• The Transactions of the Korean Institute of Electrical Engineers P
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• v.55 no.2
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• pp.110-114
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• 2006

This paper describes the accident analysis by modelling the current transformer mounting in a metal-clad switchgear at 22.9kV. In analyzing the accident, the reconstruction at the current transformer mounting(VCB connecting guide) has to be taken into account. The accident was modelled as a 3-phase ground fault occurring between the end plate of 22.9kV lines and the safety shutter at the current transformer mounting of the VCB inside the metal clad switchgear. Since the outside maintenance of the metal clad switchgear is restricted by the enclosed compartments, Its circumference has to be kept clean. Through the reconstruction results, it was confirmed that the fault of the enclosed switchboard could be reduced when the shutter made of Fe material was chanted into an insulation.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.1
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• pp.142-147
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• 2018

Private electrical facilities are judged whether it is suitable for the insulation aging condition of their incoming underground cables using DC leakage current test method. In the case where the service point of utility is the secondary side of cut out switch installed in the electric pole, there is a problem that it is difficult to separate the lightning arresters(LA) because of their high position of the pole. Therefore, the field test voltage is applied at value lower than DC 30 kV, which are stated in the inspection guideline. However, this test could reduced the insulation performance of the LA by accelerating the electrical stress of the metal oxide varistor element in the pre-breakdown region. In this study, we analyzed the relationship between the DC test voltage and the leakage current using the non-destructive DC high voltage equipment with leakage current measurement function. The results show that the leakage current increases sharply above the specified test voltage. As a consequence, it could be contributed to improve insulation aging inspection method by selecting the possible test area on the VI characteristic curve of the pre-breakdown area of the LA.

• Fire Science and Engineering
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• v.32 no.6
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• pp.1-6
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• 2018

This study is to analyze the characteristics of the yellow insulation ring type of the CSST used for tubing when it is artificially deteriorated and damaged by burning. The CSST for tubing consists of a tube, protective coating, nut, yellow insulation ring, packing, and socket. In addition, it is thought that a yellow insulation ring and rubber packing were used to connect the tube and socket in order to improve the airtightness and insulation performance. The result of the verification of the data acquired from the tests in the 95% confidence interval shows that the Anderson-Darling (AD) and P value were analyzed to be 0.945 and 0.015, respectively. This confirms that the test data of the CSST for tubing is reliable. The analysis of the arithmetic mean of the insulation resistance of a CSST showed that the CSST damaged by burning by a torch, and the one damaged by electrical burning, was $16.7k{\Omega}$ (the greatest relatively) and $208{\Omega}$ (the lowest), respectively, while it was $1.72k{\Omega}$ in the case of a normal product. Therefore, the analysis result of the insulation resistance of the CSST collected from the scene of a fire can be utilized to examine the cause of damage by burning. In addition, it was found that when the maximum current of 97 A was applied to the CSST for about 5 s using a Primary Current Injection Test System (PCITS) the protective film and insulation ring of the CSST has no difference from that of a normal product. However, a part of the metal tube was melted.

• Transactions on Electrical and Electronic Materials
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• v.16 no.6
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• pp.312-316
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• 2015

Through silicon via (TSV) technology holds the promise of chip-to-chip or chip-to-package interconnections for higher performance with reduced signal delay and power consumption. It includes high aspect ratio silicon etching, insulation liner deposition, and seamless metal filling. The desired etch profile should be straightforward, but high aspect ratio silicon etching is still a challenge. In this paper, we investigate the use of etch hard mask for finer TSVs etching to have clear definition of etched via pattern. Conventionally employed photoresist methods were initially evaluated as reference processes, and oxide and metal hard mask were investigated. We admit that pure metal mask is rarely employed in industry, but the etch result of metal mask support why hard mask are more realistic for finer TSV etching than conventional photoresist and oxide mask.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1623_1624
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• 2009

The use of arc tubes made of ceramic material further enhanced some of the metal halide lamp’s properties. These properties translate into higher efficacy with better color rendering, stable color through lamp long life. Recently, due to an increase in the application of the ceramic metal-halide lamp, the study for the property etc. according to Ballast's driving scheme and the study for arc tube material, optimization of gas and so on are being proceeded to improve the property of the lamp. Especially, to control ceramic metal-halide lamp, the vigorous study and practical use with respect to Electronic Ballast, which has been improved in the disadvantages of the conventional Magnetic Ballast are made. In this paper, Electrical characteristics and gas insulation destroy time are analyzed by comparing magnetic ballast with electronic ballast.

• Proceedings of the KIEE Conference
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• 1996.07c
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• pp.1917-1919
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• 1996

This paper aims to extract the air clearance in 22.9KV the metal enclosed switchgear. First, we investigated the actual conditions on the clearance in the metal enclosed switchgear which has been used in domestic. The test model and 9 test electrodes for the air insulation strength tests have been designed and manufactured based on the investigation results. To find optimal clearance in the metal enclosed switchgear, we performed 50% flash-over test by the up and down method and lightning impulse withstand voltage test. And we obtained results that the clearance or phase-to-phase is 230 [mm] and clearance or phase-to-earth is 210[mm].

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2009.05a
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• pp.397-400
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• 2009

When the metal sheet is subjected to the housing surface for fitting and insulating from harsh surroundings like fluid ingression or hot steam, both strength and formability have to be equally considered. In this regard, the main aim of this study is to design an apparatus of cost-effectively producing flexible fluted band with increasing the formability of embossed stainless steel sheet, which is utilized as a thermal insulation metal for housing ship engine exhauster. Designed to fabricate a maximum sheet width of 700 mm, this new apparatus consists of upper roll made of hard urethane and the female-etched lower roll made of SKD11, have a producing capacity up to 1-meter homogeneously embossed sheet for just 60 seconds. This machine is devised for the maximum operating efficiency from original sheet handling to machine setting. The embossing properties are characterized by 3-D profiling. After embossing plain metal sheet, both yield strength and elongation properties are improved simultaneously, indicating the effectiveness of the newly designed apparatus.

• Proceedings of the KIEE Conference
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• 2001.11a
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• pp.124-127
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• 2001

In this study, the electrical properties of polymer thin film layered by spin-coating method was investigated, and this polymer is one of the polymer applied to insulation layer for display, this polymer has relatively high dielectric constant, hygroscopic property and easy to make thin film by spin-coating. That is, in this study use the polymer that is cyano acrylate terpolymer, and the MIM(Metal/Insulator/Metal) structures were fabricated to measure the electrical properties such as Voltage-Current characteristics and dielectric characteristics. Also the conductivity and dielectric constant has been calculated. As a result, the conductivity in room temperature was $0.85{\times}10^{-14}{\sim}1.35{\times}10^{-14}$[S/cm]. The fact that this polymer be acted as insulator can be supported by this result. The dielectric constant was calculated as $10.39{\sim}12.05$ higher than Dopont Inc., this make it possible to accumulate more charges in insulation layer under same condition.

• Korean Journal of Optics and Photonics
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• v.21 no.3
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• pp.118-122
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• 2010

We fabricated a high power LED lamp structure which utilizes the modified COB concept based on an MCPCB with insulation layer partially removed. In the proposed structure, no insulation layer exists between the LED chip and the metal base. As a result, the heat generated in the chip is easily dissipated through the metal base. In actual measurement as well as in thermal simulation, the fabricated LED lamp structure showed superb thermal properties, compared to the SMD LED lamp attached on an MCPCB or the LED lamp based on conventional COB concept.

• Journal of Environmental Science International
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• v.20 no.11
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• pp.1499-1507
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• 2011

Practical disposal of transformer insulation oil laden with PCBs (polychlorinated biphenyls) by a chemical treatment has been studied in field work. The transformer insulation oil containing PCBs was treated by the required amounts of PEG (polyethylene glycol) and KOH, along with different reaction conditions such as temperatures and times. The reaction of PEG with PCBs under basic condition produces arylpolyglycols, the products of nucleophilic aromatic substitution. Removal efficiencies of PCBs in insulation oil before and after chemical treatment were examined. The removal efficiency of PCBs was very low at lower temperatures of 25 and $50^{\circ}C$. Under the reaction condition of PEG 600/KOH/$100^{\circ}C$/2hr, removal efficiency of PCBs was approximately 70%, showing completely removal of PCBs containing 7~9 chlorines on biphenyl frame which appear later than PCB IUPAC Number 183 (2,2',3,4,4',5',6-heptaCB) in retention time of GC/ECD. However, when increasing the reaction temperature and time to $150^{\circ}C$ and 4 hours, removal efficiency of PCBs reached 99.99% without any formation of PCDDS/PCDFs during the process. Such reaction conditions were verified by several official analytical institutions. In studying the reaction of PEG with PCBs, it confirmed that the process of chemical treatment led to less chlorinated PCBs through a stepwise process with the successive elimination of chlorines.