• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 A
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• pp.402-404
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• 2005

This paper represents the amapcity calculation method of power cables installed in a concrete construction above a bridge which is exposed to solar radiation.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2012년도 전력전자학술대회 논문집
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• pp.554-555
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• 2012

The failures in the power plant can lead to a dangerous situation according to the demand and supply of the electric power. The failure times of the domestic plant happens very often, and it has been reported as a significant loss by the power sales. Therefore, the power plant is demanded to maintain very well in order to produce a high quality of power. The rate of failures by the electricity facility is filled with 40[%] among the trouble in the failures of the power plant. The failures of power plant can cause serious accidents, magnificent losses, and chaos in our society. So, we require a significant plan to reduce such a serious problem. In this paper, I analysis the failure case of power converter in power plant, and I offer the better solution to be able to prevent the failures from power plant.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1991년도 하계학술대회 논문집
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• pp.459-461
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• 1991

This paper proposes a novel AC voltage regulator topology. The output voltage is varied by controlling voltage drop of the transformer which is connected with load in series. The waveform of output voltage is clamped sinusoidal, then harmonic components are remarkably decreased compared with conventional phase control method. The feasibility of proposed topology is verified experimentally.

• Journal of Power Electronics
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• 제8권2호
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• pp.141-147
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• 2008

This paper deals with a new and improved control technique for shunt active filters (AF) used for compensating unwanted harmonic currents injected in the mains due to nonlinear varying loads. This work is motivated by the need to find a permanent solution to the rigorous hit and trial method for evaluating system parameters in an indirect control of AF. A fuzzy pre-compensated PI (Proportional-Integral) controller is used to fuzzify the reference DC voltage of AF to the controller input so that the overshoots and undershoots in its DC link voltage are minimized and the settling time is improved. A three-phase diode rectifier with R-L (Resistive-Inductive) load is used as a non-linear load to study the effectiveness of the proposed controller of the AF. Robustness to filter parameter variations, insensitivity to controller parameter variations, and transient response has been taken as performance evaluation parameters. The results are shown through simulations in Matlab using power system block sets to demonstrate the capability of the proposed controller of the AF.

• 전자공학회논문지
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• 제52권9호
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• pp.54-62
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• 2015

낸드 플래시 기반의 SSD (Solid-State Drive)는 HDD (Hard Disk Drive) 대비 월등한 성능에도 불구하고 쓰기 회수 제한이라는 태생적 단점을 가지고 있다. 이로 인해 SSD의 수명은 워크로드에 의해 결정되어 SSD의 기술 변화 추세인 SLC (Single Level Cell) 에서 MLC (Multi Level Cell) 로의 전환, MLC에서 TLC (Triple Level Cell) 로의 전환에 있어 큰 도전이 될 수 있다. 기존 연구들은 주로 wear-leveling 또는 하드웨어 아키텍처 측면에서 SSD의 수명 개선을 다루었으나, 본 논문에서는 호스트가 요청한 쓰기에 대해 SSD가 낸드플래시 메모리를 통해 처리하는 수명관점의 효율성을 대변하는 WAF (Write Amplification Factor) 관점에서 Host I/O 스택 중 파일 시스템, I/O 스케줄러, 링크 전력에 대해 JEDEC 엔터프라이즈 워크로드를 이용해 I/O 스택 최적 구성에 대해 실험적 분석을 수행하였다. WAF는 SSD의 FTL의 효율성을 측정하는 지표로 수명관점에서 가장 객관적으로 사용한다. I/O 스택에 대한 수명 관점의 최적 구성은 MinPower-Dead-XFS로 최대 성능 조합인 MaxPower-Cfq-Ext4에 비해 성능은 13% 감소하였지만 수명은 2.6 배 연장됨을 확인하였다. 이는 I/O 스택의 최적화 구성에 있어, SSD 성능 관점뿐만 아니라 수명 관점의 고려에 대한 유의미를 입증한다.

• Nuclear Engineering and Technology
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• 제52권2호
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• pp.381-396
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• 2020

Investigations of the commercial aircraft impact effect on nuclear island infrastructures have been drawing extensive attention, and this paper aims to perform the safety assessment of Generation III nuclear power plant (NPP) buildings subjected to typical commercial aircrafts crash. At present Part I, finite element (FE) models establishment and validations for both the aircrafts and NPP buildings are performed. (i) Airbus A320 and A380 aircrafts are selected as the representative medium and large commercial aircrafts, and the corresponding fine FE models including the skin, beam, fuel and etc. are established. By comparing the numerically derived impact force time-histories with the existing published literatures, the rationality of aircrafts models is verified. (ii) Fine FE model of the Chinese Zhejiang Sanao NPP buildings is established, including the detailed structures and reinforcing arrangement of both the containment and auxiliary buildings. (iii) By numerically reproducing the existing 1/7.5 scaled aircraft model impact tests on steel plate reinforced concrete (SC) panels and assessing the impact process and velocity time-history of aircraft model, as well as the damage and the maximum deflection of SC panels, the applicability of the existing three concrete constitutive models (i.e., K&C, Winfrith and CSC) are evaluated and the superiority of Winfrith model for SC panels under deformable missile impact is verified. The present work can provide beneficial reference for the integral aircraft crash analyses and structural damage assessment in the following two parts of this paper.

• 소음진동
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• 제4권2호
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• pp.231-238
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• 1994

This paper presents an experimental method to find the vibrational transmission characteristics of structures by using the structural intensity method which is used as the important techniques of active vibration control method. Experimental results are obtained from measurements performed on a structure beam by 2, 3 and 4 position linear accelerometr array (2, 3 and 4 structural intensity : 2, 3 and 4 S.I.) methods at near and farfield conditions. These results are compared with the measurement values of conventional power flow measurement method called input power measurement in order to verify the accuracy of structural intensity methods. To minimize the errors associated with 2, 3 and 4 S.I. methods, the measurement locations were selected by the result of modal analysis and the averaged data by the inter-change of accelerometer array was utilized. In 3 and 4 S.I. methods measured wavenumber instead of theoretical wavenumber was used. This paper shows that measurements of bending wave power flow by using 2, 3 and 4 S.I. methods can give accurate values under general field conditions in structural beam and the accuracy of 2, 3 S.I. methods is higher than 4 S.I. methods. Finally, 2 position linear accelerometer array method is suggested as the practical structural intensity technique.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 추계학술대회 논문집 전력기술부문
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• pp.62-64
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• 2002

Power quality monitoring system is devoted to more concern than before, because the innovation of industrial technology needs more accurate instruments and more advanced power quality. Therefore, this paper is proposed to use digital protective relays for power quality monitoring. In addition, taking power quality events, Electrical magnetic phenomenon of IEEE std 1159, proposing that adaptive power quality event list consider limitation memory capacity and signal processing ability of protective relay. The prototype S/W of power quality analysis is also developed. Especially this prototype S/W analysis scheme is verified through many kinds of power quality events (gathering protective relay data) in EMTP simulation.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.1172-1173
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• 2008

At the moment, the control ability of wind farms is a prime research concern for the grid integration of large wind farms, due to their required active role in the power system. As more wind turbines are installed, the power from wind energy will start to replace conventional generation units and its influence on power systems cannot be neglected. Besides, because of the intermittent nature of wind the output power of wind turbines fluctuates according to wind speed variation. Especially an isolated power system with small capacity such like Jeju needs more systematic solutions and regulations(grid code). This paper presents the idea of approach for centralized operating wind farm strategy to regulate the wind farm power production to the reference power ordered by the system operator. The doubly fed induction generator(DFIG) can control active and reactive power in feasible range. So wind farm comprised of DFIG has the possibility of a controllable component in the power system. The presented wind farm control has a hierarchical structure with both a wind farm control level and a wind turbine control level.

• 비파괴검사학회지
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• 제24권2호
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• pp.197-210
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• 2004