• The Transactions of the Korean Institute of Electrical Engineers A
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• v.48 no.7
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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.

• Proceedings of the KIEE Conference
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• 1998.07e
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• pp.1647-1649
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• 1998

This paper describes the power frequency voltage and its countermeasure when a 765 kV transmission line is directly connected to a 345 kV line and operated at 345 kV voltage. The summary of this result is as follows : The western route of 765 kV transmission line doesn't need any countermeasure to reduce the power frequency voltage at the receiving end. The eastern route of 765 kV transmission needs 100 Mvar(3 phase) capacity of shunt reactor at the receiving end to reduce the power frequency voltage. The use of shunt reactors in the 765 kV transmission lines has unexpected problems, one of which is induction of high voltages on a de-energized circuit of two parallel lines. This paper examined the problem of resonance on two parallel transmission circuits in one routes.

• Proceedings of the KIEE Conference
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• 2003.07a
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• pp.199-201
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• 2003

Because of Korean power system characteristics and increasing power demand, the need of 765kV transmission line is growing gradually. Now a days, KEPCO's 765kV transmission line has been tested and stands for commercial operation. During the first stage, 765kV transmission line will be operated with two voltage grades of 765kV and 345kV, which results the unbalance of power system. So unbalanced current such as zero sequence current flows in the transmission line. In this paper, we describes the simulation study of 765/345kV parallel transmission line by using EMTDC program.

• Proceedings of the KIEE Conference
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• 1999.07a
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• pp.465-467
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• 1999

The data transmission system in MAGLEV is required a high quality and high speed for a train safety and reliability driving. In the transmission channel between a vehicle and a ground-site, Gaussian noise is negligible, but impulse noise from the chopper controlled propulsoin unit and the Power supplying device is very severe. The transmission channel must be protected from these noise. In this paper, we propose a DSSS (direct-sequence spread spectrum) modulation as a new data transmission technique in the railway and analyze this data transmission characteristics.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.7
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• pp.1221-1225
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• 2010

The application of the AC and DC lines on the same transmission tower is an economical and practical approaching that increase the power transmission capacity of an existing transmission corridor. But, In this case, Inductive and capacitive coupling between AC and DC lines on the same tower should be investigated in advance. According to the installation plan of 80kV ${\pm}$60MW bipole HVDC in Cheju, KOREA that will be commissioned until 2011, DC lines will parallely operate with 154kV 2 AC lines in existed 154kV AC 4 lines transmission tower. This paper presents the steady state analysis results about the interaction between 154kV AC and 80kV DC lines in the same transmission tower.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.1
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• pp.14-19
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• 2011

The implemetation of the AC and DC lines on the same transmission tower is an economical and practical approaching that increase the power transmission capacity of an existing transmission corridor. But, In this case, Inductive and capacitive coupling between AC and DC lines on the same tower should be investigated in advance. According to the installation plan of ${\pm}80kV$ 60MW bipole HVDC in Jeju island, KOREA that will be commissioned until 2011, DC lines will parallely operate with 154kV 2 AC lines in existed 154kV AC 4 lines transmission tower. This paper presents the transient analysis results about the interaction between 154kV AC and 80kV DC lines in the same transmission tower.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38B no.7
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• pp.535-542
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• 2013

Coordinated multi-point transmission (CoMP) is considered to be a promising technique to improve the throughput for LTE-Advanced systems. One important approach for CoMP is Joint Transmission (JT). However, the analytical model of JT has not been fully studied, as user equipments (UEs) receiving the desired signals from an adjacent base station (BS) as well as serving BS, or only serving BS were not distinguished. We derive a new analytical model to describe the call admission control in JT based systems. The performance measures of interest are the call blocking probability, and resource utilization. Furthermore, we compare the performance of JT-based systems and non-JT- based systems. The analytical results are in reasonable agreement with the simulation results.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.48 no.3
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• pp.247-256
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• 1999

In this paper, a methodology for optimal design of PID controller using the modified genetic algorithm has been proposed to improve the transient stability at system fault in HVDC transmission system, mathematical model preparation for stability analysis, and supplementary signal control by an optimal PID controller using the modified genetic algorithm(MGA). The propriety was verified through computer simulations regarding transient stability. It means that the application of MGA-PID controller in HVDC transmission system can contribute the propriety to the improvement of the transient stability in HVDC transmission system and the design of MGA-PID controller has been proved indispensible when applied to HVDC transmission system.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.1
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• pp.219-227
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• 2013

This study analyzed the effect of performance connected-type foundations of behavior and the connected beams according to the characteristics into soft clay transmission tower foundation. For this purpose, the finite element analysis model was built and connected to the transmission tower foundation mat and the contact area of the connection beam by the percentage change in the behavior and resistance characteristics were analyzed and finite element verification of the validity of the analytical model was conducted using connected-type transmission tower results of the model experiments constructed, and effective connected-type transmission tower basis of the behavior of connected beams were selected by analyzing the effect due to the increase of the stiffness. In addition, weak analysis by connected beam self-bending moment distribution was conducted.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.9
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• pp.1056-1064
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• 2010

This paper presents the approximate analysis method for the symmetric transmission line crossing the aperture in an backplane. The method of moments is used to determine the aperture impedance for the construction of the equivalent transmission line that the aperture impedance apply to the transmission line as the shunt impedance. As the results, the insertion loss increases at the specific frequency range for the impedance matching. In the case of the mismatching, we are confirmed to the insertion gain at the specific frequency. Also the horizontal length of the aperture affects to the transmission line better than vertical length. The measurement of the insertion loss is performed to verify the theoretical analysis.