• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.3
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• pp.52-58
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• 2008

The importance of. identifying the causes of electrical faults cannot be overstated because of the accidents caused by over-current that take place at the home, the office and electrical facilities due to misuse, poor products and system faults. It is necessary to gather objective, scientific data pertaining to electrical fault investigation in a product liability(PL) environment. To date, no database(DB) has been built concerning the accurate cause analysis of faultyfacilities. In this paper, accident hazard and arc scattering when over-current flows in copper wire was investigated. It was found that when over-current flows in a copper wire, the copper wire became heated and bent and beads were scattered around the wire with a flash. It was determinedthat the fusing current and time was related to the current rise per second. For example, when the current rise per second was largethe fusing current was higher than when the current rise per second was small, and the beads dispersed along a wide area. Fusing time, however, was shorter. The possibility of electrical fault became highest when the fusing current was higher. As the current rise per second is short, the dendrite structure is distributed in the surface of the copper wire. These experimental results can be utilized for a fault process DB system in the investigation and the prevention of electrical faults.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.16 no.3
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• pp.74-83
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• 2002

The maximun short circuit current of modern power system is becoming so large that circuit breaker is not expected to be able to shut down the current in the future In order cut over-currents, a system composed of a superconducting fault current limiter(SFCL) and traditional breaker seems to provide a promising solution for furture power operation. In present paper, three line-to-ground fault is assumed to happen at the center of 345kV transmission lines in a large capacity electric power system. The superconducting fault current limiter was represented using a commutation type, which consists of a non-inductive superconducting coil and current limiting element (resistor or reactor). from the viewpoint of current limiting performance, the prevention of the voltage drop at the load bus and comparision characteristics for two type SFCL. Desired design specification and operation parameters of SECL were also given qualitatively by the performance.

• Structural Engineering and Mechanics
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• v.85 no.3
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• pp.381-391
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• 2023

The seismic performance of the tall building equipped with a tuned mass damper (TMD) considering soil-structure interaction (SSI) effects is well studied in the literature. However, these studies are performed on the nominal model of the seismic-excited structural system with SSI. Hence, the outcomes of the studies may not valid for the actual structural system. To address the study gap, the reliability theory as a useful and powerful method is utilized in the paper. The present study aims to carry out reliability analyses on tall buildings equipped with TMD under near-field pulse-like (NFPL) ground motions considering SSI effects using a subset simulation (SS) method. In the presence of uncertainties of the structural model, TMD device, foundation, soil, and near-field pulse-like ground motions, the numerical studies are performed on a benchmark 40-story building and the failure probabilities of the structures with and without TMD are evaluated. Three types of soils (dense, medium, and soft soils), different earthquake magnitudes (M_w = 7,0. 7,25. 7,5 ), different nearest fault distances (r = 5. 10 and 15 km), and three seismic performance levels of immediate occupancy (IO), life safety (LS), and collapse prevention (CP) are considered in this study. The results show that tall buildings built near faults and on soft soils are more affected by uncertainties of the structural and ground motion models. Hence, ignoring these uncertainties may result in an inaccurate estimation of the maximum seismic responses. Also, it is found the TMD is not able to reduce the failure probabilities of the structure in the IO seismic performance level, especially for high earthquake magnitudes and structures built near the fault. However, TMD is significantly effective in the reduction of failure probability for the LS and CP performance levels. For weak earthquakes and long fault distances, the failure probabilities of both structures with and without TMD are near zero, and the efficiency of the TMD in the reduction of failure probabilities is reduced by increasing earthquake magnitudes and the reduction of fault distance. As soil softness increases, the failure probability of structures both with and without TMD often increases, especially for severe near-fault earthquake motion.

• Journal of Korean Society of societal Security
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• v.2 no.2
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• pp.75-83
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• 2009

When the exposed surface of rock slopes investigated, various factors have not been considered. The factors required to be considered include the vlume swelling of rock caused by stress release at the fault zone, unexposed discontinuities in the earth and so on. Also, rock slope failure occurs sometimes due to these factors. In this paper, we intend to help engineers to judge about the stability of similar new cutting-slopes or the maintenance of already cut-slope, so that they can consider these factors.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.444-445
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• 2008

This paper reviews the known techniques for diagnosing the condition of OF cable system and improving the service reliability. These tests are periodically achieved and intended to provide indications that the insulation system has deteriorated. One of these tests is analyzing the gas in oil on Oil-filled cable that is well known and widely accepted method. In this paper, this method of analysis and the relevant measurement standards overview and the concrete example of preventing fault incidence by performing this test is introduced.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.30B no.4
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• pp.85-91
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• 1993

In this paper, we propose the test pattern generation algorithm of the embedded faulty MUX for the prevention of misdiagnosis of digital systems. When the system is partitioned with a large number of functional blocks, if the faults are exsisted in a embedded MUX then it can not diagnose the wanted observation of functional block. The proposed test pattern generstion algorithm can apply the MUXs that designd 2-level and multi-level both. Fault coverage becomes 100% and so it is no necessary of the additional fault simulation and the proposed algorithm that have the regulary and easily generated 2d test patterns. And we confirmed that the reduction of test cost becomes 85%, compared with the conventional segmentation testing scheme.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.14 no.24
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• pp.199-206
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• 1991

As the development of modern technology, human works shift whose roll from physical conditions to the system monitoring tasks. In this paper, safety-presentation configuration is discussed instead of well-known fault-warning configuration. Safety-presentation configuration is verified as superior to the fault-warning configuration in hazard prevention. The estimation of system states involves the decision making environments which lack of required in formations and most of all the informations are not precise too. And the limitation of human information processing show doubtful results. So the estimation of system states is regardes as fuzzy number, and its operation produces the parameter that explain the discriminability(d), decision criterion ($\beta$) of system operator's behaviors. These two values served as performance indices. Especially the $\beta$ is a good milestone of the operator's altitude degree of caution.

• Proceedings of the KIPE Conference
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• 2014.07a
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• pp.5-6
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• 2014

According to 2013 fire statistical yearbook in the National Emergency Management Agency, the main cause of an electrical fire are classified to short circuit fault, overload fault, electric leakage, partial disconnection, and joint/contact badness. The occurrence factor of fire is electric arc or spark accompanied with electrical faults. Residual Current Protective Devices(RCDs) of high sensitivity type used at single phase (220V) cut off earth leakage and overload but the RCDs can not cut off electric arc or spark to be a main cause of electrical fire. To be improved on such problem, this thesis is proposed to a auxiliary control device for RCD cut off electric arc or spark.

• Korean Journal of Remote Sensing
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• v.37 no.6_2
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• pp.1901-1922
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• 2021

Since most large earthquakes occur by reactivation of preexisting active faults, it is important to understand the locations and characteristics of active faults in terms of earthquake hazard research and earthquake disaster prevention. Recently, several remote sensing techniques are broadly used for lineament analysis performed prior to field surveys in active fault surveys. The aim of this paper is introducing simple principles and application examples of each remote sensing technique (satellite remote sensing, airborne remote sensing, InSAR, LiDAR) widely used for active fault investigation. This paper also explains the analytical methods for the slope break generated by fault activity based on GIS and the horizontal displacement of the strike-slip fault. In discussion, we would like to discuss the problems and solutions on making DEM based on aerial photography, and a new developed technique (RRIM) to overcome the problems of DEM based on aerial LiDAR. Understanding remote sensing techniques used for active fault investigation and utilizing appropriate methods depending on the situation and limitations of each remote sensing technique are important for effective active fault investigation.

• Tunnel and Underground Space
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• v.27 no.2
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• pp.77-88
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• 2017

The geology of the study area is composed mainly of conglomerate, sandstone, and shale and basalt. It is a rock that has been observed to move relatively recently through various brittle deformation and various stress fields during the recent period. To form a gentle terrain with severe crushing. The slope is located at the intersection of the Taegok Fault in the north-northeast direction and the Bukok Fault in the western north-west direction, and many faults, fault zones and fracture zones of various sizes are developed in the rock bed. In this study, the geological characteristics of the slope are investigated and the countermeasure method is suggested. It is suggested that periodical measurement and analysis should be performed by installing a measuring instrument according to each structure for safety management of the surrounding roads and grounds during construction or reinforcement by the countermeasure method for the slope of the study area.