• Title/Summary/Keyword: Combined Transmission Line

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A Study on Overvoltage Reduction Method of Single Point Bonded Section on Combined Transmission Lines (혼합송전선로 편단접지 구간 과전압 저감 방안에 관한 연구)

  • Jung, Chae-Kyun;Kang, Ji-Won;Park, Hung-Sok;Kim, Jin
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.58 no.10
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    • pp.1881-1887
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    • 2009
  • This paper discusses the effects of ECC (Earth Continuity Conductor) for reducing the level of induced sheath overvoltages at the single point bonded section of combined transmission lines which are mixed underground power cable with overhead line in one T/L. In previous papers, the characteristics of ECC on only underground power cable systems were sufficiently analyzed. However, the result of only underground power cable systems are totally different from that of combined transmission lines because ECC is commonly grounded with overhead grounding wire at mesh of cable head. Therefore, in this paper, the installation effects of ECC have been variously analyzed considering the three kinds of fault positions, cable formation of duct and trefoil, spacing between phase conductor and ECC, and the change of overhead transmission line section length on 154kV combined transmission line. Finally, simulation results show that ECC can effectively reduce the induced sheath voltage.

Improvement of Digital Distance Relaying Algorithm Using Wavelet Transform in Combined Transmission Line (웨이브렛을 이용한 혼합송전선로에서의 거리계전 알고리즘 개선)

  • 정채균;김경호;하체웅;이종범;윤양웅
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.52 no.10
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    • pp.593-601
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    • 2003
  • Distance realy is tripped by the line impedance calculated at the relay point. Accordingly the accurate operation depends on the precise calculation of line impedance. Impedance can be accurately calculated in case of overhead line. However, in case of power cables or combined transmission lines, impedance can not be accurately calculated because cable systems have the sheath, grounding resistance, and sheath voltage limiters(SVLs). There are also several grounding systems in cable systems. Therefore, if there is a fault in cable systems, these terms will severely be caused much error to calculation of impedance. Accordingly the proper compensation should be developed for the correct operation of the distance relay. This paper presents the distance calculating algorithm in combined transmission line with power cable using wavelet transform. In order to achieve such purpose, judgement method to discriminate the fault section in both sections was proposed using D1 coefficient summation in db4. And also, error compensation value was proposed for correct calculation of impedance in power cables section.

Effects of Reclosing for Insulation Coordination in 345kV Combined Transmission Lines (345kV 혼합송전선로에서 재폐로가 절연설계에 미치는 영향)

  • Lee, Jong-Beom;Jung, Chae-Kyun;Lim, Kwang-Sik;Kang, Ji-Won
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.59 no.5
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    • pp.847-853
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    • 2010
  • This paper describes switching surge analysis for reclosing decision in 345kV combined transmission line with XLPE power cable. Reclosing operation should be decided based on the detailed technical analysis in combined transmission line because this line includes power cable section which is week on insulation. Insulation of power cable can be breakdown at the week point in case of reclosing moment. Therefore the detailed analysis has to be carried out by considering several conditions such as length ratio of power cable section, arrestor, inserting resistance, charging rate, grounding resistance, etc.. On the other hand sheath voltage on IJ(Insulated Joint) is analyzed to check dangerous condition on cable cover. Analysis is performed by EMTP/ATP. Analysis results show that reclosing can be operated as the single line-to-ground fault occurs on overhead line in 345kV combined transmission line, if the inserting resistance is considered before the operation of main circuit breaker.

Fault Location in Combined Transmission Systems Using Wavelet Transform (웨이브렛 변환을 이용한 혼합송전계통에서의 Fault Location)

  • Jung, Chae-Kyun;Hong, Dong-Suk;Lee, Jong-Beom
    • Proceedings of the KIEE Conference
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    • 2001.05a
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    • pp.226-229
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    • 2001
  • The combined transmission lines with the underground power cables are continuously expanded in power systems. So the fault of combined transmission line is increased every year as the complication of underground transmission line. In this paper. traveling wave theory and DWT wavelet transform are used for fast and accurate detection of fault location at the combined transmission line. Traveling wave travels to each bus like surge and repeats reflection and transmission till transient signal is completely disappeared. When fault is occurred on overhead and underground tine, the fault location detecting algorithm was performed with using continuous peak value time-delay of traveling wave reflected from A bus.

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A Study on Reclosing Decision on 154kV Combined Transmission Lines (154kV 혼합송전선로 재폐로 결정에 관한 연구)

  • Jung, Chae-Kyun;Park, Hung-Sok;Kang, Ji-Won;Lee, Jong-Beom
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.59 no.10
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    • pp.1761-1769
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    • 2010
  • This paper describes switching surge analysis on reclosing decision in 154kV combined transmission line with power cables. Reclosing should be operated in combined transmission line based on the technical evaluation because of insulation problem of power cable section. If the surge strikes on power cable, the breakdown can occur at week point of cable insulation. Therefore the detailed analysis is required by considering several conditions such as length ratio of power cable, arrester, fault resistance, charging rate and grounding resistance, etc.. In addition, sheath voltage on IJ(Insulated Joint) is analyzed to confirm the protective level. Simulation is performed by EMTP/ATP. Analysis results show that reclosing can be operated without any special problem by the single line-to-ground fault with fault resistance of $1\Omega$ to $50\Omega$ occurred at the overhead transmission section in 154kV combined transmission lines and trap charge of 100% and 110%.

A Digital Distance Relaying Algorithm in Combined Transmission Line Connected whth Overhead Line and Underground Cable (가공송전선로와 지중송전선로가 연계된 혼합송전선로에서 디지털 거리계전 알고리즘)

  • Ha, Che-Wung;Lee, Jong-Beom
    • Proceedings of the KIEE Conference
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    • 2000.07a
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    • pp.440-442
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    • 2000
  • This paper describes the digital distance algorithm in case of combined transmission line connected with overhead line and underground cable. Actually as fault is occurred in cable, it results in the complicated phenomena due to the several kind of grounding method in the sheath of cable. Accordingly the impedance. Therefore the correct impedance calculation algorithm is requested in combined transmission line to avoid the wrong trip of relay. This paper presents the development result of impedance calculation algorithm In such transmission line.

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Calculation Method of Dedicated Transmission Line's Meteological Data to Forecast Renewable Energy (신재생에너지 예측을 위한 송전선로의 계량 데이터 계산 방법)

  • Ja-hyun, Baek;Hyeonjin, Kim;Soonho, Choi;Sangho, Park
    • KEPCO Journal on Electric Power and Energy
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    • v.8 no.2
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    • pp.55-59
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    • 2022
  • This paper introduce Renewable Energy forecasting technology, which is a part of renewable management system. Then, calculation method of dedicated transmission line's meteorological data to forecast renewable energy is suggested. As the case of dedicated transmission line, there is only power output data combined the number of renewable plants' output that acquired from circuit breakers. So it is need to calculate meteorological data for dedicated transmission line that matched combined power output data. this paper suggests two calculation method. First method is select the plant has the largest capacity, and use it's meteorological data as line meteorological data. Second method is average with weight that given according to plants' capacity. In case study, suggested methods are applied to real data. Then use calculated data to Renewable forecasting and analyze the forecasting results.

Analysis of Lightning Overvoltage on the Underground Power Cable at the Striking of Lightning Surge to the Combined Transmission Line (혼합송전선로에 뇌서지침입시 지중송전선로에서의 뇌과전압 해석)

  • Kim, Nam-Yeol;Lee, Jong-Beom;Jang, Seong-Hwan;Gang, Ji-Won
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.51 no.10
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    • pp.502-509
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    • 2002
  • In the analysis of lightning surges, transmission towers are usually simulated by ATPDraw. The modeling of transmission towers is an essential part of the traveling wave analysis of lightning surges in transmission lines. The tower model is applied to the 154kV transmission tower of which surge performance characteristics are measured Tower surge response is computed using nonuniform, single-phase line models for both transmission tower and ground wire. The overvoltage will effect to the underground transmission line. The underground cable is combined by duct and trefoil type, and the each arrester is placed on the leading-in tube and outgoing tube. This paper analyzed the effect of lightning overvoltage on the underground cable system.

Proper Cable Arrangement Selection by Induced Voltage Evaluation of DC Cable in AC/DC Hybrid Combined Transmission Systems (AC/DC 하이브리드형 혼합송전계통에서 DC 케이블의 유도전압평가에 의한 적정배열 선정)

  • Son, Yong-Dae;Lee, Jong-Beom
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.64 no.5
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    • pp.680-688
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    • 2015
  • Hybrid type combined transmission systems is being operated by AC and DC line at the same space will be expanded instead of the overhead line. However, such hybrid type combined system has problem like the arrangement selection of DC cable for effective system operation. In this paper, to select the proper arrangement of DC cable, induced voltage of DC cable influenced by AC cable was analyzed in case of several type arrangement of DC cable. Such induced voltage is in detailed analyzed not only in case of steady, but transient state. The arrangement which has the lowest induced voltage is selected as the proper one. EMTP/ATPDraw is used for modeling and analysis of hybrid type combined transmission system.

A Study on a Fault Location Algorithm Using Wavelet Transform in Combined Transmission Systems (혼합송전계통에서 웨이브렛 변환을 이용한 고장점 탐색 알고리즘에 관한 연구)

  • Jeong, Chae-Gyun;Lee, Jong-Beom;Yun, Yang-Ung
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.51 no.5
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    • pp.247-254
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    • 2002
  • This paper describes a fault location algorithm in real combined transmission systems with underground power cable. The algorithm to calculate the fault location was developed using DWT wavelet transform and travelling wave occurred at fault point. And the proposed algorithm is also used the transient signal of one end in stead of the signal information of two ends. On the other hand, in this papers, the method to discriminate fault point between overhead line and cable section is also Proposed. Variety simulations were carried out to verify the accuracy and effectiveness of the proposed algorithm using EMTP/ATFDraw and Matlab. Simulation results show that the proposed method has the excellent ability for discrimination of fault section and fault location in combined transmission systems with power cables.