Jong-Yong Lee

Electrical Insulation Properties of Nanocomposites with SiO 2 and MgO Filler

In this paper, we attempt to improve the electrical characteristics of epoxy resin at high temperature (above ) by adding magnesium oxide (MgO), which has high thermal conductivity. Scanning electron microscopy (SEM) of the dispersion of specimens with added MgO reveals that they are evenly dispersed without concentration. The dielectric breakdown characteristics of and MgO nanocomposites are tested by measurements at different temperatures to investigate the filler`s effect on the dielectric breakdown characteristics. The dielectric breakdown strength of specimens with added decreases slowly below (low temperature) but decreases rapidly above (high temperature). However, the gradient of the dielectric breakdown strength of specimens with added MgO is slow at both low and high temperatures. The dielectric breakdown strength of specimens with 0.4 wt% is the best among the specimens with added , and that of specimens with 3.0 wt% and 5.0 wt% MgO is the best among those with added MgO. Moreover, the dielectric strength of specimens with 3.0 wt% MgO at high temperatures is approximately 53.3% higher than that of specimens with added at , and that of specimens with 5.0 wt% of MgO is approximately 59.34% higher under the same conditions. The dielectric strength of MgO is believed to be superior to that of owing to enhanced thermal radiation because the thermal conductivity rate of MgO (approximately 42 ) is approximately 32 times higher than that of (approximately 1.3 ). We also confirmed that the allowable breakdown strength of specimens with added MgO at is within the error range when the breakdown probability of all specimens is 40%. A breakdown probability of up to 40% represents a stable dielectric strength in machinery and apparatus design.

Electrical insulating properties of nano-composites according to additive

The use of a filler material in epoxy composite materials is an essential condition for reducing the unit cost of production and reinforcing the mechanical strength. However, the dielectric strength of insulators decreases rapidly due to interactions between the epoxy resin and filler particles. In contrast to existing composite materials, nano-composite materials have superior dielectric strength, mechanical strength and enduring chemical properties due to an increase in bond strength of the polymer and nano material. It has been reported that nano-fillers provide new characteristics different from properties of the polymer material. In this study, to improve the insulation capability of epoxy resin used in the insulation of a power transformer apparatus and many devices mold. To accomplish this, the addition amount of nano-SiO2 to epoxy resin was changed and the epoxy/SiO2 nano composite materials were made, and the fundamental electrical properties of them were investigated using a physical properties and analysis breakdown test. Using allowable breakdown probability, the optimum breakdown strength for designing electrical apparatus was determined. As the result, it was found out that the electrical characteristics of the nano-SiO2 content specimens were superior to the virgin specimens. The 0.4 [wt%] specimens showed the highest electrical properties among the specimens examined with an allowable breakdown probability of 20 %, which indicates stable breakdown strength in insulating machinery design.

Analysis of Partial Discharge Using Non-Linear Clustering Algorism

In this paper, we examine discharge characteristics of cross-linked polyethylene (since then; XLPE) according to void. Voltage was applied to power frequency by step method, and calibration of discharge was set to 50[pC] (slope=8.333). After the voltage was applied, for 10 [sec] (600 [cycle]), occurring discharge and number were detected. Determine of input pattern is difficult because discharge pattern is irregular. Therefore we investigated phi-q-n pattern using the clustering method, and investigated variation of center vector and cluster member

Simulated Design and Improvement of Efficiency of Organic Solar Cells

AbstractWe have performed a program simulation for design and development of highly efficient organic solar cells. We have simulated a model cell structure of ITO (indium-tin-oxide) anode/CuPc (copper phthalocyanine)/C60 (fullerene)/BCP (2, 9-dimethyl-4.7-diphenyl-1, 10- phenanthroline)/A1 (aluminum) cathode. As a result, obtained short-circuit current density (Jsc), open-circuit voltage (Voc), values of fill factor (FF), and power conversion efficiency (η) are 2.25 mA/cm2, 0.442 V, and 0.35, 0.35%,. Also, Organic solar cells were manufactured with a condition obtained from simulation. Experimentally obtained values of Jsc, Voc, and n are 1.05 mA/cm2, 0.25 V, and 0.21 %, respectively. When compared experimental results with optimum simulation structure, the values of Jsc, Voc, and n are reduced by 53, 40, and 65 %, respectively.