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  • Title/Summary/Keyword: power line data transmission

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A Fault Location Algorithm Using Adaptively Estimated Local Source Impedance for a Double-Circuit Transmission Line System (자기단 전원 임피던스 추정 기법을 사용한 병행 2회선 송전선로 고장점 표정 알고리즘)

  • Park, Gun-Ho;Kang, Sang-Hee;Kim, Sok-Il;Shin, Jonathan H.
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.61 no.3
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    • pp.373-379
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    • 2012
  • This paper presents a fault location algorithm based on the adaptively estimated value of the local sequence source impedance for faults on a parallel transmission line. This algorithm uses only the local voltage and current signals of a faulted circuit. The remote current signals and the zero-sequence current of the healthy adjacent circuit are calculated by using the current distribution factors together with the local terminal currents of the faulted circuit. The current distribution factors consist of local equivalent source impedance and the others such as fault distance, line impedance and remote equivalent source impedance. It means that the values of the current distribution factors can change according to the operation condition of a power system. Consequently, the accuracy of the fault location algorithm is affected by the two values of equivalent source impedances, one is local source impedance and the other is remote source impedance. Nevertheless, only the local equivalent impedance can be estimated in this paper. A series of test results using EMTP simulation data show the effectiveness of the proposed algorithm. The proposed algorithm is valid for a double-circuit transmission line system where the equivalent source impedance changes continuously.

Insulation coordination of 765 KV double circuit transmission line (765 KV 2 회선(回線) 송전선(送電線) 절연협조(絶緣協助))

  • Kim, Jeong-Boo;Min, Suk-Won;Lee, Dong-Il
    • Proceedings of the KIEE Conference
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    • 1988.07a
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    • pp.774-777
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    • 1988
  • This paper covers the insulation coordination of 765 KV transmission line in Korea Electric Power Corporation. The design for the lightning, switching surge, and contamination was conducted to increase the reliability of 765 KV line. The authors have used the result of a limited Westinghouse ANACOM swiching surge study of the Korea Electric Corporation's 765 KV Expansion plan. The study investigated the switching surge overvoltage distribution and maximum switching overvoltage when relosing 765 KV lines. They used the technical data of the suspension insulator for the contamination design, which was available from a foreign insulator manufacture. From this paper, the authors find out that the contamination design dominates to determine the number of insulator and the SOV design dominates the air clearance in the tower. Afterwards the authors will confirm this design by Demonstration Test with Korea Electro-technology Research Institute.

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Analysis of Medium Voltage Power-Line Channel Characteristics Considering the Skin Effect (표피효과를 고려한 중전압 전력선 채널특성 분석)

  • 김선효;이원태;이영철
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.6 no.5
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    • pp.731-738
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    • 2002
  • In this paper, we analyzed a medium voltage power line characteristics considering the skin effect for high speed data transmission. Medium power-line characteristics impedance was obtained by the S-parameter method which is used in high frequency band. Power line channel characteristics was measured using it designed coupler, it is a wide band coupler between medium powe-line and measurement system. Attenuation characteristics along the frequency was decreased linearly when skin effect was considered but attenuation characteristics along the frequency was decreased linearly when skin effect was not considered. Impedance was showed lower and lower in proportional to frequency, and variation was decreased in proportional to frequency.

A study on the transmission system realization using residential power line carrier (전등선 반송방식 통신시스템 실현에 관한 연구)

  • Kim, In-Soo;Oh, Won-Rock;Kim, Kwan-Ho;Oh, Sang-Ki
    • Proceedings of the KIEE Conference
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    • 1989.07a
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    • pp.707-711
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    • 1989
  • This system exchange half-duplex serial data at 1200 baud by FSK modulating a carrier frequency at 200KHz over the 110V A.C. power line. Transmitter output voltage to A.C. line is 4V p-p and line sensitivity is selected 2.54mV because CISPR Noise limitation is 66dBμV at 150 500KHz. The designed and realized system has abtained system margin of 58 dB and probability of error, Pe = 1.78×107 was obtained

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A Study on Description of IEC 61850 based Substation Topology for Implementing the Engineering Tool of Digital Substation (디지털변전소 엔지니어링 툴 구현을 위한 IEC 61850 국제규격 기반의 변전소 토폴로지 표현에 관한 연구)

  • Lee, Nam-Ho;An, Yong Ho;Jang, Byung-Tae
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.29 no.9
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    • pp.23-32
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    • 2015
  • In order to complete engineering works of the digital substation, Both Data transmission among a variety of IEDs and HMIs, and single line diagram of the substation might be done based on XML documents published in IEC 61850 international standards. This kind of XML based engineering process for the digital substation must be implemented not by manual written work but by the engineering tool using a computer. But most of the engineering tools do not support system based engineering works such as single line diagram of the substation but have only function to set IEDs as single device unit. Accordingly, this paper presents a new design method of the system based engineering description applicable to real IEC 61850 based substation through analyzing the current international standard and its sampled engineering file, and shows implementation of the engineering tool of the digital substation with the result of this study.

A Study on the ASK Communication Modem over Electrical Power Lines (전력선을 이용한 ASK통신 모뎀에 관한 연구)

  • 사공석진;송문규
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.17 no.9
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    • pp.951-962
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    • 1992
  • The layout of electrical power distribution networks never involved communications aspects. As a result their transmission properties severly complicate the use as data links. Futhermore bandwidth as well as transmission power is restricted. Nevertheless, power distribution net works represent a most attractive medium for digital communication purposes due to an ever increasing demand, e.g., for environment management of buildings, office automation, and remote meter reading or security monitoring. In this paper, a power line modem which is capable of transmitting and receiving data at 1200 bps using OOK-BASK through 220V AC power lines is implemented. The receiver includes noncoherent detector and performs soft decision. The OLM circuits can be simplified by use of microprocessor. The PLM also satisfies CENELEC, European standards, and can be applied to home automation system.

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On discrete nonlinear self-tuning control

  • Mohler, R.-R.;Rajkumar, V.;Zakrzewski, R.-R.
    • 제어로봇시스템학회:학술대회논문집
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    • 1991.10b
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    • pp.1659-1663
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    • 1991
  • A new control design methodology is presented here which is based on a nonlinear time-series reference model. It is indicated by highly nonlinear simulations that such designs successfully stabilize troublesome aircraft maneuvers undergoing large changes in angle of attack as well as large electric power transients due to line faults. In both applications, the nonlinear controller was significantly better than the corresponding linear adaptive controller. For the electric power network, a flexible a.c. transmission system (FACTS) with series capacitor power feedback control is studied. A bilinear auto-regressive moving average (BARMA) reference model is identified from system data and the feedback control manipulated according to a desired reference state. The control is optimized according to a predictive one-step quadratic performance index (J). A similar algorithm is derived for control of rapid changes in aircraft angle of attack over a normally unstable flight regime. In the latter case, however, a generalization of a bilinear time-series model reference includes quadratic and cubic terms in angle of attack. These applications are typical of the numerous plants for which nonlinear adaptive control has the potential to provide significant performance improvements. For aircraft control, significant maneuverability gains can provide safer transportation under large windshear disturbances as well as tactical advantages. For FACTS, there is the potential for significant increase in admissible electric power transmission over available transmission lines along with energy conservation. Electric power systems are inherently nonlinear for significant transient variations from synchronism such as may result for large fault disturbances. In such cases, traditional linear controllers may not stabilize the swing (in rotor angle) without inefficient energy wasting strategies to shed loads, etc. Fortunately, the advent of power electronics (e.g., high-speed thyristors) admits the possibility of adaptive control by means of FACTS. Line admittance manipulation seems to be an effective means to achieve stabilization and high efficiency for such FACTS. This results in parametric (or multiplicative) control of a highly nonlinear plant.

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Analysis and Comparision of Measured and Calculated Value on Magnetic Fields Strength under Transmission Lines (초고압 송전선로의 자계크기 해석과 실측 비교)

  • Cho, Sung-Bae;Lee, Eun-Woong
    • 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.

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Radio coverage prediction of RF-CBTC system under transmission power 10mW/MHz at K-AGT test line (경전철시험선에서 송신전력 10mW/MHz에 대한 열차제어용 무선시스템의 전파도달범위 예측)

  • Cho, Bong-Kwan;Jung, Jae-Il
    • Journal of the Korean Society for Railway
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    • v.10 no.5
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    • pp.589-595
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    • 2007
  • Korea Railroad Research Institute has developed the driverless rubber-tired K-AGT (Korean-Automated Guideway Transit) system from 1999 to 2005 and has done its performance and reliability tests on the test line at Gyeongsan-city. Radio Frequency Communication-Based Train Control system of K-AGT, which employed Advanced Automated Train Control scheme, detects train position using the radio propagation delay between wayside and vehicle radio equipment. In this paper, we investigate whether the transmission power of radio system can be reduced to the permitted level announced by the Ministry of Information and Communication for license-free ISM(Industrial Scientific Medical) frequency bands. We first determine radio propagation model, using the measured data at test line, and perform simulation for radio coverage prediction. From the simulation results, we identify that the radio system operated with reduced power can provide good link quality in total test line.

Study on Very High-Rate Power Line Communications for Smart Grid (스마트그리드를 위한 초고속 전력선통신기술 연구)

  • Choi, Sung-Soo;Oh, Hui-Myoung;Kim, Young-Sun;Kim, Yong-Hwa
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.60 no.6
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    • pp.1255-1260
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    • 2011
  • In this paper, we study on the reliability of Very High-rate Power Line Communication (VH-PLC) for Smart Grid, so that the resultant data rate is over 400Mbps at a physical layer. Firstly, reviewing the research trend of the PLC, we discuss the required techniques for supporting the Smart Grid. Considering a pre-specification with the value of several parameters, we investigate a multi-carrier modulation technique to overcome limitations of higher rate transmission under power line channel environments. Then, we propose a system specification of the VH-PLC in the sense of enhancing two features. One is resolving the problem of the co-existence of the deployed high-speed PLC according to the published standardization of KS X 4600-1 in Korea. The other is getting better performance on the grid adopting the diverse element techniques, such as multi-carrier modulation, a subcarrier utilization mode, a variable rate LDPC (Low Density Parity Check) code, and a time and frequency diversity technique. Further, a simulation tool, composed of an Event-Driven simulator and a Time-Driven simulator, is developed for the purpose of verifying the system performance and continuously cross-checking the test bench signal of the proposed VH-PLC system.