• Korean Membrane Journal
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• v.4 no.1
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• pp.7-11
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• 2002

A radial pleat module using a polysulfone membrane was developed. The permeation characteristics of the radial pleat module were compared with those of a flat plate module. The average module efficiency of the radial pleat module for the applied pressure range was 82% and was always greater than that of the spiral wound module. For the radial pleat module, in general, as the applied pressure increases, the flux increases and the rejection reduces. The concentration polarization causes the decrease of the flux for the long time operation. But it has been found that the radial pleat module is more efficient for the reduction of the concentration polarization because it has the more effective area per unit volume and can induce the turbulent flow in the module.

• Journal of KSNVE
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• v.4 no.2
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• pp.239-248
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• 1994

Wind tunnel tests and analyses of the response of the concrete pylon for the Seo Han Grand Bridge were conducted using aeroelastic model technique. A 1/250 scale aeroelastic model was used to measure the responses of the pylon at the several critical locations and to find any possible vibrational behavior. In order to confirm the model design and fabrication, natural frequencies and mode shapes measured from the model were compared with those from the calculation. Tests were conducted under the various angles ranging from $0^{\circ}$ to $90^{\circ}$ to find the critical angle of the wind. In order to evaluate the sensitivity of the response to changes in structural damping, a series of tests were conducted with two different values of structural damping such as 0.2% and 1.0% of critical. Additional tests were also conducted considering construction sequence.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2005.11a
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• pp.399-403
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• 2005

In this paper, we analyze on the effect of RC filter to mitigate transient overvoltage on the high voltage induction motor fed by H-bridge cascaded 7-level inverter. The switching surge voltage becomes the major cause to occur the insulation failure by serious voltage stress in the stator winding of high voltage induction motor. The effect of switching surge appears more serious in high voltage induction motor than low voltage induction motor. Consequently, we demonstrated that the RC filter connected to the motor terminals greatly reduces the transient voltage stress md ringing. The results of simulation show the suppression of transient overvoltage at the motor end of a long cable. using EMTP

• Proceedings of the KIPE Conference
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• 2014.07a
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• pp.455-456
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• 2014

본 논문에서는 인버터 스위치의 PWM 펄스 전압에 의해 발생하는 발전기 단자의 과전압 현상을 해석하기 위해, 전력 케이블과 발전기의 고주파 모델링을 제시하고, 이에 의한 과전압 현상을 해석한다. 또한, 이 과전압 현상을 억제하기 위한 적절한 형태의 인버터 출력단 dv/dt 필터를 설계하고, 선정된 dv/dt 필터 토폴로지의 필터 파라미터의 범위를 제시한다.

• Proceedings of the KIEE Conference
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• 1993.07b
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• pp.1078-1080
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• 1993

The quench performance and ramp rate sensitivity of eighteen 5-cm-aperature, 15-m-long SSC dipole magnet prototypes are discussed. All the magnets appear to reach a quench plateau near their extrapolated short sample current limit and well in excess of the operating current with very little training. Most of the magnets, however, exibit a dramatic degradation of thier quench current as a function of ramp rate, which for the most part, can be attributed to large cable eddy currents.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.663-664
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• 2007

지중송전선로 건설공사에 154kV 장조장 케이블 드럼개발 및 트레일러 일체형 Under Roller 방식을 이용한 포설장비를 개발하여 현장에 적용함으로써 신기술 신개발 공법 적용으로 인한 국제경쟁력 향상 뿐만 아니라 접속경간의 장조장 설계로 케이블 접속개소 감소로 인한 공사비절감과 공사기간 단축에 크게 기여하였다. 이와 동시에 공사를 위한 도로점용 단축으로 민원발생을 크게 감소시켰다. 현행 도로법 규제로 케이블의 운반중량이 제한되었던 케이블 표준 경간을 450m에서 최대 700m까지 가능하여 접속개소의 유연성이 확보되었을 뿐만 아니라 토목구조물(전력구,관로등)공사의 다양한 설계방법을 적용할 수 있게 되었다.

• Proceedings of the KIEE Conference
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• 2004.11b
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• pp.275-277
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• 2004

Although Jeju island Is connected with main network system by HVDC cable line, it's network assumes the form of independent system in an operating point of view. Therefore Jeju needs it's own independent capacity expansion planning. Continuos growth of demand and increase of antiquated plants in Jeju requires additional generating capacity. This paper analyzes characteristics of two alternatives which include it's own expansion of facilities and capacity expansion of network system for Jeju island. Furthermore this paper evaluates economic efficiency of those alternatives and analyzes long-term program of demand-supply of electricity.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.775-778
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• 2000

In this paper, the life-time of macro interface between Epoxy/EPDM which consists in underground power cable joints is predicted. The electrode system of specimen is designed by FEM(finite elements method). The breakdown strength of specimens are observed by applying high AC voltage at the room temperature. The breakdown times under the constant voltage below the breakdown voltage were gained. As constant voltage is applied, the breakdown time is proportion to the breakdown strength. The life exponent n is gained by inverse power law, and the long breakdown life time can be evaluated.

• International Journal of Railway
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• v.3 no.1
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• pp.1-6
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• 2010

The steel plate-girder bridges with concrete gravity piers have possibilities of overturning by lateral inertial force which can be reproduced by sudden earthquake attack. This paper explores an overturning mechanism of existing concrete gravity pier onto the sandy soil in the event of lateral push-over load by in-situ experimental observation. The in-situ push-over experiment for pier with earth anchors between spread footing and rock beds exhibits a reasonable enhancement of ductility against overturning. In unanchored system, a flexural crack at cold joint of concrete pier is not developed because of the over-turning of the pier. This leads a global instability (rotation) of pier-footing system with relatively low stresses in pier itself. While a lateral load is persistently increased in anchored system, the successive flexural cracking failure at cold joint is observed even after the local shear failure of soil due to redistribution of stress equilibrium between soil and pier structure as long as a tensile action of anchor cable is active.

• KEPCO Journal on Electric Power and Energy
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• v.7 no.2
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• pp.227-231
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• 2021

해저케이블 설치시 고비용, 민원발생, 환경오염 논란 등의 이슈가 많은 개착식 공법을 대신하여 현장에서 점차 친환경적 공법으로 자리 잡고 있는 비개착식 공법을 이용한 전력설비 건설이 활발하게 논의되고 있다. 본 논문에서는 이런 새로운 시도를 위해 필수적인 장거리 케이블 포설에 대한 새로운 방법을 현장실증을 통한 Data 확보 및 장비개발로 새롭게 제시하였다. 케이블 포설시 밀어주는 장비인 Pusher, 기존의 윈치와 Pusher 의 속도를 동기화시키는 장치 및 케이블을 꼬임없이 당기기 위한 다도체용회전형풀링아이 등을 개발하여 기존에 설치하였던 해저용특수케이블이 아닌 현재 일반적으로 사용중인 케이블의 포설가능 거리를 증가시켜 도서지역 전력공급 등을 위한 장거리케이블 포설에 비개착식 방식이 적용 가능 토록 새로운 케이블 포설공법을 개발하였다.