• Title, Summary, Keyword: Single line-to-ground fault

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Analysis of Transient Characteristics of a SFCL Applied Into Third-winding Transformer in a Single Line-to-ground Fault (1선 지락 사고 시 3 권선 변압기에 적용된 초전도 한류기의 동작 특성 분석)

  • Choi, Hye-Won;Choi, Hyo-Sang;Jung, Byung-Ik
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.62 no.7
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    • pp.1033-1037
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    • 2013
  • Coercion transformer is commonly used in the electrical grid which in three phase of distribution system. The accident of the electrical grid is divided into a single, a double, a third line-to-ground faults and a double, a third line-to-line faults. A single line-to-ground fault accounts for nearly 75[%] among them. In this research, when a Superconducting Fault Current Limiters (SFCL) was applied to the three phase power system, operation in a single line-to-ground fault and limiting characteristics of fault current according to turns ratio of third winding were analyzed. When a single line-to-ground fault happened, secondary winding's circuit was open. Then third winding's circuit with a SFCL was closed. So fault current was limited by diverted circuit. At this time, we could find out that size of the limited fault current could be changed according to third winding rate. We confirmed that limiting operation of the fault current was carried out within one-period. These results will be utilized in adjusting the size of the SFCL.

The characteristic of leakage current of ZnO block varistor according to fault conditions of three-phase four-wire distribution system (3상 배전계통의 고장조건에 따른 산화아연 피뢰기 소자의 누설전류 특성)

  • Lee, B.H.;Choi, H.S.;Kang, S.M.;Park, K.Y.;Lee, S.B.;Oh, S.K.
    • Proceedings of the KIEE Conference
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    • pp.174-177
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    • 2003
  • Kinds of most frequent faults happened on overhead distribution system are the single line-to-ground fault, the line-to-line fault and the two line-to-ground fault. Occasionally, the three line-to-ground fault and the disconnection of a wire are happened in severe conditions. In this study, the single line-to-ground fault, the line-to-line fault, two line-to-ground fault on three-phase four-wire overhead distribution system were experimentally simulated and characteristics of total leakage current of distribution arrester caused by these faults were investigated. Also, the changing aspect of total leakage current of distribution arrester caused by voltage variation was investigated. In a consequence, abnormal voltages caused by voltage variation, the line-to-line fault, the two line-to-ground fault have a little effect on total leakage current of ZnO arrester. But abnormal voltages caused by the single line-to-ground fault have an important effect on total leakage current of ZnO arrester.

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Operating properties of resistive type superconducting fault current limiters with a single line-to-ground fault (1선지락사고에 대한 초전도한류기의 동작특성)

  • Park, Hyo-Sang;Park, Chang-Joo;Lee, Sang-il;Chung, Soo-Bok;Oh, Geum-Kon;Chung, Hun-Sang
    • Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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    • pp.279-281
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    • 2003
  • We analysed the operating properties of resistive type superconducting fault current limiters (SFCLs) based on YBCO thin films with a single line-to-ground fault. When a single line-to-ground fault occurred, the short circuit current of a fault phase increased up to about 6 times of transport currents immediately after the fault instant and was effectively limited to the designed current level within 2 ms by the resistance development of the SFCL. The fault currents of the sound phases almost did not change because of their direct grounding system. The unsymmetrical rates of a fault phase were distributed from 6.4 to 1.4. It was found that the unsymmetrical rates of currents were noticeably improved within one cycle after the fault instant. We calculated the zero phase currents for a single line-to-ground fault using the symmetrical component analysis. The positive sequence resistance was reduced remarkably right after the fault but eventually approached the balanced positive resistance component prior to the system fault. This means that the system reaches almost the three-phase symmetrical state in about 60 ㎳ after the fault. The ground currents were almost 3 times of the zero phase mts since most of the fault currents flowed through the grounding line.

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Unbalanced Characteristics of the Superconducting Fault Current Limiters with a Single Line-to-ground Fault (1선 지락사고에 대한 초전도한류기의 불평형 특성)

  • Choi, Hyo-Sang;Lee, Na-Young;Lee, Sang-Il
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.18 no.9
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    • pp.851-855
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    • 2005
  • We investigated the unbalanced characteristics of the superconducting fault current limiters (SFCLs) based on YBCO thin films with a single line-to-ground fault. When a single line-to-ground fault occurred, the short circuit current of a fault phase increased about 6 times of transport currents after the fault onset but was effectively limited to the designed current level within 2 ms by the resistance development of the SFCL. The fault currents of the sound phases almost did not change because of their direct grounding system. The unbalanced rates of a fault phase were distributed from 6.4 to 1.4. It was found that the unbalanced rates of currents were noticeably improved within one cycle after the fault onset. We calculated the zero phase currents for a single line-to-ground fault using the balanced component analysis. The positive sequence resistance was reduced remarkably right after the fault onset but eventually approached the balanced positive resistance component prior to the system fault. This means that the system reaches almost the three-phase balanced state in about 60 ms after the fault onset at the three-phase system.

Double-Circuit Transmission Lines Fault location Algorithm for Single Line-to-Ground Fault

  • Yang, Xia;Choi, Myeon-Song;Lee, Seung-Jae
    • Journal of Electrical Engineering and Technology
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    • v.2 no.4
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    • pp.434-440
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    • 2007
  • This paper proposes a fault location algorithm for double-circuit transmission lines in the case of single line-to-ground fault. The proposed algorithm requires the voltage and current from the sending end of the transmission line. The fault distance is simply determined by solving a second order polynomial equation which is achieved directly by the analysis of the circuit. In order to testify the performance of the proposed algorithm, several other conventional approaches have been taken out to compare with it. The test results corroborate its superior effectiveness.

Current Limiting Characteristics of a Resistive SFCL for a Single-line-to-ground Fault in the 22.9 kV System (1선 지락사고에 대한 배전급 저항형 초전도 한류기의 전류제한특성)

  • 최효상;황시돌;현옥배
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.14 no.6
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    • pp.505-510
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    • 2001
  • We simulated the current limiting characteristics of a resistive superconducting fault current limiter (SFCL) for a single line-to-ground fault in the 22.9 kV system. The transient current during the fault increased to 6.33 kA, 5.80 kA and 3.71 kA without SFCL at the fault angles 0$^{\circ}$, 45$^{\circ}$ and 90$^{\circ}$, respectively, a resistive SFCL limited effectively the fault current to 2.27 kA in a half cycle without any DC components. The maximum quench resistance of an SFCL, 16Ω was suggested to be appropriate to limit the fault current in the 22.9 kV distribution system, considering the operating cooperation of a protective relay and the current limiting performance of an SFCL.

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A Fault Indicator Generation Algorithm using Phase Angle of Zero-Sequence Current in Ungrounded System (비접지 계통에서 영상전류 위상을 이용한 고장표시 생성 알고리즘)

  • Lim, Hee-Taek;Lim, Il-Hyung;Choi, Myeon-Song;Lee, Seung-Jae
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.57 no.7
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    • pp.1141-1149
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    • 2008
  • Most faults are single-phase-to-ground fault in ungrounded system. The fault currents of single-phase-to-ground are much smaller than detection thresholds of measurement devices, so detecting single-phase-to-ground faults is difficult and important in ungrounded system. This paper proposed to a FI(Fault Indicator) generation algorithm in ungrounded system. The algorithm just using line-to-line voltage and zero-sequence current detects fault line, fault phase, fault section and FI(Fault Indicator) at terminal device, This paper also proposed to application plan for this algorithm. In the case study, the proposed algorithm has been testified in demo system by Matlab/Simulink simulations.

A New 3D SVM Method under Single-Line-to-Ground Fault in Three Phase Four Wire Interlinking Converter (3상 4선식 인터링킹 컨버터의 1선 지락 사고 발생 시 3D SVM 기법)

  • An, Chang-Gyun;Choi, Bong-Yeon;Kim, Mi-na;Kang, Kyung-Min;Lee, Hoon;Won, Chung-Yuen
    • Proceedings of the KIPE Conference
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    • pp.106-107
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    • 2019
  • This paper propose a new 3D SVM method for three-phase four wire inverter for fault isolation at a single line ground fault. The available switching combination for isolation of a single line ground fault was analyzed. Using this method, voltage vector diagrams according to each switching combination were classified according to various ground fault situations, and 3D SVM method was performed by generating command for fault isolation. The proposed methods are mathematically analyzed and verified by PSIM simulation.

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The Advanced Protection Coordination Scheme using Phase Angle of Zero-Sequence Current in Ungrounded System (비접지 계통에서 영상전류 위상을 이용한 개선된 보호협조 방안)

  • Choi, Young-Jun;Lim, Hee-Taek;Choi, Myeon-Song;Lee, Seung-Jae
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.59 no.1
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    • pp.19-25
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    • 2010
  • Most faults are single-phase-to-ground fault in ungrounded system. The fault currents of single-phase-to-ground are much smaller than detection thresholds of measurement devices, so detecting single-phase-to-ground faults is difficult and important in ungrounded system. The protection coordination method using SGR(Selective Ground Relay) and OVGR(Overvoltage Ground Relay) is generally used in ungrounded system. But this method only detects fault line and it has the possibility of malfunction. This paper proposed to advanced protection coordination method in ungrounded system. The method just using zero-sequence current can detect fault line, fault phase, fault section at terminal device. The general protection method is used to back up protection. In the case study, the proposed method has been testified in demo system by Matlab/Simulink simulations.

Analysis on Reduction Method of Symmetrical Fault Current in a Power System with a SFCL applied into Neutral Line (전력계통의 중성선에 적용된 초전도한류기의 대칭고장전류 저감방안 분석)

  • Lim, Sung-Hun
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.23 no.2
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    • pp.148-152
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    • 2010
  • The superconducting fault current limiter (SFCL) applied into the neural line of a power system, which can limit the unsymmetrical fault current from the single-line ground fault or the double-line ground fault, was reported to be the effective application location of the SFCL in a power system. However, the limiting operation for the symmetrical fault current like the triple line-ground fault is not effective because of properties of the balanced three-phase system. In this paper, the limiting method of the symmetrical fault current in a power system with a SFCL applied into neutral line was suggested. Through the short-circuit experiments of the three-phase fault types for the suggested method, the fault current limiting and recovery characteristics of the SFCL in the neutral line were analyzed and the effectiveness of the suggested method was described.