• Journal of Korean Society for Quality Management
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• v.26 no.4
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• pp.265-276
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• 1998

A commercial nuclear power station contains at least two emergency diesel generators(EDG) to control the risk of severe core damage during station blackout accidnets. Therefore, thereliability of the EDG's to start and load-run on demand must be maintained at a sufficiently high level. Until now, a simple assessment of start and load-run success rates was used to calculate the EDG reliability. However, this method has been found to contain many defects. Recently, the work of Martz et al.(1996) proposed the use of the Bayes estimator to find EDG reliability. Shim(1996) proposed a confidence interval for the Bayes estimator, compare the above two methods. In this paper, we introduce the notion of "Composite Reliablility" to estimate the reliability of nuclear-power plant EDG, and using practical examples, illustrate which method is more a, pp.opriate in our situation.situation.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.59 no.2
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• pp.158-162
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• 2010

PSD is automatically opened and closed when subway train arrive on the station. This system was designed to control electric automatic system. These doors will provide passenger safety, energy saving and a good environment in subway. The monitoring and control systems of PSD are configured so that they can be operated in automatic mode in connection with ATO through the composite control panel in the station control room. The objective of this paper is to obtain high reliability that is essential for monitoring and control systems of PSD. The power supply is based on protection circuit using DC power bridge from two UPS. Also, stable communication system consists of CAN communication line redundancy and RF cross protection algorithm. Monitoring state display results show the validity of the proposed high reliability monitoring and control systems of PSD.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.83_84
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• 2009

The Gas Circuit Breaker for the Main Transformer in switch yard at the 1st Hapcheon hydraulic power station, has broken down by direct lightning stroke and induced stroke. so, this paper present the stable operation of equipment in switch yard through the improvement of earthing system and the protection to the lightning

• Journal of Electrical Engineering and Technology
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• v.11 no.1
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• pp.257-264
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• 2016

In this paper, new electric railway feeding system which has active transformer is modeled for evaluating the steady state analysis using PSCAD/EMTDC. Equivalent models including power supply, feeder, train and transformers are proposed for simplifying the model of the feeding system in high speed electric railway. In case study, simulation results applied to proposed model are compared with the conventional and new systems through the catenary voltage, three-phase voltage of PCC (Point of Common Coupling) and the efficiency of regenerative braking energy.

• Proceedings of the Korean Information Science Society Conference
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• 2008.06d
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• pp.480-484
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• 2008

DNP3.0은 산업 분야에서 SCADA(Supervisory Control And Data Aquisition) system의 개방형 프로토콜로 사용되어지고 있다. 본 논문에서는 개발하거나 개발된 Module들 사이에서 송 수신되는 DNP3.0 PDU를 분석할 수 있는 기능을 제공하는 DPA(DNP3.0 Protocol Analyzer) Module을 설계 및 구현하였다. 해당 Master Station에서 Request 메시지를 생성하여 Outstation으로 전송하고 Outstation에서 수신된 Request 메시지를 분석하여 Response 메시지를 생성하여 Response 한다. 또한 Master Station 과 Outstation에서 DNP3.0 프로토콜을 사용하여 통신하는 중간에서 송 수신하는 메시지를 Monitoring한다.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.29A no.4
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• pp.7-13
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• 1992

Diffraction loss occurs when the propagation path is obstructed by mountains and hills between a base station antenna and a moving vehicle antenna in mobile-radio communication. In this paper an approximate mathematical model using Fresnel-Kirchhoff diffraction theory is considered to predict propogation attenuation by natural obstacles with lateral profiles having general shapes. Field tests are conducted using helical and crossed drooping dipole antenna at 820 MHz. The theoretical analysis used in estimating the effects of hills agrees reasonably with experimental data. The results seem to be useful for estimating the level of received power, the minimum allowable input power, the optimum site of base station and consequently, planning terrestrial microwave links.

• Proceedings of the IEEK Conference
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• 2001.06a
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• pp.189-192
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• 2001

In this paper, We designed and implemented 20 watt high power amplifier which can be used for the commercial services in band of 1.86 ~ 1.870Hz at PCS. In order to satisfy ACPR, We designed by using the ADS(Advanced Design System)ver1.3. The HPA is fabricated on tepron substrate($\varepsilon_{{\gamma}}$ =3.15, H=0.78mm, T=0.02mm). The implemented HPA measured The ACPR characteristics at $\pm$ 885kHz, $\pm$ 1.25MHz, $\pm$2.25MHz. The HPA meets specification with good ACPR. The HPA is expected to use as a commercial product of PCS base station.roduct of PCS base station.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.4 no.4
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• pp.323-328
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• 2003

In this paper new control strategy of series resonant converter system for power supply of communication station is suggested. Frequency controlled series resonant converter system is robust to load variations because it is POSR(Parallel Output Series Resonant: POSR) type. And it provides stable output voltage by changing switching frequency to input voltage variations. Firstly, operation analysis about suggested series resonant converter system was carried. Then simulations using ACSL(Advanced Continuous Simulation Langage) and experiments to actual system were carried to prove characteristics of suggested system.

• Proceedings of the KIEE Conference
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• 2000.11c
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• pp.476-478
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• 2000

Objective is to design a high performance purification filter system of reactor coolant and seal injection system at nuclear power station. The purification filter systems play an important role in the stability of the nuclear and volume control system which consist the primary network systems of the nuclear power station. But the users of the purification filter systems frequently suffer from high maintenance cost which comes from lack of understanding of the system technology and domestic suppliers. It is time to establish a high performance domestic filter system manufacturing technology and optimum design for wide use in industrial applications.

• Proceedings of the KIEE Conference
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• 1998.07c
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• pp.1188-1191
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• 1998

Detailed estimation of subsurface resistivity distribution and accurate estimation of actual fault current coming into the grounding system are indispensible to optimun grounding system design. Especially, it is essential for efficient grounding design to estimate subsurface resistivity distribution quantitatively and logically. Accurate estimation of subsurface resistivity distribution has an absolute influence on calculating touch voltage, step voltage and ground potential rise (GPR) which are related with grounding design standard for human safety. In this study, thirty-three electrical sounding surveys were made in Yongdam Power Station to obtain detailed subsurface resistivity distribution and the sounding data were interpreted quantitatively using multi-layered model. The results of the quantitative resistivity models were adopted practically to calculate grounding resistance values. Analytical asymptotic equations and CDEGS program were used in grounding resistance calculation and the results were compared and reviewed in the study.