• The Transactions of the Korean Institute of Electrical Engineers P
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• v.63 no.4
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• pp.312-316
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• 2014

In this paper, a voltage sag is analyzed in case of superconducting fault current limiter (SFCL) installed in power distribution system where replaces the main power transformer to large one to meet the power demand. First, the power system is configurated to analyze the operation characteristics of the protective relay with replacement of the main transformer and application of the SFCL. Next, the method to meet the protection coordination is analyzed with large transformer using PSCAD/EMTDC. Finally, the bus voltage is investigated according to the impedance of both main transformer and SFCL in case that the SFCL is applied into feeder.

• Progress in Superconductivity and Cryogenics
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• v.10 no.3
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• pp.9-13
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• 2008

It is very important to study the protective relaying system from the viewpoint of technical analysis to apply superconducting power devices to real power systems. In this paper, we developed Superconducting Fault Current Limiter (SFCL) analysis model using Real Time Digital Simulator(RTDS) for protective relay tests in power system with SFCLs. The RTDS model has the operation mechanism of a real SFCL system.

• Progress in Superconductivity and Cryogenics
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• v.9 no.4
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• pp.28-31
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• 2007

This paper describes the consideration of 154kV protective relaying systems for applying HTS(High Temperature Superconducting) power devices to Korean power system. We investigates firstly 154kV relay systems of Korean power system and then do a basic study on the relay systems in the power system with superconducting devices. For the more detailed result, the study using EMTDC relay system modeling will be done from the viewpoint of superconducting devices application in the future.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.1
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• pp.36-42
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• 2011

This paper mainly proposes the protective coordination scheme of the microgrid system. The microgrid protection is identical to the conventional protection system separating the normal part and contingency part to reduce damage when the contingency occur at power cables, facilities. But they are different in the protection type. The conventional protection system only considers unidirectional current. However the microgrid protection should be considered not only unidirectional current but also backfeed current because various microsources and loads are installed in the microgrid system. In case the contingency occurs in microsource, when microgrid is interconnected to grid, the protection system should be configured to not separate microgrid from grid before the microsource is isolated to microgrid. And in case of fault occur in power system, the microsources should not isolated to microgrid before the static switch at PCC is tripped to separate from power system. Considering these characteristic of microgird, this paper proposes the protective coordination scheme of microgrid and implemented the on-line real time monitoring system. Especially in case the microgrid is connected to low voltage distribution system with 220/380V voltage level, the proposed protection method with power IT technology can solve the problems when the existing protective devices only applied to the microgrid system.

• Journal of Environmental Health Sciences
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• v.26 no.4
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• pp.88-96
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• 2000

The aim of the current study was to evaluate the transport system in EMT-6 cell for the uptake of the methylmercury(MeHg). Several inhibitors ere used to test used to test which potential transport system might be involoved in MeHg uptake. Probenecid was used to test the organic transport system, valinomycin for testing the effect of the membrane potential, cytochalasin B for testing the facilitated diffusive D-glucose transport system and colchicine for testing the microtubule system. Ouabain for evaluating active transport system, 4',4-diisothiocyano-2',2-stilbenedisulfonic acid(DIDS) the Cl- ion transport system and verapamil for the $Ca^{2+}$ transprot system. Significantly, MeHg decreased the synthesis of nitric oxcide(NO) and intracellular ATP in ENT-6 cells. In the condition of ouabain containing with MeHg decreased the production of NO and intracelluar ATP. In the treatment of inhibitors, ouabain showed protective effect against cytotoxicity of MeHg but ather inhibitors not showed protective effects. The protective effects of ouabain against the cytotoxicity of MeHg deoended on the concentration of added ouabain to the culture medium for MET-6 cells. These result showed that the uptake of MeHg might be involved in the active transport system. Active transports system seems to share similarities with the transport systems for the uptake of MeHg when using MeHg and MeHg-glutathione complex.x.

• Journal of Physiology & Pathology in Korean Medicine
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• v.24 no.6
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• pp.1042-1052
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• 2010

This study aimed to evaluate the protective effects of Mundongcheongpye-eum (MCE) on elastase-induced lung injury. The extract of MCE was treated to A549 cells and elastase-induced lung injury mice model. Then, various parameters such as cell-based cyto-protective activity and histopathological finding were analyzed. MCE showed a protective effect on elastase-induced cytotoxicity in A549 cells. This effect was correlated with analysis for caspase 3 levels, collagen and elastin contents, protein level of cyclin B1, Cdc2, and Erk1/2, and gene expression of TNF-${\alpha}$ and IL-$1{\beta}$ in A549 cells. MCE treatment also revealed the protective effect on elastase-induced lung injury in mice model. This effect was evidenced via histopathological finding including immunofluence stains against elastin, collagen, caspase 3, and protein level of cyclin B1, Cdc2, and Erk1/2 in lung tissue. These data suggest that MCE has a pharmaceutical properties on lung injury. This study would provide an scientific evidence for the efficacy of MCE for clinical application to patients with chronic obstructive pulmonary disease.

• KIEE International Transactions on Power Engineering
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• v.2A no.3
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• pp.83-88
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• 2002

An over current relay(OCR), one of the most frequently used protective devices, has time-current characteristics (TCC) to control its trip time according to the current level. It is because an appropriate operating time interval is necessary for coordination with other protective devices. A set of TCC curves of an OCR is, in general, given by the supplier from which a curve is selected by the operator. Therefore, in many cases, it is impossible to consider the operation condition of the given power system exactly. A novel concept of an OCR is suggested in this paper. The proposed OCR has an internal correction module so that it may produce the most adequate TCC curve according to the given protective information for coordination with other devices. With the generated TCC curve, a variety of operation and coordination conditions can be taken into consideration in an effective manner. The suggested OCR is applied to a simple test power system to show very promising results from a coordination point of view.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.17 no.6
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• pp.39-46
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• 2003

In this papers, We studied system requirement specification, hardware design and implementation, protective algorithm and software design method to implement digital protective relay which has high trust and high function of protection as well as control and metering for power transformers. Protective relay for transformer is implemented on real time using DSP, which is the specific processor for digital signal processing, as a result, it is completed by the wide improvement of arithmetic capability of protective relay. Reliability is proved testing operating value and operating time, reset value and reset time of an relaying element using protective relay tester made in NF Corporation of Japan.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.52 no.12
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• pp.675-683
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• 2003

This paper describes the correction strategy of an overcurrent relay applied in the linked line for interconnecting wind farm with utility power networks in order to improve the capability of a fault detection. The fault current measured in a relaying point might vary according to the fault conditions. Generally, the current of the line to line fault or the line to ground fault in the linked line is much higher than the set value of protective relay due to the large fault level. However, when the high impedance fault occurs in the linked line, we can't detect it by conventional set value because its fault level may be lower than the generating capacity of wind farm. And, the protective relay with conventional set value may generate a trip signal for the insertion of wind turbine generators due to the large transient characteristics. In order to solve above problems and improve protective relaying algorithms applied in the linked line, we propose a new correction strategy of the protective relay in the linked line. The presented method can detect the high impedance fault which can't be detected by conventional relay set value and may prevent the mis-operation of protective relay caused by the insertion of wind farm.

• Journal of the Korean Society of Costume
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• v.58 no.9
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• pp.166-175
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• 2008

For the structural firefighting protective clothing, it can show a synergy effect when it satisfies smart fabric to block off a harmful environmental element and ergonomics design that apply range of motion of human body and appropriate size system. There are various standards about the structural firefighting protective clothing, but it's difficult to find a rule about movement suitability because the performance of the material holds a lot of the rules. Therefore, the purpose of this study is to propose a scheme to evaluate the current structural firefighting protective clothing and to improve movement suitability by research on the actual condition. For this, the survey about wearer acceptability scale on design and size and about improvement requirements was executed gathering firefighters' opinion. Questionnaire was composed with 23 items about satisfaction on current structural firefighting protective clothing, body suitability, movement suitability, improvement requirement and subjective information. As a results, Korean firefighters demand ergonomics design of structural firefighting protective clothing which to minimize restriction of body movement and to maximize body suitability.