• Title/Summary/Keyword: Earth fault

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An Analysis Study on the Over-voltages by the Earth Fault in 22.9kV-Y Distribution Line (22.9kV 다중접지 배전선로 자락고장으로 인한 과전압 유압사고 분석연구)

  • Park, Sang-Man;Roh, Hwang-Nal;Cho, Seong-Soo;Lee, Heung-Ho
    • Proceedings of the KIEE Conference
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    • 1999.07g
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    • pp.3126-3128
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    • 1999
  • In 22.9kV-Y overhead lines, if there is an earth fault, high fault current causes surge type over-voltages around this place. There are generally two types of earth faults. One is an earth fault which occurs when a voltage line falls to earth line. The other occurs when a voltage line directly falls to the earth. This study presents an analysis method on the earth fault.

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Reactivated Timings of Yangsan Fault in the Sangcheon-ri Area, Korea (상천리 일대 양산단층의 재활동 연대)

  • Song, Yungoo;Park, Changyun;Sim, Ho;Choi, Woohyun;Son, Moon;Khulganakhuu, Chuluunbaatar
    • Economic and Environmental Geology
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    • v.49 no.2
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    • pp.97-104
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    • 2016
  • Here we firstly present that a timing of reactivated event of Yangsan fault, the major fault in the southeastern Korean Peninsula, by using combined approaches of the optimized illite-polytype quantification, the K-Ar age-dating, and the recently developed illite-age-analysis (IAA) approach for the fault clays from Sangcheon-ri area of Yangsan main fault line. Two chronological record of brittle fault-activation event at about 41.5~43.5 and 50.7 Ma were determined from 3 fault gouges suggesting a crucial reactivation time-scheme. Furthermore, the regional processes that drive tectonics to form and reactivate the Yangsan fault may be explained from the chronological analysis for additional sites along the Yangsan fault.

Back Fed Earth Fault Detection in Three Wire-Unigrounded Distribution-System By Zero Sequence Admittance (영상어드미턴스에 의한 직접접지 배전방식에서의 역가압 지락사고 검출)

  • Yoo, Myeong-Ho;Kim, Il-Dong;Han, Hong-Seok;Pak, Chul-Won
    • Proceedings of the KIEE Conference
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    • 1993.07a
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    • pp.120-123
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    • 1993
  • This paper presents the developing a new algorithm for detecting the Back fed Earth Fault in three wire-unigrounded distribution system by zero sequence admittance. So called "Backfed Earth Fault" of the electric power distribution line refers to a class of earth faults that the load-side line only is grounded, following after the distribution line broken into two parts, the source-side and the load-side. Because its mechanism differs from that of other earth faults, it is therefore, required to examine. This paper deals with the detailed software of the digital protective relay for Backfed earth fault. In order to prove that the proposed schemes is good, we performed off-line simulation using data from EMTP and ETSA(Electrcity Trust Of South Austrilia). It is shown that the suggested algorithm is never mal operated.

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Fault Plane Solutions for the Recent Earthquakes in the Central Region of South Korea

  • Hoe, Seo-Yun;Kyung, Jai-Bok
    • Journal of the Korean earth science society
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    • v.29 no.5
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    • pp.437-445
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    • 2008
  • We analyzed fault plane solutions of the recent twenty-two earthquakes which occurred from 2004 to 2006 in the central part of the Korean Peninsula by using P- and S-wave polarities along with SH/P amplitude ratios. The fault plane solution shows that strike-slip fault is dominant here, especially for the events with local magnitude equal to or greater than 3.0. However, some events with local magnitude less than 3.0 show normal fault or strike-slip fault with normal components. In the case of strike-slip fault, its orientation is almost in the direction of NNE-SSW to NE-SW almost parallel to the general trend of faults, while the compressional axis of the stress field trends ENE to E-W. The result is almost consistent with the stress field in and around the Korean peninsula, as reported previously. We cannot give any appropriate explanations to the normal faulting events along the western offshore and inland areas whether it is related to the local stress changes or tectonically unidentified extensional structures. Thus, an extension of investigations is desirable to clarify the cause of such phenomena.

Interpretation of Paleostress using Geological Structures observed in the Eastern Part of the Ilgwang Fault (일광단층 동편에서 관찰되는 지질구조를 이용한 고응력사 해석)

  • Kim, Taehyung;Jeong, Su-Ho;Lee, Jinhyun;Naik, Sambit Prasanajit;Yang, Wondong;Ji, Do Hyung;Kim, Young-Seog
    • The Journal of Engineering Geology
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    • v.28 no.4
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    • pp.645-660
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    • 2018
  • In the southeastern part of the Korean Peninsula, huge fault valleys, including the Yangsan and Ulsan faults, are recognized. These NNE-SSW trending lineaments are called as a whole Yangsan Fault System. However, this fault system is relatively poorly studied except the Yangsan and Ulsan faults. This study deduced the paleostress history based on the mutual cross-cutting relationships between geologic structures developed in the granite body near the Ilgwang fault, which is compared with previous studies. In the study area, four lineaments parallel to the Ilgwang fault are recognized, and three of them show evidences of faulting. In each lineament, both slip-senses of left-lateral and right-lateral are recognized. It indicates that these faults consistently underwent multiple deformations of inversion along the faults. The inferred paleostress directions based on the mutual cross-cutting relationships of the geological structures are as follows: 1) Tensile fractures developed in the late Cretaceous under the ENE-WSW direction of compressive stress, 2) NW-SE trending maximum horizontal principal stress generated conjugate strike-slip faults, and 3) selective reactivations of some structures were derived under the compression by the NE-SW trending principal stress.

Performance Assessment of GBAS Ephemeris Monitor for Wide Faults (Wide Fault에 대한 GBAS 궤도 오차 모니터 성능 분석)

  • Junesol Song;Carl Milner
    • Journal of Positioning, Navigation, and Timing
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    • v.13 no.2
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    • pp.189-197
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    • 2024
  • Galileo is a European Global Navigation Satellite System (GNSS) that has offered the Galileo Open Service since 2016. Consequently, the standardization of GNSS augmentation systems, such as Satellite Based Augmentation System (SBAS), Ground Based Augmentation System (GBAS), and Aircraft Based Augmentation System (ABAS) for Galileo signals, is ongoing. In 2023, the European Union Space Programme Agency (EUSPA) released prior probabilities of a satellite fault and a constellation fault for Galileo, which are 3×10-5 and 2×10-4 per hour, respectively. In particular, the prior probability of a Galileo constellation fault is significantly higher than that for the GPS constellation fault, which is defined as 1×10-8 per hour. This raised concerns about its potential impact on GBAS integrity monitoring. According to the Global Positioning System (GPS) Standard Positioning Service Performance Standard (SPS PS), a constellation fault is classified as a wide fault. A wide fault refers to a fault that affects more than two satellites due to a common cause. Such a fault can be caused by a failure in the Earth Orientation Parameter (EOP). The EOP is used when transforming the inertial axis, on which the orbit determination is based, to Earth Centered Earth Fixed (ECEF) axis, accounting for the irregularities in the rotation of the Earth. Therefore, a faulty EOP can introduce errors when computing a satellite position with respect to the ECEF axis. In GNSS, the ephemeris parameters are estimated based on the positions of satellites and are transmitted to navigation satellites. Subsequently, these ephemeris parameters are broadcasted via the navigation message to users. Therefore, a faulty EOP results in erroneous broadcast ephemeris data. In this paper, we assess the conventional ephemeris fault detection monitor currently employed in GBAS for wide faults, as current GBAS considers only single failure cases. In addition to the existing requirements defined in the standards on the Probability of Missed Detection (PMD), we derive a new PMD requirement tailored for a wide fault. The compliance of the current ephemeris monitor to the derived requirement is evaluated through a simulation. Our findings confirm that the conventional monitor meets the requirement even for wide fault scenarios.

Studies on Mineral Composition of Fault Clay in Quaternary Ipsil Fault: High Resolution Powder Diffraction Analysis (제4기 입실 단층 파쇄대에서 나타나는 단층점토의 산출상태에 따른 광물조성 연구: 고해상도분말회절 분석을 중심으로)

  • Park, Sung-Min;Kang, Han;Jang, Yun-Deuk;Im, Chang-Bock;Kim, Jeong-Jin
    • Journal of the Mineralogical Society of Korea
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    • v.20 no.2 s.52
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    • pp.83-89
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    • 2007
  • XRD, HRPD and SEM were used for mineralogical characterization of fault clay in fracture zone from Ipsil. Variations of color in fault clay exhibit significant mineral composition difference. Fault clays from Ipsil are composed mainly of smectite, laumontite, and quartz. Laumontite, a distinct fault clay in Ipsil fault, might be resulted from alteration of bed rock in fracture zone based on the result that no laumontite was found near fault rock. Fault clays from Ipsil are composed mainly of smectite.

Mechanical Properties of Fault Rocks in Korea

  • Seo, Yong-Seok;Yun, Hyun-Seok;Ban, Jae-Doo;Lee, Chung-Ki
    • The Journal of Engineering Geology
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    • v.26 no.4
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    • pp.571-581
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    • 2016
  • To understand the mechanical properties of fault rocks, data from 584 in situ and laboratory tests on fault rocks from 33 tunnels were analyzed. The unit weights of the fault rocks range from 17.3 to $28.2kN/m^3$ and the cohesion and friction angles vary from 5 to 260 kPa and $14.7^{\circ}$ to $44.0^{\circ}$, respectively. The modulus of deformation and elasticity were generally < 200 MPa. In most cases, the uniaxial compressive strength was < 0.5 MPa, and Poisson's ratios were mainly 0.20-0.35. The mechanical properties of individual rock types were analyzed using box plots, revealing that the cohesion values and friction angles of shale and phyllite have relatively wide inter-quartile ranges and that the modulus of deformation and elasticity of shale have the lowest values of all rock types. In the analysis of mechanical properties by components of fault rocks, the largest values were shown in damage zones of individual rock types.

Fault Plane Solutions of the Recent Earthquakes in the Northern Part of the Korean Peninsula

  • Lee, Min Jeong;Kyung, Jai Bok;Chi, Heon Cheol
    • Journal of the Korean earth science society
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    • v.35 no.5
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    • pp.354-361
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    • 2014
  • Fault plane solutions in North Korea and the northern part of the Yellow Sea ($37.5^{\circ}N-40.5^{\circ}N$, $124.5^{\circ}E-128.5^{\circ}E$) was studied for the earthquakes that occurred from November, 2008 to May, 2013. The analysis was based on the data collected from seismic networks in Korea and China. Fault plane solutions were obtained from P and SH wave polarities and SH/P amplitude ratioes. Most earthquakes exhibited predominantly strike-slip fault characteristics with NNE-SSW or WNW-ESE nodal planes. The P-axes trends are mainly NE-SW or ENE-WSW direction in the northern part of the Yellow Sea and inland area of North Korea except some areas in the Hwanghae province. Fault plane solutions and main axis of stress field in the study region were similar to those observed in the southern part of the Korean Peninsula.

Protection Techniques Against Electric Shock in Low Voltage DC Grounding Systems Depending on the Analysis of Earth Fault Current Paths (저압직류 접지시스템의 지락경로 흐름 분석에 따른 감전 보호기법)

  • Kim, Dong-Woo;Lim, Young-Bea;Lee, Sang-Ick;Choi, Myeong-Il;Moon, Hyun-Wook
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.65 no.1
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    • pp.232-238
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    • 2016
  • This paper presents protection techniques against electric shock in low voltage DC(direct current) grounding systems depending on the analysis of earth fault current paths. Firstly, the comparison between alternating current and direct current on human was conducted, and current threshold values for each current path and for long duration were analyzed. Secondly, the analyses of the earth fault current flows were performed depending on the grounding types and earth fault conditions. Lastly, based on these analyses, adequate protection measures of electric shock depending on low voltage DC grounding types were provided.