• Journal of Power System Engineering
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• v.8 no.4
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• pp.24-30
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• 2004

In this study, a position synchronous control algorithm applied to two-axes pneumatic cylinder driving apparatus is proposed. The position synchronous control algorithm is composed of position controller and synchronous controller. The position controller is designed to minimize the effect of several nonlinear characteristics peculiar to the pneumatic cylinder driving apparatus on position control performance. The synchronous controller is designed to reduce the synchronous error. The effectiveness of the proposed controller is proved by simulation results.

• Journal of Electrical Engineering and Technology
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• v.11 no.6
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• pp.1783-1786
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• 2016

The paper investigates the insulation properties of the supercritical $CO_2$ ($SCCO_2$) fluid as an insulating medium for electrical apparatuses. The insulating material is crucial for electrical apparatuses and $SF_6$ gas has been widely used for high power electrical apparatuses. There have been many research efforts to develop substituents for $SF_6$ gas because of high global warming potential. We obtained above 350 kV/mm insulation strength with 12.0 MPa $SCCO_2$. The positive and negative IEC standard pulses are applied between two 10 mm diameter spherical electrodes. The insulation strength of $SCCO_2$ is at least 2.5 times higher than that of $CO_2$ gas at 6.0MPa. The insulation strength of $SCCO_2$ fluid is about 10 times higher than that of $SF_6$ at 0.5MPa which is the ordinary operating pressure of electrical switchgears. Using the result, we expect that the time for switching and dielectric recovery could be reduced using $SCCO_2$ fluid as an insulating medium.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.28 no.10
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• pp.625-629
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• 2015

The second-generation HTS wire its YBCO coated conductor is widely used in the superconducting power apparatus. The YBCO coated conductor uses the normal-superconducting junction to increase the transport capacity of superconducting power apparatus when it is applied. The normal-superconducting junction can be a cause of reducing the stability of the superconducting power apparatus when a fault current is applied. Thus, in this study we have conducted the effect analysing normal-superconducting junction for the fault current using transport current and quench resistance. From the experimental results when a fault current is applied, the effect on the normal-superconducting junction is reduced the larger the amplitude of the fault current and is helpful to maintain the thermal stability of the HTS wire.

• Proceedings of the KIEE Conference
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• 1991.07a
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• pp.131-134
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• 1991

In order to determine an operating pattern of SLIM in an experimental MAGLEV vehicle, operating characteristics of SLIM are obtained using a disk type test facility. The test results are compared with the pre-estimated values. It is found that a closed loop control is required for operating at a constant slip-frequency condition which makes the normal force minimum.

• Proceedings of the KIEE Conference
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• 2003.07b
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• pp.825-827
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• 2003

There are many problems when air core reactor is used. Especially, measure instruments are influenced from magnetic field. This paper shows the research results for the magnetic field shielding on air core reactor.

• Proceedings of the KIEE Conference
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• 1991.07a
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• pp.106-109
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• 1991

A magnet is designed and analysed using a finite element method program (FLUX2D), which will be employed to the 2-module MAGLEV test vehicle for developing of DAE JEON EXPO '93 Magnetic Levitation System. Levitation force. guidance force and thermal characteristics are examined according to the variation of parameters of the magnet ie. pole width, window area, rail configuration, input current and so on. An optimal geometry of the magnet are provided.

• Proceedings of the KIEE Conference
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• 2003.04a
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• pp.59-61
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• 2003

The natural element method is a kind of meshless Galerkin method. The shape function is derived from the natural neighbor coordinates interpolation scheme. Natural neighbor shape functions are $C^0$ everywhere, except the nodes where they are $C^0$. The numerical integration is carried out using the Delaunay triangles as the background cells. The method is applied to the test problems and simulation results show that the natural element method can give accurate solutions for the electromagnetic field problems.

• Proceedings of the KIEE Conference
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• 2005.07b
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• pp.1044-1046
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• 2005

[$SF_6$] 가스차단기를 개발하기 위해서는 차단기가 동작하는 동안에 차단기 내부에서의 유동 파라메터(압력, 밀도, 온도, 속도 등)의 값을 정확하게 분석하는 것이 매우 중요하며, 특히, 아크가 존재할 경우 열가스 이동속도에 대한 분석은 필수적이다. 본 연구에서는 small-gap 측정시스템을 이용하여 시험용차단기가 동작할 때 차단부에서 발생하는 열가스의 이동속도를 측정하기 위한 연구내용을 정리하였다.

• Proceedings of the KIEE Conference
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• 1996.07c
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• pp.1769-1773
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• 1996

The remaining life of generator stator winding has been the controversial issue amomg many experts in this area. The report from Japan claims that they can predict the remaining life of generator winding, while the North American has the negative opinion about it. This study aimed at verifying the validity of both Japanese criteria and North American argument on evaluation of generator winding insulation. Non destructive and destructive tests were performed on two hydro-generators. The test results showed that the trend analysis of stator winding insulation was the better option.

• Proceedings of the KIPE Conference
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• 2005.07a
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• pp.682-686
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• 2005

Recently the study is being addressed on the energy economy as greatly as possible. The researches on light source that have higher efficiency than the exiting are performing. The high-power LED is the representative one among those. There are two fields in the research on the high-power LED, the ordinary illuminating apparatus and the night illuminating apparatus using wind and solar energy. In this paper, we validated the probability of using high-power LED as illuminating apparatus and proposed the novel LED power equipment that has more stability and better efficiency than the exiting method. By using the propose method the -R-E-A-C-T is reduced and the efficiency improved.