• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1998년도 추계학술대회 논문집
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• pp.113-116
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• 1998

This study should investigate to what extent the electric field of a vacuum interrupter might be influenced by the electric potential of floating arc shield. The electric potentials of floating shield and electric fields of a vacuum interrupter are analysed by a finite element method against variation of gap distances from 1mm to 12mm. The electric potentials of floating shield was increased with the gap distance, which is because the relative position of shield is closer to fixed contact so that the capacitance distribution inside interrupter is varied. The calculated results show that the maximum value of electric field of a vacuum interrupter with floating shield is nearly same to that without shield at shorter gap distance(below 5mm), however at larger gaps a significant increment of electric field is achieved in interrupter with shield companying with model without shield, which is due to the influence of charged floating shield.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 추계학술대회 논문집 학회본부 C
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• pp.913-915
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• 1998

This paper describes the application of two and three dimensional electric field analysis for vacuum interrupter with spiral contacts. The electric potentials of floating arc shield and electric fields in a vacuum interrupter are analysed at various gap distances from 1mm to 12mm. The electric potentials of floating shield is increased with the gap distance, which is because the relative position of shield is closer to the fixed contact so that the capacitance distribution inside interrupter is varied. The calculated results show that the maximum value of electric field in a vacuum interrupter with floating shield is nearly same to that without shield at short gap distance below 5mm, however at longer gaps more intensive electric field is achieved in interrupter with shield comparing with the model without shield, which is due to the influence of charged floating shield.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
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• pp.369-370
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• 2008

This paper describes the electric field distribution of high voltage polymer bushing with inner field shaper designs. The field control can be achieved by means of the designs of such internal field shaper. But high electric stress occurred between field shaper and central conductor by the closely space. In accordance, the floating and ring shield designs was importance for electric stress grading at critical parts of the bushing. The bushing has a central conductor, and internal ring shield or floating shield, gaps are formed between field shaper and ring shield. Accordance equipotential lines extend through gaps. Maxwell 2D simulator based on the boundary element method was also introduced in order to verify the reliability of the polymer bushing.

• 한국전기전자재료학회논문지
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• 제22권5호
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• pp.436-442
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• 2009

This paper describes a study on the design of compact polymer bushing with inner control shield. In the bushing, a high electric stress occurred between field shaper and central conductor by the closely space. Also coaxial cylindrical shield has a great height along the axis to control an electric field. Consequently, all the potentials are raised axially along the field shaper and electric stress is concentrated on a part of the surface of the FRP tube near the upper end of the field shaper. In accordance, the field control can be achieved by means of the designs of such inner control shields. The floating and ring shield designs was decreased electric field concentration at critical parts of the bushing. The shield gaps is formed between field shaper and ring shield. Accordance equipotential lines extend through gaps. As a result, the resulting electrical stress are thus reduced in the range $17{\sim}23%$ in the bushing with floating and ring shield designs. Maxwell 2D simulator based on the boundary element method was also introduced in order to verify the reliability of the polymer bushing. The optimized design uses internal elements for electric stress grading at critical parts of the bushing.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제48권10호
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• pp.693-698
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• 1999

Vacuum interrupters have a special asymmetric electrode structure to generate an magnetic field and consequently to increase the interrupting ability. Accordingly 2-dimensional analysis has a large analysis error because radial flux can not be considered. In this paper, in order to analyse the electric field distribution of a vacuum interrupter with arc shield more accurately, 3-dimensional finite element method(FEM) is used. The induced electric potentials of floating shield was increased with the gap distance, which is because the relative position of shield is closer to the fixed contact so that the capacitance distribution inside interrupter is varied. The calculated results also show that the induced potential of shield causes electric field distortion so that the maximum value of electric field in a vacuum interrupter with arc shield is higher than that without one.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2010년도 하계학술대회 논문집
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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.

• 한국해양공학회지
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• 제34권2호
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• pp.77-88
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• 2020

In this study, heading characteristics and heading control performances were evaluated to achieve the wave shield effect. The wave shield effect originating from heading control reduces the relative motions of moored vessels in a floating liquefied natural gas bunkering terminal (FLBT). Therefore, loading and off-loading performances are improved through reduced relative motion. For the objective of this study and efficiency of the analysis, a simplified model was used that assuming no relative motion of the moored vessels in the FLBT. The simplified model involved modeling the environmental loads and inertia of several floating bodies, including FLBT, into the environmental loads and inertia of a single vessel. The simplified model was validated through comparisons with model tests. With the simplified model, heading characteristics and heading control simulations were performed using low-frequency planar motion equations. The heading characteristics and heading control performances of FLBT were analyzed through the results of simulations under the expected environmental conditions. The capacity of the tunnel thrust for the heading control performance was confirmed to be adequate for improvement of the loading and off-loading performances using the wave shielding effects under the operation conditions.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 추계학술대회 논문집
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• pp.234-234
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• 2009

This paper illustrates the use of electric field computation to optimize the design of high voltage composite bushing. In the bushing, a high electric stress occurred between field shaper and central conductor by the closely space. Also coaxial cylindrical shield has a great height along the axis to control an electric field. Consequently, all the potentials are raised axially along the field shaper and electric stress is concentrated on a part of the surface of the FRP tube near the upper end of the field shaper. Maxwell 2D simulator based on the boundary element method was also introduced in order to verify the reliability of the polymer bushing. The optimized design uses internal elements for electric stress grading at critical parts of the bushing.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2010년도 춘계학술대회 논문집
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• pp.35-35
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• 2010

This paper illustrates the use of electric field computation to optimize the design of high voltage composite bushing. In the bushing, a high electric stress occurred between field shaper and central conductor by the closely space. Also coaxial cylindrical shield has a great height along the axis to control an electric field. Consequently, all the potentials are raised axially along the field shaper and electric stress is concentrated on a part of the surface of the FRP tube near the upper end of the field shaper. Maxwell 2D simulator based on the boundary element method was also introduced in order to verify the reliability of the polymer bushing. The optimized design uses internal elements for electric stress grading at critical parts of the bushing.

• 한국습지학회지
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• 제10권3호
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• pp.79-86
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• 2008

전형적인 농촌유역을 가지는 충남 아산시 마산저수지는 상류 유역으로부터 다량의 점, 비점오염물질이 유입되어 과영양 상태를 나타내는 농업용 저수지이다. 주요 유입하천인 황산천과 초사천의 수질('05년~'06년)은 TN과 TP 등 영양염류와 유기물의 농도가 매우 높은 수준을 유지하고 있으며, 이로 인해 마산저수지의 수질은 COD가 농업용수 기준을 초과하는 상태를 보여주고 있다. 이러한 저수지의 수질개선을 위해 저수지 유입부에 설치 및 관리가 용이한 조립식의 오염물질 침강장치를 개발하여 그 효과를 평가하고자 하였다. 그 결과 침강시설의 평균 정화효율은 부유물질(SS) 55.7%, 총질소(TN) 61.0%, 총인(TP) 55.9%로 장정렬등(2004)이 제시한 부댐형 침강지의 정화효율에 비해 안정적으로 높은 효율을 보였을 뿐 만 아니라 저비용으로 높은 수질개선 효과를 거둘 수 있는 경제적인 시설로서 저수지 수질개선에 효과적인 것으로 사료된다.