• Proceedings of the KIEE Conference
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• 2001.04a
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• pp.353-356
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• 2001

This paper describes an analysis of electromagnetic system of Magnetic Switch using 3D and 2D finite element method. The electromagnetic blowout force acting on the arc is obtained by 3D finite element method. So, we are researching the arc chamber for dc current using permanent magnet.

• Proceedings of the KIEE Conference
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• summer
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• pp.788-790
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• 2004

This paper describes the phenomenon of the molten metal bridge theory of the arc discharge at opening contacts. And we analyze the magnetic force and drag force acting on the arc column in the DC magnetic contactor Arc cooling time by the force convection is calculated in the thermal dynamic equation using mean temperature method. Since arc gas lost conduction characteristics below a such temperature, it verify that the process of forming and extinguishing arc is able to analyze in terms of temperature characteristic by simulation and experiments of the 3 types arc extinction unit. It propose the practical simulation method to improve the electrical endurance of dc contactor.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.2
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• pp.184-190
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• 2009

One of the purposes of arc control is to change its state to the diffuse state before current zero as soon as possible. This can provide optimal conditions for full extinction of arc by minimizing the quantity of residual plasma between contacts near current zero. TRV(transient recovery voltage) occurs at current zero at the same time with current interruption. If there is substantial residual plasma near current zero it can cause 'post arc current' by the interaction of its conductance with TRV. In this paper, arc control ability as a function of configuration of spiral type VI contacts was compared on the criteria of the time taken for arc to reach to the diffuse state.

• Proceedings of the KIEE Conference
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• 2002.07b
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• pp.888-890
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• 2002

We derived a theory of increasing electromagnetic force acting on arc column for reducing arcing time between electric contacts. A simulation method of arc velocity is presented by calculating blowout force using 3D FEM and drag acting on arc column. This paper is proposed 3 types arc extinguish chamber of different fulx path and is presented electromagnetic force and arc velocity of each model.

• Progress in Superconductivity and Cryogenics
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• v.2 no.1
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• pp.24-30
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• 2000

This paper present the characteristics of the internal induced voltage and arc phenomena in liquid helium at the energy transfer from a superconducting magnet to a load resistor. Especially generation mechanism of the oscillated wave from of the coil terminal voltage is analyzed by considering circuit constant of the superconducting magnet, load condition and arc resistance of the mechanical opening switch. The wavefront and peak portion of the voltage are strongly influenced by arc discharge triggered by the switch separation in liquid helium. Abrupt arc extinction leads to voltage oscillation with an enormous peak. It is suggested that the superconducting magnet should be designed to ensure the internal surge when arc is possibly formed by switch opening or coil short circuit between turns or layers. Finally, a suppression method of the oscillating surge is proposed based on the load condition.

• Proceedings of the KIEE Conference
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• 1998.07c
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• pp.1217-1219
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• 1998

For the improvement of an adaptive SPAR(Single-Phase Auto-Reclosure) and novel protection schemes, it is important to simulate arc faults. But, it is difficult to reproduce the real arc behaviour, i.e. the extinction phenomenon exactly by computer simulations due to extremely random behavior of secondary arc. This paper proposes a new computer modeling techniques for the primary and the secondary arc separately, which can be implemented with EMTP MODELS routine, and the performance of the proposed model is simulated on a typical 154 [kV] korean transmission line system.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2005.05a
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• pp.69-73
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• 2005

The arc dispersion and contacts characteristics were analyzed according to switching off Residual Current Protective Device(RCD) switch. Arc dispersion process was taken by high speed imaging system at a rate of 10,000 frames per second. When RCD was switched from on to off, art was observed and it took about 2.3[ms] from the generation of arc to the extinction of arc. When RCD was switched from off to on, arc was not observed. We repeated switching on and off 1000, 3000 and 6000 times. After repetition, the surface characteristics of contacts were taken by stereo microscope and Scanning Electron Microscope(SEM). From the scattering patterns analysis of arc and the analysis of deteriorated contacts, it could be applicable to the research of electric fire and arc suppression.

• Proceedings of the KIEE Conference
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• 2001.10a
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• pp.18-20
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• 2001

This paper describes are quenching chambers of three type for Magnetic Switch and analyzes electromagnetic blowout force acting on the arc using 3D finite element method we make prototype device of each model and establish characteristics of arc quenching by measuring arcing time. This paper compares electromagnetic blowout to inverse arcing time. As the result this proposes the improving method for arc quen performance in DC magnetic switch.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.10a
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• pp.454-457
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• 1997

The purpose of this study is to develop an optimal model, using existing models, that is able to estimate the amount of spatter utilizing artificial neural network in the short circuit transfer mode of gas metal arc (GMA) welding. The amount of spatter generated during welding can become a barometer which represents the process stability of metal transfer in GMA welding, and it depends on some factors which constitute a periodic waveforms of welding current and arc voltage in short circuit GMA welding. So, the 12 factors, which could express the characteristics for the waveforms, and the amount of spatter are used as input and output variables of the neural network, respectively. Two neural network models to estimate the amount of spatter are proposed: A neural network model, where arc extinction is not considered, and a combined neural network model where it is considered. In order to reduce the calculation time it take to produce an output, the input vector and hidden layers for each model are optimized using the correlation coefficients between each factor and the amount of spattcr. The est~mation performance of each optimized model to the amount of spatter IS assessed and compared to the est~mation performance of the model proposed by Kang. Also, through the evaluation for the estimation performance of each optimized model, it is shown that the combined neural network model can almost perfectly predict the amount of spatter.

• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.696-698
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• 2001

This paper considers the research of the hybrid interrupter which adopts both rotating arc and thermal expansion technology. The operating principle of this device depends on rapid arc rotation due to the magnetic field created by the fault current through a coil which is mounted on contacts and also relies on the principle of thermal expansion created by arc energy in extinguishing chamber and finally causes pressure rise in expansion volume. To develope this type of interrupter, we introduced analytical analysis including electromagnetic and arc fluid simulation and experimental analysis including construction of current source generation facility and arc behavior measurements. In this research, the principle of the interrupting techniques are given and analytical and experimental results of hybrid interrupter which is developed by new technology is introduced.