• 대한전기학회:학술대회논문집
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.2069-2070
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• 2011

In this paper, the fault diagnosis for a gearbox of BLDC motor. The stator of BLDC motor consists of coil winding so it is easy to cool down and it also has a high reliability. In addition, it doesn't have a brush so it is less trouble and good in maintenance. Coupling with the motor which is the power sources, the gear has a high power transfer efficiency and various rotation speed. The gear gets a high driving force through deceleration. Thus it has been widely used. The gearbox fault detection area has not attracted much attention from electrical engineering community. A few papers describe gearbox fault based on vibration. Gearbox fault is diagnosed through FFT analysis of current and voltage. Fault characteristic frequency side band detected by calculating fault frequency. A threshold value is suggested by comparing normal peak value with fault peak value using detected fault characteristic frequency side band. Experimental results demonstrate that motor current and voltage signal analysis are viable tools in detecting these gear faults. Lower side band(LSB) is bigger than upper side band(USB) in current FFT. LSB and USB are similar in voltage FFT. Finally, fault diagnosis system that can easily detect flaws is developted for gearbox of BLDC motor.

• 한국지형학회지
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• 제26권1호
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• pp.93-106
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• 2019

The Yangsan Fault is one of the main fault systems in the Korean peninsula. It can be divided into three segments (northern, central, and southern) by its paleoseismic and structural geologic properties. Based on the geomorphic features of the northern segment, which includes the Yugye Fault, we identified deflected streams as a geomorphic marker of strike-slip component of the fault, and knickpoints along the streams as evidence of dip-slip component of the fault. Geomorphic analyses showed that (1) the horizontal displacements of deflected streams decreased and (2) the retreat amounts of knickpoints tend to increased toward north along the lineament. We interpreted the variations caused by strain partitioning; that is, there might be some increases of the vertical component toward north, whereas the main strike-slip fault system dies out, splaying into horsetail structure toward north. Based on the response time of the landforms, these interpretations imply that (1) there were differences between horizontal slip rate and vertical slip rate along strike, and/or (2) there were different timings between horizontal and vertical deformations by fault.

• 대한전기학회논문지:전력기술부문A
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• 제55권1호
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• pp.18-23
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• 2006

Recently as the power system has been becoming massive and complicated, most of the faults bring on severe proliferation effects. Because of the complexity of the power system it is not easy to analyze faults-the calculation of current flows under fault conditions. Therefore many researches have been performed in this area. As a result of those efforts, the protective equipments for a power system have been designed to operate properly and without damage when the highest possible fault current is flowing in the power system. Most of the fault data can be also acquired from intelligent protection equipments. The fault data saved in them don't always include the fault type information. n you don't have knowledge about the fault analysis, it becomes useless. So this paper presents 3 topics to increase a reusability of them as followings. First, describes a fault data using the XML(extensible Markup Language). It would be a well-formed and valid document complied with suggested XML DTD(Document Type Definition). In this paper I suggest a standard DTD to describe the power system fault. If the XML document describes any power system faults is validated against suggested DTD, it is possible to be used in any applications. Second, sends them through the web using the XML web service. Last, presents the rapid and accurate algorithm for a fault type determination of the fault data received from the web. In the ultimate the client to request the server to analyze a fault data is provided the correct information what kind of fault is occurred.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2000년도 추계 학술발표회 논문집 Proceedings of EESK Conference-Fall 2000
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• pp.33-40
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• 2000

The assessment of earthquake hazards involved consideration of earthquake magnitude, frequency, last movement and probability of occurrence. The appraisal of earthquake potential is feasible because historical data show a good correlation between earthquake size and the fault rupture parameters of length, displacement, and area. Additionally, the characteristics of fault behavior should be considered to evaluate the earthquake potential magnitude. In this study, in order to evaluate the earth quake potential by the fault behavioral patterns, based on the experimental background which the geometric characteristics of the individual domains, such as strike, width, fault tip patterns, and orientation of secondary shears reflect sliding behavioral patterns in each section, the straight sections of A, D and E domains were examined to the creeping section of stably sliding. In contrast, the curved section of B domain was examined to the locked section of stick-slip movement. These results of studies can be applied to evaluate the earthquake potential magnitude from the fault structural parameters.

• 한국해양공학회지
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• 제15권4호
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• pp.101-107
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• 2001

This paper describes a fault diagnosis method by a T-invariance of Petri Net (PN). First, a complicated fault system with some failure is modeled into a PN graphic expressions. Next, the PN model is analyzed by using the backward chaining of T-invariance to find out causes of the faults. In this step, an inter-node search technique which is suggested in this paper is applied for reducing searching area in the fault system. Also, a novel idea to compose incidence matrices which have different dimension each other in PN model is proposed. As the new knowledges which is discovered newly about faults can be added easily to conventional systems, the diagnosis system will be very flexible. Finally, the proposed method is applied to the automobile fault diagnosis system to confirm the validity of the method.

• 자원환경지질
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• 제30권2호
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• pp.143-151
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• 1997

The history of the Palgongsan Fault comprises the growth-fault, the dormant and the strike-slip phases. Dissecting the Palgongsan Granite, the Palgongsan Strike-slip Fault, which is the product of the final phase, sinistrally offset about 5.5 km as shown in the dislocation of the Hasandong Formation. Faulting, sedimentation and igneous activity were inter-related in the early phases of the Palgongsan Fault. Some other faults such as the Dansan Pond Fault and the Hayang Fault have also been discovered, and their some stratigraphic implications and the ages of faulting are discussed. The anomalous development of the Jindong Formation in the study area and the related stratigraphic problems are discussed. It has been confirmed that the Konchonri Formation deposited over the Chaeyaksan Volcanic Formation in spite of the recent doubts on their such stratigraphic relation. The chronological sequence of the volcanisms of the Kyongsang Basin has been summarized.

• 한국초전도ㆍ저온공학회논문지
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• 제7권2호
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• pp.16-20
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• 2005

As power systems grow more complex and power demands increase, the fault current tends to gradually increase. In the near future, the fault current will exceed a circuit breaker rating for some substations, which is an especially important issue in the Seoul metropolitan area because of its highly meshed configuration. Currently, the Korean power system is regulated by changing the 154kV system configuration from a loop connection to a radial system, by splitting the bus where load balance can be achieved, and by upgrading the circuit breaker rating. A development project applying 154kV Superconducting Fault Current Limiter (SFCL) to 154kV transmission systems is proceeding with implementation slated for after 2010. In this paper, SFCL is applied to reduce the fault current in power systems according to two different application schemes and their technical impacts are evaluated. The results indicate that both application schemes can regulate the fault current under the rating of circuit breaker, however, applying SFCL to the bus-tie location is much more appropriate from an economic view point.

• Structural Engineering and Mechanics
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• 제56권5호
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• pp.855-870
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• 2015

In this paper the effects of fling-step and forward-directivity on the seismic performance of steel eccentrically braced frames (EBFs) are addressed. Four EBFs with various numbers of stories (4-, 8-, 12- and 15-story) were designed for an area with high seismic hazard. Fourteen near-fault ground motions including seven with forward-directivity and seven with fling-step effects are selected to carry out nonlinear time history (NTH) analyses of the frames. Furthermore, seven more far-field records were selected for comparison. Findings from the study reveal that the median maximum links rotation of the frames subjected to three set of ground motions are in acceptable range and the links completely satisfy the requirement stated in FEMA 356 for LS performance level. The arrival of the velocity pulse in a near-fault record causes few significant plastic deformations, while many reversed inelastic cycles result in low-cycle fatigue damage in far-fault records. Near-fault records in some cases are more destructive and the results of these records are so dispersed, especially the records having fling-step effects.

• 조명전기설비학회논문지
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• 제26권5호
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• pp.34-39
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• 2012

The DAS(Distribution Atomization System) determines a faulted section by using a FI(Fault Indicator) when the fault is occurred on the distribution networks. Sometimes FI is malfunction when the ground fault is occurred on a the distribution networks. As a result difficulties to make decision of faulted section. The cause of the FI malfunction is that the determination using the limited information of the installed area. In this study, a method is proposed to determine faulted section using the amount of the fault current instead of using the FI. This method is determinated faulted section using the fuzzy inference for the collected information from the all switches. The usefulness of the proposed algorithm is verified through the simulation test using PSCAD/EMTDC.

• 동굴
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• 제65호
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• pp.1-10
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• 2004

Joint reflects the structure of the earth. And in many cases joints controls the developments of stream directions. In this studying area three joint sets are represented. One is concentrated to the north and the other is deviated $50^{circ}-60^{circ}$ from north to east and west. It is uncertain that the master joint set is a fault line, but the presence of the structural line is evident from the joint strike frequency. The Spearman's $\Upsilon$ between joint patterns and the stream directions is about 0.73.