• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.1132-1135
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• 2008

The sludge grown up in steam generators of nuclear power plants shortens the life-cycle of steam generators and reduces the output of power plants. So KHNP(Korea Hydro and Nuclear Power), the only nuclear power utility in Korea, removes it periodically using a steam generator lancing system during the outage of plants for an overhaul. KEPRI(Korea Electric Power Research Institute) has developed lancing systems with high pressured water nozzle for steam generators of nuclear power plants since 2001. In this paper, the design of a partial inter-tube lancing system for model F type steam generators will be described. The system is actuated without a DC motor inner steam generators because the motors in a steam generator make a trouble from high intensity of radioactivity as a break down.

• Journal of Electrical Engineering and Technology
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• 제8권4호
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• pp.787-798
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• 2013

This paper proposes a special power circuit topology and its corresponding control strategy for an energy recovery power accumulator battery pack testing system (PABPTS), which is particularly used in electric vehicles. Firstly, operation principle and related parameter design for the system are illustrated. Secondly, control strategy of the composite power converter for PABPTS is analyzed in detail. The improved scheme includes a high accuracy charge and discharge current closed loop. active power reference for the grid-side inverter is provided by the result of multiplication between battery pack terminal voltage and test current. Simulation and experimental results demonstrate that the proposed scheme could not only satisfy the requirements for PABPTS with wide-range current test, but also could recover the discharging energy to the power grid with high efficiency.

• Journal of Power Electronics
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• 제11권3호
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• pp.256-263
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• 2011

This paper utilizes free oscillation and energy injection principles to generate and control the high frequency current in the primary track of a contactless power transfer system. Here the primary power inverter maintains natural resonance while ensuring near constant current magnitude in the primary track as required for multiple independent loads. Such energy injection controllers exhibit low switching frequency and achieve ZCS (Zero Current Switching) by detecting the high frequency current, thus the switching stress, power losses and EMI of the inverter are low. An example full bridge topology is investigated for a contactless power transfer system with multiple pickups. Theoretical analysis, simulation and experimental results show that the proposed system has a fast and smooth start-up transient response. The output track current is fully controllable with a sufficiently good waveform for contactless power transfer applications.

• 예술인문사회 융합 멀티미디어 논문지
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• 제8권11호
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• pp.215-222
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• 2018

본 논문에서는 슈퍼커패시터를 적용한 에너지 저장장치에 대해서 연구하였다. 납축전지등을 사용하였던 기존방식과는 다르게 슈퍼커패시터를 사용하여 고출력을 달성할 수 있으며, 이러한 특징으로 인하여 연구된 저장장치는 비상전원용 전력을 공급할 수 있을 뿐만 아니라, 전력품질 개선이나 짧은 순간에 큰 출력을 요구하는 고속 기동용 모터등의 전원시스템으로도 사용이 가능한 장점이 있다. 에너지변환 시스템은 양방향 인버터와 컨버터로 구성되어 고속, 고출력의 충전, 방전을 수행할 수 있는 장점도 있다. 양방향 인버터를 이용한 two loop 제어기 설계 방법이 제시되었고, 실험과 제작을 통해 설계 방법의 정합성을 입증하였다. 설계 순서는 먼저 상태공간 평균화 기법과 Decoupling 기법을 이용하여 선형화된 전달함수를 계산하였다. 다음 20% 오버슈트와 안정시간을 만족시키는 전류 제어기 설계를 한 후에 오버슈트 없는 전압과 10배 이상 느린 안정시간을 가지는 전압제어기를 설계한 후 단위계단응답 커브를 통해 원하는 설계특성이 나오는 지를 확인하는 과정으로 이루어진다. 설계된 제어기들은 계통과 단위 역률을 이루며 제어되기 때문에 전력품질 향상을 이룰 수 있으며, 빠른 응답특성과 정상상태 오차를 0으로 만들 수 있는 우수한 제어특성을 가지고 있음을 확인할 수 있었다.

• 전력전자학회논문지
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• 제15권2호
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• pp.87-95
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• 2010

정보화 시대가 가속화됨에 따라 컴퓨터는 우리 일상 생활에서 없어서는 안 되는 필수품으로 자리잡게 되었다. 특히 방대한 데이터 처리량과 데이터 보안에 대한 인식 증가로 인해 인터넷을 기반으로 하는 클라이언트-서버 시스템이 일반화되고 있으며 그에 발 맞추어 65조원 정도의 시장규모를 가지는 서버 컴퓨터 시장 역시 경기와 상관없이 매년 꾸준히 성장하고 있다. 하지만 국내 서버 시장의 경우 높은 기술력과 생산력을 바탕으로 한 해외제품에 전적으로 의존하고 있는 실정이다. 따라서 본 특집 논문에서는 새로운 블루 오션인 서버 시장에 진입하고자하는 국내 업체에 도움이 되고자 서버용 컴퓨터의 핵심 부품인 서버용 전원 장치의 국내외 기술 및 개발 동향에 대하여 살펴보고자 한다.

• 전기학회논문지
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• 제62권1호
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• pp.143-148
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• 2013

When the fault occurs in power system, the fault-current exceeds breaking capacity of the circuit breaker. So, reliablity of the power system is decreased sharply. Superconducting fault-current limiter (SFCL) is operated without impedance in normal state. The fault-current is limited by its impedance during the fault condition. However, the SFCL has several weak points such as huge size, high-price, liquid-nitrogen operation for the real power system. In this paper, We suggested the high-speed interrupter to limit the fault-current in case of the single line-to-ground fault. In addition, we compared the high-speed interrupter with the SFCL to ensure the operation reliability. The proposed interrupter detected the fault-current through the CT, and the power was supplied by operation of the SCR control system. In this experiment, the power of high-speed interrupter was applied after the 4.8[msec] from fault instant. The on-off operation of the interrupter was started after half-cycle from the fault. The fault-current was flowed into the impedance element by the switching operation of the high-speed interrupter. So, the fault current was limited within one cycle, and then it didnt exceed the capacity of a circuit breaker. We confirmed that there was slight difference between the SFCL with high-speed interrupter in terms of limiting-time of the fault-current and switching speed of the SCR. The high-speed interrupter was considered to be more efficient than the SFCL in size, cost or reliability.

• 대한전기학회논문지:전력기술부문A
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• 제52권11호
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• pp.625-631
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• 2003

The purpose of this paper is to assess experimentally system stability of the 154 ㎸ transmission system due to the current of the forthcoming AC High-Speed Railway (HSR) era. It introduces a simple method to evaluate the system stability The proposed method also shows the relationship between stability and power losses, and the stability indices made by the numerical process proposed in this paper will be used to assess whether a system can be stabilized or not. This paper also presents the improvement of the stability via loss reduction using STATCOM. Reactive power compensation is often the most effective way to improve both power transfer capability and system stability. The suitable modeling of the electric railway system should be applicable to the PSS/E. In the case study the proposed method is tested on a practical system of the Korea Electric Power Corporation (KEPCO) which will be expected to accommodate the heavy HSR load. Furthermore, it prove that the compensation of voltage drop and its by-product, loss reduction is closely related to improvement of system stability.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1998년도 전력전자학술대회 논문집
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• pp.171-174
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• 1998

The development of the high-frequency induction-heating for 2700kW power range intend to make localization at forging and rolling mill part by technical innovation. And, the development makes to increase our's competitive power at technique, quality and cost. This paper describes the heart of high-frequency induction-heating technique, switching technique, a few problem in common using as an unsatisfied technique, load adjustment technique, system control, diagnostic system, and auto-interface etc.

• 한국반도체및디스플레이장비학회:학술대회논문집
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• 한국반도체및디스플레이장비학회 2004년도 춘계학술대회 발표 논문집
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• pp.154-158
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• 2004

Power inductor is usually used in the field of the power circuit of a cellular phone, TFT LCD module etc.. This paper presents the development process of Power Inductor Full Automation Winding/Welding System for TFT LCD. This process, the process algorithm, high precision welding current control, design of welding head, high speed, high precision feeding mechanism, and user interface process control program technologies are included.

• 조명전기설비학회논문지
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• 제29권1호
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• pp.86-93
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• 2015

Globally, wind power development is experiencing dramatic growth and wind power penetration levels are increasing. Wind generation is highly variable in time and space and it doesn't guarantee the system reliability and secure system operation. As wind power capacity becomes a significant portion of total generation capacity, the reliability assessment for wind power are therefore needed. At present, this operational reliability assessment is focusing on a generation adequacy perspective and does not consider transmission reliability issues. In this paper, we propose the critical transmission operating constraint prediction(CTOCP) system with high wind power penetration to enhance transmission reliability.