• 전기학회논문지
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• 제56권3호
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• pp.547-555
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• 2007

In order to transmit energy generated through the stator winding of a doubly-fed induction generator (DFIG), we need to synchronize the generated voltage vector with the grid voltage vector. However, the existing synchronization methods work only when the encoder is installed at a specific position and equivalent constant is precise. In order to solve this problem, a new synchronization method has been proposed and a way of applying the method to existing doubly-fed induction generator control algorithm has been also proposed. The validities of the methods proposed were verified by using a prototype converter for a 1.5MW-class doubly-fed induction generator and experimental results showed the validity of that against variation of an encoder positions, generator parameters, and grid voltages.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제50권7호
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• pp.329-333
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• 2001

The pulsed poser system has been widely used to many applications, such as E/P(Electrostatic Precipitator), DeNox/DeSOx power system, ozon generator, etc. A pulse energy efficiency for load depends on the rising time, peak value, pulse duration and impedance matching, etc. The pulse generator generally required for short pusle duration and high peak value was forced to consider its volume and economy. In this study, developing a compact pulse generator that applied for cascading method to be made of two pulse transformers, we compared cascading voltage with non cascading one by applying the pulse energy to load. Adopting cascading technique to pulse transformer, we found that average cascading voltage was about 60[%] of theoretical value. Maximum cascading ratio was calculated at 60 times compared with non cascading voltage.

• 한국에너지공학회:학술대회논문집
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• 한국에너지공학회 1994년도 춘계학술발표회 초록집
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• pp.138-143
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• 1994

A simplified steam generator model has been developed for the simulation of the operational transients of CANDU nuclear power plant. For the analysis of the secondary side, a control volume approach is used and the flow conservation equations are applied for each control volume. The typical steam generator control logic such as the level control and the pressure control are incorporated into the steam generator model with appropriate interface conditions. The steam line including ASDV, CSDV, and governor valve also has been modeled. Test results for typical operational transient case show reasonable transient behavior of steam generator in a real time basis, which is promising for a CANDU engineering simulator.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2002년도 추계학술대회 논문집
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• pp.78-81
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• 2002

The paper discuses characteristics of an axial-flux permanent-magnet generator for a gearless wind energy system which aims to be satisfied with variable operating conditions. Design and construction of an axial-flux permanent- magnet generator with power output at 60[Hz], 300[r/min] for wind energy system is introduced. Finite-element method (FEM) is applied to analyze generator performance at variable load. The results of FE analysis show this generator Is feasible for use with a wind turbine.

• 전기학회논문지P
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• 제57권4호
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• pp.377-382
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• 2008

For stator winding protection of AC generator, KCL(Kirchhoff's Current Law) is widely applied. Actually a CRDR(Current Ratio Differential Relay) based on DFT(Discrete Fourier Transform) has been used for protecting generator. It has been pointed out that defects can occur during the process of transforming a time domain signal into a frequency domain one which can lead to loss of time domain information. Wavelets techniques are proposed for the analysis of power system transients. This paper introduces an algorithm to choose a suitable Mother Wave1et for generator stator fault detection. For optimal selection, we analyzed db(Daubechies), sym(Symlets), and coif(Coiflects) of Mother Wavelet. And we compared with performance of the choice algorithm using detail coefficients energy and RMS(root mean square) error. It can be improved the reliability of the conventional DFT based CRDR. The feasibility and effectiveness of the proposed scheme is proved with simulation using collected data obtained from ATP (Alternative Transient Program) package.

• 한국에너지공학회:학술대회논문집
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• 한국에너지공학회 1994년도 추계학술발표회 초록집
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• pp.135-140
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• 1994

An improved steam generator model has been developed for the DSNP simulation of normal operational transient behavior of CANDU nuclear power plant. For more realistic prediction of steam generator behavior during transient, tube bundle region is divided into two separate control volumes, subcooled region and saturated region, and the variation of thermal hydraulic properties in the control volume is accounted for more realistic estimates of outlet enthalpy of each control volume. Test results for typical CANDU operational transient case show reasonable transient behavior of steam generator with overall CANDU operation and improved operational characteristics of steam generator with power variation.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.2508-2513
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• 2003

This paper presents a nuclear steam generator tube inspection/maintenance robot system. The robot assists in automatic non-destructive testing and the repair of nuclear steam generator tubes welded into a thick tube sheet that caps a hemispherical or quarter-sphere plenum which is a high-radiation area. For easy carriage and installation, the robot system consists of three separable parts: a manipulator, a water-chamber entering and leaving device for the manipulator and a manipulator base pose adjusting device. A software program to control and manage the robotic system has been developed on the NT based OS to increase the usability. The software program provides a robot installation function, a robot calibration function, a managing and arranging function for the eddy-current test, a real time 3-D graphic simulation function which offers remote reality to operators and so on. The image information acquired from the camera attached to the end-effecter is used to calibrate the end-effecter pose error and the time-delayed control algorithm is applied to calculate the optimal PID gain of the position controller. The developed robotic system has been tested in the Ulchin NPP type steam generator mockup in a laboratory.

• 에너지공학
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• 제24권2호
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• pp.91-102
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• 2015

관류식 직관형 증기발생기의 열수력 설계와 성능분석을 위한 해석코드를 개발하였다. 개발한 물리적 모델과 수치 해석 코드를 검증하기 위해 설계 제원이 공개되어 사용되고 있는 관류식 직관형 증기발생기를 개발된 코드를 이용해 해석하고 설계 자료와 비교하였다. 또한 동일한 증기발생기를 최적 열수력 안전해석코드인 MARS를 이용하여 해석한 뒤 비교분석하였다. 열전달면적, 압력 및 온도분포 등의 계산 결과는 설계 자료 및 MARS 코드의 계산 결과와 대부분 일치하게 나타났다. 최종적으로 개발된 코드가 직관형 증기발생기의 열적 설계 최적화 및 민감도 분석을 목적으로 폭넓게 사용될 수 있음을 확인하였다.

• 대한기계학회논문집A
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• 제37권12호
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• pp.1567-1572
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• 2013

방사성동위원소 열전발전기는 장반감기 알파 혹은 베타 핵종에서 방출하는 하전입자를 차폐하여 방사선에너지를 열에너지로 전환하고 이때 발생하는 열전재료의 온도차를 이용하여 전력을 생산하는 시스템이다. 이 기술은 에너지 밀도가 높고 수명이 길며 신뢰성이 높아 우주개발, 국방 등 극한 환경에서 사용되는 장치, 센서 및 로봇 등의 에너지원으로 그 효용성이 매우 높다. 본 연구에서는 방사선 차폐해석 및 열전달 해석을 통하여 차폐체, 그리고 최대 온도구배를 가지는 열전재료의 형상과 배치를 결정하여 열전발전기 기초설계를 도출하였다.

• 대한토목학회논문집
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• 제29권6D호
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• pp.675-683
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• 2009

본 논문에서는 도로와 철도에서 자동차와 열차주행시에 발생하는 진동에너지를 건축-토목 구조물에 활용 가능한 전기에너지로 변환하는 진동력 발전시스템 인프라 구축을 위한 기초 개념에 대해 연구하였다. 본 연구에서는 자기유도기술을 활용하여 진동에너지를 전기에너지로 변환하는 진동력 발전장치를 제안하고, 자기유도기술의 기본 원리 및 진동력 발전장치의 동적특성에 대해 설명하였다. 마지막으로 외력과 진동속도에 따라 진동력 발전장치에서 발생하는 기전력의 세기와의 상관관계를 분석하기 위해 다양한 변수를 두고 실내실험을 수행하였고, 이러한 실험결과를 토대로 시험용 진동력 발전장치의 적용성과 효용성을 분석하여, 최대 가용 전력을 획득하기 위한 진동력 발전시스템의 최적설계에 대한 기초 자료를 확보하였다.