• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2011년도 제42회 하계학술대회
• /
• pp.274-275
• /
• 2011

Fault current problems is considered a serious issue in the power system because large fault currents not only cause many side effects to the equipments of power system but also lead to severe problems, such as blackouts. This paper deals with the structural analysis and 3-phase fault current stability of the future Seoul metropolitan power system. The simulation composition and analysis are performed with the 4th KEPCO power supply planning data using PSS/e. Through the results of the simulations, it can be observed that the future Seoul metropolitan system results in a fault current which exceeds the circuit breaker (CB) rate. This unremovable fault current can cause critical damage to power system. To resolve the problem, the algorithm for the application of Voltage Sourced Converter Back-to-Back High Voltage Direct Current (VSC BTB HVDC) is being proposed. where the most suitable location for solving fault current problem in Seoul metropolitan area is being implemented.

• 지구물리
• /
• 제9권3호
• /
• pp.219-230
• /
• 2006

Since the key issue that 'the Yangsan fault is seismically an active fault" was raised in 1983, thegeological and geomorphological studies of active fault have been made by many researchers. These studies are mainly focused on the Yangsan fault system(YFS) and Ulsan fault system(UFS) due to many historical earthquakes occurred in this area. There are two different types of active faultings under the ENE-WSW horizontal stress field in the southeastern part of the Korean Peninsula. The NNE-trending YFS is the most prominent right-lateral strike-slip fault and has a continuous trace about 200 km long. Some part of this system has been active during the late Quaternary with evidences clearly recognized on both the northern (Yugyeri and Tosung-ri areas) and southern parts (Eonyang to Tongdosa area) of the YFS. in the southern part, the estimated vertical slip rate is about 0.02 - 0.07 mm/yr, and the lateral slip rate may be several times larger than the vertical rate. The most recent event occurred prior to deposition of Holocene alluvium, in the northern part, the fault trend locally changes to almost N-S, dips to the east and has reverse movement. The average vertical slip rate is estimated to be less than 0.1 mm/yr. The most recent event probably occurred after 1314 years BP (AD 536). The NNW-SSE (or N-S) trending UFS is a predominantly reverse fault that built up U-ie eastern mountain and has been active during U-ie late Quaternary. The fault trace is not straight but irregularly undulates along the foot of the mountain on the east. From the disturbed terraces along U-ie fault, the average vertical slip rate on U-iis system is estimated to be about 0.08.13mm/yr. The latest event is not well studied, but seems to have occurred after the last glacial maximum in the Malbang fault and 14,000 years BP in the Kalgok fault of the UFS. However, important issues such as fault segmentation, recurrence interval, age of Quaternary deposits need further studies.

• Nuclear Engineering and Technology
• /
• 제37권3호
• /
• pp.259-264
• /
• 2005

This paper presents a vital area identification (VAI) method based on the current fault tree analysis (FTA) and probabilistic safety assessment (PSA) techniques for the physical protection of nuclear power plants. A structured framework of a top event prevention set analysis (TEPA) application to the VAI of nuclear power plants is also delineated. One of the important processes for physical protection in a nuclear power plant is VAI that is a process for identifying areas containing nuclear materials, structures, systems or components (SSCs) to be protected from sabotage, which could directly or indirectly lead to core damage and unacceptable radiological consequences. A software VIP (Vital area Identification Package based on the PSA method) is being developed by KAERI for the VAI of nuclear power plants. Furthermore, the KAERI fault tree solver FTREX (Fault Tree Reliability Evaluation eXpert) is specialized for the VIP to generate the candidates of the vital areas. FTREX can generate numerous MCSs for a huge fault tree with the lowest truncation limit and all possible prevention sets.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2002년도 춘계학술대회논문집
• /
• pp.39-52
• /
• 2002

Research Direction The significant research direction in mechanical fault diagnosis area: Theorles and approaches for fault feature extracting and fault classification. Identification Complicated fault generating mechanism and its model Intelligent fault diagnosis system (including the expert system and network based remote diagnosis system) One of the Key Points： Fault feature extracting techniques based on (modern) signal processing(omitted)

• 한국지진공학회논문집
• /
• 제27권3호
• /
• pp.157-162
• /
• 2023

As a result of active geological investigation of faults in Korea, many Quaternary faults have been identified and some of them were judged to have potential to generate earthquakes. Those faults need to be considered as additional seismic sources in the seismic hazard analysis. When a fault is introduced as a new source, the earthquakes generated by the fault should be removed from the area sources that include any part of the fault, to avoid double counting. In practice, however, double counting cannot completely be avoided as the complete separation of the fault-generated earthquakes from the area sources is impossible due to uncertainties related to the earthquake location, subsurface structures of faults, etc. When a new fault source is introduced, the only constraint is the invariance of earthquake frequency. The maximum earthquake and the Richter-b value should also be subject to change, but there are no competent approaches to estimate the change due to incomplete separation of earthquakes. To gain insight into the effect of a new fault source, an example calculation of the seismic hazard were carried out. The example calculation shows that addition of a new fault source centers seismic hazard around the fault source.

• 한국지형학회지
• /
• 제26권1호
• /
• pp.79-91
• /
• 2019

This study analyzed the distribution of fluvial landforms, fault-related geomorphic features and lineaments around the area of Ungchon-Ungsang in the Dongrae Fault, and discusses the charateristics of geomorphic development based on those. As a result, the NE-SW lineaments are predominantly developed in many numbers within the study area, and the NW-SE or N-S secondary lineaments are developed induced by multiple deformation with the Yangsan Fault. Geomorphologically, the early tectonic history of the Ungchon-Ungsang basin is largely divided into three stages ; 1) the Tertiary fault activity and formation of fracture zone, 2) development of erosional basin, 3) local crustal movements and development of fault-related topography. It is assumed that alluvial fans, deflected channel and stream piracy were formed by local tectonic movements related to faultings during the Quaternary.

• 한국지구과학회지
• /
• 제26권5호
• /
• pp.436-442
• /
• 2005

한반도 남동부 경상분지의 동부에 위치한 언양 지역 일대에서 양산 단층대에 대한 물리 탐사를 수행하였다. 본 연구에 사용된 물리 탐사의 종류는 중력과 전기비저항 탐사이며 한국지질자원연구원에서 수행된 항공자력탐사자료를 분석하였다. 양산 단층대 중 언양 지역을 가로지르는 2개의 측선을 따라 총 71개 측점에서 중력을 측정하였으며, 동일한 위치에서 쌍극자배열을 이용한 전기비저항 탐사를 수행하였다. 또한, 이 지역의 광역적인 지질구조를 살펴보기 위하여 항공 자력 탐사자료를 분석하였다. 탐사 결과는 예상 단층선을 따라 동서지역의 전기 비저항, 밀도 및 자력의 분포가 서로 다른 양상으로 발달하여 있음을 보여주고 있다. 탐사 지역을 가로지르는 단층의 모습은 수직으로 잘 발달되어 있으며, 단층선을 따라 파쇄대가 자리 잡고 있음을 알 수 있는데 이는 선행 연구의 결과와 일치하고 있다. 또한 중력 자료의 경우 탐사지역의 북쪽에 비해 남쪽에서 단층 반응의 크기가 커짐을 확인할 수 있다. 본 연구의 성과는 앞으로 양산단층의 특성을 연구하는 다른 연구들의 기초 자료로 사용될 수 있을 것이다.

• JSTS:Journal of Semiconductor Technology and Science
• /
• 제11권4호
• /
• pp.318-328
• /
• 2011

Stage-level reconfigurable chip multiprocessor (CMP) aims to achieve highly reliable and fault tolerant computing by using interwoven pipeline stages and on-chip interconnect for communicating with each other. The existing crossbar-switch based stage-level reconfigurable CMPs offer high reliability at the cost of significant area/power overheads. These overheads make realizing large CMPs prohibitive due to the area and power consumed by heavy interconnection networks. On other hand, area/power-efficient architectures offer less reliability and inefficient stage-level resource utilization. In this paper, I propose a hierarchical multiplexing interconnection structure in lieu of crossbar interconnect to design area/power-efficient stage-level reconfigurable CMP. The proposed approach is able to keep the reliability offered by the crossbar-switch while reducing the area and power overheads. Experimental results show that the proposed approach reduces area by up to 21% and power by up to 32% when compared with the crossbar-switch based interconnection network.

• Journal of Electrical Engineering and Technology
• /
• 제10권3호
• /
• pp.729-739
• /
• 2015

An algorithm for fault detection and classification method for wide-area protection in Korean transmission systems is proposed. The modeling of 345-kV and 765-kV Korean power system transmission networks using the Electro Magnetic Transient Program - Restructured Version (EMTP-RV) is presented and the algorithm for fault detection and classification in transmission lines is developed. The proposed algorithm uses the Wavelet Transform (WT) and Singular Value Decomposition (SVD). The Singular value of Approximation coefficient (SA) and part Sum of Detail coefficient (SD) are introduced. The characteristics of the SA and SD at the fault conditions are analyzed and used in the algorithm for fault detection and classification. The validation of the proposed algorithm is verified by various simulation results.

• 자원환경지질
• /
• 제21권2호
• /
• pp.131-137
• /
• 1988

Geological and electrical resistivity surveys were carried out to investigate subsurface geology and geologic structure of the Bonghwajae area in the Okchon zone. Pseudosections of the apparent electrical resistivity distribution along the three survey lines were obtained by using dipole-dipole electrode array method, and models of subsurface geology and geologic structure by using two dimensional finite difference method. The Bonghwajae fault zone exists around Bonghwajae area in the north-south direction, and is a boundary between Okchon Group and Choson Supper Group. Metabasite and hornblende gabbro intruded along the Bonghwajae fault zone remaining two fracture zones with low resistivity value of 20 ohm-m and widths of about 100m and 70-300m. They strike nearly N-S and dip westward with a high angle of $60-70^{\circ}$. Sochangri fault with a width of about 160m exists between Jisogori and Bonghwajae, by which Bonghwajae fault zone is displaced about 1km in the east-west direction. Hornblende gabbro whose electrical resistivity value is in the range of 5000-8000 ohm-m intruded the metabasite of 2000-4500 ohm-m after the Sochangri fault had formed. Great Limestone Group is widely distributed in the east of Bonghwajae fault zone, and interbeds so called Yongam formation of graphitic black slate with an extremely low electrical resistivity value of 2 ohm-m.