• 한국통신학회논문지
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• 제30권12A호
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• pp.1136-1146
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• 2005

본 논문에서는 전력선 통신을 위해 사용되는 고압 배전선로에서 통신신호 및 잡음신호에 의해 방사되는 방사전계강도를 계산하였다. 전력선 통신 네트워크의 2포트 등가모델 및 기본적인 전송선로 이론을 이용해 입력임피던스를 계산하였다. 그리고 계산된 입력임피던스를 이용해 전력선상 전류를 계산하고 최종적으로 방사전계강도를 계산하였다. 전력선의 특성임피던스가 매우커서 입력 단에서의 반사가 심하기 때문에 입력임피던스는 일정한 주기를 가지는 정재파 형태를 가진다. 계산된 전류 및 방사전계 또한 이러한 형태임을 알 수 있었다. 실제 측정한 결과계산 치와 측정치가 매우 유사함을 알 수 있었다.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제51권7호
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• pp.316-321
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• 2002

In this Paper, the channel characteristics of the medium voltage(22.9kV) power line to analysis the broadband power line communication in the frequency range up to 30MHz was measured. With the sideband electrical coupler in the operating frequency range from DC to 30MHz, we measured characteristic impedance, noise and attenuation of the medium voltage power line, and then characteristic impedance was measured at the state of unloaded medium voltage power line by Scattering parameter method of Vector Network Analyzer. As a measurement result, Channel impedance shows 100~380$\Omega$ at the less than 15MHz and 70~230$\Omega$ at the more than 15 MHz. Noise characteristics of power line shows -75dBm at 20MHz and Narrowband interference noise was from 3 MHz to 7MHz.

• 대한전기학회논문지:시스템및제어부문D
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• 제54권1호
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• pp.56-60
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• 2005

In the power-line communication(PLC) systems, the power line is a wired medium. However, the power line channel has the multi-path fading characteristics like the wireless channel in the wireless communication systems because it has the signal reflection and divergence by the impedance mismatching between many branch lines and loads. So the analysis of the multi-path characteristics is very important, and it has been doing by the several measurement methods for the impulse response between the transmitter and the receiver. PN sequence method has originally been used as a wideband impulse response measurement mettled for wireless channel, but it is recently being applied to not only the wireless channel but also the wired channel like the power line channel. This method is more useful and effective for the long distance communication channel like the medium voltage power distribution line with the multi-paths[1]. In this thesis, we have measured impulse response for the medium voltage power distribution line channel by the wideband measurement method using PN sequence, analytically studied the measured data and presented the results.

• 대한전기학회논문지:시스템및제어부문D
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• 제54권6호
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• pp.409-416
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• 2005

For broadband high-data-rate power line communication with the allocated frequency bandwidth from 2 to 30 MHz on medium voltage (MV) distribution power lines, a signal coupling unit is developed. The coupling unit is composed of a coupling capacitor for coupling communication signal, a drain coil, and an impedance matching part. The coupling capacitor made of ceramic capacitor is designed for transmission property of better than 1 dB in the frequency range. The drain coil is used for preventing low frequency high voltage from junction of medium voltage power line in case that a coupling capacitor is not working properly any more. Also, using ferrite core, a novel broadband impedance matching transformer is developed. A complete coupling unit with a coupling capacitor, a drain coil, and a matching transformer is housed by polymer for good isolation and distinguishing from high voltage electric facilities. Each is fabricated and its frequency behavior is tested. Finally, complete signal couplers are equipped in a MV PLC test bed and their performance are measured. The measurement shows that the coupling capacitor works excellently.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 D
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• pp.3040-3042
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• 2005

During the last several years, interest in broad-band power line communications (PLC) has been grown over medium voltage(MV) power distribution lines as well as low voltage lines. This paper introduces a medium voltage PLC test field that is set up in the suburbs of Euiwang city in Korea. This test field could be used not only for the measurement of communication channel environment but also for internet service. This paper shows the configuration of medium voltage test field with network devices like MV signal coupler and the results of channel environment like noise and impulse response. It also shows the service performance of PLC access network through network management system.

• 대한전자공학회논문지TC
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• 제42권11호
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• pp.67-78
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• 2005

본 논문에서는 전력선 통신(PLC) 시스템에 사용되는 고압 배전선로의 임피던스 특성을 해석하였다. 해석을 위해 전력선 통신 네트워크의 2포트 등가모델을 구현하였다. 등가모델 및 기본적인 전송선로 이론을 적용하여 전력선 통신 입력 단에서의 임피던스를 계산하였다. 또한 고압 커플러, 동축케이블 등의 특성을 제거한 전력선 자체의 입력임피던스를 계산하였다. 계산결과의 검증을 위해 고압 실증시험장에서 측정을 하였다. 측정결과 전력선 자체의 입력 임피던스는 $200\~300\;{\Omega}$의 값을 가졌으며, 주파수가 증가할수록 전력선 특성임피던스의 절반에 수렴하였다. 또한 측정치와 계산치가 매우 유사하였다.

• 대한전기학회논문지:시스템및제어부문D
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• 제53권5호
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• pp.345-352
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• 2004

Currently, high data rate PLC(Power Line Communications), up to 100 Mbps, which use frequency bandwidth between 2 MHz and 30 MHz is investigated very hard, and commercial PLC modem for low voltage powerline network (indoor) is coming soon into communication market. For the purpose of developing a fit communication system which has little distortion of signal and attenuation, it is surely necessary to know about channel environments of powerline. Especially, the impedance measurement of the powerline and impedance matching are very important. As is known, since medium-voltage powerline (22.9 ㎸) is still working, it is not so simple to measure the powerline impedance. In our study, a portable impedance measurement equipment is developed. It consists of coupling capacitor, a drain coil and impedance matching transformer. The equipment is easily connected to medium voltage line and impedance of power line is measured using a network analyzer. Also, measurement results are used for impedance matching of PLC signal. In fact, matching transformer with several different impedances are used. The matching transformer is connected between coupling capacitor and signal port. In this paper, the developed portable impedance measurement equipment and impedance measurement results are presented. Also impedance matching technique using matching transformers will be explained. We showed the result of the improved performance by the impedance matching.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 D
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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.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 C
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• pp.2345-2347
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• 2005

In this paper, impedance characteristics of overhead medium-voltage (MV) power lines is reported for power line communication (PLC) over an MV power line network. For analysis, a two-port equivalent network model of MV power lines is derived. By applying the transmission line theory, reflection behavior and impedance of power lines are investigated. For verification, impedance of power lines is measured at a test field for an MV PLC. The results show that impedance of MV power lines is between $200{\Omega}$ and $300{\Omega}$ and converges to a half of their characteristic impedance.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제53권12호
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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.