• 전기학회논문지
• /
• 제61권4호
• /
• pp.643-649
• /
• 2012

The diagnosis technique of stator winding faults based on Motor Current Signature Analysis(MCSA) was suggested. Park's vector pattern, the circle that is drawn by d-q transformed currents($i_d$, $i_q$), is widely used for stator winding faults detection. The current Distortion Ratio(DR), defined by the ratio of max axis and min axis of ellipse of Park's vector's pattern, was more simple and powerful method than the Park's vector pattern. In this study, a calculation method of distortion ratio of Park's vector pattern was suggested for auto diagnosis of stator winding short fault and usefulness of suggested calculation method of distortion ratio was verified through simulation using LabVIEW program.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2011년도 제42회 하계학술대회
• /
• pp.2075-2076
• /
• 2011

The stator winding faults diagnosis technique based on MCSA is as follows. Firstly, collecting the 3 phase motor currents, that signal is transformed by (d-q transform, $i_d$, $i_q$). Park's vector pattern, the circle that is down by d-q transformed currents($i_d$, $i_q$). The circle is widely used for stator winding faults detection. The current distortion ratio(DR), defined by the ratio of max-axis and min-axis of ellipse of Park's vector's pattern. In this study, distortion ratio of Park's vector pattern is suggested for Auto diagnosis of stator winding short fault and usefulness of distortion ratio is verified through simulation using LabVIEW program.

• 전기학회논문지P
• /
• 제55권4호
• /
• pp.202-206
• /
• 2006

In this paper, an auto detection method of stator winding fault of small induction motor is suggested. The Park's vector pattern which is obtained from 3-phase current signal by d-q transforming, is very good to detect winding fault. Comparing the Park's vector pattern of testing motor with its of healthy motor, the Park's vector pattern of fault motor is became an ellipse and the asymmetry is increased by the winding fault series. So for detecting the dis-symmetry, id-filtered function, Min-value, and Max-value are suggested for auto detecting. Using LabVIEW programing, 3-phase healthy motor and several kind of winding fault motors are tested and the test results are shown that the suggested method can gives us a possibility of an auto detecting winding fault.

• Ocean Science Journal
• /
• 제42권3호
• /
• pp.153-163
• /
• 2007

This study is based on a series of numerical modeling experiments to understand the tidal circulation in the Kangjin Bay (KB). The tidal circulation in the KB is mostly controlled by the inflow from two channels, Noryang and Daebang which introduce the open ocean water into the northern part of the KB with relatively strong tidal current, while in the southern part of the KB, shallowest region of the entire study area, weak tidal current prevails. The model prediction of the sea level agrees with observed records at skill scores exceeding 90 % in terms of the four major tidal constituents (M2, S2, K1, O1). However, the skill scores for the tidal current show relatively lower values of 87, 99, 59, 23 for the semi-major axes of the constituents, respectively. The tidal ellipse parameters in the KB are such that the semi-major axes of the ellipse for M2 range from 1.7 to 38.5 cm/s and those for S2 range from 0.5 to 14.4 cm/s. The orientations of the major-axes show parallel with the local isobath. The eccentricity values at various grid points of ellipses for M2 and S2 are very low with 0.2 and 0.06 on the average, respectively illustrating that the tidal current in the KB is strongly rectilinear. The magnitude of the tidal residual current speed in the KB is on the order of a few cm/s and its distribution pattern is very complex. One of the most prominent features is found to be the counter-clockwise eddy recirculation cell at the mouth of the Daebang Channel.

• 한국지리정보학회지
• /
• 제14권4호
• /
• pp.182-193
• /
• 2011

지역 규모에 따른 한국 남부해역 표층 수온의 시 공간적 변동 패턴을 비교하고자 시기적으로는 31년간(1980~2000)의 동계와 하계를, 지역적으로는 남부해역 전체 해역(A 지역)을 비롯하여 제주도를 중심으로 서부 해역(B 지역)과 동부 해역(C 지역) 등 세 해역을 선정하였다. 수온의 시간적 변동 패턴을 위해서는 회귀분석을, 수온의 공간적 변동패턴 분석을 위해서는 수온의 가중평균중심과 표준편차타원체 분석이 각각 적용되었다. 수온의 회귀분석 결과 세 지역에서 두계절 모두 장기적으로 상승하는 경향을 보였다. 하지만 31년 평균수온이 하계에는 세 지역 모두 유사하였지만, 동계에는 C 지역이 B 지역보다 높게 나타났다. 두 계절 수온의 공간적 변동 패턴은 세 지역에서 각기 다름을 보였다. A 지역에서는 동-서 방향, B 지역에서는 남동-북서 방향, C 지역에서는 남서-북동 방향으로 나타났다. 아울러 동계에 수온의 가중평균중심 위치와 평균 수온과의 관계가 A와 B 지역에서는 상관성이 있는 반면, C 지역에서는 상관성이 없게 나타났다. 따라서 수온의 시 공간적 변동패턴 분석 시 지역적 규모를 고려해야 함을 알 수 있다.

• Nuclear Engineering and Technology
• /
• 제43권2호
• /
• pp.133-140
• /
• 2011

In this paper, a deformation measurement technology for nuclear fuel rods is proposed. The deformation measurement system includes a high-definition CMOS image sensor, a lens, a semiconductor laser line beam marker, and optical and mechanical accessories. The basic idea of the proposed deformation measurement system is to illuminate the outer surface of a fuel rod with a collimated laser line beam at an angle of 45 degrees or higher. For this method, it is assumed that a nuclear fuel rod and the optical axis of the image sensor for observing the rod are vertically composed. The relative motion of the fuel rod in the horizontal direction causes the illuminated laser line beam to move vertically along the surface of the fuel rod. The resulting change of the laser line beam position on the surface of the fuel rod is imaged as a parabolic beam in the high-definition CMOS image sensor. An ellipse model is then extracted from the parabolic beam pattern. The center coordinates of the ellipse model are taken as the feature of the deformed fuel rod. The vertical offset of the feature point of the nuclear fuel rod is derived based on the displacement of the offset in the horizontal direction. Based on the experimental results for a nuclear fuel rod sample with a formation of surface crud, an inspection resolution of 50 ${\mu}m$ is achieved using the proposed method. In terms of the degree of precision, this inspection resolution is an improvement of more than 300% from a 150 ${\mu}m$ resolution, which is the conventional measurement criteria required for the deformation of neutron irradiated fuel rods.

• 대한전자공학회논문지SP
• /
• 제47권1호
• /
• pp.91-96
• /
• 2010

본 논문에서는 핵연료봉의 변형에 대한 고정도 검사방법을 제안한다. 핵 연료봉과 이를 관측하는 영상 센서의 광축을 수직으로 구성한다. 영상 센서의 광축을 기준으로 45도 또는 그보다 높은 각도로 레이저 라인빔을 연료봉 표면에 조사하면 연료봉의 수평 방향 변위가 영상 센서에서는 수직 방향 변위로 관측된다. 핵 연료봉 표면에 일정 각도로 입사된 레이저 라인빔이 영상 센서면에서는 일정 두께를 갖는 포물선 형태로 관측되게 된다. 센서 화면에 나타나는 일정 두께의 포물선을 영상처리하여 타원으로 모델링하고 타원의 장축과 단축의 기울기를 구한다. 포물선의 변곡점과 모델링한 타원의 장축과 단축이 교차하는 지점을 특징점으로 추출한다. 이와 같은 영상처리 알고리즘을 이용하여 핵 연료봉의 수평방향 변위에 따른 특징점 좌표의 수직방향 편차를 계산한다. 크러드가 형성된 핵연료봉 시편에 대해 고해상도 영상센서를 사용하여 실험한 결과 중성자 조사후 핵연료봉의 변형 검사기준인 $150{\mu}m$ 보다 3배 이상 개선된 $50{\mu}m$ 이하의 검사 정밀도를 달성하였다.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1999년도 하계학술대회 논문집 D
• /
• pp.1717-1719
• /
• 1999

The chief advantage of polymer arrester. from design of pressure relief, anti-contamination, electrical failure was reduced by outdoor polymer housing. In the first for development of pressure relief design for polymer arrester, fault current and surge were studied through experiments of electrical. Designed the FRP inner tube and unit modules for pressure relief housing. Tested the performance of unit modules for pressure relief of polymer arrester, and the result was successful. The pressure relief of polymer arrester depend on design pattern of diamond shape and ellipse. Study on the pressure relief of FRP inner tube for outdoor polymer arrester. Designed and manufactured FRP inner tube of polymer arrester. Tested the fault current of polymer arrester per 10 kA, 10 cycle.

• 한국전기전자재료학회논문지
• /
• 제22권2호
• /
• pp.178-183
• /
• 2009

This paper introduces experimental investigates of an accident pattern for the distributing cross linking-polyethylene(XLPE) cable terminations considering product liability(PL) law environment. The influence of defects such as thickness and length decrease of XLPE, an impurity on XLPE and the gap between stress-con of housing and semi-conductor on insulating properties of the termination have been studied. The thickness and length decrease of XLPE decrease ac breakdown strengths. Breakdown traces of XLPE that is damaged by knife displayed ellipse shape. The gap of between stress-con and semiconductor deteriorates dielectric strength of XLPE seriously.

• 한국위성정보통신학회논문지
• /
• 제9권4호
• /
• pp.57-62
• /
• 2014

본 논문에서는 빅 데이터를 이용하여 범죄 발생 패턴을 분석하는 알고리즘을 제안하고 구현했다. 제안된 알고리즘은 대검찰청에서 수집하여 공개한 범죄관련 빅 데이터를 사용하며, 표준편차 타원체 및 공간밀도 분석과 같은 공간통계분석을 통해 서울시의 2011-2013년 범죄발생 패턴을 분석했다. 범죄 발생 빈도수를 이용하여 범죄발생지역, 시간, 요일, 장소의 위험지수를 구했고, 범죄 패턴 분석 알고리즘을 통해 범죄 발생 확률을 구했다. 이를 통해 공간통계분석을 했다. 제안된 알고리즘의 구현 결과, 서울시의 각 구별로 범죄발생 패턴이 다르다는 것을 파악할 수 있었고, 다양한 범죄발생 패턴을 분석하고 범죄발생확률을 위험지수를 통해 수치화하여 위험도를 정량적으로 산출할 수 있었다.