• 제목/요약/키워드: Combined Transmission Line

검색결과 96건 처리시간 0.024초

TEM 형과 Loop 형의 전송소자를 이용한 16채널 3T Body 전송코일의 자장 균일도와 안전도 비교 (The Comparison of Field Uniformity and SAR between TEM, Loop and Combined Elemented 16 Channel Transmit Arrays)

  • 류연철;김영범
    • 전기학회논문지
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    • 제63권3호
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    • pp.404-408
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    • 2014
  • In this research we evaluate the excitation homogeneity and SAR of three different Tx arrays after B1+ Shimming in the human body at 3T. Through the simulations, we compared the field properties that are standard deviation and mean value of transverse magnetization for 1) strip line TEM array, 2) rectangular loop array, 3) combined array of strip line element and rectangular loop and shown the utilities of B1+ shimming in human body model. After B1+ shimming, it is evaluated four different types of SAR for body mesh through whole body simulation; those are average, maximum 1-cell, maximum 1-gram, and maximum 10-gram SAR. It appears that in this particular comparison an array based on strip line elements can produce better homogeneity and lower SAR than an array of rectangular loops or an array of combined elements (strip line and loop). While many factors are considered in designing coils for production, it is hoped that methods and results like these will be used in the future to guide decisions and maximize benefit.

UPFC가 연계 된 강진-장흥 송전선로 보호용 거리계전기의 동작특성에 관한 연구 (A Study on Operation Zone of Adaptive Distance Relay on Transmission Line Connected UPFC Between Kangjin and Jangheung)

  • 이승혁;정창호;김진오;정현수
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2003년도 하계학술대회 논문집 A
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    • pp.305-307
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    • 2003
  • This paper presents an apparent impedance calculation procedure for distance relaying of transmission line involving FACTS (Flexible AC Transmission System) devices, particularly the UPFC (Unified Power Flow Controller), between Kangjin and Jangheung in Korea. With the changes of UPFC's parameters, the measurement and protective range (trip boundaries) of the adaptive distance relay can also be changed. So, it is the most important part in the field of system protection to analyze the operating characteristic of relaying system. The presence of UPFC significantly affects the trip boundaries which are also adversely affected by fault resistance combined with remote end infeed. This paper presents the apparent impedance calculations and the distance relay setting characteristics for faults involving the UPFC in the KEPCO system.

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A Novel Algorithm for Fault Classification in Transmission Lines Using a Combined Adaptive Network and Fuzzy Inference System

  • Yeo, Sang-Min;Kim, Chun-Hwan
    • KIEE International Transactions on Power Engineering
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    • 제3A권4호
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    • pp.191-197
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    • 2003
  • Accurate detection and classification of faults on transmission lines is vitally important. In this respect, many different types of faults occur, such as inter alia low impedance faults (LIF) and high impedance faults (HIF). The latter in particular pose difficulties for the commonly employed conventional overcurrent and distance relays, and if undetected, can cause damage to expensive equipment, threaten life and cause fire hazards. Although HIFs are far less common than LIFs, it is imperative that any protection device should be able to satisfactorily deal with both HIFs and LIFs. Because of the randomness and asymmetric characteristics of HIFs, their modeling is difficult and numerous papers relating to various HIF models have been published. In this paper, the model of HIFs in transmission lines is accomplished using the characteristics of a ZnO arrester, which is then implemented within the overall transmission system model based on the electromagnetic transients program (EMTP). This paper proposes an algorithm for fault detection and classification for both LIFs and HIFs using Adaptive Network-based Fuzzy Inference System (ANFIS). The inputs into ANFIS are current signals only based on Root-Mean-Square (RMS) values of 3-phase currents and zero sequence current. The performance of the proposed algorithm is tested on a typical 154 kV Korean transmission line system under various fault conditions. Test results demonstrate that the ANFIS can detect and classify faults including LIFs and HIFs accurately within half a cycle.

DB Index 방식 상시 유도전압 시뮬레이터의 개발 (Development of DB index method simulator for induced voltage in steady state)

  • 푸준;권오상;김철환;정창수;유연표
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2006년도 제37회 하계학술대회 논문집 A
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    • pp.284-285
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    • 2006
  • This paper presents DB Index method simulator for induced voltage to a communication line from an overhead power transmission line in steady state. DB index method is based on EMTP simulation results. The simulation is implemented for 3,500,000 cases which are combined by employing transmission line parameter of KEPCO.

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자율 학습 신경회로망을 이용한 고장상 선은 알고리즘 (The Discrimination of Fault Type by Unsupervised Neural Network)

  • 이재욱;최창열;장병태;이명회;노장현
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2004년도 하계학술대회 논문집 A
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    • pp.384-387
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    • 2004
  • The direction and the type of a fault on a transmission line need to be identified rapidly and correctly, The work described in this paper addresses the problem encountered by a conventional algorithm in a fault type classification in double circuit line, this arises due to a mutual coupling and CT saturation under the fault condition. We present an approach to identify fault type with novel neural network on double circuit transmission line. The neural network based on combined unsupervised training method provides the ability classify the fault type by different patterns of the associated voltages and currents.

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사고현장과 사령실간 화상전송기술에 관한 연구(II) (A study on the moving picture transmission method between the accident sites and control center(II))

  • 장석각;조봉관
    • 한국철도학회:학술대회논문집
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    • 한국철도학회 2003년도 추계학술대회 논문집(III)
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    • pp.653-658
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    • 2003
  • This study is represented a method to give connect to optical cable from accident site and reviewed the method to transmission a moving image to control centre by real time, following the study of image transmission method in copper cable section where is a main line of railroad communication. Concept of network is studied to use cable and equipment effectively, and it's also reviewed technology of digital image transmission system and image evaluation methods, in spite of the pixel of camera and monitor resolution determine quality of image when moving image transferring by point to point. In addition, this study is reviewed checks and considerations of image transmission equipment (codec) with various transmission methods in room test, and then examined and analyzed wire/wireless combined transmission methods at wayside.

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전력계통안정화를 위한 간접적응 비선형제어 (Indirect adaptive nonlinear control for power system stabilization)

  • 이도관;윤태웅;이병준
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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    • pp.454-457
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    • 1997
  • As in most industrial processes, the dynamic characteristics of an electric power system are subject to changes. Amongst those effects which cause the system to be uncertain, faults on transmission lines are considered. For the stabilization of the power system, we present an indirect adaptive control method, which is capable of tracking a sudden change in the effective reactance of a transmission line. As the plant dynamics are nonlinear, an input-output feedback linearization method equipped with nonlinear damping terms is combined with an identification algorithm which estimates the effect of a fault. The stability of the resulting adaptive nonlinear system is investigated.

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비선형 적응제어를 이용한 전력계통 안정화 (Power system stabilization via adaptive feedback linearization)

  • 윤태웅;이도관
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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    • pp.1221-1224
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    • 1996
  • As in most industrial processes, the dynamic characteristics of an electric power system are subject to changes. Amongst those effects which cause the system to be uncertain, faults on transmission lines are considered. For the stabilization of the power system, we present an indirect adaptive control method, which is capable of tracking a sudden change in the effective reactance of a transmission line. As the plant dynamics are nonlinear, an input-output feedback linearization method is combined with an identification algorithm which estimates the effect of a fault.

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Right/Left-Handed 전송 선로를 결합한 가변 대역 저지 필터 (Tunable Bandstop Filter with Combined Right/Left-Handed Transmission Lines)

  • 성규제;김일규;김영;윤영철
    • 한국전자파학회논문지
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    • 제19권10호
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    • pp.1122-1128
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    • 2008
  • 본 연구에서는 Right-handed 전송 선로(RHTL)의 저역 통과 특성과 Left-handed 전송 선로(LHTL)의 고역 통과 특성을 결합한 구조의 가변 대역 저지 필터를 제안하였다. RHTL, LHTL의 분산 특성을 ABCD 행렬을 통해 구하고 차단 주파수를 계산하였다. 바렉터 다이오드와 칩 인덕터를 이용하여 RHTL,LHTL 단위 셀을 구성하고 각각 4개의 단위 셀이 연결된 RHTL, LHTL을 병렬로 연결하여 가변 대역 저지 특성을 구현하였다 제작된 가변 대역 저지 필터는 저역 차단 주파수 $280{\sim}395$ MHz, 고역 차단 주파수 $770{\sim}940$ MHz의 가변 특성을 갖는다.

A 90°-Bent Spur-Line Combined CRLH ZOR Bandpass Filter for the Channel of the UWB Communication System

  • Lee, Changhyeong;Kahng, Sungtek
    • Journal of Electrical Engineering and Technology
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    • 제13권2호
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    • pp.928-935
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    • 2018
  • In this paper, a compact fully printable bandpass filter is suggested for a low-frequency channel 3.2 GHz ~ 3.7 GHz in the Ultra-Wideband (UWB) communication system. It is featured with a small geometry of $0.5{\lambda}_g/15$ and a low insertion loss despite using FR4 as a cheap substrate of a high dielectric loss. This is made possible by generating zeroth-order-resonance (ZOR) from one cell comprising two series resonances obviously separated from one shunt resonance as a third-order bandpass filter. Especially, the series resonance elements are combined with spur-lines bent by 90 degrees, which makes the port-impedance matched well and eliminates spurious hikes in the stopband, while the overall size remains almost unchanged. The design is carried out by setting up the equivalent circuit and the circuit simulation is checked by the full-wave EM analysis. The structure is manufactured and measured to show that the circuit modeling and EM simulation results agree with the measured data.