• Proceedings of the KIEE Conference
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• 2000.07a
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• pp.458-460
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• 2000

In this paper, we analyze the inductive coupling between overhead power transmission lines and neighbouring gas pipelines or other conductors, when they parallel to a line section in a phase-to-earth fault is assumed on the transmission line. A numerical procedure employing the finite-element method(FEM) is used in conjunction with Faraday's law, in order to predict the current in a faulted transmission line as well as the induced voltages across points on a pipeline running parallel to the faulted line and remote earth. The results lead to conclusion that may be useful to power system engineers.

• International Journal of Aeronautical and Space Sciences
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• v.18 no.3
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• pp.588-600
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• 2017

We develop a wireless, contact free power transfer mechanism that is safer than the direct metallic contact and robust to imperfect alignment on landing at the base station. A magnetic field is created using inductors on both the transmitting and receiving sides. We use the inductive wireless recharging to increase autonomy and decrease the sensor interference by reducing the inductor loop size. By locating four independent small receiver loops and corresponding four circuits around the quadrotor UAV, we can increase safety from circuit malfunctions in comparison to the use of just one loop. On the base station, four folding robotic bars are used to realign the receiver loops over the transmitter loops. After adequate recharging as measured by battery voltages or power consumption at the bae station, the UAV sends a signal to the base station to open the robotic bars and takes off once freed from the robotic bars.

• Proceedings of the KIEE Conference
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• 2000.07c
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• pp.1993-1995
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• 2000

In this paper, we calculate the magnetic field and analyze the inductive interference in conductive material around power transmission line. To compute induced eddy currents as well as magnetic fields, finite element method(FEM) is used for numerical calculation. The characteristics, transmission line height, conductive earth and mitigation wire are taken account of FEM analysis. This research also shows that mitigation wire reduces amount of eddy current in buried pipe line.

• Progress in Superconductivity and Cryogenics
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• v.24 no.4
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• pp.11-15
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• 2022

We conducted numerical calculations to obtain the critical current as a function of the magnetic flux through the topologically trivial and non-trivial superconducting quantum interference devices (SQUIDs), with varying the capacitive and inductive couplings of Josephson junctions (JJs). Our calculation results indicate that a nontrivial SQUID is almost indistinguishable from trivial SQUID, considering the effective capacitance coupling. When the SQUID contains 2π- and 4π-periodic supercurrents, the periodicity of the current-flux relation can be distinguished from the purely trivial or nontrivial SQUID cases, and its difference is sensitive to the relative ratio between the topologically trivial and nontrivial supercurrents. We believe that our calculation results would provide a practical guide to quantitatively measure the portion of the topologically nontrivial supercurrents in experiments.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.4
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• pp.2355-2362
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• 2014

Electric railway induces interference voltage on wayside communication cable which brings about communication errors, malfunction of devices, and safety problem. The magnitude of the induced voltage depends on the electromagnetic field coupling which is affected by metallic installations such as rail and track structures. This paper provides an experimental analysis of the screening effect of metallic pipe on the inductive voltage caused on communication cable. The measurements at a high-speed rail site show that the screening effect of metallic pipe is about 20% when the separation distance between the pipe and communication cable is 1~2 m. The screening effects is less than 1% and can be neglected when the separation distance is more than 4 m. These results are useful to evaluate the screening effects of the metallic installations such as water pipe, gas pipe, and reinforcing bar.

• Journal of Power Electronics
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• v.16 no.4
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• pp.1245-1255
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• 2016

The single resonant inverter is widely employed in typical inductive power transfer (IPT) systems to generate a high-frequency current in the primary side. However, the power capacity of a single resonant inverter is limited by the constraints of power electronic devices and the relevant cost. Consequently, IPT systems fail to meet high-power application requirements, such as those in rail applications. Total harmonic distortion (THD) may also violate the standard electromagnetic interference requirements with phase shift control under light load conditions. A power regulation approach with selective harmonic elimination is proposed on the basis of a parallel multi-inverter to upgrade the power levels of IPT systems and suppress THD under light load conditions by changing the output voltage pulse width and phase shift angle among parallel multi-inverters. The validity of the proposed control approach is verified by using a 1,412.3 W prototype system, which achieves a maximum transfer efficiency of 90.602%. Output power levels can be dramatically improved with the same semiconductor capacity, and distortion can be effectively suppressed under various load conditions.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.12
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• pp.1659-1665
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• 2015

In general, AT(Auto-transformer) is used to improve voltage sag and inductive interference in power lines and communication lines in AC electrical railway feeding system. Especially, Korean AT feeding system has different composition compared to other countries like Japan or France, so that it has some special characteristics. However, relays imported from other countries have been used in Korea, and settings of these relays should be modified and reflect distinct characteristics of Korean AT feeding system. Therefore, study about fault analysis based on modeled AT feeding system is important. In this paper, we modeled a single track AT feeding system by using PSCAD and analyzed fault current flow in case of trolley-rail short circuit fault. Finally, we presented current magnitude of each branch expressed by boosting current of AT.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.10a
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• pp.45-48
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• 2011

The electrodeless fluorescent lamp is relatively new luminaire and has been known as the high energy saving lamp which has long life and environment-friendly. But these kind of lamps have some risks to cause harmful radio interference unavoidably due to its own inductive characteristics. In this paper we measured the radio disturbance characteristics of the induction lamp with the operating frequency at 250 kHz, and compared the values with the limits of relevant standards. Finally we have estimated the interference protection distance between the induction lamps and some services around their operating frequencies, and considered the desirable future scopes and limits of the applications for these kind of lamps.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.18 no.4
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• pp.138-143
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• 2004

This paper analyzed harmonics from high speed railway traction to high speed railway substation and provide a reduction method of harmonics using the passive filter. A substation supplies the electric power to a train or can supply the electric power to several trains. According to the number of trains covered by a substation, characteristics of harmonics are investigated. These harmonics affect transformer heating and inductive interference. In order to get rid of the damage from the harmonics, this paper presented minimizing method of harmonics. The proposed method is verified in simulation using the PSCAD/EMTDC.

• Progress in Superconductivity
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• v.8 no.2
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• pp.138-142
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• 2007

We observed discrete fluxon-flow resonance steps in high magnetic fields in a stack of Josephson junctions with lateral size of $1.5{\times}17{\mu}m^2$. The measurement sample was prepared by sandwiching a stack of $Bi_2Sr_2CaCu_2O_{8+x}$ intrinsic Josephson junctions between two Au electrodes by using the double-side-cleaving technique. This technique allowed us to isolate the intrinsic Josephson junction structures from the inductive interference of the basal stack. The resonance steps observed are in good agreement with the collective Josephson fluxon dynamics that are in resonance with the plasma oscillation modes inside the stacked Josephson junctions.