• 대한전기학회:학술대회논문집
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.392-393
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• 2011

본 논문에서는 제주 한림 풍력발전소와 한림 변전소간에 구축할 예정인 ${\pm}80kV$ 60MW HVDC 시스템의 절연 설계를 위해, 각 구성품의 절연 등급을 수 계산으로 설계하였다. 계산된 절연등급을 기반으로 한림 변전소와 한림 풍력 단지에 설치되는 HVDC 기기들의 최소 절연거리를 IEC 규격에 맞게 설계하였다. AC/DC 기기의 특정 전압 등급에 견딜 수 있는 최소 거리는 실제 시스템 설치 시 반영함으로써 검증하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 Techno-Fair 및 추계학술대회 논문집 전기물성,응용부문
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• pp.99-100
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• 2008

Composite insulators are rapidly replacing their porcelain counterparts in electrical substation applications. The composite insulator provide technical and safety ad vantages over other types of insulator. These insulators consist of a FRP(Fiber-reinforced polymer), with two metal flanges and silicone rubber. In this paper, we have investigated the influence of electric field different shaped silicone shed under $SF_6$ gas. As a result, shape of silicone rubber does not effected a electric field. However, the shape of shed can be decided the creepage distance.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2010년도 춘계학술대회 논문집
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• pp.1006-1010
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• 2010

This paper discusses the numerical study on the stability of the high-speed EMU by developing its lumped parameter model including the effect of the creepage. The 6, 10 and 14 degrees-of-freedom (DOF) lumper parameter dynamic models are developed and the critical hunting speeds calculated from each model via Matlab software are analyzed and compared. It is demonstrated that the critical hunting speeds decrease while the degrees-of-freedom increase. In addition, the parametric study is conducted to extract major design parameters to influence on the stability of the high-speed EMU.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2010년도 춘계학술대회 논문집
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• pp.963-969
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• 2010

The railway vehicle consists of wires, bodies, bogies and wheelsets, and each part has very complex mechanism. In this paper, wheel-rail contact algorithm is implemented using C++ and inserted into the ODYN which is a dynamic analysis program. To analyze wheel-rail contact mechanism, information such as contact points, contact angle and rolling radius is calculated according to the wheel and rail profile. Using this information, a table for the calculation of the wheel-rail contact analysis is made according to the lateral displacement. And, the creepage and normal force are calculated and a creep force is estimated by the FASTSIM. To verify the reliability of the wheel-rail contact algorithm, results of the program are compared with the ADAMS/Rail and paper. Finally, a wheelset of the railway vehicle is modeled using ODYN and simulated static and dynamic analysis. And, to verify the reliability of the simulation results, a displacement, velocity, acceleration and force are compared with results of ADAMS/Rail.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 추계학술대회 논문집
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• pp.927-939
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• 2007

This paper concerns dynamics of a wheel-axle set on a tangent track which was already published in a book titled "Dynamics of Railway Vehicle Systems" authored by Garg and Dukkipati [1], pointing out several missing terms and erroneous parts in the derived expressions on the conventional governing equations of motion. It is indicated that the x-direction components of normal forces at left and right wheel-rail contact points in the equilibrium axis were missed. Another point is that in deriving the creepages the disturbed velocity components in both x and y directions in the equilibrium axis should not be disregarded in the first term of the numerators. When considering the creepage in the y direction in the body coordinate system, the second term of lateral velocity at the contact point also cannot be neglected. Besides, the hyper-assumptions in the final expressions of vertical components of normal forces at left and right wheel-rail contact points have been recovered in reaching the final stage of analytical model development. Finally it is noteworthy that the process of applying creep theory is deemed to contain a little bit inconsistencies and ambiguities to be clear.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2015년도 제46회 하계학술대회
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• pp.1141-1142
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• 2015

실리콘 고무는 옥외용 폴리머 애자 또는 부싱 등에 주로 사용되고 있으며, 이에 대한 연구가 많이 진행되어 지고 있다. 최근에는 나노 기술이 발달함에 따라 전기 재료에 나노 사이즈의 필러를 첨가하여 재료의 특정 특성들을 향상시키는 연구들이 진행되어 지고 있다. 본 논문에서는 전기적인 성능을 향상시키고자 나노 사이즈의 $Al_2O_3$를 첨가한 상온 경화형 실리콘 고무에 대한 연구를 진행하였으며, DC 전계와 오염 상황 하에서 연면 파괴 강도를 측정하였으며, 접촉각과 표면 저향률을 측정하였다. 실험 결과, 필러 함량이 증가할수록 연면 절연 파괴 강도와 표면 저항률은 증가하였으며 접촉각은 감소하였다. 또한, 일정 함량 이상에서는 연면 절연 파괴 강도와 표면 저항율이 감소하는 것으로 나타났다.

• 산업기술연구
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• 제20권B호
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• pp.95-103
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• 2000

A model trains must have similitude with its original model not only in shape but also in motion. Motion characteristics of a model train under considerations are maximum velocity in straight and circular tracks and stopping distance. Equations of motions are derived to obtain maximum speed and stopping distance based on the Newton's Second Law and the energy principal. To accurately predict traction and resistance force between wheel and rail. wheel slip, or creepage, is taken into consideration. To verify the equations of motion, various experiments have been carried out including measurement of gear efficiency, location of mass center, rolling resistance force, traction force, slip, maximum velocity and stopping distance. This paper addresses how the experiments are setup and carried out in detail. Also the results of experiments are compared with the analytical prediction, which showed good agreements with each other.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 추계학술대회논문집
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• pp.174-177
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• 2007

In this paper the noise characteristics of metro train is investigated experimentally. It is primarily aimed at observing the squealing noise radiation of each wheel when the vehicle pass the curve sections. This will be used to understand the noise excitation mechanism at the contact area between squealing wheels and rails which induce squeal noise at curve sections. To identify the related key parameters and boundary conditions on-board monitorings of the noise, vibration of the wheel and bogie and displacement behaviour of the wheels and rails have been done. In this paper only noise measurement and results are discussed. From spectrogramms squeal noise due to creepage and noise due to flange contact of the wheels could be identified. At the moment of the curve passing the highest squeal levels are found on the front inner wheel. However since curve noise depends on variable factors more analyses will be followed to identify the squealing wheels and the noise excitation.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2015년도 제46회 하계학술대회
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• pp.1169-1170
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• 2015

공기를 주 절연매질로 사용하는 전력기기의 소형화 추세속에서 제품의 절연성능을 확보하기 위해 '절연배리어'인 고체절연물이 사용된다. 고체절연물의 연면 절연성능은 운전 환경에서 발생된 수분 및 오염원 등에 영향을 받기 쉽기 때문에, 다양한 오염도 조건에서 고체절연물의 연면 절연파괴특성 분석이 필요하다. 본 논문에서는 전력기기에 폭넓게 적용되는 있는 고체절연물에 대하여 평등전계가 모의된 평판 - 평판 전극 실험 조건에서 연면거리 및 오염도를 정량화한 전기전도도에 따른 AC 연면 절연파괴특성을 분석하였다. 그 결과, AC 연면 절연파괴전계는 고체절연물 재질에 관계없이 단(短) 갭에서 연면거리에 대한 의존성을 거의 보이지 않았다. 또한, PC 연면 절연파괴전계는 BMC 및 에폭시 대비 높았으며, 이것은 재질에 따른 연면 절연파괴 형태 및 표면의 소수성 차이와 관련이 있는 것으로 사료된다.

• Corrosion Science and Technology
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• 제5권1호
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• pp.27-32
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• 2006

One of the critical issues in the coating specification is the allowable limit of surface contaminant(s) - such as soluble salt(s), grit dust, and rust - after grit blasting. Yet, there is no universally accepted data supporting the relationship between the long-term coating performance and the amount of various surface contaminants allowed after grit blasting. In this study, it was attempted to prepare epoxy coatings applied on grit-blasted steel substrate dosed with controlled amount of surface contaminants - such as soluble salt(s), grit dust, and rust. Then, coating samples were subjected to 4,200 hours of cyclic test(NORSOK M-501), which were then evaluated in terms of resistance to rust creepage, blistering, chalking, rusting, cracking and adhesion strength. Additional investigations on the possible damage at the paint/steel interface were carried out using an Electrochemical Impedance Spectroscopy(EIS) and observations of under-film-corrosion. Test results suggested that the current industrial specifications were well matched with the allowable degree of rust, whereas the allowable amount of soluble salt and grit dust after grit blasting showed a certain deviation from the specifications currently employed for fabrication of marine vessels and offshore facilities.