• Journal of Radiation Protection and Research
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• v.39 no.2
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• pp.103-108
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• 2014

Following the emergency work in Fukushima Daiichi nuclear power plant, more attention was paid for the radiation protection of workers working under severe accident condition. The protection procedure for the emergency workers, including the on-site emergency center, the seismic isolated building and the reestablishment of the radiation protection framework were analyzed to investigate drawbacks and deficiencies which led to adverse effects on the emergency planning and on emergency workers' health and comfort. Those drawbacks were identified and studied, and then suggestions were made to enhance the emergency working condition to avoid any future problems during severe accident emergency work and management.

• Proceedings of the IEEK Conference
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• 2002.06b
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• pp.169-172
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• 2002

A protection integrated circuit which enables the stable operation of the rechargeable battery should be designed with a low-power architecture because it consumes the power of the battery. This paper proposed a low-power scheme especially when the several series-connected batteries are provided. By adopting a time sharing control of the batteries, the chip size and power consumption could be reduced.

• Corrosion Science and Technology
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• v.14 no.1
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• pp.12-18
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• 2015

Since the operation period of nuclear power plants has increased, the degradation of buried pipes gradually increases and recently it seems to be one of the emerging issues. Maintenance on buried pipes needs high quality of management system because outer surface of buried pipe contacts the various soils but inner surface reacts with various electrolytes of fluid. In the USA, USNRC and EPRI have tried to manage the degradation of buried pipes. However, there is little knowledge about the inspection procedure, test and manage program in the domestic nuclear power plants. This paper focuses on the development and build-up of real-time monitoring and control system of buried pipes. Pipes to be tested are tape-coated carbon steel pipe for primary component cooling water system, asphalt-coated cast iron pipe for fire protection system, and pre-stressed concrete cylinder pipe for sea water cooling system. A control system for cathodic protection was installed on each test pipe which has been monitored and controlled. For the calculation of protection range and optimization, computer simulation was performed using COMSOL Multiphysics (Altsoft co.).

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.9
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• pp.2253-2260
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• 2009

The typical distribution systems have the power flow from distribution substations (sources) to customers (load) only as one direction. However, in the case where new energy power sources are connected to distribution systems, the output variations of new energy sources to distribution systems, which is so called reverse power flow, may cause the bi-directional power flow. So, the reverse power flow has severe impacts on typical power system, for example power quality problems, protection coordination problems, and so on. Therefore, this paper proposes the algorithm for Multi-functional protection devices in distribution systems in the case where new energy sources are interconnected. The proposed algorithm is verified to show the effectiveness by simulating and experimenting the prototype systems.

• Proceedings of the KIEE Conference
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• 2005.11b
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• pp.344-346
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• 2005

The recovery time of developing SFCL(Superconducting Fault Current Limiter) has an uncertainty. In general, the recovery time is estimated at 1 sec and more, even though the progress of SFCL technology is considered. However, auto reclosing time of circuit breaker is 0.5 sec in Korean distribution power system. It is impossible to apply only one SFCL to power system because the recovery time is over the reclosing time of protection system. This study proposes a new SFCL system for distribution power system application. The proposed systems consider auto reclosing action for the protection in practical power system and consist of tow parallel SFCLs.

• Proceedings of the KIEE Conference
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• 2001.07a
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• pp.246-248
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• 2001

For protection of power system, it is a prerequisite to action characteristics of protective relay about a changing environment in power system and correcting the setting value. A substation operator always reside to correct of a relay, however there are problem of efficiency. Recently, power system operation become manless and supervision and control of incident is required anywhere, introduction of new concept as a intellectual manless protective relay is a recent trend. This paper is the web-based protective relay setting program that a manager make an analysis of operation and incident of power system through the web at a remote place corresponding recent manless of system and approach the protection relay and then can correct the error.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.10
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• pp.73-77
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• 2010

Most accidents occurred in power receiving & transforming facility are ground fault. The quality of power supply is deteriorated since the ground fault is not detected promptly. This paper analyzes the problems about system-grounding type of 2 step power receiving & transforming facility, arrangement of protection relaying scheme and ground-fault protection system of ungrounded system. Then, this paper presents the arranging scheme of system-grounding type to improve power supply reliability.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.54 no.12
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• pp.580-585
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• 2005

The recovery time of developing SFCL(Superconducting Fault Current Limiter) has an uncertainty. In general, the recovery time is estimated at 1 sec and more, even though the progress of SFCL technology is considered. However, auto reclosing time of circuit breaker is 0.3 or 0.5 sec in Korean power system. It is impossible to apply only one SFCL to power system because the recovery time is over the reclosing time of protection system. This study proposes two new SFCL systems for power system application. The proposed systems consider auto reclosing action for the protection in practical power system and consist of tow parallel SFCLs.

• Proceedings of the KIEE Conference
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• 2003.07b
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• pp.1154-1156
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• 2003

본 논문은 IPM의 구동부, 과열, 과전류, 단락 및 제어부의 부족전압 제어하는 IC의 설계중 Over-Temperature protection기능에 대한 것으로서 기존의 온도센서나 과열검출 Tr을 사용하지 않고, 온도에 따른 MOSFET의 Rds(on)변화를 검출하여 과열을 방지하는 Direct Over Temperature protection기능을 PSpice를 이용하여 modelling하고 simulation 한 결과에 대해서 기술하였다.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.12
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• pp.74-80
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• 2013

Generator faults does not happen more often than the transmission and substation facility faults. However, impacts on the power system by generator faults are very large. In order to minimize the impact of generator faults, generator protection and control system with high reliability is required. Most of the generator relay in generator protection and control system of large power plant of Korea is operated by imports from abroad. Accordingly, in order to accumulate source technology and increase the import substitution effect, localization of multi-function generator protection IED is being developed. This paper deals with the implementation of a multi-function prototype IED H/W, which can be command and data exchange through communication for measuring, monitoring, protection and control. And the IED specification, various relay elements, measurement elements, communication functions, module function, and test system for the prototype IED H/W are described.