatus. Because epoxy resin provide electrical and mechanical characteristic which is excellent, it is desirable to apply epoxy resin as a spacer and post insulation in Gas Insulated Switchgear (GIS). In this study, we have investigated the influence of surface electric field attached particle contaminated spacer surfaces under SF6 gas. Also, we performed analysis of electric field. As a result, when the particle was attached on spacer, we found out a surface electric field of characteristics.

• Journal of the Korean Applied Science and Technology
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• v.23 no.3
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• pp.238-242
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• 2006

Polyimide is a well-known organic dielectric material, which has not only high chemical and thermal stability but also good electrical insulating and mechanical properties. In this research, the electric conduction mechanism of PI Ultra-Thin Films was investigated at room temperature. At low electric field, ohmic conduction $(I{\propto}V)$ was observed and the calculated electrical conductivity was about $4.23{\times}10^{-15}{\sim}9.81{\times}10^{-15}\;S/cm$. At high electric field, nonohmic conduction $(I{\propto}V^2)$ was observed and the conduction mechanism was explained by space charge limited region effect. The dielectric constant of PI Ultra-Thin Films was about 7.0.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.30 no.10
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• pp.672-676
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• 2017

Electrical energy is playing an increasingly vital role as the primary energy source in everyday life. With the increase in electric power consumption, power facilities are under an increasing stress and must operate at a high capacity. Consequently, the demand for electric power cables in power transmission and distribution lines is rapidly increasing. Underground distribution lines have been steadily replacing the aboveground lines owing to the increase in electric power demand and the need to increase the supply voltage. In addition to line damage, worker safety is of primary concern in this type of underground infrastructure. In this study, to improve the safety of workers dealing with underground transmission lines, we analyzed the electromagnetic field generated around the distribution line and determined the basic criteria for developing a device that can detect a live underground line.