• Journal of the Institute of Electronics Engineers of Korea TC
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• v.42 no.11
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• pp.67-78
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• 2005

In this paper, impedance characteristics of overhead medium-voltage (MV) power line for power line communication (PLC) is analyzed. For analysis, a two-port equivalent network model of MV power lines is derived. By applying the equivalent model and basic transmission line theory, input impedance at the signal induction part is calculated. And also calculated input impedance of power line itself that the medium voltage coupler and coaxial cable effect are removed. For verification, impedance of power lines is measured at a test field for an MV PLC. The results show that impedance of MV power line itself is between $200\;{\Omega}\;and\;300\;{\Omega}$ and converges to a half of their characteristic impedance with increasing frequency. And also measured data is very similar to calculated data.

• Journal of Korea Society of Industrial Information Systems
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• v.19 no.4
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• pp.25-32
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• 2014

Powerline communications (PLC) is a promising medium for network access technology where smart grid aided network services can be provided. In the presence of frequency selective fading in the PLC channel, orthogonal frequency division multiplexing (OFDM) is a technique for reliable communications. This paper presents a spectral efficient method using a superimposed hidden pilot for OFDM-based PLC systems. Based on the scheme using a hidden pilot, it is possible to estimate the channel with no consumption of bandwidth, but with utilization of power allocated to the hidden pilot. Computer simulations showed that the proposed scheme provides higher achievable data rate than that of the conventional schemes in low voltage and medium voltage transmission lines.

• Journal of Advanced Marine Engineering and Technology
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• v.36 no.8
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• pp.1111-1116
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• 2012

At present, indoor optical wireless communications using LED lightings has been widely studied. The combination of this technology to the low voltage powerline grid installed in each home makes an efficient method for fulfilling the premise of broadband access for home networking. In this paper, white LEDs were used for both illumination and remote-control, so that information can be broadcast within a room for control the optical wireless systems. We implemented a model car to evaluate the performance of optical wireless remote-control. The requirement for levels of illumination suitable for communication were investigated and applied to design the test-bed. In spite of limitation of line-of-sight communications, it will open up new applications to the optical wireless remote control system in an electromagnetic interference region.

• Proceedings of the KIPE Conference
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• 2004.07b
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• pp.742-746
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• 2004

전력선 가입자망은 그 잠재적인 활용도가 매우 높아 국내외 전력 회사들의 관심도가 매우 높아지고 있다. 기존의 단순한 전력 공급만을 목적으로 하던 수용가의 전력선을 통신망으로 이용하면 전기 이용은 물론 정보가전기기, 컴퓨터 기기 등의 홈 네트워킹, 홈 오토메이션 및 인터넷 통신이 가능하게 됨으로써 관련 업종의 경쟁력 제고와 전력 사용기기를 최적 제어함으로써 가정의 편리성과 에너지 효율을 극대화 할 수 있다. 또한 전력선망을 보유한 전력회사에서는 원격 수요관리, 검침 및 자동화 기술을 통하여 보다 효율적인 전력 운영과 수용가 이익을 증대화 시킬 수 있다. 본 논문에서는 전력선 통신을 이용하여 원격검침, 수요관리, 고객 관리 및 전력 정보 제공, 심야전력 관리 및 감시 등의 다양한 서비스를 경제적으로 제공하기 위하여 우리나라 실정에 맞는 전력부가 서비스 시스템의 주요 기기들을 설계하고 개발한다.

• Proceedings of the KIPE Conference
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• 2008.06a
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• pp.148-150
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• 2008

지구온난화와 화석연료의 고갈 등 에너지관련 문제들이 발생함에 따라 제한된 자원의 효율적인 소비가 중요한 연구주제로 다루어지고 있다. 특히 자원수입국인 우리나라의 경우는 국제 유가 급등과 같은 에너지파동에 상당히 민감하기 때문에 에너지 관리를 통한 정확한 수급정책 수립 및 효율적인 소비생활이 무엇보다 중요하다. 이를 위해 우선적으로 취할 수 있는 해결책 중의 하나가 댁내 가전기기의 불필요한 전력낭비를 최소화하는 것이다. 이번 연구에서는 전력선통신(PLC)기반 원격검침 인프라를 활용하여 1차적으로 가전기기의 대기전력을 지능적으로 관리함으로써 전력낭비를 최소화하고 2차적으로 전력소비모니터링 서비스를 제공함으로써 사용자가 능동적으로 전력소비를 줄일 수 있도록 하는 지능형 홈에너지 관리시스템을 개발하였으며, 실제 수용가를 대상으로 구축, 운영함으로써 향후 에너지를 효율적으로 관리할 수 있는 방안을 제시하고자 한다.

• Proceedings of the KIEE Conference
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• 2004.07d
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• pp.2652-2654
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• 2004

홈 네트워크나 가로등 제어에 가장 적합한 솔루션 중 하나가 전력선 통신기술이다. 전력선 통신의 사용 주파수 대역은 $50kHz{\sim}450kHz$으로, 이 주파수 대역은 잡음이 매우 많이 존재한다. 또한 시공간에 따른 변화의 요인이 많이 존재하기 때문에 채널 모델링이 매우 어려운 실정이며, 이를 극복할 수 있는 방안으로 영교차점을 이용한 전력선 모뎀을 설계하고자 한다. 변조 방식은 Chirp 심볼을 사용하고, 주파수 대역은 $100kHz{\sim}400kHz$를 사용하였다. 전력선 채널로부터 정보를 획득하기 위해서 효율적인 수신기 구조를 채택하였다. 즉 채널 상황에 적응이 가능하고, 상관에 필요한 필터의 계수를 들어오는 심볼로부터 구하는 방법으로, 다음에 들어오는 심볼과의 상관값을 구하여 정보 신호를 판별하는 형태로 구성하였다. 영교차점을 기준으로 신호를 송수신하는 형태를 취했으며, 영교차점 기준에 들어오는 잡음은 chirp의 대역 확산 특성에 의해서 억제될 수 있다. 이런 기술에 의해서 견실한 전력선 통신 모뎀구현이 가능하였다.

• Journal of Advanced Marine Engineering and Technology
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• v.40 no.9
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• pp.799-804
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• 2016

Broadband powerline communication (BPLC) uses distribution lines as a medium for achieving effective bidirectional data communication along with electric current flow. As the material characteristics of power lines are not good at the communication channel, the development of power line communication (PLC) systems for internet, voice, and data services requires measurement-based models of the transfer characteristics of the network suitable for performance analysis by simulation. In this paper, an analytic model describing a complex transfer function is presented to obtain the attenuation and path parameters for a multipath power line model. The calculated results demonstrated frequency-selective fading in multipath channels and signal attenuation with frequency, and were in good agreement with the experimental results. Inductive coupling units are used as couplers for coupling the signal to the power line to avoid physical connections to the distribution line. The inductance of the ferrite core, which depends on the frequency, determines the cut-off frequency of the inductive coupler. Coupling loss can be minimized by increasing the number of windings around the coupler. Coupling efficiency was improved by more than 6 dB with three windings compared to the results obtained with one winding.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.29 no.7
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• pp.566-569
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• 2018

A power line coupler that can apply high-frequency power to a railway overhead line structure was analyzed. It is difficult to supply auxiliary power to an overhead line in a high-voltage environment, and doing so requires a long-distance transfer. A method is proposed that utilizes the resonance on the Rogowski coil, which does not use a magnetic core. A simple overhead line structure was fabricated that consisted of a contact wire, messenger wire, and dropper. Couplers of various sizes were fabricated and deployed on the messenger wire, and the transfer characteristics of the two couplers were compared at a distance. As a result of applying the matching circuit to the coupler, the transmission efficiency was 53% at a distance of 2.5 m. The proposed method shows that it is possible to apply the auxiliary power by using the existing conductor in a special structure, such as the overhead line.

• Journal of Korea Multimedia Society
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• v.8 no.5
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• pp.660-669
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• 2005

In this paper 10Mbps master-slave based PLC modems are tested for measuring and analyzing both network and application level performances in the general buildings. The devices under test consist of one master PLC modem and three slave modems. The selected parameters for inspecting the performances are throughput, latency and frame loss rate from the RFC 2544, and one-to-many and many-to-one throughput from the RFC 2285. The results of the performance test show that the PLC modems have Performed better in data transmission when the frame size is increased and the transmission speed is decreased. It is expected that these results will be useful to analyze the effect of noise sources when compared to the performance test under the noiseless environments.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.15 no.2
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• pp.109-116
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• 2022

In this paper, we propose a band rejection filter (BRF) with a state variable filter (SVF) structure to effectively remove the influence of 60 Hz line frequency noise introduced into the sensor system. The conventional BRF of the SVF structure uses an additional operational amplifier (OPAMP) to add a low pass filter (LPF) output and a high pass filter (HPF) output or an input signal and a band pass filter. Therefore, the notch frequency and the notch depth that determine the signal attenuation of the BRF greatly depend on the tolerance of the resistors used to obtain the sum or difference of the signals. On the other hand, in the proposed BRF, since the BRF output is formed naturally within the SVF structure, there is no need for a combination between each port. The notch frequency of the proposed BRF is 59.99 Hz, and it can be confirmed that it is not affected at all by the tolerance of the resistor through the Monte Carlo simulation results. The notch depth also has an average of -42.54dB and a standard deviation of 0.63dB, confirming that normal operation as a BRF is possible. Also, with the proposed BRF, noise filtering was applied to the electrocardiogram (ECG) signal that interfered with 60 Hz noise, and it was confirmed that the 60 Hz noise was appropriately suppressed.