• Proceedings of the KIEE Conference
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• 1992.07b
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• pp.669-672
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• 1992

The increasing application of Vacuum Circuit-Breakers (VCB) on utility and industrial systems has prompted and detailed investigation of vacuum switching surge mechanisms and protections. This paper arranges arc-extinguishing principles of magnetic field in vacuum in order to disperse rapidly arc generated from vacuum contacts on switching VCR and plans establishment of protection means to protect high-voltage motor against surge voltage magnitude and transient voltage rate of rise

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.7
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• pp.24-28
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• 2013

Fire-hited electrical equipment has possibility of deterioration. So its replacement is essential in terms of safety. However, the economic burden is increased. Therefore, the replacement or re-use of it is to be determined by tests. But the research of Integrity Assessment on Fire-hited electrical equipments is very rare. In this paper, we tested to determine the replacement or re-use of Fire-hited vacuum circuit breaker. And provided the data for the integrity assessment through the analysis of its deterioration.

• Proceedings of the KIEE Conference
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• 2002.07a
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• pp.232-234
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• 2002

A Vacuum Circuit Breaker Model for simulation of transient overvoltages was developed by using the PSCAD/EMTDC. The Model includes the power frequency chopping current. Breaker withstand voltage, and quenching capability of High frequency currents. To verify the abilities of the breaker model, the simulation on the Lindmayer's single-phase circuit was carried out. The results show that using the proposed model, the transient overvoltages, current chopping, and multiple reignitions of vacuum breaker are properly reproduced as real phenomena. In further study, virtual chopping current will be incorporated into the model for 3 phase system.

• Proceedings of the KIEE Conference
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• 2001.05a
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• pp.305-308
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• 2001

The first objective of this study is to set up the switching surge analysis method in motor driving distribution system. The simplified model which can simulate the motor energization and circuit breaker re-ignitions, and each circuit element model is presented in this paper. The second objective is to calculate the quantify of surge over-voltage in real nuclear power station. And the surge suppressing measures are verified on the simulation basis. It is clarified that most cases are not satisfactory to meet the IEEE standard 522-1992 without using surge suppressing measures. In cases that the surge arrester are installed in distribution board at the load side of circuit breaker. The IEEE specification is fully met.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.127-127
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• 2010

This study describes the optimal design of shield to improve the insulation performance of vacuum interrupter(VI). Axi-symmetric finite element routine including floating boundary condition for shields was applied to analyze electric potential and field distribution in VI. A ($\mu-\lambda$) Evolution Strategy(ES) is employed as optimization method. Three design variables of shield are selected for minimizing the maximum electric field strength in VI. Finally, optimal solution for shield is obtained and compared with the result of the prototype.

• Proceedings of the KIEE Conference
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• 2004.04a
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• pp.18-20
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• 2004

This paper formulates the principle of the permanent magnetic actuator (PMA) and its dynamic characteristic calculation applicable to High Voltage Vacuum Interrupter (38kV/31.5kA). The new type of PMA is need to apply to High Voltage Vacuum Interrupter for large stroke length and contact force at interrupter. Consequently this paper describes the ideal matching of the new type of PMA mechanism with the characteristics required to operate successfully, reliably and efficiently a High Voltage Vacuum Interrupter.

• Proceedings of the KIEE Conference
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• 2002.11d
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• pp.39-42
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• 2002

In this study, the computational heat transfer of the high-voltage vacuum circuit breaker was investigated. Higher normal current-ratings and stabilized thermal characteristics become more important in existing circuit breakers in order to satisfy market needs. Increases in current-ratings have an even greater effect on the Joule heating in the main circuit of the breakers. The thermal design must account for this increase in heat produced for the breaker to meet various temperature-rise limits set by industry standards. We are studying to enhance the normal current-ratings without major frame change of our present production models. As the method used in this research, we performed the computational analysis using the commercial Package, ICEPAK. We could get optimized thermal design suitable for 25% upgraded normal current-ratings through parametric study.

• Progress in Superconductivity
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• v.12 no.1
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• pp.23-26
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• 2010

A double line commutation (DLC) type SFCL with first peak limiting function has been proposed for ideal fault current limiting operation. Very fast switching (commutation) without any arc or high voltage problems for any kind of switching device is needed for the first peak current limiting. We've tried to find suitable conditions for a successful switching of a Vacuum Interrupter (VI) with HTS elements as a Peak Current limiting Resistance (PCR).

• Proceedings of the KIEE Conference
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• 1994.07a
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• pp.100-102
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• 1994

VCB, with its big arc extinction in very short switching time, produces the high switching surge voltage which may cause the breakdown of motor insulation or acceleration of insulation deterionation. To protect motor winding insulation, we developed the computer algorithm for simulating the surge occurred in VCB by EMTP. And we established the effect of the C-R surge absorber by the surge measurement in the motor-VCB circuit.

• Proceedings of the KIEE Conference
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• 1994.07a
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• pp.15-17
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• 1994

As VCB has many advantages which is an excellent interruption capability, compact structure, easy maintenance and light weight, it has been widely used as a load breaker. But steep-fronted surge voltage due to high frequency extinguishing capability in switching has been occurred. If it impinges into induction motor, it acts on the electrical stress, and causes to deteriorate winding insulation. In this research, in order to protect motor insulation from the steep-fronted reignition surge, the occurring condition, the cause of the reignition surge and the influence of circuit parameters which have been an effect on the occurrence of reignition and multiple reignition surge has been also analyzed.