• Journal of Drive and Control
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• v.12 no.4
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• pp.21-27
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• 2015

The accurate position control of pneumatic driving apparatus is considered in this paper. In pneumatically actuated positioning systems, accurate positioning as an electrical servo has been known to be difficult because of the friction force and compressibility of the air. For good control performance of the pneumatic system, an actuator mounted with externally pressurized air bearings is produced to compensate for friction force. For the controller design, the governing equation of the pneumatic driving apparatus is derived. In order to reduce the nonlinear characteristics of the control valve, linearized control input is derived from the relation between the effective area of the valve and the control input. The experimental results are presented to show the results of the improved position control of the pneumatic driving apparatus.

• Proceedings of the KIEE Conference
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• 2003.07d
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• pp.2666-2668
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• 2003

The most widely employed grounding apparatus in distribution systems is a driven rod. But this method has some difficulties to get a specified ground resistivity in cities or islands. Recently, the new ground apparatus are proposed. This paper describes the research which relates with the system to evaluate the performance of novel grounding apparatus.

• Proceedings of the KIPE Conference
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• 2002.11a
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• pp.209-212
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• 2002

In electrical machinery and apparatus, the most important problem is protect of machinery and apparatus in duo to transient phenomena and overload on operation. Particularly by advanced technology of late, there is demand for low cost of equipments and high percentage of use of equipments. Therefore, protection of machinery and apparatus in condition of overload is more valued considering that all efficiency increase is passed by operating all machinery and apparatus in condition of heavyload. In this paper, the suggested system is add overload protect system using CT in condition of overload.

• 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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• 2004.07c
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• pp.1897-1899
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• 2004

In this paper, in order to analyze the characteristics of degradation by salt water with insulation cover and OC wire(outdoor cross-linked polyethylene insulated wire) used in power receiving system, an experimental apparatus has been designed and fabricated. An insulation cover and OC wire were installed in an experimental apparatus, and degraded in each case of 2%, 5%, 10% salinity during 12 weeks. An optical microscope was used to observe a changing process of sample surface, and an electrical safety was analyzed by measuring dielectric breakdown voltages of samples. As salinity increased, so ununiformity of sample surface increased. The breakdown wasn't produced to 50kV about samples regardless of salinity, testing period.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.234-235
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• 2006

In this study, we experimented deterioration characteristics of PVC insulation wires for electrical apparatus by series arcing and analyzed the heat generation at the contacts of wires, glowing/growing process of copper oxide, waveforms of contact voltage, current, power dissipation, and so on. We found out that how glowing contacts and surface arcing can decompose PVC insulation and that subsequent series arc can lead to ignition. We expect that these results are useful for improving fire protection technology by providing a better understanding of how electrical fires can initiate.

• Proceedings of the KIEE Conference
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• 1987.11a
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• pp.7-10
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• 1987

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.05a
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• pp.187-191
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• 2002

The characteristics of Electrical breakdown liquid nitrogen($LN_2$) were studied under simulated Quenching conditions for application of HTS apparatus. The experimental results for various quench condition revealed that the breakdown voltage of $LN_2$ with bubble flow velocity and gap spacing, Also, it did a electric field and potential distribution interpreting at the liquid nitrogen when the bubble existed, The plots of equipotential lines for three cases are also shown.

• Progress in Superconductivity and Cryogenics
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• v.5 no.1
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• pp.52-55
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• 2003

For the dielectric insulation design of any high temperature superconducting (HTS) apparatus in the electrical power systems, the breakdown properties of cryogenic coolants such as $LN_2$ are an important factor of the insulating engineering. Therefore, this paper presented an experimental investigation of breakdown phenomena in $LN_2$ under AC voltage. And we studied the breakdown properties of LN2 with decreasing temperature. Also, the Weibull plots of the breakdown voltage of subcooled $LN_2$ at 65 K for the needle-plane electrode with electrode distance d= 10 mm are studied. The dependence of breakdown voltage for needle-plane and pancake coil-pancake coil electrode on temperature is illustrated. The experimental data suggested that the breakdown voltage of L$N_2$ depend strongly on the temperature of $LN_2$. The breakdown characteristics of $LN_2$ under quasi-uniform and non-uniform electrical field for temperature ranging from 77 K to 65 K were clarified.

• Journal of international Conference on Electrical Machines and Systems
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• v.1 no.2
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• pp.18-22
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• 2012

This paper presents a method and the experimental measurement system for the determination of Jiles-Atherton model parameters of the 30ZH120 electrical steel sheet. The paper utilizes Epstein Square devices to proceed with the experiment and measurement on a group of hysteresis loops of some certain transformers which use the 30ZH120 electrical steel sheet under two different lap ways. The approach relies on the simulated annealing optimization method in order to minimize the error between the measured and modeled hysteresis curves and yield the best five Jiles-Atherton model parameters. A convenient program, based on the Simulink platform, that can identify the J-A model parameters automatically from the experimental saturated hysteresis loop which is used to model the nonlinear characteristics of the electrical steel sheet, is developed. Research shows that the simulated annealing optimization method gets satisfactory results.