• 제목/요약/키워드: ground connection

검색결과 310건 처리시간 0.029초

지중송전케이블계통에서 절연통의 과전압 해석 및 억제대책 검토 (Analysis of Overvoltage and Reduction Methods of Insulation Joint Box in Underground Power Cable Systems)

  • 홍동석;정채균;이종범;서재호;조한구
    • 대한전기학회논문지:전력기술부문A
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    • 제51권2호
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    • pp.102-108
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    • 2002
  • This paper describes the overvoltage analysis and reduction methods of insulation joint boxes in underground transmission power cables when direct lightning surge strikes to overhead transmission line. An actual 154kV combined transmission line with underground Power cables was modelled in ATPDraw for simulation. Simulations were performed to analyze the overvoltage between insulation joint boxes, sheath-to-ground voltage according to the distance between cable conductors, cable lengths, burying types, CCPU connection types. The most effective method to reduce the induced overvoltage of Insulation joint boxes was proposed. It is evaluated that the proposed reduction method riven from the detailed simulations can be effectively applied to the actual underground power cable systems.

Effects of near-fault loading and lateral bracing on the behavior of RBS moment connections

  • Yu, Qi-Song Kent;Uang, Chia-Ming
    • Steel and Composite Structures
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    • 제1권1호
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    • pp.145-158
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    • 2001
  • An experimental study was conducted to evaluate the effects of loading sequence and lateral bracing on the behavior of reduced beam section (RBS) steel moment frame connections. Four full-scale moment connections were cyclically tested-two with a standard loading history and the other two with a near-fault loading history. All specimens reached at least 0.03 radian of plastic rotation without brittle fracture of the beam flange groove welds. Two specimens tested with the nearfault loading protocol reached at least 0.05 radian of plastic rotation, and both experienced smaller buckling amplitudes at comparable drift levels. Energy dissipation capacities were insensitive to the types of loading protocol used. Adding a lateral bracing near the RBS region produced a higher plastic rotation; the strength degradation and buckling amplitude were reduced. A non-linear finite element analysis of a one-and-a-half-bay beam-column subassembly was also conducted to study the system restraint effect. The study showed that the axial restraint of the beam could significantly reduce the strength degradation and buckling amplitude at higher deformation levels.

Interface treatment in shotcrete jacketing of reinforced concrete columns to improve seismic performance

  • Vandoros, Konstantinos G.;Dritsos, Stephanos E.
    • Structural Engineering and Mechanics
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    • 제23권1호
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    • pp.43-61
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    • 2006
  • An investigation of the effectiveness of the interface treatment when column concrete jacketing is performed is presented. Alternative methods of interface connection were used in order to investigate the performance of strengthened concrete columns. These connecting techniques involved roughening the surface of the original column, embedding steel dowels into the original column and a combination of these two techniques. The experimental program included three strengthened specimens, one original specimen (unstrengthened) and one as-built specimen (monolithic). The specimens represented half height full-scale old Greek Code (1950's) designed ground floor columns of a typical concrete frame building. The jackets of the strengthened specimens were constructed with shotcrete. All specimens were subjected to displacement controlled earthquake simulation loading. The seismic performance of the strengthened specimens is compared to both the original and the monolithic specimens. The comparison was performed in terms of strength, stiffness and hysteretic response. The results demonstrate the effectiveness of the strengthening methods and indicate that the proper construction of a jacket can improve the behaviour of the specimens up to a level comparable to monolithic behaviour. It was found that different methods of interface treatment could influence the failure mechanism and the crack patterns of the specimens. It was also found that the specimen that combined roughening with dowel placement performed the best and all strengthened columns were better at dissipating energy than the monolithic specimen.

DEVELOPMENT OF CONCRETE FILLED TUBE AS A PILLAR PILE FOR TOP DOWN METHOD

  • Jee-Yun Song;Hong-Chul Rhim;Seung-Weon Kim
    • 국제학술발표논문집
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    • The 3th International Conference on Construction Engineering and Project Management
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    • pp.808-813
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    • 2009
  • Top-down method is widely used for urban area construction for its advantages in reducing environmental problems such as dust and noise, and saving construction cost depending on given conditions of a construction site. Because the excavation and construction of super- and sub-structures of the building have to be proceeded simultaneously, a column has to be embedded prior to excavation. This column is called a pillar column or pre-founded column. Usually a wide flange section is used for these columns. To place the columns, usually the diameter of casing holes needs to be larger than the section of the wide flange itself in order to accommodate a couple of tremie pipes for pouring concrete. In this paper, a newly developed method of using circular pipe as an alternative to the existing wide flange section is discussed. The crucial part of the new method is to develop a connection between the circular column and concrete flat slabs. For shear force transfer from concrete slab to the concrete filled tube (CFT) column, shear jackets with studs and shear bands are proposed. The studs are welded on the jackets at shop and placed around the circular column on site. The shear bands are welded on the outer side of the CFT at shop and inserted into ground with the CFT. Test results and application of the method to a construction site are also provided in this paper.

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골프드라이빙 스트로크시 역학적 분석 (Mechanical Analysis of golf driving stroke motion)

  • 박광동
    • 한국운동역학회지
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    • 제12권1호
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    • pp.205-219
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    • 2002
  • This research seeks to identify the plantar pressure distribution graph and change in force in connection with effective golf drive strokes and thus to help ordinary golfers have appropriate understanding on the moving of the center of weight and learn desirable drive swing movements. To this end, we conducted surveys on five excellent golfers to analyze the plantar pressure applied when performing golf drive strokes, and suggested dynamic variables quantitatively. 1) Our research presents the desire movements as follows. For the time change in connection with the whole movement, as a golfer raises the club head horizontally low above ground from the address to the top swing, he makes a semicircle using the left elbow joint and shaft and slowly turns his body, thus lengthening the time. And, as the golfer twists the right waist from the middle swing to the impact with the head taking address movement, and does a quick movement, thus shortening the time. 2) For the change in pressure distribution by phase, to strike a strong shot with his weight imposed from the middle swing to the impact, a golfer uses centrifugal force, fixes his left foot, and makes impact. This showed greater pressure distribution on the left sole than on the right sole. 3) For the force distribution graph by phase, the force in the sole from the address to halfway swing movements is distributed to the left foot with 46% and to the right foot with 54%. And, with the starting of down swing, as the weight shifts to the left foot, the force is distributed to the left sole with 58%. Thus, during the impact and follow through movements, it is desirable for a golfer to allow his left foot to take the weight with the right foot balancing the body. 4) The maximum pressure distribution and average of the maximum force in connection with the whole movement changed as the left (foot) and right (foot) supported opposing force, and the maximum pressure distribution also showed much greater on the left sole.

무용접 복합말뚝 수평거동특성 및 연결부 안정성 평가 (Lateral Behavior and Joint Stability of Non-Welding Composite Pile)

  • 고준영;신윤섭;정상섬;부교탁
    • 한국지반공학회:학술대회논문집
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    • 한국지반공학회 2009년도 춘계 학술발표회
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    • pp.108-118
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    • 2009
  • As increasing demand on marine structures and skyscrapers, a deep shaft pile is frequently to be used for the place having weak ground strength. Because heavy horizontal force is generally applied on upper part of pile foundation used in engineering field, steel pile is highly used due to its high resistance to shear force and bending moment, and its capability to carry heavy loads. The steel pile has advantage in good constructibility, high applicability on site and easy handing, but has disadvantage in cost, more expensive than other material pile. This study is to examine the composite pile that makes economical construction possible by reducing material cost of pile; using steel and PHC pile A non welding connection method is applied to this composite pile. This study had step of comparison with the result of numerical analysis after analyzing the result of field test. Numerical analysis is the process of analyzing lateral behavior of non welding composite pile. Moreover, detailed analysis was implemented in order to evaluate joint stability. As a result of the analysis, we could interpret that the stability of the connection part is ensured as seeing the smaller internal stress than approved internal stress. Based on this study, we analyzed lateral behavior of non welding composite pile, which ensured the stability of connection part.

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무용접 복합말뚝의 항타관입성 분석에 관한 연구 (Driveability Analysis of Non Welding Composite Pile)

  • 신윤섭;김남호;부교탁;이종수
    • 한국지반공학회:학술대회논문집
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    • 한국지반공학회 2008년도 추계 학술발표회
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    • pp.729-737
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    • 2008
  • As increasing demand on marine structures and skyscrapers, a deep shaft pile foundation is more to be used for the place having weak ground strength. Because heavy horizontal force is generally applied on upper part of pile foundation used in civil or architectural construction, steel pile is largely used with its high resistance to shear force and bending moment, and its capability to carry heavy loads. The steel pile has advantage in good constructibility, high applicability on site and easy handing, but has disadvantage in cost, more expensive than other material pile. This study is about the Composite pile that makes economical construction possible by reducing material cost of pile; using steel and PHC pile simultaneously while preserving the advantage of steel pile that large resistance to horizontal force and bending moment. A Non Welding connection method is applied to this composite pile and this method could reduce the cost and period of construction and could increase the quality of construction by solving the problem of current welding method and by improving the workability of pile connection. In this study, characteristics of driveability of non welding composite pile is analyzed prior to main project while the purpose of main project is proving the applicability of Non Welding Composite Pile by conducting various kind of loading test to analyze the characteristics behaviour of Non Welding Composit Pile and by verifying stability of non welding connection pile.

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쿼드콥터형 드론에 설치된 가스총 결합유닛의 개발 (Development of the Connection Unit with a Gas Gun Installed in a Quadcopter-type Drone)

  • 전준하;강기준;권현진;장세명;정재복;백재구
    • 한국항공우주학회지
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    • 제46권9호
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    • pp.774-781
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    • 2018
  • 본 연구에서는 쿼드콥터형 소형 무인 드론에 이산화탄소를 작동 기체로 하는 가스총을 설치하여 가축 방역에 응용할 수 있는 발사체 및 결합 유닛을 개발하였다. 시스템은 상용 드론과 가스총, 솔레노이드 밸브, 무선 통신 제어기 등으로 구성된다. 발사된 탄환의 속도를 측정하고, 지상 시험, 실제 비행체에의 탑재 시험 등을 거쳐 최종 검증하였다. 본 연구 개발을 통하여 농업, 소방 등의 다양한 방역 및 방재 분야에 발사체 기술을 적용할 수 있는 가능성을 확인하였다.

고추의 산화성(酸化性)에 대한 Citric Acid의 상승효과 (Synergistic Effect of Citric Acid on Antioxidant Property of Red Pepper)

  • 양기선;유주현;황적인;양융
    • 한국식품과학회지
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    • 제6권4호
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    • pp.193-198
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    • 1974
  • 고추분말(粉末), 고추피(皮)의 알코올추출물(抽出物), 알코올추출물(抽出物)과 유기산(有機酸)을 기질(基質)인 식용대두유(食用大豆油)에 첨가(添加)하여 암소저장(暗所貯藏) 조건하(條件下)$(45.0{\pm}0.5^{\circ}C$$55.0{\pm}0.5^{\circ}C)$에서 과산화물형성(過酸化物形成) 억제효과를 검토한 바, 다음과 같은 결과(結果)를 얻었다. 1) 고추, 후추, 계피분말(粉末)은 모두 어느정도의 항산화효과를 나타냈으며, 이들 간(間)의 항산화효과는 거의 비슷하였다. 2) 고추피(皮)와 고추씨분말(粉末)은 모두 항산화효과를 나타냈으며, 고추피(皮)는 고추씨 분말(粉末)보다 강(强)한 항산화효과를 나타냈다. 3) 고추피(皮)의 알코올추출물(抽出物)의 강(强)한 항산화효과를 나타냈으며, 잔사(殘渣)는 거의 항산화효과를 나타내지 못하였다. 4) 고추피(皮)의 알코올추출물(抽出物)의 항산화효과는 알코올추출물(抽出物)의 농도가 짙을수록 거의 비례(比例)해서 강(强)하게 나타났다. 5) 고추피(皮)의 알코올추출물(抽出物)과 유기산(有機酸)의 병용효과는 구연산이 매우 강(强)하게, Vitamin C (ascorbic acid)는 강(强)하게 항산화효과를 나타냈으나, 인산의 경우 오히려 촉진(促進)되었다. 6) 고추피(皮)의 알코올추출물(抽出物) 0.1%와 구연산의 농도(濃度)에 따른 병용효과는 구연산의 농도(濃度)가 0.04%일때 가장 강(强)하게 나타냈다.

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소방용수시설의 공설소화전 종류에 따른 사용 준비시간 비교분석 (Comparison Analysis of Ready to Use Time Depending on The Type of Public Fire Hydrant of Fire-fighting Water Facility)

  • 전재인;공하성
    • 문화기술의 융합
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    • 제5권4호
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    • pp.87-92
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    • 2019
  • 이 연구는 공설소화전에 대한 지상식 및 지하식 소화전의 소방용수 사용 준비시간을 분석하였다. 1단계인 장비 준비시간은 지상식은 20.50초, 지하식은 24.67로 나타났다. 이와 같이 준비시간이 다소 차이가 난 것은 지하식 소화전은 맨홀 뚜껑을 개방하는 빠루와 지하식 소화전 본체 관구에 연결하기 위하여 스탠드 파이프가 추가로 필요했기 때문이다. 2단계인 물탱크차의 보수구에 숫커플링의 수관결합은 지상식은 48.50초, 지하식은 49.00초로 비슷하게 나타났다. 이것은 물탱크차 보수구에 소방호스를 연결하는 동작이 같기 때문이다. 3단계인 본체 관구에 수관 결합은 지상식은 43초, 지하식은 174.33초로 나타났는데 이와 같이 수관을 소화전 관구에 연결하는 시간이 큰 차이가 난 것은 지하식 소화전은 맨홀 뚜껑을 개방한 후 소화전 본체 관구에 스텐드 파이프를 연결한 후에, 스텐드 파이프 관구에 수관을 결합하는 추가 과정이 필요하여 소요시간을 크게 올린 것으로 판단된다. 4단계인 제수 밸브와 스핀들 개방은 지상식은 66.50초, 지하식은 78.83초 소요되었다. 이 같은 차이가 난 것은 지상식 소화전의 스핀들은 본체 관구위에 위치하여 쉽게 개방이 가능하지만, 지하식은 맨홀 아래 관구 옆에 위치하여 개방 장비인 복스퍼너를 연결하는 추가시간이 필요하여 나타난 결과로 판단된다.