• Wind and Structures
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• 제29권5호
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• pp.339-359
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• 2019

Pre-stressed concrete poles are among the supporting systems used to support transmission lines. It is essential to protect transmission line systems from harsh environmental attacks such as downburst wind events. Typically, these poles are designed to resist synoptic wind loading as current codes do not address high wind events in the form of downbursts. In the current study, the behavior of guyed pre-stressed concrete Transmission lines is studied under downburst loads. To the best of the authors' knowledge, this study is the first investigation to assess the behaviour of guyed pre-stressed concrete poles under downburst events. Due to the localized nature of those events, identifying the critical locations and parameters leading to peak forces on the poles is a challenging task. To overcome this challenge, an in-house built numerical model is developed incorporating the following: (1) a three-dimensional downburst wind field previously developed and validated using computational fluid dynamics simulations; (2) a computationally efficient analytical technique previously developed and validated to predict the non-linear behaviour of the conductors including the effects of the pretension force, sagging, insulator's stiffness and the non-uniform distribution of wind loads, and (3) a non-linear finite element model utilized to simulate the structural behaviour of the guyed pre-stressed concrete pole considering material nonlinearity. A parametric study is conducted by varying the downbursts locations relative to the guyed pole while considering three different span values. The results of this parametric study are utilized to identify critical downburst configurations leading to peak straining actions on the pole and the guys. This is followed by comparing the obtained critical load cases to new load cases proposed to ASCE-74 loading committee. A non-linear failure analysis is then conducted for the three considered guyed pre-stressed concrete transmission line systems to determine the downburst jet velocity at which the pole systems fail.

• 조명전기설비학회논문지
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• 제28권9호
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• pp.35-44
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• 2014

This study was to secure the safety of poor appearance distribution concrete poles effectively and to reduce the replacement costs of them by developing a soundness evaluation index. The researcher of this study investigated poor appearance types of concrete pole, collected 53 of test samples, and tested pole strength. As a result of strength test, only 17 percent of poor appearance concrete poles were below 2.0 of safety factor spec. As results of multiple regression analysis, it is verified that surface air void, horizontal crack, net-shaped crack, elapsed year, vertical crack, and deterioration in concrete compressive strength have statistically negative effects on safety factor of concrete poles in a significant level. The researcher set up a soundness evaluation index by using multiple regression equation, and suggested that poor appearance concrete poles should be replaced or reinforced only in case of soundness evaluation score of 150 or above.

• 전기학회논문지
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• 제67권6호
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• pp.702-707
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• 2018

In case of Lighting occurs in Domestic combined distribution line, normally the voltage for the neutral line increase dramatically. General connection for underground cable is bundled common earth type so the lightning over voltage increase at the concentric-neutral line is not big enough to give impact on cable sheath. But in case of Non bundled common earth type it is necessary to analyze the phenomena on cable sheath caused by lightening overvoltage. Especially pole and cable joint are the core factor to consider. In this paper concrete pole and cable joint were evaluated in case of Non bundled common earth type combined distribution Line. EMTP simulation model has been designed and several case study were made. Also several experimental test were made to verify the simulation result.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 하계학술대회 논문집
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• pp.79-81
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• 2000

Outdoor insulation of overhead distribution lines with wood, concrete and steel pole has been safety under various environmental conditions including contamination, moisture condensation, rain and lightning overvoltages. In this paper introduce to FRP technology of the power distribution single pole. FRP pole has been used very much as high strength material for insulators because of its high strength and good insulation properties. In addition, FRP pole was made by filament winding method. In a filament winding process, a band of continuous resin-impregnated rovings or monofilaments is wrapped around a rotating mandrel and cured to produce axisymmetric hollow parts.

• 조명전기설비학회논문지
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• 제23권6호
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• pp.118-124
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• 2009

본 연구에서는 콘크리트전주가 수직 및 80[$^{\circ}$] 경사 건주된 경우에 대한 강도시험을 통하여 보통지선이 없는 수평 지선의 시설 가능범위를 파악하기 위한 콘크리트전주의 강도특성시험을 수행하였다. 수직으로 건주된 전주에 대한 1주기 강도시험 결과 일반용, 중하중용, 고강도용 콘크리트전주의 안전율은 각기 2.8, 2.5, 2.1로서 모든 전주가 안전율 2.0이상은 확보하는 것으로 나타났다. 그러나 수직으로 건주된 전주 상부의 휨 정도가 2[$^{\circ}$] 이상일 때 전주에 균열이 발생하며, 이 때에 작용하는 하중은 천주의 설계하중과 유사한 값을 나타내었다. 따라서 현장에 시설된 전주가 견고한 지반에 2[$^{\circ}$]이상 휘어져 있는 전주라면 설계하중에 근접한 하중이 상시 작용하고 있는 상태이기 때문에 지선 및 지주 등을 시설하여 보강이 반드시 필요함을 알았다.

• 한국방재학회:학술대회논문집
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• 한국방재학회 2007년도 정기총회 및 학술발표대회
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• pp.433-436
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• 2007

We analyzed the sloped ground safety factor, which is not presented in the design specification, using a computational analysis program L-Pile Plus 13.8. To achieve this we chose a required parameter set and a level ground safety factor presented in the design specification, and then determined its values comparing with the change of the safety factor according to the parameter. Using these parameters, we estimated the sloped ground safety factor for the slope of 35 degrees considering the improvement value of the slope presented in the design specification. As a result of this analysis, we obtained the smaller safety factor by about 0.7 times than the case of the level ground and verified that a number of concrete poles fail to assure 1 degree of the safety factor. We, therefore, concluded that an adjustment of the embedment depth is required in the case of the sloped ground.

• 한국지반환경공학회 논문집
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• 제13권11호
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• pp.5-10
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• 2012

연약지반 내의 많은 콘크리트 전주가 외부의 힘에 의하여 파괴되어 왔다. 본 연구에서는 근가의 설치심도 및 근가의 개수를 변화시키면서 토압과 변위분석을 실시하여 근가가 콘크리트 전주의 안정성에 미치는 영향을 분석하였다. 근가의 깊이 3가지 중 1.5m 깊이에 설치하는 것이 적절한 것으로 보이며, 2.25m 깊이에 근가를 설치하면 과도한 굴착으로 인한 교란으로 변위가 크게 나타난다. 근가를 깊게 설치할수록 수동영역의 토압은 작아지고 주동토압은 커진다. 두 개의 근가를 설치하면 한 개의 근가를 설치할 때보다 전주의 상단의 변위는 43.8%, 지표에서는 55.6% 감소한다.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2005년도 학술대회 논문집
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• pp.391-394
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• 2005

This paper describes the touch voltages and potential distributions according to the distance between distribution concrete pole and ground rod when the current is injected to a ground rod through overhead ground wire. Touch voltage is measured in four directions. The touch voltage and ground potential distribution per 1 A are analyzed. The touch voltage was the highest at the around surface just above the ground rod.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 C
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• pp.2286-2288
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• 2005

This paper describes impulse grounding impedance and touch voltage when impulse current is injected to grounding systems for distribution concrete pole. Impulse grounding impedance is a significant factor in analyzing transient grounding impedance. The touch voltage is measured in four directions. The maximum touch voltage was 520V and the minimum touch voltage was 47.3V when the input current was 100A.

• 조명전기설비학회논문지
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• 제23권1호
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• pp.36-40
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• 2009

콘크리트 전주는 배전선로 지지물로서 널리 사용되고 있다. 전주의 접지저항을 규정치 이내로 유지하기 위하여 동피복 접지봉을 포함한 여러 종류의 접지전극들이 사용되어 왔다. 전주 내부에는 철근이 들어있기 때문에 지중에 매설되는 전주 하단은 어느 정도 구조체접지극으로서 작용을 하게 된다. 본 논문에서는 전주 접지선으로 시험전류를 주입하면서 주입되는 전류와 금속 접지극으로 분류되는 전류를 각각 측정하였다. 이로써 전주 구조체로 분류되는 전류의 간접측정이 가능하였다. 측정결과에 근거하여 금속 접지극의 접지저항과 전주 구조체로 분류되는 전류크기 간의 상관관계를 분석하였다.