• 대한전기학회논문지:전력기술부문A
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• 제48권7호
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• pp.832-838
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• 1999

Recently, there are growing concerns about power frequency electric and magnetic fields coming out from the high voltage transmission lines, because of the wide spread perception of their probable harmful effect on human body. In connection with this trend, this paper describes the electric and magnetic fields measurement result around 154 kV and 345 kV transmission lines, a comparison of measured EMF to calculated one and the correlations between transmission lines currents and measured magnetic fields. Daily maximum and minimum magnetic field quantities under the selected 154 kV and 345 kV transmission lines had been measured for 1 year of 1997 and the average value of magnetic field exposure under the lines were calculated and presented based on the measured data.

• 대한전기학회논문지:전력기술부문A
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• 제55권5호
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• pp.195-201
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• 2006

Tower footing resistance and fault current division factor are important design factors for evaluation of the lightning performance of the transmission line and/or design of the grounding electrode system. The periodic measurement of those factors are also important to verify that the grounding performance of the towers has been maintained good. However, the direct measurement of those factors in operating or energized condition is very difficult because of many practical reasons, such as the difficulty of disconnecting overhead groundwires from the tower under test. With supports by GECOL (General Electricitiy Company of Libya), we had a special chance to conduct Fall-Of-Potential (FOP) test on the energized 220 kV transmission towers before and after disconnecting the overhead groundwires from the towers under test. In this paper, the FOP test results on the towers and the fault current division factors estimated from the comparision of the FOP tests with and without overhead groundwires were presented. The computer models for the FOP test simulations were also constructed to find that the simulated results agreed very well with the measured ones.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 A
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• pp.542-544
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• 2005

Recently, the principal processes of T/L design tend to computerize and therefore integrated T/L design system has been developed. Since, it makes the automatic selection of T/L route, tower position and optimum design possible, computerized design method is applied all over the world. KEPCO introduced Optimal PowerLINE for T/L design in Myanmar 500kV project that is as a part of overseas project. And as a result of that work, effective and economical design was carried out. This paper presents the comparative analysis between Previous method and Optimal PowerLINE method for investigating practical application to Myanmar 500kV T/L design.

• 조명전기설비학회논문지
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• 제21권5호
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• pp.112-119
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• 2007

가공송전 도체는 정상 동작조건 하에서 전력회사의 선로 설계지침에 규정된 지상고를 안정범위 내에서 항상 유지할 수 있어야 한다. 따라서 새로운 선로를 건설하거나 노화도체의 장력을 다시 조정하거나 또는 전력용량을 최대화하기 위해 동적송전용량을 모니터링하는 경우에, 도체 이도를 측정/또는 모니터링하는 것은 매우 중요하다. 본 연구에서는 도체의 카테너리 각도로 이도 및 장력을 추정하기 위한 새로운 방법을 제안한다. 가공송전선로의 대부분의 도체들은 전형적인 카테너리 곡선을 나타내므로 철탑 측의 카테너리 각도로부터 도체의 카테너리 곡선을 유일하게 결정할 수 있다. 이 카테너리 곡선을 토대로 도체의 이도나 수평장력을 쉽게 추정할 수 있다. 몇 가지 시뮬레이션과 간단한 실험 결과를 통하여 제안된 방법이 가공송전선의 도체 이도와 장력을 측정/또는 모니터링하는데 효과적으로 사용될 수 있음을 확인하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.466-467
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• 2008

In case of a line-to-ground fault at transmission lines, a portion of fault current will flow into the earth through the footings of the faulted tower causing electrical potential rise nearby the faulted tower footings. In this situation, any buried pipelines or structures nearby the faulted tower can be exposed to the electrical stress by earth potential rise. Although many research works has been conducted on this phenomena, there has been no clear answer of the required separation distance between tower footings and neary buried pipeline because of its dependancy on the soil electrical charactersics of the concerned area and the faulted system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.280_281
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• 2009

The past 3 years study on the lightning faults data shows that the main reason is shielding failure rather than back flashover. Accordingly, we need to thoroughly consider about shielding failure angle of tower. Also, transmission line damage caused by shielding can be minimized if we avoid the steep slope area as a transmission line route.

• Structural Engineering and Mechanics
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• 제31권3호
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• pp.241-264
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• 2009

In this paper, the dynamic behavior for a group of transmission towers linked together through electrical wires and subjected to a strong ground motion will be investigated in detail. In performing the seismic analysis, the wires and the towers concerned are modeled, respectively, by using the efficient cable elements and the 3-D beam elements both considering geometric nonlinearities. In addition, to enhance the reliability and applicability of analytical outcome, a sophisticated soil-structure interaction model will be utilized in analyses. The strength capacities and the fracture occurrences for the main members of the tower are examined with the employment of the appropriate strength interaction equations. It is expected that by aid of this investigation, those who are engaged in code constitution or in practical designing of transmission towers may gain a better insight into the roles played by the interaction force between towers and wires and by the configurations of transmission lines under strong earthquake.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 A
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• pp.452-454
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• 2001

This paper described the calculation results of lightning flashover rate on the 345kV and 154kV transmission system of KEPCO. The back-flashover rate and shielding failure rate was calculated by FLASH(lightning flashover rate calculation program from IEEE) and KEPRI's own program which is based on the EGM(Electro Geometrical Model) method. The estimated lightning flashover late of 345kV transmission system of double circuit was 1.0 flash per 100km-year, and the lightning flashover rate of 154kV transmission line was 2.0 flash Per 100km-year approximately.

• Journal of Electrical Engineering and Technology
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• 제10권3호
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• pp.1144-1153
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• 2015

The resonant mechanism of reradiation interference (RRI) over 1.7MHz from power transmission lines cannot be obtained from IEEE standards, which are based on researches of field intensity. Hence, the resonance is ignored in National Standards of protecting distance between UHV power lines and radio stations in China, which would result in an excessive redundancy of protecting distance. Therefore, based on the generalized resonance theory, we proposed the idea of applying model-based parameter estimation (MBPE) to estimate the generalized resonance frequency of electrically large scattering objects. We also deduced equation expressions of the generalized resonance frequency and its quality factor Q in a lossy open electromagnetic system, i.e. an antenna-transmission line system in this paper. Taking the frequency band studied by IEEE and the frequency band over 1.7 MHz as object, we established three models of the RRI from transmission lines, namely the simplified line model, the tower line model considering cross arms and the line-surface mixed model. With the models, we calculated the scattering field of sampling points with equal intervals using method of moments, and then inferred expressions of Padé rational function. After calculating the zero-pole points of the Padé rational function, we eventually got the estimation of the RRI’s generalized resonant frequency. Our case studies indicate that the proposed estimation method is effective for predicting the generalized resonant frequency of RRI in medium frequency (MF, 0.3~3 MHz) band over 1.7 MHz, which expands the frequency band studied by IEEE.

• Wind and Structures
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• 제27권2호
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• pp.71-88
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• 2018

At the University of Western Ontario (UWO), numerical tools represented in semi-closed form solution for the conductors and finite element modeling of the lattice tower were developed and utilized significantly to assess the behavior of transmission lines under downburst wind fields. Although these tools were validated against other finite element analyses, it is essential to validate the findings of those tools using experimental data. This paper reports the first aeroelastic test for a multi-span transmission line under simulated downburst. The test has been conducted at the three-dimensional wind testing facility, the WindEEE dome, located at the UWO. The experiment considers various downburst locations with respect to the transmission line system. Responses obtained from the experiment are analyzed in the current study to identify the critical downburst locations causing maximum internal forces in the structure (i.e., potential failure modes), which are compared with the failure modes obtained from the numerical tools. In addition, a quantitative comparison between the measured critical responses obtained from the experiment with critical responses obtained from the numerical tools is also conducted. The study shows a very good agreement between the critical configurations of the downburst obtained from the experiment compared to those predicted previously by different numerical studies. In addition, the structural responses obtained from the experiment and those obtained from the numerical tools are in a good agreement where a maximum difference of 16% is found for the mean responses and 25% for the peak responses.