• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.12A
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• pp.1136-1146
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• 2005

In this paper, the radiative electric field intensity due to the communication signal and conductive noise is calculated in overhead medium voltage power lines for power line communication. The input impedance is calculated by means of 2 port equivalent model of medium voltage power line network and basic transmission line theory. And then, currents is calculated by calculated input impedance and finally, the emissive electric field is calculated. The input impedance appears like a standing wave form with a fixed cycle because high reflection at the input terminal due to the characteristic impedance of medium voltage power line is very large. A calculated current and radiative electric field also appears like this form. From the measurement results, the measured results are very similar to the calculated results.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.9A
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• pp.983-990
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• 2004

In this paper, we calculated the input impedance of the power line communication(PLC) networks using medium voltage power line. First of all, we proposed input and output teoninal model of PLC network, and calculated the input impedance applying the attenuation constants by radiation loss, conductor loss, dielectric loss. From the calculation result, we knew that the attenuation by radiation loss was largest, and the input impedance appears like a standing wave fonn with a fixed cycle because the high reflection at the input terminal for the characteristic impedance of the power line is very large. And also the cycle of input impedance depends on the coaxial cable length, and the amplitude depends on the characteristic impedance of power line and losses. From the measurement result, calculated result was very similar to the measured result.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11b
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• pp.30-33
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• 2001

This thesis deal with ferroelectric and ferrimagnetic materials, PZT/Ferrite ceramics. We conducted test of magnetical and electrical measurement. From this measurement, We obtained tunability and we can control characteristic impedance($Z_0$) from permeability($\mu$) and dielectric constant($\varepsilon$) for impedance matching in transmission line.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11a
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• pp.30-33
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• 2001

This thesis deal with ferroelectric and ferrimagnetic materials, PZT/Ferrite ceramics. We conducted test of magnetical and electrical measurement. From this measurement, We obtained tunability and we can control characteristic impedance(Z$_{0}$) from permeability($\mu$) and dielectric constant($\varepsilon$) for impedance matching in transmission line.e.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.9 no.5
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• pp.67-71
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• 2010

This paper proposes new dual-band impedance transformers based on the L-section circuit topology. The proposed circuits consist of a transmission line section with a stub line either at the source or at the load end. The dual-band operating conditions are analyzed in detail and simple design equations are derived in terms of the line lengths and impedances for the different circuit topologies and load conditions. The dual-band operation is confirmed through the design, fabrication and measurement in microstrip circuits based on the proposed method.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.4
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• pp.849-856
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• 2009

Truncal obesity associated with insulin resistance and metabolic syndrome increase the likelihood of hypertension, various cardiovascular diseases, hyperlipidemia and coronary heart diseases. International Diabetes Federation (IDF) experts recognized that it is necessary to develop the simple diagnostic tool which is applicable to diagnose truncal obesity worldwide, and proposed the method using a waist circumference but there is a limit to estimate subcutaneous fat distribution. However, waist line is also influenced by total fat capacity less than the intra abdominal fat. The more having severe obesity, the more correlation coefficient between waist line and intra abdominal fat is low. Therefore, this thesis defines a new abdominal impedance measurement position and impedance-index to analysis central obesity. This proposes the new model to estimate abdominal obesity using the abdominal impedance-index and CT images acquired fro 160 Korean subjects. The proposed model shows that the abdominal fat distribution has a higher correlation than waist line. (Adj R2=0.809, 0.667 and 0.687 with abdominal fat area, visceral fat area and subcutaneous fat area respectively).

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.03b
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• pp.26-26
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• 2010

Line to ground faults or lightning strikes in electrical power systems produce high frequency overvoltages. With this reason, a wide band analysis of the ground impedance is necessary. In the paper, design of a wideband ground impedance meter which can measure the ground impedance in ranges from 65 Hz to 1.5 MHz is described. Also, a noise elimination method by a digital band-pass filter during measurement is proposed. The maximum measurement error of the meter is estimated 3 % in full ranges.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.65 no.1
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• pp.47-52
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• 2016

Fault location identification in the transmission line is an essential part of quick service restoration for maintaining a stable in power system. The application of digital schemes to protection IEDs has led to the development of digital fault locators. Normally, the impedance measurement had been used to for the location detection of transmission line faults. It is well known that the most accurate fault location scheme uses two-ended measurements. This paper deals with the complete design of a fault locator using GPS time-synchronized phasor for transmission line fault detection. The fault location algorithm uses the transmitted relaying signals from the two-ended terminal. The fault locator hardware consists of a Main Processor Unit, Analog Digital Processor Unit, Signal Interface Unit, and Power module. In this paper, sample real-time test cases using COMTRADE format of Omicron apparatus are included. We can see that the implemented fault locator identified all the test faults.

• Proceedings of the KIEE Conference
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• 2002.07d
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• pp.2640-2642
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• 2002

In this paper, we show the channel characteristics measurement system the frequency range up to 30MHz for medium voltage Power Line Grid. Power line channel characteristics are investigated by means of various measurement instruments. Measurement system consists of medium voltage coupler, impedance measurement part, noise measurement part, voltage sensing part and communication part. Measured data will be used for PLC channel modeling and PLC network system design.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.53 no.12
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• pp.620-625
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• 2004

In this paper, we studied the emissive electric field due to the communication signal and the noise in medium voltage power-line. There are many types of conductive noise in power-line channel, which gives rise to radiation. And if the DMT carrier signal was excited, the current by this term was added to the current by noise and, generate radiation. We calculated input impedance by means of signal input network model of medium voltage power-line channel for calculating these currents. We calculated currents by input impedance and, calculated the emissive electric field by this calculated currents. From the measurement results, we knew that the measured results are very similar to the calculated results and if the input signal power level was higher than -40 dBm, the emissive electric field exceeds FCC radiation limit level 69.5 dB$\mu$V/m.