• Proceedings of the KIEE Conference
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• 2001.11b
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• pp.406-410
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• 2001

For 4-conductor bundle transmission line spacer damper are equipped so as to keep the spacing between sub conductors. For 4-conductor bundle the subspan spacing of a spacer damper is determined and applied in order that the bundle may get restored to a normal state when 4-conductor bundle is rolled by rigid body vibration due to wind. But 4 conductors of 345kV 4-conductor bundle transmission line were twisted by the angle of $315^{\circ}$ for the first time korea. In this paper, we will analyze the reason of the power line twisting of 4-conductor bundle which occurred for the first time in korea and offer the preventive countermeasures for this

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.48 no.7
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• pp.542-549
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• 1999

Corona discharges form at the surface of a transmission line conductor when the electric-field intensity on the conductor surface exceeds the breakdown strength of air. In order to decrease the electric-field intensity on the conductor surface, a new 6 conductor bundle has been studied. This bundle, hybrid conductor bundle, consists of using a larger subconductor at the bottom two conductor positions in the 6-conductor bundles of each phase of the line. The electric field on these two larger subconductors is reduced which in turn reduces the corona noise. It is shown that this is a better solution for decreasing the electric-field intensity than ether the conventional bundle or the asymmetric bundle proposed by EPRI.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.41 no.4
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• pp.339-345
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• 1992

Estimates of maximum amplitudes of conductor galloping are needed in order to determine appropriate phase-to-phase clearances on the overhead lines. One approach to obtaining these estimates is through the use of mathematical models of conductor galloping. Unfortunately, the models that consider both vertical conductor motion (Den Hartog type) and torsional conductor motion are often too complex for practical use. However, the estimates of maximum amplitude obtained from galloping models that assume only vertical (Den Hartog type) conductor motion tend to be too conservative. This paper presents the DF method to obtain the estimates of the amplitude and the frequency of galloping limit cycle, along with the wind pressure at which they occur, from a nonlinear dynamic model that considers both Den Hartog type and torsional conductor motion. From these results, the useful data for the line design guide and further insight into the mechanism of the conductor galloping are obtained.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.9
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• pp.61-69
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• 2006

The tensile strength of an overhead transmission line's conductor in response to an aging is being assessed in this paper. It is our view that, the decrement in the conductor's tensile strength is a key index that can be used to determine a conductor's end of life and a current limits. This paper describes a probabilistic method of assessing this index for main transmission lines which are responsible for the north bound power flow in the Seoul metropolitan area. Such an assessment can be a useful guide for economic system operation.

• Wind and Structures
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• v.6 no.4
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• pp.307-324
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• 2003

The paper presents results of studies concerning wind-induced aeolian vibration and fatigue of a 110 kV covered conductor overhead line. Self-damping measurement techniques are discussed: power method is found to be the most reliable technique. A method for compensating tension variations during the self-damping test is presented. Generally used empirical self-damping power models are enhanced and the different models are compared with each other. The Energy Balance Analysis (EBR) is used to calculate the aeolian vibration amplitudes, which thereafter are converted to bending stress for the calculation of conductor lifetime estimate. The results of EBA are compared with field measurements, Results indicate that adequate lifetime estimates are produced by EBA as well as field measurements. Generally the EBA gives more conservative lifetime expectancy. This is believed to result from the additional damping existing in true suspension structures not taken into account by EBA. Finally, the correctness of the line design is verified using Cigre's safe design tension approach.

• Journal of the Korea Convergence Society
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• v.4 no.4
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• pp.49-57
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• 2013

The lightning shielding of different 500 kV HVAC-TL high voltage AC transmission lines was analyzed. The studied transmission lines were horizontal flat single circuit and double circuit transmission lines. The lightning attractive areas were drawn around power conductors and shielding wires. To draw the attractive areas of the high voltage transmission lines, transmission line power conductors, shielding wires and lightning leader were modeled. Different parameters were considered such as lightningslope, ground slope and wind on lightning attractive areas. From the calculated results, the power conductors voltages affected on attractive areas around power conductors and shielding wires. For negative lightning leader, the attractive area around the transmission line power conductor increased around power conductors stressed by positives voltage and decreased around power conductors stressed by negative voltage. In spite of this, the attractivearea of the transmission line shielding wire increasedaround the shielding wire above the power conductor stressed by the positive voltage and decreased around the shielding wire above the power conductor stressed by negative voltage. The attractive areas around power conductors and shielding wires were affected by the surrounding conditions, such as lightning leader slope, ground slope. The AC voltage of the transmission lines made the shielding areas changing with time.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.5
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• pp.112-119
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• 2007

Under normal operating condition, the conductor of overhead transmission line could be always hold it's clearance within the safety margin that is specified in the line design guide of power company. Hence it may be very important to measure/or monitor the dip of the conductor, when building a new line, re-tensioning for an aged conductor, or monitoring dynamic line rating to maximize power capability. In this paper, we suggest a new method to estimate the dip and tension by catenary angle of the conductor. Since most conductors in overhead transmission lines show typical catenary curves, it can be uniquely determined the catenary curve for the conductor from the catenary angle at tower. Based on the catenary curve, the dip or horizontal tension can be easily estimated. Through some simulation and simple experimental results, it is verified that the suggested method can be effectively applied to measure/or monitor conductor dips and tensions in the overhead transmission lines.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.10
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• pp.123-129
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• 2010

During the past 2 decades, many electric power companies have been searching various solutions in order to supply power with economical and more efficiency in the present transmission utilities. Most interesting method to increase the line capacity of overhead transmission lines without constructing any new line might be to adapt Dynamic Line Rating(DLR). Specified rating is normally determined by any current level, not by conductor temperature. Although specified rating is essential to design transmission line, dip may be the most important factor in limiting transmission capacity. Transmission lines built by the oldest dip criterion among the 3 different design criteria for conductor dip are nearly over one-half of all Kepco's transmission lines. This paper describes an up-rating method for those transmission lines in order to apply DLR technique. Based on limit dip conductor temperature and current of the transmission lines, limitation performance and effectiveness in applying DLR with weather model are analyzed. As a result of analysis, it can be shown that an improved method could be effectively used for increasing the line rating of old transmission line which was built by the design criterion with low dip margin.

• Journal of the Korean Society of Industry Convergence
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• v.24 no.3
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• pp.307-313
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• 2021

In this study, the comparative analysis, among the design standard value of distribution power, the calculated value from the measurement data of strand and the empirical data of the distribution line itself, have been performed for the elastic coefficients and linear expansion coefficients of distribution line conductors. The empirical values of elastic coefficients were lower about 10.6%(892kgf/mm²) than those of the design standard value of the distribution power and there were a little difference between the empirical values of linear expansion coefficients and the design standard value of the distribution power. From the above results, it could be concluded that the empirical values of conductor characteristics should be used in the dip design and installation of distribution line.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.7B
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• pp.601-607
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• 2008

The induced voltages by AT power feeding system of electrified traction line to telecommunication line are calculated with the method of multi-conductor line solution in the CCITT Directives. There is a screening effect by railway line itself among various shielding factors against induction. It is the argue point whether the multi-conductor line solution contains the railway line effect since the calculation method does not show any expression about shielding factors. So this paper illuminates the mysterious question by reviewing the shielding factor principle on traction system, scrutinizing the Japanese bible about induction, analyzing the multi-conductor line solution itself, and comparing the result calculation considering the effect of railway screen. This paper concludes that multi-conductor line solution contains the screening effect of railway lines.