가스절연지상개폐기 PD 자동진단기법 연구

김영달,전시식,차동욱 대한전기학회 2022 전기학회논문지 Vol.71 No.1

Partial discharge diagnosis is being carried out to prevent failure of ground switch of distribution facilities. However, the reliability of partial discharge diagnosis is insufficient because the results are different depending on how the experts classify the partial discharge and noise signals. Therefore, in this paper, a method to automatically classify partial discharge and noise signals was studied in order to improve the reliability of the partial discharge diagnosis results of ground switch. Partial discharge and noise signal are obtained through the High Frequency Current Transformer(HFCT). And the features were extracted based on the pulse shape analysis, the standard deviation and gravity center of signal. The features are used as input to neural networks and learned using back-propagation. In addition, the structure of neural networks was optimized through genetic algorithm.

Regression Analysis of Vibration Phenomenonon the Load Capacity and Elapsed Year of a Power Transformer

김영달 한국조명.전기설비학회 2009 조명·전기설비학회논문지 Vol.23 No.3

The majority of the causes for the failures of power transformers in operation are mechanical defects due to vibration. The vibration phenomenon was measured from the power transformers in operation in the substations. The vibration measurement was performed in a 6×4 structure on one side of each transformer. The vibrations of the measured points were presented in two and three dimensions and analyzed. The results, according to the elapsed year of the transformer and the load capacity to the transformer, were analyzed. These results could be used as basic data with which to establish vibration standards for power transformers. In addition, the load capacity-vibration phenomenon correlation was examined and regression analysis was performed to derive the estimation function. The vibration phenomenon according to the elapsed years was also estimated to derive the function. Then the analysis of the power transformers was used to set vibration standards for them based on the vibration data.

화염에 의한 ACSR 송전선의 표면 특성에 관한 연구

김영달 한국조명전기설비학회 2003 조명·전기설비학회논문지 Vol.17 No.6

본 논문은 산불 화염에 의한 ACSR 송전선의 열화특성을 분석하기 위하여 인공화염장치를 이용하여 건전 전선을 일정 시간 간격으로 화염을 가하는 실험을 하였다. 이 때 발생되어지는 표면 특성을 확인하였다. 표면 특성 실험은 금속현미경으로 표면 특성을 확인하였다. 또한, 포항지역에 가설되어 운전 중이던 ACSR 480[$\textrm{mm}^2$]가 산불 열화로 인하여 철거된 전선을 수거하여 표면 특성 시험 및 분석 결과와 인공화염장치를 이용한 실험 결과를 비교$.$분석하였다. 이 두 개의 분석자료를 이용하여 향후 산불에 의해 열화된 전선의 상태를 예측할 수 있는 데이터베이스를 만들고, 또한 산불로 인한 ACSR 전선의 수명 진단에 필요한 자료를 제공하고자 한다. This paper deals with the experimental results that apply to a new wire by an artificial flame-maker because it's difficult to directly analyze the characteristic of deterioration by a forest fire. Those results include surface characteristics for a conductor. In addition, there's been an experiment and analysis about the surface characteristics of the wire of ACSR 480$\textrm{mm}^2$ which was removed from Pohang area by a forest fire. Then, the database will be made to predict the state of deteriorated wires by a forest fire using those two data, and data necessary to diagnose the life state of an ACSR wire affected by a forest fire will be given.

평면형 다이폴 안테나를 이용한 UHF RFID 태그 안테나 특성

김영달,이영훈,권원현,Kim Young-Dal,Lee Young-Hun,Kwon Won-Hyun 한국전자파학회 2005 한국전자파학회논문지 Vol.16 No.2

본 논문에서는 RFID 칩 실장이 용이한 접지면이 첨가된 평면형 미엔더 형태의 평면형 다이폴 안테나를 이용 하여 UHF 대역에서 동작하는 RFID 태그용 안테나를 제안하였다. 태그의 크기를 명함 크기로 구현하기 위해서 안테나는 meander 형태로 구현하였으며, 안테나의 특성 개선을 위하여 T-정합법을 사용하였고, RFID 칩 실장이 용이한 구조를 구현하기 위해서 접지면을 첨가하였다. 논문에서 제안한 방법을 통하여 구현한 안테나의 크기는 $100\times60\;mm^2$이고, 유전체는 FR4를 사용하였다. 실험 결과 방사 패턴은 다이폴 안테나와 같이 전 방향(omnidirectional) 특성이며, 중심 주파수는 427 MHz, -10 dB 반사 손실 대역폭은 8 MHz, 최대 반사 손실은 21 dB이다. 따라서 본 논문에서 제안한 방법을 이용하여 RFID 칩 실장이 용이한 RFID 태그용 안테나를 구현할 수 있다. In this paper, we are proposed the antennas for RFID tag operated at UHF band which are inserted ground plane easy to mount the RFTD chips at the antenna surfaces. In order to implemented antenna for RFID tag which the size is same as conventional name card, the structure of the antenna is meander type, matching method for improvement characteristics of the antenna use T matching method, ground plane is inserted at the antenna substrate fer mounting RFID chips. The substrate size of implementation is $100\times60\;mm^2$ and the FR4 substrate is used. Results of the experiment, the center frequency of the implemented antenna is 427 MHz, -10 dB return loss bandwidth is 8 MHz, maximum return loss is 21 dB, the radiation pattern is omnidirectional. From these results, we are conformed application for UHF RFID tag antenna.

화염에 의한 ACSR 송전선의 기계적 특성에 관한 신뢰성 분석

김영달 한국조명전기설비학회 2003 조명·전기설비학회논문지 Vol.17 No.6

본 논문에서는 직접적인 방법으로는 산불로 인한 전선의 열화특성을 분석하기 어려우므로 인공화염장치를 이용하여 건전 전선을 일정 시간 간격으로 화염을 가하는 실험을 하였다. 기계적 실험은 인장강도, 연신율 및 비틀림 수 실험을 수행하였다. 또한, 포항지역에 가설되어 운전 중이던 ACSR 480[$\textrm{mm}^2$]가 산불 열화로 인하여 철거된 전선을 수거하여 기계적 특성 시험 및 분석결과와 인공화염장치를 이용한 실험결과를 비교$.$분석하였다. 이 두 개의 분석 자료를 이용하여 향후 산불에 의해 열화된 전선의 상태를 예측할 수 있는 데이터베이스를 만들고, 또한 산불로 인한 ACSR 전선의 수명 진단에 필요한 자료를 제공하고자 한다. This paper deals with the experimental results that apply to a new wire by an artificial flame-maker because it's difficult to directly analyze the characteristic of deterioration by a forest fire. Those results include tension load, extension rate and torsion number for a conductor. In addition, there's been an experiment and analysis about the mechanical characteristics of the wire of ACSR 480$\textrm{mm}^2$ which was removed from Pohang area by a forest fire. Then, the database will be made to predict the state of deteriorated wires by a forest fire using those two data, and data necessary to diagnose the life state of an ACSR wire affected by a forest fire will be given.

徐敬德의 氣一元論과 李滉의 理一元論과의 比較硏究

金永達 대한철학회 1972 哲學硏究 Vol.15 No.-

시가지 발파공해의 억제대책에 관한 연구

김영달 三陟大學校 1994 論文集 Vol.27 No.-

Ground vibration is the most serious of the factors affecting the surface constructs in an urban blasting. To set up a control measure for ground vibration, I took into account the open-air blastings conducted by the Samchok factory of Dongyang Cement Co. Ltd. The damage limit of blasting vibration was fixed on the peak particle velocity 5cm/sec, which was proposed by Langefors and USBM, while the generalized form V=KL??d ?? was used for the blasting vinbration formula. The results are as follows. 1) The constant K, which is determined by the ground condition, was found to be 38.95 in the vertical direction. 2) The index m was found to be 0.5, which is determined by the quanity of the charging gun-powder. 3) The distance diminution index n was found to be 1.54, which is determined by the distance between the blasting point and the measuring point.

大學과 社會

金永達 단국대학 1965 檀苑 Vol.5 No.1

The Little Foxes : Play and Film

김영달 聖潔大學校 人文科學硏究所 1996 人文科學論叢 Vol.1 No.-

6도체 무볼트형 Spacer Damper의 진동현상에 관한 연구

김영달 한국조명전기설비학회 2003 조명·전기설비학회논문지 Vol.17 No.3

Sparer damper는 다도체 송전선로에서 각 소도체 간의 간격을 유지시켜 주며, 전기적 및 기계적인 외부 요인들에 의해 발생되어진 진동에너지로부터 파생되어지는 각종 피해로부터 전선을 보호하기 위해 적절한 간격을 두고 설치된다. 송전선로에서 발생되어진 진동현상의 결과에 의해 전선의 소손 또는 단선 등의 사고를 방지 및 유지 보수시 어려움을 충분히 감안하여 최적의 요소기술을 구현하는 것이 가장 중요하다. 그러므로 본 논문에서는 Spacer damper에 대한 진동특성 해석은 도선 운동의 지배방정식, Spacer damper의 운동방정식, Spacer damper가 체결된 전선의 경간 내 운동, 정적 처짐 해석 및 유한 차분법에 의한 수치해석 등의 해석적인 방법을 이용하여 정립하였다. 또한 실제 상황에 따라 수시로 변화되는 각종 진동현상을 시뮬레이션하여 Spacer damper의 설치 간격을 검토 하였으며, 새로이 얻어진 해석적인 방법을 토대로 향 후 765kV 송전선로용 6도체 무볼트형 Spacer damper의 각종 진동현상을 해석 할 수 있을 것이다. Spacer dampers maintain the constant gaps between each conductor in a bundle conductor-transmission line, and are installed at proper intervals to keep a line from all sorts of damages derived from the vibration energy caused by mechanical or electrical external factors. It is most important to embody a technology which considers difficulties of maintenance and repair, and has optimum elements in order to prevent accidents such as destruction by fire or the snapping of a wire by the effect of vibration phenomenon coming from transmission lint In the resent thesis, therefore, the analysis of vibratory characteristics of spacer damper is set up by analytical methods such as the analysis of conductor motion's governing equation, the equation of spacer damper's motion, spacer damper-fastened wire's motion in a span and the numerical analysis of finite difference method. Furthermore, the installation distance between spacer dampers was scrutinized by simulations of various vibration phenomena which change at any time as actual conditions do, and hereafter difference method. Furthermore, the installation distance between spacer dampers was scrutinized by simulations of various vibration phenomena which change at any time as actual conditions do, and hereafter we will be able to analyze all kinds of vibration phenomena coming from a boltless spacer damper with 6 bundle conductor for 765kV transmission line based on new analytical methods.