• 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.

• Wind and Structures
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• v.18 no.3
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• pp.235-252
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• 2014

An effective numerical technique to calculate the reactions of a multi-spanned transmission line conductor system, under arbitrary loads varying along the spans, is developed. Such variable loads are generated by High Intensity Wind (HIW) events in the form of tornadoes and downburst. First, a semi-closed form solution is derived to obtain the displacements and the reactions at the ends of each conductor span. The solution accounts for the nonlinearity of the system and the flexibility of the insulators. Second, a numerical scheme to solve the derived closed-form solution is proposed. Two conductor systems are analyzed under loads resulting from HIW events for validation of the proposed technique. Non-linear Finite Element Analyses (FEA) are also conducted for the same two systems. The responses resulting from the technique are shown to be in a very good agreement with those resulting from the FEA, which confirms the technique accuracy. Meanwhile, the semi-closed form technique shows superior efficiency in terms of the required computational time. The saving in computational time has a great advantage in predicting the response of the conductors under HIW events, since this requires a large number of analyses to cover different potential locations and sizes of those localized events.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.7
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• pp.734-743
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• 2010

In this paper, we analyzed the EMP coupling for the nonuniform transmission lines, such as twisted cables, using the chain matrix algorithm and the multi-conductor analysis. The BLT method is widely used for the EMP coupling analysis of the transmission line, however, it is difficult to apply to the nonuniform transmission lines. In order to analyze the EMP coupling of nonuniform transmission lines, the whole nonuniform transmission line is divided into incremental uniform line sections of the finite numbers, and the coupling in each small sections is now summed up to get the EMP coupling effect of the entire nonuniform transmission line. To verify the proposed EMP coupling analysis method, the result of the EMP coupling simulation is compared with the solution of BLT equations for a uniform transmission line case. The proposed method is applied to the twisted cable over ground in case of being illuminated by the HEMP in order to analyze the EMP coupling.