• KIEE International Transactions on Electrophysics and Applications
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• v.4C no.2
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• pp.68-72
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• 2004

The performance of copper-tungsten for electrodes used in an ultra high voltage interruption system was evaluated by means of an interruption test, which requires a large-scale apparatus and high cost. In this study, prior to the interruption test, the characteristics of a Cu-W electrode were estimated through the DC arc test, which is a simple, low cost procedure. The DC arc characteristics of a 20wt%Cu-80wt%W electrode were investigated with the change of tungsten powder size distribution and the addition of nickel. In specimens containing a high volume fraction of large sized tungsten particles, the relative density and hardness of sintered Cu-W electrodes increased while the electrical conductivity and the DC arc resistance decreased. Furthermore, the relative density became enhanced with the increase of the amount of nickel while the hardness and electrical conductivity diminished and the DC arc resistance worsened.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.05e
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• pp.11-14
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• 2003

Sintered Cu-W has been used for the electrode of GIS for interrupting the abnormal current. In this study the effect of Ni addition in Cu-W electrode was investigated. Cu-W electrodes used contains 0.1~0.2wt% Ni and were conducted the experiments which was attacked by DC arc test (70V-70A) for 300 times periodically. As the contents of Ni in Cu-W electrode increase, the hardness and electrical conductivity were decreased. The weight change ($\Delta$mg) of electrode after DC arc test increased with increasing Ni contents and test times. The hardness and electrical conductivity of electrode after DC arc test were decreased compared with non-arc affected electrode, which was owing to the defects near surface of electrode and degradation by arc heat. It was considered that Cu in the Cu-W electrode was scattered to all directions by arc heat, therefore, the electrodes were damaged and deformed in the surface and cross-section of electrode. It is difficult to estimate directly the characteristics of Cu-W electrode for GIS related with high voltage and current from the results of DC arc test conducted in this study. However, the results of the effect of Ni addition in Cu-W electrode could be applied for the research of electrode for GIS.

• The Transactions of the Korean Institute of Power Electronics
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• v.17 no.1
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• pp.21-26
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• 2012

In recent years, DC distribution systems are becoming hot issue due to the increase in digital loads and DC generation systems according to the expansion of renewable energy technologies. However, removing the fault current in DC grids is comparably difficult since the current in DC grids has no zero-crossing point like in AC grids. Thus, developing dedicated DC circuit breakers for DC grids is necessary to get safety for people and electrical facilities. This paper proposes magnet arc extinguishing method to develop a 300[$V_{DC}$]/10[A] DC circuit breaker. The performance of the proposed DC circuit breaker was verified by an experimental circuit breaker test system built in this research.

• The Transactions of the Korean Institute of Power Electronics
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• v.27 no.3
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• pp.175-179
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• 2022

Magnetic arc extinguishing technology is effective as an extinguishing device for low-voltage direct current (DC) circuit breakers with a resistive load of ≤4 kW. The separation distance between the magnet and the electrical contact must be shortened to increase the magnetic arc extinguishing force. However, if the magnet is installed too close to the electrical contact points, the magnet is exposed to high temperatures due to the arc current generated when the load current is cut off and the magnetism is lost. To solve this problem, the effective magnetic flux density at the electrical contact can be maintained high by placing the arc extinguishing magnet in a tandem structure with the electrical contact point between them, and the proper separation distance between the contact points and the magnet can be maintained. In addition, an electric arc extinguishing technology that emits arc energy using a series circuit of diode and resistor is used to suppress the continuous arc voltage generated by the inductive load. For the proposed circuit breaker, the breaking characteristics are analyzed through the breaking test for the DC load of the 760 V level, the load power of 4 kW, and the time constant of 5 ms, and an appropriate arc extinguishing design guideline is proposed.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.66 no.3
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• pp.144-149
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• 2017

There is a little research on DC arc detection when compared to a large number of literature and patents on AC arc detection. However, as DC energy sources such as photovoltaic power generation facilities and fuel cells are introduced, research on DC arc has become as important as AC arc detection in terms of circuit protection and system reliability enhancement. In this paper, we have developed an arc detection method for photovoltaic system using frequency analysis. Through various experiments, it was confirmed that the proposed method effectively detects the arc.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.213-213
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• 2011

DC arc plasmatron is powerful plasma source to apply etching and texturing processing. Even though DC arc plasmatron has many advantages, it is difficult to apply an industry due to the small applied area. To increase an effective processing area, we suggest a DC-RF hybrid plasma system. The DC-RF hybrid plasma system was designed and made. This system consists of a DC arc plasmatron, RF parts, reaction chamber, power feeder, gas control system and vacuum system. To investigate a DC-RF hybrid plasma, we used a Langmuir probe, OES (Optical emission spectroscopy), infrared (IR) light camera. For RF matching, PSIM software was used to simulate a current of an impedance coil. The results of Langmuir probe measurements, we obtain a homogeneous plasma density and electron temperature those are about $1{\times}1010$ #/cm3 and 1~4 eV. The DC-RF hybrid plasma source is applied for plasma etching experimental, and we obtain an etching rate of 10 ${\mu}m$/min. through a 90 mm of reaction chamber diameter.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.68 no.1
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• pp.215-219
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• 2019

Development of DC interruption technology is being studied actively for enhanced DC grid reliability and stability. In this study, coil type superconductor DC circuit breaker was proposed as DC interruption. It is integration technology that combined current-limiting technique using superconductor and cut-off technique using mechanical DC circuit breaker. Superconductor was applied to the coil type. In simulation, Mayr arc model was applied to realize the arc characteristic in the mechanical DC circuit breaker. PSCAD/EMTDC had used to model and perform the simulation. To find out the protection range of coil type superconductor DCCB, the working operation have analyzed based on the rated voltage of DCCB. The results confirmed that, according to apply the limiting device, the protection range was increased in twice. Therefore, the probability of failure of interruption has lowered significantly.

• Proceedings of the KIPE Conference
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• 2014.07a
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• pp.524-525
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• 2014

In this paper, we propose algorithm plan variable for detection of DC arc. Changes of surrounding frequencies of harmonic wave is proposed to detect DC arc. To prove validity of these variables, we analyzed frequency based on the measured data and waveform of load current by performing the experiment which generates DC arc by using DC arc generator regulated in UL1699 was carried out.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.5B no.4
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• pp.306-311
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• 2005

In this paper, the electromagnetic force acting in the arc column of 3 different extinction units is compared with using the FEM (Finite Element Method) and the arc velocity is calculated by the drag force of the fluid mechanics. The experiment for breaking the arc current was performed in each model at 100 volts in order to measure the arcing time. The outcome was compared with the computing value. As a result, this paper proposes that the divided U-shaped grid is able to shorten arcing time and improve the electric performance. It also suggests a methodology for comparing and analyzing the result obtained by simulation and experiment.

• 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.