• 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.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.10
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• pp.952-957
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• 2003

The purpose of this paper is analyses about in 12kV/50kA vacuum interrupter with an axial magnetic field type electrode system through the studies of electromagnetic phenomena. Vacuum interrupter is important in electric safety part. In this paper, we performed analysis of electric field, magnetic field, current density in AMF electrode using the Maxwell 3D simulation. The current distribution and magnetic field in simple models are analyzed to verify its efficiency and accuracy. In addition the validity of FEM is confirmed by performing the analyses of distribution in current density and magnetic flux density.

• 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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• 1998.07e
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• pp.1635-1637
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• 1998

This paper describes on the basic study for the insulation design of vacuum interrupter using Finite Element Method. For the basic study of insulation design, first, the maximum electric field was calculated on each curvature radius of arc shield and electrode. Second, the maximum electric field was also calculated on applied voltage and end shield with or not. Thus, the maximum electric field calculated have an effect on curvature radius and voltage polarity.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.15 no.5
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• pp.460-467
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• 2002

This paper deals with the distribution characteristics of the current density and axial magnetic flux density on the vacuum interrupter with axial magnetic field type using 3 dimension finite element analysis. An axial magnetic field parallel to the current flow in the arc column can improve the current breaking capacity of vacuum interrupter by affecting the arc mode. The axial magnetic flux density on the contact electrode surface is analyzed by inputting external current as a function of the transient time for sine half wave. And it also is analyzed within the gap distance of the contact electrode. The peak value of current but is decreased with the descending current on the contact electrode surface and within the gap distance of the contact electrode. The residual magnetic field is generated on the contact electrode surface and within the gap distance in the instant of zero current, which is due to the influence of eddy currents. The phase shift due to eddy currents, defined as time difference between the maximum value of current and axial magnetic field, is about 1ms in the center point of gap distance.

• Proceedings of the KSME Conference
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• 2004.11a
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• pp.447-452
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• 2004

Vacuum interrupters in order to be used in various switch-gear components such as circuit breakers, distribution switches, contactors, etc. spread the arc uniformly over the surface of the contacts. The electrodes of vacuum interrupters are made of sinter-forged Cu-Cr materials for good electrical and mechanical characteristics. Since the closing velocity is 1-2m/s and impact deformation of the electrode depends on the strain rate at that velocity, the dynamic behavior of the sinter-forged Cu-Cr is a key to investigate the impact characteristics of the electrodes. The dynamic response of the material at intermediate strain rate is obtained from the high speed tensile test machine test and at the high strain rate is obtained from the split Hopkinson pressure bar test. Experimental results from both quasi-static and dynamic compressive tests are interpolated to construct the Johnson-Cook model as the constitutive relation that should be applied to simulation of the dynamic behavior of the electrodes. The impact characteristics of a vacuum interrupter are investigated with computer simulations by changing the amount of chromium content.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.28 no.10
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• pp.630-635
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• 2015

A vacuum Interrupter (VI), a core part that composes the breaking part of medium-voltage vacuum circuit breaker (VCB), has the excellent insulation performance and arc-extinguishing capability. $SF_6$ gas had been used for the external insulation of VIs since the dielectric strength of $SF_6$ gas is superior to that of other insulation gases. However, because of environmental problems related with global warming, a solid-insulated technology was recently researched. The functionally graded material (FGM), as changing spatially the distribution of the relative permittivity inside an insulator, can reduce the electric field stress at the specific region. Especially, the external insulation performance of the VI with the molded FGM insulator is greatly improved as compared with that of the existing VI or the VI with a new external shield. In this paper, the effectiveness of this FGM insulator is verified by the numerical simulation.

• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.672-674
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• 2001

Axial magnetic field(AMF) type electrode can increase the interrupting capability of vacuum interrupters. But, this interrupting capability vary with design parameters such as shape of electrode, slits of contact, material of contact and so on. In this paper, shown arc characteristics of unipolar axial magnetic field type electrode for vacuum interrupter by design parameters such as shape of contact slits and diameter of contact. And, confirmed vacuum arc configuration by individual design parameter using high speed camera.

• Proceedings of the KIEE Conference
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• 1999.11b
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• pp.95-97
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• 1999

This paper describes electromagnetic repulsion force of multipolar axial magnetic field type electrodes for vacuum interrupter used in vacuum circuit breaker. It was distinguished that repulsion force of multipolar axial magnetic field type electrode in consideration of eddy current effect between upper electrode and lower electrode by finite element method. And it was found out that suitable contact weight of multipolar axial magnetic field type electrode for vacuum circuit breaker from repulsion force analysis results by finite element method.

• Proceedings of the KIEE Conference
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• 2007.11a
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• pp.210-211
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• 2007

Once high current flows through the vacuum interrupter, eddy current occurs due to the time-varying axial magnetic field caused by the current(AC) and it causes a decrease in axial magnetic field generated by current flowing through coil electrode. but if there are slots on contact electrode it is possible to increase the amplitude of axial magnetic field by reducing the influence of eddy current. there has been many studies about the number of slot of the contact electrode[1][2][3]. In this paper, in addition to these previous results we deal with the influence of the length and width of the slots on axial magnetic field at the mid-gap plane in 4 segment coil type vacuum interrupter by using 3D finite element method software.