• Transactions on Electrical and Electronic Materials
• /
• 제18권5호
• /
• pp.303-309
• /
• 2017

The flexible AC transmission system (FACTS) provides a new advanced technology solution to improve the flexibility, controllability, and stability of a power system. The unified power flow controller (UPFC) is outstanding for regulating power flow in the FACTS; it can control the real power, reactive power, and node voltage of distribution networks. This paper investigates the performance of the UPFC for power flow control with a series of step changes in rapid succession in a power system steady state and the response of the UPFC to distribution network faults and islanding mode. Simulation was carried out using the MATLAB's simulink sim power systems toolbox. The results, which were carried out on a 5-bus test system and a 4-bus multi-machine electric power system, show clearly the effectiveness and viability of UPFC in rapid response and independent control of the real and reactive power flows and oscillation damping [6].

• KEPCO Journal on Electric Power and Energy
• /
• 제2권4호
• /
• pp.543-548
• /
• 2016

Live-line maintenance for electric power lines is very dangerous because of their ultra-high voltage environments and the risks of falling from heights. Recently, drone technology has been spotlighted due to its maneuverability and stable controllability, and has been being applied to maintenance works in the electric power industry. This paper presents a new type of drone that can be transformable by introducing biomimetics to its mechanism and can run on an overhead ground wire as well as it can fly. Its technical feasibility was confirmed through experiments.

• Journal of Power Electronics
• /
• 제5권2호
• /
• pp.83-98
• /
• 2005

As wind turbine technology and control has advanced over the last decade, this has led to a high penetration of wind turbines into the power system. Whether it be for a large wind turbine or an offshore wind farm with hundreds of MW power capacity, the electrical system has become more and more important in controlling the interaction between the mechanical system of the wind turbine and the main power system. The presence of power electronics in wind turbines improves their controllability with respect not only to its mechanical loads but also to its power quality. This paper presents an overview of a developed simulation platform for the modeling, design and optimization of wind turbines. The ability to simulate the dynamic behavior of wind turbines and the wind turbine grid interaction using four simulation tools (Matlab, Saber, DIgSILENT and HAWC) is investigated, improved and extended.

• 대한전자공학회논문지SD
• /
• 제40권9호
• /
• pp.692-701
• /
• 2003

본 논문에서는 저 전력소모와 높은 테스트용이성을 동시에 고려하기 위한 새로운 게이트 레벨 논리변환 방법을 제안한다. 주출력에서 관측될 확률이 낮은 CFF(Compact Fanout Free)를 찾아내고, 해당 CFF가 모든 주출력에서 관측불가능한 조건에서는 리던던트 연결을 첨가하여 내부에서 발생하는 스위칭 동작을 제거한다. 일반적으로 논리 변환된 회로의 테스트 용이성은 떨어지는 경향이 있다. 그러나 제안된 방법에서 첨가된 리던던트 연결은 테스트 모드에서 테스트 포인트로 동작하며 CFF의 제어도와 관측도를 동시에 향상시키게 된다. 따라서 논리 변환된 회로는 정상 모드에서는 전력 손실이 매우 낮으며, 테스트 모드에서는 높은 테스트용이성을 갖는다. 제안하는 논리 변환 방법의 효율성을 보이기 위하여 MCNC 벤치마크 테스트 회로에 대하여 실험을 수행하였다. 실험 결과로부터 변환된 회로의 전력소모는 최대 13%정도 감소하며, 고장 검출율은 오히려 증가함을 확인할 수 있다.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2005년도 학술대회 논문집 정보 및 제어부문
• /
• pp.113-115
• /
• 2005

To explore the seafloor, an observation instrument should be laid there for a long time and it should be again withdrawn. This system must be designed low power consumption model because it operates for a long period, but because power control don't execute or simply control algorithm executes, power efficiency is low. Hereupon, a power control algorithm for retrieval system using the ultrasonic communication that was improved its controllability and movability was presented in this paper. Likewise, the logicality of control algorithm and remote control system were ascertained by experiments.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2004년도 전력전자학술대회 논문집(1)
• /
• pp.214-218
• /
• 2004

Switched Reluctance Motor (SRM) offers the advantages of simple and robust motor construction, high speeds and high efficiencies over a wide operating range of torque and speed, excellent controllability. However, SRM has the disadvantages of high current harmonics, and low power factor because of a capacitor filter is inserted in the power converter and inductance of SRM is high, it has pulse waveform of current. This paper deals with an energy efficient converter fed SRM system with the reduced harmonics and improved power factor and with higher efficiency. The validity of the proposed scheme is verified via experiment. We are implemented the proposed control system using 80C196KC micro-controller.

• 유공압시스템학회논문집
• /
• 제7권3호
• /
• pp.13-19
• /
• 2010

Hydraulic systems are widely used as a power transfer and/or power control system due to its flexibility, controllability, accuracy and high power density. Valve controlled and/or pump capacity controlled systems are normally adopted as a control device, but nowadays pump speed controlled systems are emerging as a new energy-efficient hydraulic control system. In this paper the pump speed controlled system for the cylinder position control of a counter balance circuit is investigated by simulation study and position control experiments were carried out. As a result, the possibility and efficiency of the pump speed controlled system were verified.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2002년도 전력전자학술대회 논문집
• /
• pp.11-15
• /
• 2002

Switched Reluctance Motor (SRM) offers the advantages of simple and robust motor construction, high speeds and high efficiencies over a wide operating range of torque and speed, excellent controllability. However, SRM has the disadvantages of high current harmonics, and low power factor because of a capacitor filter is inserted in the power converter and inductance of SRM is high, it has pulse waveform of current. This paper deals with an energy efficient converter fed SRM system with the reduced harmonics and improved power factor and with higher efficiency. The validity of the proposed scheme is verified via experiment. We are implemented the proposed control system using 80C196KC micro-controller.

• 한국안전학회지
• /
• 제32권1호
• /
• pp.134-139
• /
• 2017

This study has been performed to investigate the risk perceptions of employees in nuclear power plants. A representative sample of 473 employees was surveyed(about 79% response rate). The questionnaire included scales on both risk perceptions of critical five hazards that could be occurring in the nuclear power plants and two psychometric attitudes. Higher risk perceptions between managers and non-managers to five hazards used in this study were entirely obtained from the managers. It was also found that the perceived higher hazards were in the following order: radiation exposure, radioactive release, explosion, fire and radioactive waste. For the controllability, higher risk perceptions to the all factors were obtained from the managers, and higher ones were non-managers in the dread.

• 한국원자력학회:학술대회논문집
• /
• 한국원자력학회 1997년도 춘계학술발표회논문집(1)
• /
• pp.45-50
• /
• 1997

The conventional MOX fuel shows adverse controllability in view of its neutronic characteristics such as decreased soluble boron worth and effective delayed-neutron fraction compared to the UO$_2$ fuel. In order to mitigate these disadvantages, we devised a new concept of the hybrid UO$_2$-MOX fuel pellet with dual structure such that its outer annular section contains. UO$_2$ fuel and its inner cylindrical bar contains MOX fuel. The lattice physics code HELIOS was used to evaluate the neutronic characteristics of three different types of fuel pellets ; UO$_2$ fuel pellet, MOX fuel pellet, and hybrid UO$_2$-MOX fuel pellet. Results show that the hybrid UO$_2$-MOX fuel pellet generally has intermediate neutronic tendency between UO$_2$ fuel and MOX which could diminish the problems arising from the use of the conventional MOX fuel.