• 한국소음진동공학회논문집
• /
• 제11권6호
• /
• pp.200-207
• /
• 2001

In this paper, a new method for Partial field decomposition is developed that is based on the beamforming algorithm for the application of acoustical holography to a composite sound field generated by multiple incoherent sound sources. In the proposed method, source Positions are first predicted by MUSIC(multiple signal classification) algorithm. The composite sound fields can then be decomposed into each partial field by the beamforming. Results of both numerical simulations and experiments show that the method can find each partial field very accurately and effectively, and that it also has Potential to be used for application to distributed sources.

• 한국안전학회지
• /
• 제18권3호
• /
• pp.69-74
• /
• 2003

To investigate the partial discharge and electric field distribution in cable joint parts, we measured the partial discharge and electric field in specimen. The specimens which cross-linked polyethylene(XLPE) and ethylene propylene diene ethylene(EPDM) are used to insulating material for underground cable md cable jointing parts. The polymers are used to insulating material in switchgear which is a kind of transformer equipment and in ultra-high voltage cable. Its using is increasing gradually, the electrical insulation properties are not only excellent but also mechanical property is excellent. And because it is possible to be made void of several type in insulator while it is produced, which the electrical field distribution is changed by void, it has a critical influence to insulator performance. The underground cable is connecting by the jointing material, insulating breakdown and the electric ageing which are caused by several mixing impurity and the damage of cable insulator layer, which reduced the life of cable while intermediate joint kit is connected. Therefore, the computer simulation is used to estimating insulator performance, XLPE is used to the insulating material of ultra-high voltage cable and EPDM is used to insulator layer in joint material kit, and which are produced as specimen. And it is analyzed the electric field concentrating distribution and partial discharge by modeling of computer simulation in void and cable joint kit.

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2018년도 추계 학술논문 발표대회
• /
• pp.12-13
• /
• 2018

Reinforced concrete works account for 40 to 50 percent of the total construction work. However, the shortage of construction workers is a problem in the delay of the construction period of reinforced concrete. The partial rebar prefabrication is one of the ways to shorten construction period. Thus, this study compared the partial rebar prefabrication and field fabrication method through work sampling. As a result, the partial rebar prefabrication showed a significant decrease in time compared to field fabrication method. As a result of this study, it is expected to be used as a reference for the efficient selection of reinforced concrete methods.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2008년도 추계학술대회 논문집 전기설비전문위원
• /
• pp.218-221
• /
• 2008

Due to a variable noises in the field underground lines, clear technology of noises is very important in the diagnosis technology of partial discharge. Therefore we progressed filter test to improve the measuring test of partial discharge in a field. We applied to field test after making W-LC filter for partial discharge measurement, and then designed experimental environment such as under- ground distribution lines of field. Measuring sensor for test was UHF sensor. And we analysed those using the Lemke Probe and oscilloscope (TDS-3054, Tektro- nix). Finally, we obtained excellent data of noise decrement in the joint box of 22.9[kV] distribution lines from above experiment.

• International Journal of Contents
• /
• 제3권4호
• /
• pp.15-21
• /
• 2007

Image morphing deals with the metamorphosis of one image into another. The field morphing depends on the manual work for most of the process, where a user has to designate the control lines. It takes time and requires skills to have fine quality results. It is an object of this paper to propose a method capable of realizing the semi-automation of field morphing using adaptive vertex correspondence based on image segmentation. The adaptive vertex correspondence process efficiently generates a pair of control lines by adaptively selecting reference partial contours based on the number of vertices that are included in the partial contour of the source morphing object and in the partial contour of the destination morphing object, in the pair of the partial contour designated by external control points through user input. The proposed method generates visually fluid morphs and warps with an easy-to-use interface. According to the proposed method, a user can shorten the time to set control lines and even an unskilled user can obtain natural morphing results as he or she designates a small number of external control points.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2007년도 춘계학술대회 논문집 전기설비전문위원
• /
• pp.72-74
• /
• 2007

Due to a variable noises in the field underground lines, clear technology of noises is very important in the diagnosis technology of partial discharge. Therefore we progressed filter test to improve the measuring test of partial discharge in a field. We applied to field test after making W-LC filter for partial discharge measurement, and then designed experimental environment such as underground distribution lines of field. Measuring sensor for test was UHF sensor. And we analysed those using the Lemke Probe and oscilloscope (TDS-3054, Tektronix). Finally, we obtained excellent data of noise decrement in the joint box of 22.9[kV] distribution lines from above experiment.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2005년도 제36회 하계학술대회 논문집 C
• /
• pp.2277-2279
• /
• 2005

Due to a variable noises in the field underground lines, clear technology of noises is very important in the diagnosis technology of partial discharge. Therefore we progressed filter test to improve the measuring test of partial discharge in a field. We applied to field test after making W-LC filter for partial discharge measurement, and then designed experimental environment such as under-ground distribution lines of field. Measuring sensor for test was UHF sensor. And we analysed those using the Lemke Probe and oscilloscope (TDS-3054, Tektronix). Finally, we obtained excellent data of noise decrement in the joint box of 22.9[kV] distribution lines from above experiment.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1995년도 하계학술대회 논문집 C
• /
• pp.1081-1084
• /
• 1995

Internal voids located within an insulation will arise partial discharge that causes local breakdown and even the entire insulation breakdown. For HV apparatuses, it is usual case that several voids are formed within non-uniform electric field condition rather than single void within uniform field, which can be solved analitically. The purpose of this work is to study partial discharge and breakdown characteristics of an insulation according to the distribution pattern of two disc-type voids that are located within non-uniform field. The results from numerical field analysis and experiments show that the electric field within the voids decreases as they are arranged more serially, which accordingly results in the increase of partial discharge inception field(PDIF) much higher than that of single void model. With parallel arranged voids, PDIF is almost the same as that of single void model. On the other hand, AC breakdown strength decreases as voids are arranged more serially, which is a natural result considering the reduction of effective insulation thickness. For parallel voids, this effect cannot he noticed where as they show different pattern compared with single void and serial void models in $\Phi$-Q-N analysis. Considering these results may leads us to the conclusion that, in the evaluation of insulating products through PD test, it is not sufficient to determine only PDIV or existence of PD at predetermined voltage level. We could evaluate more accurately by considering all the available data such as PDIV, PD magnitude, PD occurring phase, number of PD pulses, and etc.

• 한국안전학회지
• /
• 제14권4호
• /
• pp.100-107
• /
• 1999

The purpose of the study is to investigate the effect of H$_2$ pressure on partial discharge (PD) activity and aging rate in turbine generator winding insulations. A series of field tests and laboratory tests were peformed to investigate the effect of $H_2$ pressure on PD activity. Field tests were conducted at two unit turbine generators in two conditions, in $H_2$ pressure and in air atmosphere. Obtained results are as follows ; 1) ${\Delta}tan{\delta}$ and maximum partial discharge are reduced with increase of $H_2$ pressure and partial discharge inception voltage. 2) The reduction ratio of ${\Delta}tan{\delta}$ due to $H_2$ pressure is higher than one of PD magnitude. 3) Partial discharge pulses suffer from attenuation and distortion when transmitted along windings, because of the complex L-C network between windings. From the result, partial discharge pulses are subjected to resonance phenomena in a generator winding.

• 한국결정성장학회지
• /
• 제6권3호
• /
• pp.406-414
• /
• 1996

본 연구에서는 금속타겟을 이용한 반응성 스퍼터링법을 이용하여 PZT 박막 증착후 냉각시 산소분압에 따른 박막의 상형성 거동 및 전기적 특성에 미치는 영향을 고찰하였다. 냉각시 산소분압의 감소에 따라 박막 표면의 휘발에 기인하여 표면거칠기는 증가하였고 입성장은 거의 일어나지 않았다. 산소분압이 증가할수록 각형비가 보다 우수한 hysteresis 특성을 얻을 수 있었고 산소분압이 감소함에 따라 remanent polarization과 retained polarization이 감소하였으며, 항전계의 감소가 관찰되었다. 산소분압에 따른 유전율-전압 특성 측정에서 산소분입이 감소함에 따라 internal bias field의 증가가 관찰되었으며, 유전율도 조금씩 감소하였다. Field accelerated retention 시험결과 냉각시 산소분압이 감소함에 따라 nonswitched polarization의 증가가 관찰되었고 bias time이 증가함에 따라 nonswitched polarization이 감소하였다.