• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.927-928
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• 2007

Recently IEC has made considerations on testing Enclosed low-voltage switchgear and controlgear assemblies under conditions of arcing due to internal faults. This paper will make a study on testing Enclosed low-voltage switchgear and controlgear assemblies under conditions of arcing due to internal faults that is suggested by IEC.

• Proceedings of the KIEE Conference
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• 1997.07a
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• pp.89-93
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• 1997

Various types of nozzles and arcing contacts for EHV class GCB have been made to investigate the arc-resistant characteristics of them during short-circuit tests. The tested results are presented and analyzed to give useful information for GCB nozzle and contact manufacturers.

• The Korean Journal of Applied Statistics
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• v.14 no.1
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• pp.91-101
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• 2001

It has been shown that the multiple trees predictors are more accurate in reducing test set error than a single tree predictor. There are two ways of generating multiple trees. One is to generate modified training sets by resampling the original training set, and then construct trees. It is known that arcing algorithm is efficient. The other is to perturb randomly the working split at each node from a list of best splits, which is expected to generate reasonably good trees for the original training set. We propose a new combined multiple regression trees predictor which uses the latter multiple regression tree predictor as a predictor based on a modified training set at each stage of arcing. The efficiency of those prediction methods are compared by applying to high throughput screening of chemical compounds for biological effects.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.7
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• pp.976-980
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• 2018

The traction power system is configured to transmit electricity to the vehicles through mechanical contact between the OCL (Overhead Contact Line) and the pantograph. The system measures the current collection performance of the OCL, or the OCL installation condition is examined through maintenance for commercial operation. Maintenance continues to check the conditions through visual inspection by walking and inspection vehicles. The current collection performance is divided into the percentage of arcing(%), the contact force, and the uplift. The percentage of arcing is composed of a vision based system and used to verify the performance of a new OCL. However, it is not always possible to measure the current collection performance during commercial operation, and maintenance based on human resources can not be replaced. This paper presents the minimum performance condition of video devices in the current collection system of commercial vehicles. In addition, a continuous arcing was measured, and current collection performance was examined on the traction power system at the 250 km/h. It was analyzed with a minimum duration of arc of 1 ms. The frame rate is then shown by comparing the number of frames in the image at the time intervals of the number of the arcing. It is expected that the result of this study can be used for examining the minimum performance of video devices depending on their purpose.

• Journal of Welding and Joining
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• v.19 no.1
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• pp.33-39
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• 2001

The welding quality by Gas Tungsten Arc Welding shows very high level, but the welding speed is lower than that of gas metal arc welding. Also, the welding quality by automatic GTAW is variable as the arc characteristics is changed by the consumption of electrode tip. The purpose of this study is to investigate the relation between the properties of tungsten electrode tip and the various arc characteristics at high current region. In this study, the high welding current 200A was applied to the repeated arc start test and long term arcing test using the $\phi$3.2 tungsten electrodes with cone angle 30$^{\circ}$, 45$^{\circ}$, 60$^{\circ}$sharp tip, and 60$^{\circ}$surface polished (S.P.) sharp tip. It was confirmed that the maximum arc pressure by the initial electrode condition was highest in 45$^{\circ}$sharp tip, and the next in 60$^{\circ}$sharp tip, the last was in 30$^{\circ}$sharp tip and 60$^{\circ}$S.P.. But, the maximum arc pressure after the repeated arc start test and long term arcing test was decreased considerably. But, the maximum arc pressure was highest also in 45$^{\circ}$ sharp tip after the tests, the next was in 30$^{\circ}$sharp tip, and the last was in 60$^{\circ}$sharp tip and 60$^{\circ}$S.P.. The arc start characteristics was the most excellent in 60$^{\circ}$S.P., By long term arcing test, the lanthania included in tungsten electrode was extinguished at tip surface preferentially, therefore the arc characteristics of electrode tip got worse.

• Journal of the Korean Institute of Gas
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• v.11 no.1 s.34
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• pp.18-22
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• 2007

The fault current through the earth originated from a power line ground fault might cause arcing through the soil to an adjacent pipeline, which might bring about not only a catastrophic accident such as gas explosion and oil leakage but also a hazard to the safety of workers responsible for the maintenance and repair of the pipeline. In this paper we investigated the arcing phenomena through soil between a power line tower and a pipeline and outlined the standards for the separation distance of a buried pipeline adjacent to the power line tower.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.7
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• pp.1294-1303
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• 2009

This paper presents a new numerical algorithm for fault discrimination and fault location estimation when occur to arcing ground and arcing line to line on transmission lines. The object of this paper is developed from new numerical algorithm to calculate the fault distance and simultaneously to make a distinction between transient and permanent faults. so the first of object for propose algorithm would be distinguish the permanent from the transient faults. This arcing fault discrimination algorithm is used if calculated value of arc voltage amplitude is greater than product of arc voltage gradient and the length of the arc path, which is equal or greater than the flashover length of a suspension insulator string[1-3]. Also, each algorithm is separated from short distance and long distance. This is difference to with/without capacitance between short to long distance. To test the validity of the proposed algorithms, the results of algorithm testing through various computer simulations are given. The test was simulated in EMTP/ATP simulator under a number of scenarios and calculate of algorithm was used to MATLAB.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1345-1347
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• 2008

This paper described a method of determining whether arcing is present in a low-voltage wiring system. We simulated the series arcing that generated in electrical loads and fabricated a arc detection module which can discriminate between normal and arcing state. The module consists of a high-pass filter with a low cut-off frequency of 3 kHz to attenuate power frequency voltage and an active band-pass filter with a frequency of 4 kHz ${\sim}$ 8 kHz to detect series arc signals only. We tested an Incandescent lamp that was controlled by a dimmer and analysed. The module consists of a high-pass filter with a low cut-off frequency of 3 kHz to attenuate power frequency voltage by 80 dB and an active band-pass filter with a frequency of 4 kHz to detect series arc signals only. From the experimental results, we could detect series arc signals without an influence of non-linear loads.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.48 no.3
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• pp.185-191
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• 1999

The fuse used in the high voltage distribution line often fails due to the active ionization caused by the strong electric field at fuse terminal. To suppress the ionization at the high voltage and high capacity current limiting fuse, the particle size and compactness of silica sand, the design, length, notch number and material of element, the diameter and length of fuse body must be considered carefully. However, these are not many proper which is treated with the inherent interrupting characteristics from many parameters at present. Because of these reasons, time and effort are needed to develop the new type fuse by the fuse designers in relation with the inherent characteristics from each of parameters. In this paper we choose 7 parameters with weight value based on study and experimentation and analyzed the characteristics of arcing period. In addition, we proposed the experimental method to experimentation and analyzed the characteristics of arcing period. In addition, we proposed the experimental method to extract the optimal design parameters with minimal effort as related the mutual effect from each of the parameters.

• Applied Science and Convergence Technology
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• v.23 no.5
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• pp.261-264
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• 2014

$SrTiO_3$ (STO) single crystal irradiated with a 3-MeV proton beam exhibits blue and green mixed luminescence. However, the same proton beam when used to irradiate STO with a very thin layer of deposited Pt does not show any luminescence. This Pt layer prevents any damage which may otherwise be caused by arcing, which stems from the accumulated surface voltage of tens of kV due to the charge induced by secondary electrons on the surface of the insulator during the ion beam irradiation process. Hence, the luminescence of ion-irradiated STO originates from the modification of the STO surface layer caused by arcing rather than from any direct ion beam irradiation effect. STO treated with atmospheric-pressure plasma, a simple and cost-effective method, also exhibits the same type of blue and green mixed luminescence as STO treated with an ion beam, as the plasma also creates a layer of surface damage due to arcing.