• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제55권5호
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• pp.245-249
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• 2006

Corona characteristics of conductors are dependent on the electric field conditions in the immediate vicinity of the conductors. In case of DC transmission line, particularly, the space charge plays an important role in the electric field distribution. Therefore, DC corona cage simulation is necessary for long-term test in the same conditions. This paper presents the results of designing and constructing hardwares such as DC power supply, measurement system and DAS to carry out the simulation. The corona cage longitudinally is divided into five equal length sections and three inner sections of those are isolated from the ground of outer cage. The measurement items are radio noise, corona current, television noise, audible noise and meteorological conditions. In the next step, various simulations about the type and configuration of two or three candidate conductors will be conducted. And then finally an environmentally-friendly conductor for HVDC overhead transmission line will be decided.

• Journal of Information Processing Systems
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• 제15권2호
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• pp.331-343
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• 2019

Dynamic thermal rating of the overhead transmission lines is affected by many uncertain factors. The ambient temperature, wind speed and wind direction are the main sources of uncertainty. Measurement uncertainty is an important parameter to evaluate the reliability of measurement results. This paper presents the uncertainty analysis based on Monte Carlo. On the basis of establishing the mathematical model and setting the probability density function of the input parameter value, the probability density function of the output value is determined by probability distribution random sampling. Through the calculation and analysis of the transient thermal balance equation and the steady- state thermal balance equation, the steady-state current carrying capacity, the transient current carrying capacity, the standard uncertainty and the probability distribution of the minimum and maximum values of the conductor under 95% confidence interval are obtained. The simulation results indicate that Monte Carlo method can decrease the computational complexity, speed up the calculation, and increase the validity and reliability of the uncertainty evaluation.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 추계학술대회 논문집 학회본부
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• pp.35-37
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• 1997

The jumper devices of overhead transmission lines are getting increased in size with the adaptation of higher voltage and bundled conductor. Incensement of jumper devices size caused to large swing angle and flashover with tower post or arm. The suspension I type string type jumper devices are used for swing restraint of suspension type. This paper is compared and analysized to its swing characteristics. The results showed that suspension I string type has a good effects.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 전기설비
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• pp.46-48
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• 2005

Wind-induced oscillations are known to cause damage to the conductors and related hardware through fatigue, clashing of the bundled conductors and bolt loosening. Wake-induced oscillations have been known since the advent of bundled conductors. they are caused by aerodynamically unstable forces acting on the leeward conductors in the wake of the windward conductors, In order to control it, spacer dampers are installed in transmission lines with bundled conductors. Spacer damper installation is very important, it can cause damage to the conductors and spaer damper itself. This paper suggests importance of spacer damper installation in bundled conductor systems.

• KEPCO Journal on Electric Power and Energy
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• 제2권3호
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• pp.383-389
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• 2016

국내 154 kV 복도체 가공송전선로를 대상으로 전자력에 의한 소도체간 접촉현상을 실증적으로 재현하고 대처 방안을 제시하였다. 도체에 흐르는 전류의 크기가 클수록, 스페이서의 간격이 클수록 소도체간에 작용하는 전자력은 크게 측정되었다. 스페이서 간격이 68 m일 경우 전류 크기가 2,000 A 일 때부터 소도체는 불안정한 상태가 되어 소도체간 간격이 변화하는 횡방향 진동이 시작되었다. 스페이서 간격이 136 m일 경우 전류 크기가 증가할수록 소도체간 간격은 좁아지다가 2,250 A 일 때 두 소도체는 완전히 접촉하였다. 스페이서 간격에 따른 전자력의 크기를 도식화하고 안전한 스페이서 간격을 제시하였다. 시험선로와 실선로 간에는 접촉현상이 발생하는 조건이 상이한 것으로 나타났으며, 이는 송전선로 가선 과정에서 도체에 가해진 여러 형태의 잔류 응력, 바람 조건 등의 차이 때문으로 판단되었다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.2094-2095
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• 2008

In order to protect conductors from oscillations or vibrations due to winds, spacer dampers or spacers are installed on bundled conductors in overhead transmission lines. Generally the spacer damper clamp can move slightly according to oscillation directions, namely conductor direction, vertical & horizontal direction This is for reducing fatigue phenomena of the clamps. Sometimes movement of the clamp to conductor direction raises a doubt for its necessity. Then this paper carried out oscillation tests to know clamp displacement due to the subspan oscillation.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1987년도 정기총회 및 창립40주년기념 학술대회 학회본부
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• pp.143-146
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• 1987

Fiber optics provide a solution to the problems at interference, capacity and reliability in communication. Approximately 20 kilometera of a six-fiber, multimode, longwave($1.3{\mu}m$), graded index silica glass fiber optic cable was helically wrapped around a phase conductor at a Korea Electric Power Corporation(KEPCO) 154KV transmission line. This paper presents an economic comparison of several fiber optic cable installation alternative and discusses the characteristics at the helically wrapped fiber cable, as well as the entire installation, including high voltage phase-to-ground (PTG) end termination, and splicing. The fiber link was installed for the field trial and practical use with overhead composite optical fiber cable which installation performed a few years earlier some other location and is intended to accommodate not only telephone but also supervisory Control and Data Acquisition(SCADA), protective relaying, and telemetry functions.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
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• pp.104-105
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• 2008

According to previous report, aged sleeves of old transmission line showed several defaulted installation patterns, which is biased or corrosive-fractured of steel sleeve installed cases. The latter case occupied almost 25 percent of investigated aged sleeves. These defects can cause serious accidents such as rapid increasing of sag or falling out of overhead conductor from sleeves. This paper studies thermal properties and tension for ACSR conductor in case of fractured steel sleeve model. The detailed results were presented in the text.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 C
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• pp.1709-1711
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• 2001

The remaining life of ACSR(Aluminum Conductor Steel Reinforced) wires exposed to the atmosphere for a long period relies on the extent of deterioration caused by environmental factors such as atmospheric corrosion, galvanic corrosion, crevice corrosion and fatigue corrosion. We investigated the tensile characteristics of ACSR wires in a coastal area through several mechanical tests, and analyzed the constituents of them using SEM(scanning electron microscope). Test samples are parts of ACSR 97[$mm^2$] overhead transmission lines in that area. The result shows that ACSR wires exposed to salt may lead to rapid mechanical deterioration.

• Wind and Structures
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• 제34권2호
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• pp.173-183
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• 2022

The galloping of iced conductors has long been a severe threat to the safety of overhead transmission lines. Compared with normal transmission lines, the ultra-high-voltage (UHV) transmission lines are more prone to galloping, and the damage caused is more severe. To control the galloping of UHV lines, it is necessary to conduct a comprehensive analysis of galloping characteristics. In this paper, a large-span 1000-kV UHV transmission line in China is taken as a practical example where an 8-bundled conductor with D-shaped icing is adopted. Galerkin method is employed for the time history calculation. For the wind attack angle range of 0°~180°, the galloping amplitudes in vertical, horizontal, and torsional directions are calculated. Furthermore, the vibration frequencies and galloping shapes are analyzed for the most severe conditions. The results show that the wind at 0°~10° attack angles can induce large torsional displacement, and this range of attack angles is also most likely to occur in reality. The galloping with largest amplitudes in all three directions occurs at the attack angle of 170° where the incoming flow is at the non-iced side, due to the strong aerodynamic instability. In addition, with wind speed increasing, galloping modes with higher frequencies appear and make the galloping shape more complex, indicating strong nonlinear behavior. Based on the galloping amplitudes of three directions, the full range of wind attack angles are divided into five galloping regions of different severity levels. The results obtained can promote the understanding of galloping and provide a reference for the anti-galloping design of UHV transmission lines.