• Proceedings of the KIEE Conference
• /
• 1999.07a
• /
• pp.302-304
• /
• 1999

Voltage sag and swell are the most severe factors affecting power quality in distribution systems. This paper discusses an approach to ensure a high quality power supply to critical loads appling voltage-sag compensator. The proposed system consists of a PWM voltage source inverter, connected in series with the line through a single-phase transformer. The operation Principle and Power circuit configuration of the proposed voltage sag compensator are introduced. And then the transfer function of compensator is derived from simplified single phase power circuit, and simulated so that the benefits of this proposed compensator is confirmed through the open loop response.

• Proceedings of the KIEE Conference
• /
• 2000.07d
• /
• pp.2495-2497
• /
• 2000

Level control in the steam generator of a nuclear power plant is important process. But, the low power operation of nuclear power plant causes nonlinear characteristics and non minimum phase characteristics (swell and shrink), change of delay. So, we can't lead good results with conventional PID controller. Particularly, the design of controller with constraints is necessary. This paper introduces MPC(Model Predictive Control) with constraints and designs a good performance MPC controller in spite of the input constraints and nonlinear characteristics, non-minimum phase characteristics

• Proceedings of the KIEE Conference
• /
• 2003.07a
• /
• pp.375-377
• /
• 2003

수용가에게 영향을 끼치는 전력품질 문제를 다루기 위해서는 3상 전압변동, 전압불평형, 순간전압상승(Swell), 순간전압강하(Sag), 순간정전(Interruption)등의 발생시 측정된 Data들을 근간으로 하여 전력품질을 분석할 필요가 있다. 본 논문에서는 이를 위해 개발된 PQMS DataBase 분석프로그램을 소개하기로 한다.

• Journal of the Korean Institute of Telematics and Electronics S
• /
• v.35S no.5
• /
• pp.68-74
• /
• 1998

Block-based interframe interpolation algorithms cause severe block effect because the algorithm interpolates the skipped frame by using block based motion vector. Therefore, in this paper, we propose an algorithm that reduces the block effect in the interpolated frames. First, we propose an algorithm that obtains backward motion vector by using forward motion vector received from the transmitter. In order to predict well covered and uncovered region, backward motion vector is needed as well as forward motion vector. Second, we propose the algorithm which segments the motion boundary blocks into regions and obtains the motion vector of each region from candidates that consist of the motion vectors of neighbor blocks. This algorithm makes it possible that the moving object and the background, in spite of being in the same block, have different motion vectors from each other so that the block effect can be reduced. According to the results of simulation, the proposed algorithm is superior to conventional algorithm in subjective quality a swell as in objective quality.

• The Transactions of the Korean Institute of Electrical Engineers A
• /
• v.54 no.1
• /
• pp.1-7
• /
• 2005

This paper proposes a novel UPQC(unified power quality conditioner) based on H-bridge modules, isolated through single-phase multi-winding transformers. The dynamic performance of proposed system was analyzed by simulation with PSCAD/EMTDC, assuming that the UPQC is connected with the 22.9kV distribution line. The proposed system can be directly connected to the transmission line without series injection transformers. It has flexibility in expanding the operation voltage by increasing the number of H-bridge modules and can compensate reactive power, harmonics, voltage sag and swell, voltage unbalance. The proposing UPQC has the ultimate capability of improving power quality at the point of installation on power distribution systems.

• Proceedings of the KIEE Conference
• /
• 2007.04b
• /
• pp.5-9
• /
• 2007

본 논문에서는 실제 운용 중인 현장에서 노이즈 및 서지 신호를 측정 분석하여, 그 결과를 토대로 이들 노이즈 신호를 제거할 수 있는 접지시스템 및 내부 보호 설비를 제안하여 시공하였다. 실제 운용 중인 설비 내에 유도 흑은 침입하는 전원 계통의 sag, Swell, Transient, 서지 그리고 고조파와 같은 노이즈와 접지시스템을 통해 유입되는 다양한 노이즈 신호를 차단하여 빠르고 안전하게 제거하는 방안을 연구하였다. 이를 위해 운용 중인 설비의 다양한 노이즈 신호를 실측하였고, 실측된 결과로부터 전달 및 침입 경로를 예측하여, 기존 접지 구성 및 내부 배선의 문제점의 개선하고 노이즈 및 서지의 실제적 차단을 위한 접지시스템과 내부 보호 설비를 설계 제안하였다. 또한 설계 시뮬레이션 결과와 현장 시공 결과를 비교하여 제안된 설비의 성능을 확인하였고, 시공 후 설비 운용 중에 노이즈 및 서지 신호를 재 측정하여 기존 설비 운용시 측정했던 결과를 비교 분석하여 제안 보호 설비의 개선된 성능을 최종 확인하였다.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
• /
• 2005.11a
• /
• pp.327-331
• /
• 2005

This paper gives the information for fault and malfunction of the Elevator for the passenger. For analyzing the fault and malfunction of the elevator equipment we research the report of fault and malfunction which is written by ATP electric director and Elevator maintenance company during recently one year. We analyze the number of fault and malfunction according to classified by month, season, time and classify the kind of fault and malfunction such as stop, fault of door, malfunction of floor indication and so on. And now we research fault and malfunction for the power quality such as Sag, Swell, Interruption, Harmonic, electric voltage rise and so on at elevator equipments and are testing Elevator imitation equipment.

• Proceedings of the KIEE Conference
• /
• summer
• /
• pp.1254-1256
• /
• 2004

This paper deals with a novel 3-phase power quality disturbance generator. The proposed generator can be applied to the performance that of custom power devices. Voltage sag, swell and outage are provided by the generator. The control scheme for the disturbance generation is simple, and hardware setup is cost effective, compared with conventional scheme. The operating principle of the generator is described and the usefulness verified through simulation with 10KVA power rating.

• 한국방재학회:학술대회논문집
• /
• 2008.02a
• /
• pp.321-324
• /
• 2008

Water retaining pavement is a pavement to lower the surface temperature by using evaporation of the water that the pavement contains when the pavement is heated by the sun in the daytime, so, to improve performance, the performance can absorb water. Most of the high-performance material that absorbs water swell $2\sim3$ times as much volume when it contact with water. Water retaining material exists independently of the material in the cement. so it doesn't have the space to expand. Therefore, the performance of absorbing water is decreased. Therefore, this study was to develop a foamed concrete and evaluation of performance characteristics using high absorptiveness resin. The result has been evaluated as excellent compared to other materials.

• Proceedings of the KIEE Conference
• /
• 2007.07a
• /
• pp.770-771
• /
• 2007

Wind power plant is based on the wind energy so the active power is frequently changed and connected to grid according with wind condition. These characteristics are bed effect to distribution line. On this reserch, we want to analyze the quality of electric power synchro/asynchronous generation system in Dae Kwan Ryung wind farm. The contents of analysis are active/reactive power variation and total demand distortion and transiency and sag/swell phenomena. we hope this research can contribute to the power quality improvement.