• Title/Summary/Keyword: fault interpretation

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컴퓨터 영상처리에 의한 윤활시스템의 상태진단

  • 서영백;박흥식;전태옥;이충엽
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • 1997.04a
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    • pp.224-231
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    • 1997
  • Microscopic examination for the morphological estimation of wear debris on the oil-lubrcated moving system is an accepted method for machine condition and fault diagnosis. However wear particle anaysis has not been widely accepted industry because it is dependent on expert interpretation of particle morphology and relies on subjective assessment criteria. This paper was undertaken to estimate the morphology of wear debris on the oil-lubricated movig system by computer image analysis. The wear test was performed under different sliding conditions using a wear test device made in our laboratory and wear testing specimen of the pin-on-disk-type was rubbed in pararline series base oil. In order to describe characteristics of debris of various shape and size, four shape parameters (50% volumetric diameter, aspect, roundness and reflectivity) have been developed and outlined in the paper. A system using such techniques promises to obviate the need for subjective, human interpretation of particle morphology in machine condition monitoring.

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Dissolved Gas Analysis Interpretation System for Power Transformers using Statical Fuzzy Function (통계적 퍼지 함수를 이용한 전력용 변압기 유중가스 판정 시스템)

  • Cho, Sung-Min;Kim, Jae-Chul;Shin, Hee-Sang;Kweon, Dong-Jin;Koo, Kyo-Sun
    • Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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    • 2007.11a
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    • pp.275-278
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    • 2007
  • Dissolved gases analysis (DGA) is one of the most useful techniques to detect incipient faults in power transformers. Criteria interpreting DGA result is the most important. Because of difference of operation environment, construction type, oil volume, and etc, the interpretative criteria of DGA at KEPCO must be different with other standard like IEC-60599, Rogers and Doernenburg. In this paper, we collected the DGA data of the normal condition transformers and the incipient fault transformer to suggest the most appropriate criteria. Using these data, this paper suggests appropriate condition classification algorithm. Suggested algorithm can help to detect incipient fault earlier without unnecessary sampling.

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The Analysis of Temperature and Electric Field due to Contact Failure in Power Substation (수변전설비에서 접점 불량에 따른 열 및 전계 분포 해석)

  • Kim, Ki-Joon
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.29 no.5
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    • pp.307-311
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    • 2016
  • Although there are existing Residual Current Protective Device (RCD) including detect electric leakage and elements such as short circuit and surge, the occurrence of incidents caused by electric faults, including fire, are still constant. The purpose of this study is to analyze the causes of accidents through the electric field distribution in the interpretation of the fault contact breaker. Simulation results by the arc fault has shown the convergence of temperature and electric field to the defect. Through their simulation results, the main cause of erosion phenomena in circuit breaker bar is the electric arc by concentration of electric field not due to dissolve by temperature.

Fault Prediction and Diagnosis Using Fuzzy Expert System (퍼지 전문가 시스템을 이용한 고장 예측 및 진단)

  • 최성운;이영석
    • Journal of the Korea Safety Management & Science
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    • v.1 no.1
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    • pp.7-17
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    • 1999
  • As the loss from break-downs and errors, which became more frequent with the growth of elaborateness, complexity and in scale of the plant and equipments, are enormous, the improvement in the reliability, maintenance, safety, and qualify become to have interest. The fault diagnosis is a systematic and unified method to find errors, which is based on the interpretation that data, subconsciously, have noises. But, as most of the methods are inferences based on binomial logic, the uncertainty is not correctly reflected. In this study, we suggest, to manage the uncertainty in the system efficiently on the point of predictive maintenance, We should use fuzzy expert system, which make the decision considering uncertainty possible by taking linguistical variable and fixed quantity by using the fuzzy theory concepts on the basis of an expert's direct observation and experience.

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Semi-analytical Method for Predicting Shaft Voltage in Field-excited Synchronous Generators

  • Doorsamy, Wesley;Cronje, Willem A.
    • Journal of Power Electronics
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    • v.14 no.5
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    • pp.859-865
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    • 2014
  • This study presents an electromagnetic model for predicting shaft voltages in a 2-pole field-excited synchronous generator. After the first observations on shaft voltages were made more than a century ago, extensive work has been conducted on eliminating, mitigating, and integrating the aforementioned phenomena. Given that emphasis has been placed on modeling shaft- and bearing-induced voltages in AC motors driven by variable frequency drives, similar efforts toward a model that is dedicated to generators are insubstantial. This work endeavors to improve current physical interpretation and prediction methods for shaft-induced voltages in generators through semi-analytical derivation. Aside from the experimental validation of the model, investigations regarding the behavior of shaft voltages under varying machine complexities and operating conditions clarify previous uncertainties regarding these phenomena. The performance of the numerical method is also assessed for application in eccentricity fault diagnosis.

Identification of the Singal Fault Zone in the Kiheung Reservoir Area by Geotechnical Investigations (기흥저수지 지역의 지반조사를 통한 신갈단층대 확인)

  • Gwon, Sun-Dal;Kim, Sun-Kon;Lee, Soung-Han;Park, Kwon-Gyu
    • Economic and Environmental Geology
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    • v.45 no.3
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    • pp.295-306
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    • 2012
  • In this study, the Singal fault zone in the Gyeonggi massif is identified in the Kiheung area. Geotechnical investigations were carried out to locate and characterize of the Singal fault zone in the Kiheung reservoir area. The N-S striking Shingal fault is known to be a Riedel-type strike-slip fault within the Choogaryung rift. Along the fault zone, 62 bore holes were drilled and electrical resistivity survey of about 11km, and vibroseis seismic refraction and reflection survey of about 500m were done. From the result of investigations, it is found that the fault zone, consisting mainly of gouge and breccia, has maximum width of 300 meters with anastomosing geometry of secondary fractures developed subparallel to the fault zone. We interpret these geometric features to be the result of structural development of flower-structure type at the restraining band of strike-slip fault. However, there are uncertainties of this interpretation because there are virtually no outcrops in the area. Further investigation to understand geometric features and linkage style of the fault zone.

Preliminary strong ground motion simulation at seismic stations within nuclear power plant sites in South Korea by a scenario earthquake on the causative fault of 2016 Gyeongju earthquake

  • Choi, Hoseon
    • Nuclear Engineering and Technology
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    • v.54 no.7
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    • pp.2529-2539
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    • 2022
  • Stochastic and an empirical Green's function (EGF) methods are preliminarily applied to simulate strong ground motions (SGMs) at seismic stations within nuclear power plant (NPP) sites in South Korea by an assumed large earthquake with MW6.5 (scenario earthquake) on the causative fault of the 2016 Gyeongju earthquake with MW5.5 (mainshock). In the stochastic method, a ratio of spectral amplitudes of observed and simulated waveforms for the mainshock is assumed to be an adjustment factor. In the EGF method, SGMs by the mainshock are simulated assuming SGMs by the 2016 Gyeongju earthquake with MW5.0 (foreshock) as the EGF. To simulate SGMs by the scenario earthquake, a ratio of fault length to width is assumed to be 2:1 in the stochastic method, and SGMs by the mainshock are assumed to be EGF in the EGF method. The results are similar based on a bias of the simulated response spectra by the two methods, and the simulated response spectra by the two methods exceeded commonly standard design response spectra anchored at 0.3 g of NPP sites slightly at a frequency band above 4 Hz, but considerable attention to interpretation is required since it is an indirect comparison.

Kinematic Interpretation for the Development of the Yeonghae Basin, Located at the Northeastern Part of the Yangsan Fault, Korea

  • Altaher, Zooelnon Abdelwahed;Park, Kiwoong;Kim, Young-Seog
    • The Journal of Engineering Geology
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    • v.32 no.4
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    • pp.467-482
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    • 2022
  • The Yeonghae basin is located at the northeastern part of the Yangsan fault (YSF; a potentially active fault). The study of the architecture of the Yeonghae basin is important to understand the activity of the Yangsan fault system (YSFS) as well as the basin formation mechanism and the activity of the YSFS. For this study, Digital Elevation Model (DEM) was used to highlight the marginal faults, and structural fieldwork was performed to understand the geometry of the intra-basinal structures and the nature of the bounding faults. DEM analysis reveals that the eastern margin is bounded by the northern extension of the YSF whereas the western margin is bounded by two curvilinear sub-parallel faults; Baekseokri fault (BSF) and Gakri fault (GF). The field data indicate that the YSF is striking in the N-S direction, steeply dipping to the east, and experienced both sinistral and dextral strike-slip movements. Both the BSF and GF are characterized dominantly by an oblique right-lateral strike-slip movement. The stress indicators show that the maximum horizontal compressional stress was in NNE to NE and NNW-SSE, which is consistent with right-lateral and left-lateral movements of the YSFS, respectively. The plotted structural data show that the NE-SW is the predominant direction of the structural elements. This indicates that the basin and marginal faults are mainly controlled by the right-lateral strike-slip movements of the YSFS. Based on the structural architecture of the Yeonghae basin, the study area represents a contractional zone rather than an extensional zone in the present time. We proposed two models to explain the opening and developing mechanism of the Yeonghae basin. The first model is that the basin developed as an extensional pull-apart basin during the left-lateral movement of the YSF, which has been reactivated by tectonic inversion. In the second model, the basin was developed as an extensional zone at a dilational quadrant of an old tip zone of the northern segment of the YSF during the right-lateral movement stage. Later on, the basin has undergone a shortening stage due to the closing of the East Sea. The second model is supported by the major trend of the collected structural data, indicating predominant right-lateral movement. This study enables us to classify the Yeonghae basin as an inverted strike-slip basin. Moreover, two opposite strike-slip movement senses along the eastern marginal fault indicate multiple deformation stages along the Yangsan fault system developed along the eastern margin of the Korean peninsula.

A Study on the Legal Character of Contractual Liability in Freight Agency under Chinese Contract Law (중국계약법상 화물운송대리에서의 계약책임과 귀책원칙)

  • KIM, Young-Ju
    • THE INTERNATIONAL COMMERCE & LAW REVIEW
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    • v.66
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    • pp.119-148
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    • 2015
  • Generally, the liability for breach is defined as the civil liability that arises from the conduct of violation of a contract. There are two notable principles governing liability for breach that have fundamental impacts on the unified Contract Law of the People's Republic of China (hereinafter Chinese Contract Law) in the remedies. In China, during the drafting of the Contract Law, there was a great debate as to whether damages for breach of contract ought to follow the fault principle or to follow the strict liability principle. Ultimately the Chinese Contract Law follows the model of the CISG on this point, namely, it follows the strict liability principle (article 107) with an exemption cause of force majeure. Under Chinese Contract Law, it is interpreted as strict liability in principle. Strict Liability is a notion introduced into Chinese Contract Law from the Anglo-Saxon Law. The strict liability or no fault doctrine, on the contrary, allows a party to claim damages if the other party fails to fulfill his contractual obligations regardless of the fault of the failing party. Pursuant to the strict liability doctrine, if the performance of a contract is due, any non-performance will constitute a breach and the fault on the party in breach is irrelevant. This paper reviews problems of legal character or legal ground of contractual liability in Chinese contract law. Specifically, focusing on the interpretation of Chinese contract law sections and analysis of three cases related contractual liability in freight agency, the paper proposes some implications of structural features of Chinese contract law and international commercial transactions.

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Interpretation of Seismic Profiles in the Sora and North Sora Sub-basins, South Sea of Korea (남해 소라 및 북소라 소분지 일대의 탄성파단면 해석)

  • Lee, Sung-Dong;Oh, Jin-Yong;Park, Myong-Ho;Chang, Tae-Woo
    • The Korean Journal of Petroleum Geology
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    • v.14 no.1
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    • pp.63-73
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    • 2008
  • The seismic interpretation was carried out to understand the evolution of the Sora and North Sora Sub-basins, South Sea of Korea. Both sub-basins belong to the Domi Basin, which is located in the northeastern margin of East China Sea Basin with Fukue Basin of Japan. Age assignment of each strata in this study was based on the data of boreholes and seismic interpretation in NW Japan. Four regional horizons were identified, and five geological units; Y(basement), Q(Eocene$\sim$Middle Oligocene), M(Middle Oligocene$\sim$Early Miocene), L(Early Miocene$\sim$Late Miocene) and D(Late Miocene$\sim$Present) groups in ascending order. Structural trends of the main boundary faults and the basin-fill sediment are different between the Sora and North Sora Sub-basins; i.e., trend of the main boundary-faults, dip of horizons, distribution of basin and development of growth fault. These results imply that the Sora Sub-basin would have opened earlier than the North Sora Sub-basin.

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