• 전력전자학회논문지
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• 제26권5호
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• pp.315-324
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• 2021

A solid state transformer (SST) that can interface an MVAC of three-phase 13.2 kV and a 1.5 kV DC distribution. SST consists of an AC/DC converter and a DC/DC converter with a high-frequency isolation transformer (HFIT). The AC/DC converter consists of cascaded NPC full-bridge to cope with the MVAC. The DC/DC converter applies a quad active bridge (QAB) topology to reduce the number of the HFIT. Topology analysis and controller design for this specific structure are discussed. In addition, the insulation of HFIT used in DC/DC converters is considered. The discussion is validated using a 300 kVA three-phase SST prototype.

• 전기의세계
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• 제25권5호
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• pp.51-53
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• 1976

• 융합정보논문지
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• 제7권6호
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• pp.201-207
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• 2017

수전설비의 고장은 산업과 가정 등 전력을 사용하는 모든 곳에 정전사고를 발생시켜 많은 불편과 문제의 원인이 되고 있다. 수전설비 고장의 주요 원인으로는 노후화를 비롯하여 태풍, 지진을 비롯한 자연재해와 동물 등으로 파악되고 있다. 현재는 수전설비의 온도가 높아지면 고장이 발생한다는 추측만으로 온도의 고온이 지속되는 것을 모니터링한다. 따라서 적기에 수전설비의 고장에 대응하기 어려운 측면이 존재하는 것이 사실이다. 이 논문에서 제안하는 수전설비 모니터링 시스템은 갑작스런 자연재해 등으로 인한 고장을 제외한 일반적인 고장에 대해 효율적으로 대응하는 방안으로 제안한다. 수전설비 모니터링 시스템은 열 감지 센서를 부착하여 수전설비를 실시간으로 감시하고, 감시한 데이터를 수집하여 인공신경망을 이용한 학습을 통해 축적된 정보를 이용하여 고장을 예측한다. 인공신경망의 학습과 실험을 통하여 제안 방식이 효율적임을 보였다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.1732-1735
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• 2003

In this paper, a DSP-based test apparatus for Control Rod Drive Mechanism (CRDM) that is used in nuclear power plants is described. Using this apparatus, we can test the mechanical and electrical characteristics of CRDM and obtain some information about how to improve the CRDM further and how to design a power controller to actuate the CRDM. Since firing angles can be directly applied to the gate-drive circuits of thyristors in the power controller by using this apparatus, the maximum and minimum values of firing angles within available limits are easily measured. Also step-current inputs help us investigate each coil's response characteristics. Therefore, we can easily find the range of control gains which enables a stable CRDM operation in insertion and withdrawal actions at high speed, mid speed, and low speed. Since this apparatus has a test mode in which an insertion or withdrawal action is divided into several phases so that the current command for each phase is given step by step, we may judge whether the CRDM works as expected or not. We also describe a fault detection capability of the test apparatus for the power controller by using discrete Fourier transform.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1990년도 추계학술대회 논문집 학회본부
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• pp.63-67
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• 1990

An axial flux magnet for a magnetic levitation system is designed and analysed by finite element simulations. The results are compared with those of experiment in order to verify the analysing method. Lift force, air gap flux density and temperature characteristics of the magnet showed fairly good agreement with each other.

• 조명전기설비학회논문지
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• 제14권3호
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• pp.77-80
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• 2000

본 논문은 有無效 섣둡jJ設觸의 投貴위치와 그 용향을 적정화하여 동일한 설비투자량에 대하여 전력손실을 최소화하는 방안에 대하여 설명하였다. 유효 및 무효전릭의 미소증분에 대한 손실의 변화를 나타내는 모선의 손실감도를 소개하고 전력송실을 최대한 개선하기 워한 유무효전력 설비의 투자지표로 이용하였다. 각 모선에 주어지는 투자지표의 우선순위에 따라 유효 및 무효전력설비가 투자되어 전력손실을 최소화한다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 D
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• pp.2666-2668
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• 2003

The most widely employed grounding apparatus in distribution systems is a driven rod. But this method has some difficulties to get a specified ground resistivity in cities or islands. Recently, the new ground apparatus are proposed. This paper describes the research which relates with the system to evaluate the performance of novel grounding apparatus.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1990년도 추계학술대회 논문집 학회본부
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• pp.37-42
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• 1990

In order to obtain optimal design criteria and operating parameters, a Single-sided Linear Induction Motor (SLIM) is analysed by using a 2-D finite element method with magnetic and current vector potential. In the analysing procedures, the governing equation is derived from Maxwell's equation combined with the magnetic vector potential. As a forcing term, 3-phase voltage source is employed using the Kirchhoff's voltage law in order to look into effects of the unbalanced 3-phase currents and air gap flux density. Also, 2ndary eddy current distribution, longitudinal end and transverse edge effects are in turns visualized by flux lines in 3 different analysing planes as functions of frequency and input power.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 A
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• pp.395-397
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• 2002

Recently, electric heating using midnight power has brought a rapid increase. Therefore, the increase of midnight power use has much influenced on midnight load pattern and share more than 20% of total midnight electricity consumption. Hence, the distortion of load by using midnight power apparatus is severe and made the usage pattern ineffective electricity usage pattern. This paper analyze the load pattern of midnight power apparatus and policies that can effectively build midnight load. In addition, it provides policies on shifting midnight power apparatus load.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 하계학술대회 논문집 Vol.5 No.1
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• pp.441-444
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• 2004

Each electrical apparatus radiates various infrared as the condition of surface and load current. Because heat distribution of the apparatus changes as the condition, it is able to analyze the condition of the apparatus by using the distribution. However, methods having been used to measure the heat distribution cannot compare normal condition with abnormal, and the apparatus has diagnosed by intuition. This paper deal with a program that is able to analyze changed temperature distribution. The program is to analyze temperatures on pixels in selected region of interest or position and is able momently and logically to analyze condition of the apparatus. The results are able to apply to a on-line monitoring system.