• Proceedings of the KIEE Conference
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• 1994.11a
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• pp.270-273
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• 1994

The capacitive current breaking capability as well as the short circuit current breaking capability is a very important factor in the performance of a circuit breaker. The dielectric recovery capability between poles should be considered in the desist of a circuit breaker because approximately two times of the maximum power system voltage might be applied between poles after the capacitive current be interrupted. The electric field and flow field analyses were utilized in the calculation of dielectric recovery characteristics between poles of 800kV model interrupter. The results show that the separation between moving main contact and moving arcing contact will affect to decrease significantly the electric field strength of a moving arcing contact and an insulation cover, to increase slightly the electric field strength of a fixed arcing contact and to decrease consequently the dielectric recovery capability between poles of the interrupter.

• Journal of Welding and Joining
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• v.16 no.6
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• pp.52-58
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• 1998

The effect of Si content in welding wires on th arc stability was investigate, in the region of short circuit transfer and spray transfer. In the region of short circuit transfer, with increasing Si content, average arcing time and average short circuit time were increased. Therefore, droplet transfer frequency was decreased, due to the increase of arcing time and peak current at the moment of arc-reiginition was increased, due to the increase of short circuit time. In the region of spray transfer, the fluctuations of arc current and arc voltage was the most stable in wire with Si content of about 00.60 wt.%.

• Journal of Welding and Joining
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• v.17 no.1
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• pp.55-61
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• 1999

The effect of S content in welding wires on the arc stability was investigated, in the region of short circuit transfer and spray transfer. In the region of short circuit transfer, with increasing S content, average arcing time and average short circuit time were decreased. Therefore, droplet transfer frequency was increased, due to the reduction of arcing time and peak current at the moment of arc-reiginition was decreased, due to the decrease of short circuit time. In the region of spray transfer, the fluctuation degree of arc current and arc voltage became more stable, with increasing S content.

• Proceedings of the KIEE Conference
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• 1989.07a
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• pp.443-446
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• 1989

154kV insulator strings are frequently damaged by lightning strokes, overvoltage and contamination. And this insulator damage inflicts a loss on the power company. The purpose of this paper is to develop the arcing horn as a protective device of 154kV insulator strings against lightning flashover and overvoltages. So We have developed the arcing horn which is suitable for 154kV transmission line and estimated the performance of arcing horn by high current arcs and high voltage tests.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.472-473
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• 2007

This study evaluated electrical characteristics of the manufactured arcing horn whose rated voltage and nominal discharge current were 18kV and 2.5kA, respectively. In this study, residual voltage and lightning impulse flashover voltage were examined. The arcing horn showed excellent electrical characteristics that residual voltage and lightning impulse flashover voltage were 55kV below and 121kV at 115mm, respectively. Therefore the manufactured arcing Horn is considered that it would show good performance for protecting electrical wires and line post insulators from lightning impulse, if it were applied to real fields.

• Proceedings of the KIEE Conference
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• 1999.07a
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• pp.351-353
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• 1999

In this paper, electric field analysis of 170kV class GCB is carried out. Considering the movement of arcing contacts during circuit interruption, electric field analysis between moving and fixed contacts is performed with changing the stroke length. From analysis results, electric field stresses are high at stationary arcing contact, moving arcing contact and varies at changing nozzle shapes. Specially, the stationary arcing contact shape has an significant effect on the capacitive small current interruption and the reduction of the electric field stress at this area is important. Varying the shape of stationary arcing contact, electric field analysis is carried out and the optimal shpae of the fixed arcing contact where the electric field stress is low is designed.

• 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.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.31 no.10
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• pp.832-839
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• 2007

The geometry and dimensions of an expansion chamber are decisive factors in thermal puffer plasma chamber designs. Because they together dominate the temperature and speed at which the cooling gas from the chamber flows back through a flow channel to the arcing zone for the successful interruption of fault currents. In this study, we calculated the flow and mass transfer driven by arc plasma, and investigated the effects of a flow guide installed inside a thermal puffer plasma chamber. It is found that the existing cold gas of the chamber mixes with hot gases entrained from the arcing zone and is subjected to compression due to pressure build-up in the chamber. The pressure build-up with the flow guide is larger than that without due to a vortex which rotates clockwise around the chamber center. By the reverse pressure gradient, the mixing gas of the chamber flows back out for cooling down the residual plasma near current zero. In the case with the flow guide, the temperature just before current zero is lower than that without, and the Cu concentration with high electrical conductivity is also less than that without the flow guide.

• Proceedings of the KIEE Conference
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• 1998.07a
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• pp.161-163
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• 1998

The interruption performance of EHV class gas circuit breakers critically depends on the flow conditions inside interrupter and the external circuit conditions. In case of puffer type gas circuit breakers the flow conditons are significantly influenced by arcing time. In this paper the calculated results of RRRV and pressure rise at current zero with varying arcing time are presented and the effect of arcing time on the thermal interruption performance of EHV class gas circuit breakers is analyzed.

• Proceedings of the KIEE Conference
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• summer
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• pp.1106-1108
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• 2004

The arcing contact wear of circuit breakers can be the major cause for the maintenance requirement. The control of arcing times as short as possible but larger than the given minimum arcing time may be the effective way to mitigate the contact wear and to lessen the expenditure of a maintenance. In this paper the method for minimizing the arcing time is described. The basic concept used in the proposed method is the estimation of the current interruption instant from the informations such as the phase angle at the instant of trip commands and the magnitude of interrupted currents.