진행파를 이용한 디지탈 거리 계전기법의 고장발생각에 따른 고장거리 산출 보정에 관한 연구

정주환,서희석,김철환,신명철 成均館大學校 科學技術硏究所 1992 論文集 Vol.43 No.1

For many years digital protective methods have employed for the calculation of transient phenomena on power system networks caused by faults. This paper presents a travelling wave digital protection scheme to be used as an ultra high speed EHV/UHV transmission line relay. A detection of fault is made by a highly reliable relaying algorithm which makes use of the modal components of the voltage and currents which are caused to be superimposed on the steady state prefault power frequency components following the fault inception. Some of the potential problems and limitations associated with fault angles are achieved using correction factor. Varification of the algoithm is presented through digital computer numerical simulation using electromagnetic transients program(EMTP).

영광 원자력발전소 3,4호기의 계통 병입에 따른 전력계통의 안정도 해석

박철원,권명현,김철환,신명철 成均館大學校 科學技術硏究所 1994 論文集 Vol.45 No.2

This paper deals with consideration for transient stability of power system The analysis of transient stability is very important because it detects the possibility of large scale outage by system collapse caused system configuration change and load unbalance. Two units YGN 3&4 will be connected to the YGN 1 & 2 switchyard through two 345KV circuits until 1996 because of the nuclear power plant construction according to power demand increment. Therefore it is necessary to study stability analysis, fault capacity calculation and power flow problem in assumption of two units YGN 3&4 operation interconnected with the power system Finally, considerations of the effect of interconnection and the establishment of preservation methods for reliability of stable opration of the power system are included in this paper.

디지탈 계전기법에 의한 전선로 보호의 최적화

신명철,김철환,성낙환 成均館大學校 科學技術硏究所 1990 論文集 Vol.41 No.1

To maintain the high reliability and stability in the large scale electric power system for a stabilized power supplying, it requires an accurate high speed digital distance relaying techniques. For this purpose, when it comes to faults with the power system, the digital distance relaying techniques must be investigated to extract the fundamental frequency component and to predict fault location. In this thesis, it is presented the methodology of DFT(discrete Fourier transform), which accompanied aliasing, picket -fence effect, and leakage in the process of extracting fundamental frequency component and an algorithm of extracting fundamental frequency component, using the Kalman filter theory to improve upon these disadvantages. Also, a two-state and three---state Kalman filter are considered for the symmetrical components estimatin of voltages and currents respectively. It is presented an efficient digital distance relaying techniques for the purpose of extracting fundamental frequency component. Also, to confirm the validity of Kalman filtering techniques, it is shown the experimental results obtained by using the digital simulation of power system. And, it is discussed the extracted results of fundamental frequency components by means of the Fourier transform and Kalman filtering techniques.

상호상관 함수를 이용한 지중선로 고장점 추정

朴星完,林泳範,鄭州桓,成洛煥,金喆煥,申明徹 成均館大學校 科學技術硏究所 1994 論文集 Vol.45 No.2

This paper is intended as an investigation of fault location for underground line. Over the past few decades a considerable number of studies have been made on protection of underground line. However, these approaches require the interruption of electric power supply from source for fault location estimation. Therefore, we proposed fault location algorithm for underground line protection without interruption of electric power supply. Cross correlation function is used in this algorithm. Also, EMTP data is used to demonstrate the capability of the proposed fault location algorithm.

大學生의 스포오츠 關心度에 關한 調査硏究 : 團體競技와 個人競技를 中心으로 Centering on team sports and individual sports

崔圭喆,蔡煥國 동국대학교 경주대학 1984 論文集 Vol.3 No.-

Finding from researching the degree of interest in sports on 900 college student (male'500 : female, 400) was as follows. 1. The percentage of team sports that college men hoped to participate in as a player was53.2%, and individual sports, 46.8%. On college women the percentage of team sports was 26%, and individual sports, 74%. 2. The percentage of team sports that college men disliked was 26%, and individual sports, 42.8%. On college women, the percentage of team sports was 20%, and individual sports, 80%. 3. The percentage of team sports that college men has viewed was 82.8%, and individual sports, 17.2%. On college women, the percentage of team sports was 75.9%, and individual sports, 24.1%. 4. The percentage of team sports that college men hoped to view was 72.8%, and individual sports, 27.2%. On college women, the percentage of team sports was 39.5%, and individual sports, 60.5%. 5. The percentage of team sports that college men hoped to get exercise actually was 63.2%, and individual sports, 36.8%. On college women, the percentage of team sports was 33.5%, and individual sports, 66.5%. 6. The percentage of team sports that college men will encourage to their second generation was 56.4%, and individual sports, 43.6%. On college women, The percentage of team sports was 37.5%, and individual sports, 62.5%.

확장칼만필터 기반 무인잠수정 항법의 성능평가

임종환,강철웅 제주대학교 공과대학 첨단기술연구소 2004 尖端技術硏究所論文集 Vol.15 No.2

This paper presents extended Kalman filter based navigation performances of an autonomous underwater vehicle(AUV). The system is composed of a mother ship (small unmanned marine prober) on the surface of the water and an unmanned underwater vehicle in the water. The mother ship is equipped with a digital compass and a GPS for position information, and extended Kalman filter is used for position estimation. For the localization of the AUV, we used only non-inertial sensors such as a digital compass, a pressure sensor, a clinometer and ultrasonic sensors. From the orientation and velocity information, a priori position of the AUV is estimated by applying the dead reckoning method. A posteriori position of the AUV is, then, updated by using the distance between the AUV and a mother ship on the surface of the water together with the depth information from the pressure sensor. The performances of the navigation system has been estimated in various situations through sets of simulations.

地震荷重이 작용하는 高層建物 垂直構造材의 縮小量 補正에 의한 影響 評價

엄철환 위덕대학교 산업기술연구소 2005 산업기술연구소 논문집 Vol.9 No.1

수직 구조부재에 작용하는 축력은 건물의 고층화에 따라 상당한 축소현상을 발생시키고 있다. 기둥 축소현상은 구조물의 사용성을 감소시킬 뿐만 아니라, 초기 구조설계에서 예측치 못한 2차 응력의 발생으로 인해 구조물 자체의 안전에도 영향을 미칠 수 있다. 수직 구조부재의 축소량을 예측하는 주된 목적은 인접 부재간의 부등 축소를 보정하기 위한 것이다. 본 연구에서는 지진 하중을 발생할 때 시공 과정 중에 보정된 수직 구조부재와 보정되지 않은 수직 구조부재에서 발생하는 응력을 비교하였다. Increased height of buildings causes severe shortening of vertical structural members due to the accumulated axial load. It not only decreases the serviceability of a structure but also affect significantly the stability of a structure itself due to the secondary stress. The main purpose of estimating the shortening of vertical structural members is to compensate the differential shortening of adjacent members. This paper presents the comparison of stresses between the vertical structural members compensated during construction process and the non-compensated vertical structural members under the seismic load and represents that the precise compensation of vertical structural members is important.

그리드 연관성을 이용한 지능로봇용 환경 지도 형상의 신뢰성 향상에 관한 연구

임종환,이세진,강철웅 제주대학교 공과대학 첨단기술연구소 2005 尖端技術硏究所論文集 Vol.16 No.2

This paper addresses a new feature map building method that can minimizes the appearance of phantom features by using only sparse sonar data. The approach is composed of extraction of features and building a probability grid map using only the footprint of sparse sonar data, estimation of position uncertainty of the feature, and evaluation of the reliable features. A virtual circle association frame model has been developed, which associates two sonar footprints into a virtual circle frame. Using this model, geometric primitives such as line, point, or arc features are separately extracted. While extracting the feature, a grid map is also built using the orientation probability approach. Position uncertainty of each extracted feature is, then, estimated by considering both the position uncertainty of the robot and the measurement uncertainty of the sonar sensor. Finally, the reliable features among all extracted ones are evaluated from grid association method. The proposed methods have been tested in a real home environment with a mobile robot.

폐비닐여재를 적용한 부착성장식 공법의 유기물 및 영양염 제거 특성

서종환,김진우,안철우,이철승,박진식,김수생 동아대학교 환경문제연구소 2003 硏究報告 Vol.25 No.2

This study was carried out to demonstrate the removal characteristics of organic materials & nutrients in attached growth process applied Synthetic Wasted Polyethylene Media which is reused from wasted vinyl in rural. The results are as follows: 1. Removal efficiencies were indicated COD_(cr), 91.4, 92.4, 93.9%, T-N 56.9, 61.4, 65.1% and all T-P 45% or more with HRT 10, 12, 14 respectively. 2. It is indicated BOD volume load 0.18~0.40kg/ ㎥ ·d, COD volume load 0.28~0.53kg/ ㎥ ·d and NH₄-N volume load 0.12kg/ ㎥ ·d respectively. In conclusion, It is showed activated sludge process is replaced with this process applied Synthetic Wasted Polyethylene Media and this process is considered the methods that solve wasted vinyl troubling in a rural.

응집공정에 적합한 In-Line 정적혼화기를 이용한 혼화공정의 개선

정철우,강민수,최시환,정수일,손인식,강임석 대한상하수도학회 2003 상하수도학회지 Vol.17 No.3

The rapid mixing process for coagulation is a critical component in a water treatment plant. However, at the present time a detailed understanding of the rapid mixing by in-line mixer or generally accepted criteria for the design of in-line static mixer are not available. The aim of this work is therefore to improve the understanding of how the in-line static mixer works and how to better utilize it in coagulation process in water treatment. To investigate the performance of static mixer, coagulation experiments were conducted to compare the static mixer to the traditional backmixer under several coagulation conditions. Experiments were also performed to compare the coagulation efficiency of different mixing type of static mixer which were made using different flow rates and the number of elements equipped in a pipe. The static mixer performed better than the backmixer for all coagulation and mixing conditions tested. Especially, the static mixer was very effective in the surface charge neutralization, as showing higher reduction of negative charge with increasing mixing intensity. However, little difference was observed in the performance of the static mixer equipped with 2, 3, and 5 elements. Also, in a series of bench-scale studies of rapid mixing, the in-line static mixer performed better than the traditional backmixer for both adsorption and charge neutralization (A/N) mechanism and sweep coagulation mechanisms. Especially, the static mixer was more efficient at producing A/N mechanism conditions as a result of its fast and uniform dispersion of the coagulant.