• Proceedings of the KIEE Conference
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• 2003.11a
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• pp.85-87
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• 2003

본 논문은 2기 5모선 모의계통에 3상 단락고장을 발생시킬 경우, 해당 모선에서 각 차단기가 분담하는 고장전류를 PSCAD/EMTBC3.0을 이용하여 분석한 결과이다. 적용된 차단기 개극시간(Contact Parting Time, CPT) 및 아크시간(Arc Time) 등은 실제 차단기 제작사(효성, 현대중공업 및 LG산전)들로부터 조사/수집하여 적용하였으며, 적용 대상계통은 PSS/E 분석결과와 비교/검토하여 검증하였다. 이는 기존 혹은 신설 차단기 적정 차단용량을 선정하는데도 활용가능 할 것으로 보인다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.7 no.1
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• pp.18-24
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• 1982

The Tree phenomenon of the PMMA resin depends on an annex of the inorganic fillers and water. If the internal of an arganic insulating materials exist the fault of inorganic fillers, Void and Projecting part, the high voltage concentrates in this place. It leaves a trace about the partical breakdown and this phenomenon develops into the degration of insulating material. This paper researchses that have an effect on the tree phenomenon by the inorganic fillers and water. The results is as follow. (1) The growth of tree are less the influence of inorganic fillers. Because , the constant of water are more. (2) If the tree branches contact the inorganic filler, the advance are relaxation.

• Economic and Environmental Geology
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• v.18 no.4
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• pp.369-379
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• 1985

The geological structures and some of the stratigraphy in the area studied are being thought to be ambiguous and controvertible. The present study intended to clarify these ambiguities by correct interpretation of the geological structures and lithostratigraphy of the area concerned. The so-called "Sambangsan formation", which was designated as an unknown age by the Taebaksan Geological Investigation Corps (1962) and as the mid Cambrian age by T. Kobayashi (1966) and I.S. Kim (1983), has been determined by the present study as the $Hongj{\breve{o}}m$ series of Carbo-Permian age resting unconformably on the Cambro-Ordovician limestone formations. This determination was supported by conodont study concurrently carried out by I.S.Kim. The so-called "Daehari formation", which was renamed by the later study group after the original "Sambangsan formation" distributed in the area from southwest of Sambangsan toward southwest to $Juch{\breve{o}}n$, possesses more or less the same lithlogy as "Sambangsan formation" of the old designation in the eastern of the area, but different lithology in the western localities where Sadong formation, the basal sandstone member of the Kobangsan formation and the green shale member of the Nokam formation are cropped out. The narrow belt of the complex mixture of the $Py{\breve{o}}ngan$ group in-between limestone formations extending over 16km with a width of 500m to 1000m was formed by the faults: the northern boundary with the limestone formations is a fault contact all the way through entire area and the southern boundary is either fault contact in most of the area and unconformity in some other area. The $Hongj{\breve{o}}m$ formation on the Mt. Sambangsan shows rather steeply dipping nearly isoclinal folds which plunges $10^{\circ}$ to $20^{\circ}$ southward. There are also field evidences that the limestone formations distributed in both north and south of the Hongjom formation (erstwhile "Sambangsan formation") along the Sambangsan ridge are the same formations and show the same folding as the $Hongj{\breve{o}}m$ formation. Therefore, these limestone formations should be rezoned in the light of the new structural interpretation although they were differently designated in the previous studies as $Py{\breve{o}}ngchang$ and $Y{\breve{o}}ngw{\breve{o}}l$-type of the Joson Group. The structures developed in the area mostly faults, which acted as one of the guides for the new interpretation of the geology and structure of the area are described and shown on the geologic map.

• Aerospace Engineering and Technology
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• v.13 no.1
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• pp.27-36
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• 2014

Generally, satellites continuously monitor that its major functions are working properly and their hardware are in a good status using several SOH data. In case a fault that is not recognized as a temporal problem or a failure that can be considered to propagate its damage to the other parts are detected, fault management logic is performed automatically without any contact of ground station. In this paper, attitude error detection using sun sensors on a rotating solar array is proposed. Attitude error can be detected by comparing the offset angle between the actual data computed from the sun sensor and the data predicted from the orbit and ephemeris information for the two types of solar array operation method. During the eclipse, the output of attitude error detection method becomes zero because the sun sensor output cannot be provided. Finally, the proposed method is analyzed through the data processing using on-orbit data.

• Aerospace Engineering and Technology
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• v.13 no.2
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• pp.29-37
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• 2014

Telemetry, satellite event and error information are used to check the satellite status in ground station. Different from telemetry which only informs the parameter value, event and error gives explicit information of a certain operation or status. Event also contains ground action information because every command execution is logged as event. Currently, those information is gathered and applied only for monitoring of the satellite. However, the load of the operation is getting grown because of the excessively increased information of the satellite with the number of satellite increasement. Also, the process of reporting problem to developer (or an expert) induce time delay for satellites fault management. In this paper, we propose a satellite operation assistant system which collects event sequence and stores in different group by its feature, and then recommends or executes an appropriate action for the identified abnormal state. This system is applicable to on board system for resolving LEO-satellite autonomous fault situation since is has limited contact time.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.142.2-142.2
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• 2015

Plasma etch endpoint detection (EPD) of SiO2 and PR layer is demonstrated by plasma impedance monitoring in this work. Plasma etching process is the core process for making fine pattern devices in semiconductor fabrication, and the etching endpoint detection is one of the essential FDC (Fault Detection and Classification) for yield management and mass production. In general, Optical emission spectrocopy (OES) has been used to detect endpoint because OES can be a simple, non-invasive and real-time plasma monitoring tool. In OES, the trend of a few sensitive wavelengths is traced. However, in case of small-open area etch endpoint detection (ex. contact etch), it is at the boundary of the detection limit because of weak signal intensities of reaction reactants and products. Furthemore, the various materials covering the wafer such as photoresist (PR), dielectric materials, and metals make the analysis of OES signals complicated. In this study, full spectra of optical emission signals were collected and the data were analyzed by a data-mining approach, modified K-means cluster analysis. The K-means cluster analysis is modified suitably to analyze a thousand of wavelength variables from OES. This technique can improve the sensitivity of EPD for small area oxide layer etching processes: about 1.0 % oxide area. This technique is expected to be applied to various plasma monitoring applications including fault detections as well as EPD.

• Fire Science and Engineering
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• v.20 no.1 s.61
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• pp.71-76
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• 2006

The major causes of electrical fire are classified to short circuit fault, overload fault, electric leakage and electric contact failure. The occurrence factor of the fire is electric arc or spark accompanied with electrical faults. Residual Current Protective Device(RCD) of high sensitivity type used at low voltage wiring cuts off earth leakage and overload, but the RCD can't cut off electric arc or spark to be a major factor of electrical fire. As the RCDs which are applied low voltage distribution panel are prescribed to rated breaking time about 30[ms](KS C 4613), the RCDs can't perceive to the periodic electric arc or spark of more short wavelength level. To be improved on such problem, this paper is proposed to a auxiliary control apparatus for RCD trip on electric arc or spark due to electrical fire. Some experimental results of the proposed apparatus is confirmed to the validity of the analytical results.

• Journal of the Korean Institute of Gas
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• v.4 no.3 s.11
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• pp.26-32
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• 2000

Because of the continuous growth of energy consumption, and also the tendency to site power lines and pipelines along the same routes, the close proximity of high voltage structures and metallic pipelines has become more and more frequent. Moreover, normal steady state and fault currents become higher as electric networks increase in size and power Therefore, there has been and still is a growing concern(safety of people marking contact with pipeline, risk of damage to the pipeline coating, the metal and equipment connected to pipeline, especially cathodic protection system) about possible hazards resulting from the influence of high voltage power system on metallic structures(gas pipeline, oil pipeline and water pipeline etc.). Therefore, we analyze the interference problems when the gas pipeline is buried with power cable in the same submarine tunnel. This paper present the results of the study about interference mechanism, AC corrosion limitation of safety voltage and analysis of induction voltage.

• Economic and Environmental Geology
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• v.25 no.2
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• pp.167-177
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• 1992

The gravity measurement has been conducted at 53 and 34 stations with an interval of 1~1.5 km along the national roads of about 47 km and 34 km running from Duksungri to Yangpori and from Angangri to Byungpori, Kyungsangbookdo, respectively. The subsurface geology and geologic structure of Tertiary Pohang and Janggi basins along two survey lines are interpreted quantitatively by applying Fourier series and Talwani methods for Bouguer gravity anomaly. The depths of Conrad discontinuity vary from 11.8 to 12.5 km and 11.5 to 13.2 km along the survey lines between Duksungri and Yangpori, and Angangri and Byungpori, respectively. The depths of pre-Cambrian Gneiss complex underneath Kyungsang Supergroup vary from 3.8 to 4.2 km and 3.8 to 4.6 km along the survey lines between Duksungri and Yangpori, and Angangri and Byungpori, respectively. Massive granite bodies which are not exposed along the survey line between Duksungri and Yangpori are distributed on a large scale at the subsurface between Duksungri and Ochun, and Daegokri and Yangpori. Along the survey line between Angangri and Byungpori, it is exposed at Angangri, and extends underneath Chungrimdong, Pohang city. Andesite is distributed on a small scale underneath Pohang city and Ochun. The thicknesses of Tertiary Yonil and Janggi Groups are 0.2~0.9 km and 0.1~0.5 km, respectively. The Tuffaceous rocks which are the lowest formation of Tertiary sedimentary rocks are distributed with the thickness of 0.2 km at the surface and between Kyungsang Supergroup and Yonil or Janggi Groups. The Yonil and Janggi Groups are in fault contact by a fault running through Ochun and Chungrimdong, Pohang city. Two other faults are newly found near Heunghae-eup and Hyungsan river.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.371-372
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• 2007

The major causes of electrical fire are classified to short circuit fault, overload fault, electric leakage and electric contact failure. The occurrence factor of the fire is electric arc or spark accompanied with electrical faults. Residual Current Protective Device (RCD), that is Earth Leakage Circuit Breaker(ELB) and Molded_case Circuit Breaker (MCB), of high sensitivity type used at low voltage wiring cuts off earth leakage and overload, but the RCD can't cut off electric arc or spark to be a major factor of electrical fire. As the RCDs which are applied low voltage distribution panel are prescribed to rated breaking time about 30[ms] (KS C 4613), the RCDs can't perceive to the periodic electric arc or spark of more short wavelength level. To be improved on such problem, this research development is proposed to a auxiliary control apparatus for RCD trip on electric arc or spark due to electrical fire. Some experimental results of the proposed apparatus is confirmed to the validity of the analytical results.