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.

물을 전기분해하여 제조한 수소/산소 혼합가스의 특성에 관한 연구

이환철,정목근 대진대학교 신과학연구소 1998 신과학연구 Vol.1 No.-

물을 전기분해하여 제조한 수소/산소 혼합가스의 응폭특성과 연소특성에 관해 연구하였다. 자동차용 점화코일을 이용한 고압방전장치를 제작하였으며, 이를 이용하여 응폭실험을 행한 결과에 따르면 강력한 외부로의 폭발이 있고난 후 진공이 형성되면서 응폭현상이 일어남을 확인할 수 있었다. 그러나 응폭특성이 수소/산소 혼합가스만의 유일한 특성인가에 대해서는 현재 결론을 내리기에는 어려운 실정이다. 또한 텅스텐금속의 연소실험결과에 따르면 수소/산소 혼합가스나 산소-LPG가스 모두 텅스텐금속을 연소시킬 수 있으므로,실제로는 대기중의 산소와 텅스텐금속이 산화반응을 일으켜 텅스텐산화물이 형성됨에 따라 녹는점이 1400-1600℃로 낮아진 결과로 판단되지만 보다 정확한 결론을 내리기 위해서는 좀 더 많은 연구가 필요하다고 판단된다.

高校 體育敎科 內容 및 學習經驗에 關한 調査硏究 : 大邱·慶北地區를 中心으로 Focus Mainly on Taegu, Kyungbuk Province district

車哲煥 慶北大學校 師範大學 體育學硏究會 1984 體育學會誌 Vol.12 No.-

In order to research and analyze this study on learning experience and the curriculum of physical education in girls senior high school, Question in paper method is used. As a result of this survey, it is Concluded as follows: 1. In the unit of track and field, every study course deals with shor-distance race, 800-meter race, long jumping expecially throwing events are inclined to be made light of. 2. In gymnastics unit, balance training, mat-training are laid emphasis on, and it shows that teaching is generally neglected in the training of vaulting horse and is also neglected in the difficult events. 3. Teaching is executed in the field of pass, dribble training which is fundamental skill in the ball events, but step by step teaching is not carried out. And it also shows that hard matters in teaching of fundamental skill are not generally treated with. 4. It is general tendency that Seasonal sports is took no notice of. Especially Ice events are enirely neglected. 5. This survey also shows that the teaching of the hard matters and articles indispensable in the safe learning is generally neglected. Exclusive teaching is also ignored in the fundamental athletics such as track and field and gymnastic. 6. The tondency of teaching the Subject in accordance with interest is Outstanding but continuous and step by step teaching is not considered on the whole.

21世紀 體育, Sports의 方向摸索을 위한 小考

李喆熙,裵元煥,李達源 啓明大學校 生活科學硏究所 1993 科學論集 Vol.19 No.-

This study was investigated for the purpose of conereting the arm of the physical education and acquiring intrinsic area of the physical education and contributing human culture in highly developed industrial society of the future. The conclusions were summerized as follows; In highly developed industrial society, sports activity for health and leisure by changing of physical education environment will be increased. The mass sports and sports science which social group carrys out positively will be accelerated. With recognition change for physical education, Eco-sports will be important sports. By developing sports scientification, Techno-sports will be more developed. The attitude and a view of value of the people for the sports will be more promoted. The conception of Pro-sports will be changed and the acceleration of political tool of physical education will be done in international sports. The role of physical education scientists who have the specialization and self-confidence of academy and deep experience will be large.

정양호 연안대의 수생 유관속식물상과 군집구조

오경환,김철수 慶尙大學校 기초과학연구소 1986 基礎科學硏究所報 Vol.2 No.-

호수생태계의 식생구조에 대한 연구의 일환으로 경남 합천군 대양면에 소재한 정양호의 연안대에서 1986년 4월부터 9월까지 수생유관속 식물군집을 조사하여 다음과 같은 결과를 얻었다. 1. 조사대상 지역에서 조사된 수생유관속식물은 43과 79속 90종 16변종 1품종으로서 총 107종류였으며, 생활형별로는 정수식물이 79.4%, 침수식물 9.3%, 부수식물 7.5%, 부엽식물 3.7% 등으로 정수식물이 가장 많았다. 2. chi-square test에 의한 종간상관분석 결과 34종의 식물이 5% 또는 1% 수준에서 양이나 음의 상관을 나타내었으며 사마귀풀, 세모고랭이, 물옥잠, 수염마름 등이 양의 상관빈도가 높았고 유전마름과 말즘은 음의 상관빈도가 높았다. 3. 조사지역의 식생은 개구리밥, 생이가래, 자라풀, 유전마름, 네마름, 검정말, 말즘, 새우가래, 이삭물수세미, 붕어마름 등 10종으로 구성된 개방수면 지역의 식물군과 사마귀풀, 세모고랭이, 물옥잠 등을 포함하여 23종으로 구성된 습지 식물군으로 구별되었다. Flora and vegetation structure for the aquatic vascular plants were investigated in the littoral zone of Lake Jungyang, Gyeongsangnam-do, Korea from April to September, 1986. The flora was composed of 43 families, 79 genera, 90 species, 16 varieties, and 1 forma or 107 taxa. Among them, 79.4% were emergent plants, 9.3% submersed plants, 7.5% free-floating plants, and 3.7% floating-leaved plants, respectively. It was shown that 34 species of the aquatic vascular plants were positively or negatively correlated each other at 5% or 1% level from the results of association analysis by chi-square test. The vegetation in the area could be classified into two groups: the open-water vegetation composed of 10 species such as Spirodela polyrhiza, Salvinia natans, Hydrocharis dubia, Trapa natans, Trapa bicornis, Hydrilla verticillata, Potamogeton crispus, Potamogeton maackianus, Myriophyllum spicatum, Ceratophyllum demersum, and the marsh vegetation of 23 species including Potamogeton distinctus, Sagittaria trifolia, S. aginashi, Alopecurus aequalis var. amurensis, Polypogon fugax, Beckmannia syzigachne, Zizania latifolia, Eleocharis dulcis, E. mamillata var. cyclocarpa, Scirpus triqueter, Cyperus iria, Aneilema keisak, Monochoria korsakowi, Persicaria thunbergii, P. hastato-sagittata, P. hydropiper, Ranunculus cantoniensis, Ludwigia prostrata, Myriophyllum ussuriense, Oenanthe javanica, Nymphoides peltata, Trapella sinensis var. antennifera, and Lobelia chinensis.

A.Smith의 경제사상과 시장질서

박철환 江陵大學校統一問題硏究所 2000 統一問題硏究 Vol.16 No.-

거리계전기법 적용을 위한 고장발생시 잡음의 모델링

신명철,김철환 成均館大學校 科學技術硏究所 1989 論文集 Vol.40 No.1

A more specialized area of transient evaluations is transmission line fault detection and protection systems. During the first cycle or two following a power system fault, a high-speed protective relay is expected to make a decision as to the severity or location of the fault, usually based on 60 HZ information, i.e. the phase and magnitude of 60HZ voltage or current signals. However, the signal is badly corrupted by noise in the form of a dc offset or frequencies above 60HZ. Furthermore, fault-induced signals are influenced by the line length, conductor configuration and the nature of the earth return. One of several possible sources of transients in protection measuring signals is in the primary system for which protection is required in its response to the impact of short circuit fault on-set. Other sources are in the primary voltage and current transducers from which protection signals are derived, and, often of particular importance, in the interface circuits between the transducer secondaries and the comparator and measuring elements of the protection system. However, the noise signals that will be described in this paper are due to the main power system only and do not include errors due to current or voltage transducers.