• Journal of the Institute of Electronics Engineers of Korea TC
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• v.41 no.12
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• pp.115-124
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• 2004

In this paper, we introduce the advanced compact transmission line with periodic stepped stubs. They are more effective than normal stubs in ATL. The short stepped stubs loading of transmission line work as effective shunt capacitance and that was proved by equivalent circuit based on transmission line theory and quasi-static analysis. And the compact branch-line coupler and the compact rat-race coupler via proposed compact microstrip line were designed at 1.8 ㎓. They have 677 ㎟ and 913 ㎟, respectively, and they are 62% and 45% of normal design.

• Wind and Structures
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• v.8 no.2
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• pp.121-134
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• 2005

Wind-induced vibrations measured in the Tsuruga Test Line are characterized in this paper by single-channel data analysis based on piecewise application of Prony's method. Some of events were identified as galloping, while most of events were buffeting responses, which were confirmed partly by the buffeting analysis. Effects of end condition etc. on the response characteristics are also discussed.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.41 no.12
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• pp.109-114
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• 2004

In this paper, we introduce the concept of ILCTL(inductively loaded compact transmission line) that is new type of compact transmission line. ILCTL was realized by periodic narrow transverse slits working as series inductances in microstrip line. And compact hybrid rat-race couplers were designed by using the proposed ILCTL. The microstrip line hybrid rat-race coupler with silts of 8 per quarter wavelength at 1.8 GHz has reduced size of 60% as compared with conventional one and it is proved by simulation of EM solver with full-wave analysis based on MoM and measurements.

• Journal of Electrical Engineering and Technology
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• v.8 no.4
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• pp.694-703
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• 2013

In electric power system, the line stability indices adopted in most of the instances laid stress on variation of reactive power than real power variation of the transmission line. In this paper, a proposal is made with the formulation of a New Voltage Stability Index (NVSI) which originates from the equation of a two bus network, neglecting the resistance of transmission line, resulting in appreciable variations in both real and reactive loading. The efficacy of the index and fuzzy based load flow are validated with IEEE 30 bus and Tamil Nadu Electricity Board (TNEB) 69 bus system, a practical system in India. The results could prove that the identification of weak bus and critical line in both systems is effectively done. The weak area of the practical system and the contingency ranking with overloading either line or generator outages are found by conducting contingency analysis using NVSI.

• Tunnel and Underground Space
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• v.15 no.4 s.57
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• pp.296-304
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• 2005

This study is to observe stray currents generated around the steel tower by domestic transmission network system and analysis stability of electric detonator. It is measured the stay current of each ten place at steel tower of 765 kV, 345 tV, 154 tV transmission line among domestic transmission network system. Stay currents measured a total of 40m at intervals of 4m toward a line direction and a line vertical direction centering around steel tower. Temperature of the surface, EC, water content also are measured. Although stay currents show the highest values, that is 12 percent of at 4m and less than 1 percent of 40m with Institute of Makers of Explosives(IME) regulations. It is shown correlation between stay currents and water content$\cdot$EC$\cdot$temperature of the surface. Stay currents measured at line direction and line vertical direction were little different and the shape of diminution was also shown a similar aspect.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.05a
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• pp.218-221
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• 2003

In this report, we test the features that the outside environment of subscriber lines have an effects on ADSL's electrical transmission performance with a suspected cases of line. I observed an influence of AM broadcasting jamming, and also analysis of an incoming lines of various kinds, a line distance, a connection way, Bridge Tap influencing ADSL's electrical transmis-sion performance. To have a maximum effect of Adsl electrical transmission, I came to a conclusion that we have to make use of the older copper wire cable line to fit the situation at the present and we must change it into the excellent optical fiber cable one by one.

• Journal of Electrical Engineering and Technology
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• v.9 no.6
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• pp.2049-2057
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• 2014

In this paper, a numerical method for analyzing coupling between high-altitude electromagnetic pulse (HEMP) as external field and a shielded twisted pair (STP) cable is proposed, which is based on an expanded chain matrix. Load responses of electromagnetic (EM) field excitation in uniform transmission line (TL) are solved by Baum-Liu-Tesche (BLT) equations in frequency domain, however, it is difficult to apply BLT equations to solve load responses of STP cable because the iteratively changing configuration of each twisted pairs are involved in cable. To avoid this problem and decrease memory and CPU time, we proposed the expanded chain matrix modeling method that is calculated using ABCD parameters, and applied multi-conductor transmission line (MTL) theory to consider the EMP coupling effectiveness of each twisted pairs. The results implemented by the proposed method are presented and compared with those obtained by the finite-difference time domain (FDTD) method as a kind of 3D full wave analysis.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.51 no.1
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• pp.5-14
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• 2002

In this paper, we analyze inductive interference in conductive material around 345 kV power transmission line, and evaluate the effects of mitigation wires. Finite element method (FEM) is used to numerically compute induced eddy currents as well as magnetic fields around powder transmission lines. In the analysis model, geometries and electrical properties of various elements such as power transmission line, buried pipe lines, overhead ground wire, and conducting earth are taken into accounts. The calculation shows that mitigation wire reduces fairly good amount of eddy currents in buried pipe line. To find the optimum magnetic field shielding location of mitigation wire, we applied evolution strategy algorithm, a kind of stochastic approach, to the analysis model. Finally, it was shown that we can find more effective shielding effects with optimum location of one mitigation wire than with arbitrary location of multi-mitigation wires around the buried pipe lines.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.9
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• pp.875-880
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• 2011

We design and analyze the cloaking circuit using 2D transmission line structure to make up for the weakness of the established cloaking circuit using only lumped inductor and capacitor elements. The 2D transmission line structure enables one to conveniently design the cloaking circuit with available element values. All the necessary analysis and synthesis(design) formulas have been derived. A cloaking circuit for a cylindrical scatterer in free space has been designed based on the provided design formulas and its effects have been investigated using the circuit simulator ADS. The effect of the cloaking medium for this specific case has been observed to be about 10.5 dB.

• Transactions on Electrical and Electronic Materials
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• v.18 no.5
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• pp.279-286
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• 2017

In this paper, an optimal approach for the wide-area regulation of control devices in a transmission network is proposed. In order to realize an improved voltage profile and reduced power loss, existing devices such as tap-changing transformers, synchronous machines, and capacitor banks should be controlled in a coordinated and on-line manner. It is well-understood that phasor measurement units in transmission substations allow the system operators to access the on-line loading and operation status of the network. Accordingly, this study proposes efficient software applications that can be employed in area operation centers. Thus, the implanted control devices can be regulated in an on-line and wide-area coordinated approach. In this process, efficient objective functions are devised for both voltage profile improvement and power loss reduction. Subsequently, sensitivity analysis is carried out to determine the best weighting factors for these objectives. Extensive numerical studies are conducted on an IEEE 14-bus test system and a real-world system named the Azarbayjan Regional Transmission Network. The obtained results are discussed in detail to highlight the promising improvements.