• Journal of Electrical Engineering and Technology
• /
• v.10 no.3
• /
• pp.865-876
• /
• 2015

Voltage stability is one of the most critical security issues which has not yet been well resolved to date. In this paper, an analytical method called PQ plane analysis with consideration of the reactive power capability of wind turbine generator and the wake effect of wind farm is proposed for voltage stability study. Two voltage stability indices based on the proposed PQ plane analysis method incorporating the uncertainties of load-increasing direction and wind generation are designed and implemented. Cases studies are conducted to investigate the impacts of wind power incorporation with different control modes. Simulation results demonstrate that the constant voltage control based on reactive power capability significantly enhances voltage stability in comparison of the conventional constant power factor control. Some meaningful conclusions are obtained.

• Proceedings of the Korean Information Science Society Conference
• /
• 2002.04a
• /
• pp.43-45
• /
• 2002

이 논문에서는 pq개의 PE(Processing Element)를 가진 SIMD처리기에서 기억 장치 접근시간을 감소시키기 위한 충돌회피 기억장치를 제안했다. 이 기억장치는 MxN 배열내 자료들의 임의의 위치에서 일정 간격인 블록형태와 8방향 선형태인 pd개의 자료들의 동시 접근을 지원한다. 기억모듈 수는 pq보다 큰 소수이고, 간격은 기억모듈 수의 배수가 아닌 양수이다. 간단하고 빠른 주소계산회로와 이동회로를 위해, 요구된 자료들에서 첫번째 자료의 기준 주소와 pq개의 주소간의 차들로 구분한 후, 주소간의 차들은 첫번째 자료 요소의 기억모듈번호로부터 번호에 따라 오름차순 정렬되고 빠른 기억모듈에 저장된다. 그래서 m개의 주소간의 차이들에 첫번째 자료의 기준주소 더해진 후, 첫 번째 요소의 기억모듈 번호에 의한 오른쪽 회전이 간격을 가진 9가지 서브어레이 모두이게 요구된다. 9가지 자료 이동 형태를 멀티플렉싱과 회전에 의해 1가지로 감소시킨 효율적인 자료 이동 회로를 제안하였다. 제안된 충돌회피기억 장치는 이전기억 장치와 비교하여 자료 접근형태, 간격, 자료 배열의 크기에 제한, 하드웨어 비용, 속도, 복잡도면에서 개선하였다.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2002.04a
• /
• pp.695-698
• /
• 2002

이 논문에서는 SIMD처리기에서 기억장치 접근시간을 감소시키기 위한 기억장치를 제안했다. 이 기억장치는 MxN 배열내 자료들의 임의의 위치에서 일정 간격인 블록형태와 8방향 선형태인 pq개의 자료들의 동시접근을 지원한다. 기억모듈 수는 pq보다 큰 소수이고, 간격은 기억모듈 수의 배수가 아닌 양수이다. 간단하고 빠른 주소계산회로와 이동회로를 위해, 요구된 자료들에서 첫번째 자료의 기준 주소와 pq개의 주소간의 차들로 구분한 후, 주소간의 차들은 첫번째 자료요소의 기억모듈번호로부터 번호에 따라 오름차순 정렬되고 따른 기억모듈에 저장된다. 9가지 자료 이동형태를 멀티플렉싱과 회전에 의해 1가지로 감소시킨 효율적인 자료 이동 회로를 제안하였다. 제안된 충돌회피 기억장치는 이전 기억장치와 비교하여 자료 접근형태, 간격, 자료 배열의 크기에 제한, 하드웨어 비용, 속도, 복잡도면에서 개선하였다.

• Proceedings of the KIPE Conference
• /
• 2005.07a
• /
• pp.90-92
• /
• 2005

As the developing of industry, the nonlinear equipments as inverter, converter, SMPS(Switching Mode Power Supply) and motor have been increased. But the sensitive electronic loads to the power quality, such as computer's and other electronic equipments, have been spreaded out very fast. Thus, the power quality (PQ) problems and the real time power quality monitoring (PQM) are one of the important issues industry and building area for the intelligent control of the systems. One of them, PQM using PLC(Power Line Communication) have good merits that can send and receive the PQ information without any new network line. This paper presents the PQM hardware and software to monitor the PQ information by using PLC that meets the categories of IEEE Std. 1159.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.17 no.5
• /
• pp.438-444
• /
• 2012

This paper deals with the active and reactive power control of Grid connected system. It was shown that active power and reactive power can be dependently controlled with two individually adaptable parameters. The two parameters are power angle and voltage magnitude. Transient state will occur with active or reactive power reference value variation. This paper presents a new control strategy for active and reactive power control of less interaction and improved transient response. The paper details the control technique by the mathematical and electrical network analysis of the methodology. The performance was verified through computer simulation using MATLAB Simulink and experiment.

• Proceedings of the KSME Conference
• /
• 2003.04a
• /
• pp.1309-1314
• /
• 2003

The high precision positioning mechanism is used in various industrial fields. It is used in semiconductor manufacturing line, test instrument, Bioengineering, and MEMS and so on. This paper presents a positioning mechanism with dual servo system. Dual servo system consists of a coarse stage and a fine motion stage. The course stage is driven by VCM and the actuator of fine stage is the PZT. The purposes of dual servo system are stability, higher bandwidth, and robustness. Lead compensator is applied to this control system, and is designed by PQ method. Designed compensator can improve property of positioning mechanism.

• Proceedings of the KIEE Conference
• /
• 2001.07b
• /
• pp.1070-1072
• /
• 2001

In recent years, customers and power supplies are interested in power quality. Demands of customers are change from standard quality of distribution power system to various high quality of distribution power system. so, it is necessary to apply power quality compensator, in our project, we develop the power quality compensator of 150kVA which compensates power factor and voltage sag, interruption. it is very frequently occurred power qualify problems[1,2]. As a series and shunt compensator, power quality compensator consists of two inverters with common do link capacitor bank. It compensates the current quality in the shunt part and the voltage qualify in the series part. In this paper we present the design and control algorithm of power quality compensator. As a control algorithm is implemented by digital controller, we consider sample-and-hold of signals. In this simulation, we use EMTDC/PSCAD V3.0 software which can simulate instantaneous voltage and current.

• Journal of Broadcast Engineering
• /
• v.19 no.4
• /
• pp.468-477
• /
• 2014

This paper proposes a novel perceptual quality-based (PQ-based) video coding method with foveated contrast sensitivity (FCS). Conventional methods on PQ-based video coding with FCS achieve minimum loss on perceptual quality of compressed video by exploiting the property of human visual system (HVS), that is, its sensitivity differs by the spatial frequency of visual stimuli. On the other hand, PQ-based video coding with foveated masking (FM) exploits the difference of the sensitivity of the HVS between the central vision and the peripheral vision. In this study, a novel FCS model is proposed which considers both the conventional DCT-based JND model and the FM model. Psychological study is conducted to construct the proposed FCS model, and the proposed model is applied to PQ-based video coding algorithm implemented on HM10.0 reference software. Experimental results show that the proposed method decreases bitrate by the average of 10% without loss on the perceptual quality.

• Journal of Power Electronics
• /
• v.6 no.4
• /
• pp.307-314
• /
• 2006

This paper presents a wavelet and neural network based technology for the monitoring and classification of various types of power quality (PQ) disturbances. Simultaneous and automatic detection and classification of PQ transients, is recommended, however these processes have not been thoroughly investigated so far. In this paper, the hardware and software of a power quality data acquisition system (PQDAS) is described. In this system, an auto-classifying system combines the properties of the wavelet transform with the advantages of a neural network. Additionally, to improve recognition rate, extraction technology is considered.

• Proceedings of the KIEE Conference
• /
• 2006.11a
• /
• pp.396-398
• /
• 2006

Predictive maintenance is not an unfamiliar concept because it has been used to predict the failures of electrical equipment such as transformers, motors and so on. By thoroughly monitoring the status of individual equipment and tracing how the various characteristics change over time, we can be aware of its exact condition and prevent the impending failure by taking appropriate actions. In this paper, I will extend the concept of predictive maintenance for individual electrical equipment to the power distribution system and show how to use the data obtained from power quality monitors to improve the power system.