• 한국전자통신학회논문지
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• 제12권1호
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• pp.109-114
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• 2017

본 연구에서는 mA급 유효성분(저항성) 누설전류를 감지할 수 있는 모듈을 개발하였다. 감지된 누설전류를 기술표준규격에서 규정하는 0.03초 이내에 차단을 할 수 있도록 16 bit 신호처리 프로세서인 MSP430 프로세서를 사용하여 모듈을 구현하였다. 개발된 모듈은 스마트그리드의 스마트분전반에서 감전예방을 위한 모듈로 적용 가능할 것으로 기대된다.

• 조명전기설비학회논문지
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• 제15권3호
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• pp.67-73
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• 2001

본 논문에서는 ZnO 피뢰기 소자에 대한 내구성 평가와 열화실험을 위한 저항분 누설전류 검출장치의 개발과 열화진단기법에 대하여 기술하였다. 저항분 누설전류는 ZnO 피뢰기 소자가 정상상태인지 불안정상태인지에 대한 판단의 지표로서 사용할 수 있다. 본 논문에서는 보상회로로 구성된 저항분 누설전류 측정시스템을 설계하여 구성하고, 실증실험으로서 ZnO 소자에 대한 저항분 누설전류의 측정과 고속프리에 변환기법(Fast Fourier transform)을 통해 저항분 누설전류의 주파수특성을 조사·분석하였다. 분석결과 제안한 저항분 누설전류의 측정 시스템은 실험실에서 산화아연 바리스터의 전기적·물성적 특성을 연구하고, 전력계통에 있어서 ZnO 피뢰기의 열화의 진단과 예측기술을 개발하는데 유용하게 활용할 수 있다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 춘계학술대회 논문집
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• pp.1422-1424
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• 2004

Various deterioration diagnostic techniques and devices are suggested, and most of which measure leakage current components as an indicator of arrester ageing. However, the techniques based on the magnitude of leakage current measure simply RMS or peak value of leakage current components and do not provide detailed information needed in the diagnosis. In this study, we found that the phase vs. wave height of total leakage current is changed or a new wave height is produced with arrester ageing. To complete the new technique, we designed an arrester diagnostic device which is composed of a current detection circuit, an optical transmission circuit, and an analysis program. After measurement of the total leakage current, magnitudes, phase vs. wave height, and harmonics of the leakage current components are analyzed by the microprocessor based device. From the experimental results, we confirmed that the device can measure most parameters needed for the arrester diagnostics and analyze an initial deterioration state.

• 상하수도학회지
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• 제35권2호
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• pp.121-133
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• 2021

This study set up the estimates of leakage management efficiency evaluation and leakage management goal that could be used in local water distribution networks efficiency business and modernization business. The data were analyzed using data envelopment analysis and multiple regression analysis. To this end, with leakage management input indices concerning leakage reduction activities (e.g., aged pipe replacement, water meter replacement, leakage restoration, and leakage detection) and leakage management calculation indices (e.g., the increase of revenue water ratio and the reduction of leakage ratio), the data on 22 K-water consignment local water supply systems were analyzed for the years from 2004 through 2018. Using the results of efficiency analysis by data envelopment analysis, the other DMUs (Decision Making Unit) benchmarked the DMU with the highest efficiency to maximize the leakage management efficiency for all DMUs. Through this, leakage management goal estimates were drawn with the input indices of four leakage reduction activities and calculation indices of the increase of revenue water ratio and the reduction of leakage ratio by multiple regression analysis for each group based on the revenue water ratio and leakage ratio. The correlation coefficients of the leakage management goal estimate for the criteria for the revenue water ratio amounted to 0.553 and 0.771. The correlation coefficients of the leakage management goal estimate for the criteria for leakage ratio were 0.397 and 0.865. Accordingly, we estimated the quantity and priority of four leakage reduction activities for the target leakage ratio and revenue water ratio.

• 한국정보통신학회논문지
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• 제15권2호
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• pp.419-424
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• 2011

누전, 아크 그리고 과부하로 인한 전기화재를 탐지하고 제어할 수 있는 시스템보드(system- on-board)를 구현하였다. 이를 위하여 화재방지제어 시스템 IC를 사용하였으며, 누설전류 검출을 위한 GF(ground fault)신호 검출회로, 아크(arc fault)신호 검출회로, 그리고 과전류가 발생할 경우 입력전압을 제어할 수 있는 과부하신호 검출회로를 설계하였다. GF신호 검출회로와 아크신호 검출회로는 누설전류와 아크신호에 각각 잘 동작하였으며, 과부하(overload) 신호 검출회로는 노이즈나 부하변동에 따른 오동작 없이 과부하시에만 동작함을 확인하였다.

• 상하수도학회지
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• 제33권4호
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• pp.299-309
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• 2019

Waterworks facilities inevitably experience some amount of leakage even if there is a lot of investment or state-of-the-art technology that is applied such as DMA(District Metered Area) system construction, leakage detection, repair, pipe rehabilitation, etc. The primary reason is the leakage is naturally restored over time. In the UK, this restoration characteristic is defined as NRR(Natural rate of rise of leakage) and used to decision making for prioritizing active leakage control of DMAs. However, this restoration characteristic is well recognized, but researches on NRR in the water distribution system are insufficient in Korea. In this study, the estimation method of NRR was developed suitable for applicating in Korea considering of SCADA data, water infrastructure, and water usage patterns by modification of the UK's NRR method. The proposed method was applied to 9 DMAs and verified it's applicability by comparing with the other water loss performance indicators. It is expected that the proposed method can be used to support decision making for sustainable NRW(Nor-revenue water) management in the water distribution system.

• JSTS:Journal of Semiconductor Technology and Science
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• 제13권4호
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• pp.402-409
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• 2013

An innovative application of voltage-contrast (VC) inspection allowed inline detection of NMOS leakage in dense SRAM cells is presented. Cell sizes of SRAM are continual to do the shrinkage with bit density promotion as semiconductor technology advanced, but the resulting challenges include not only development of smaller-scale devices, but also intra-devices isolation. The NMOS leakage caused by the underneath n+/P-well shorted to the adjacent PMOS/N-well was inspected by the proposed electron-beam (e-beam) scan in which VC images were compared during the in-line process step of post contact tungsten (W) CMP (Chemical Mechanical Planarization) instead of end-of-line electrical test, which has a long response time. A series of experiments based on the mechanism for improving the intra-well isolation was performed and verified by the inline VC inspection. An optimal process-integration condition involved to the tradeoff between the implant dosage and photo CD was carried out.

• Journal of Magnetics
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• 제22권1호
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• pp.34-42
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• 2017

Material defects in the Steam Generator Tubes (SGT) of sodium cooled fast breeder reactor (PFBR) can lead to leakage of water into sodium. The water and sodium reaction will lead to major accidents. Therefore, the examination of steam generator tubes for the early detection of defects is an important requirement for safety and economic considerations. In this work, the Magnetic Flux Leakage (MFL) based Non Destructive Testing (NDT) technique is used to perform the defect detection process. The rectangular notch defects on the outer surface of steam generator tubes are modeled using COMSOL multiphysics 4.3a software. The obtained MFL images are de-noised to improve the integrity of flaw related information. Grey Level Co-occurrence Matrix (GLCM) features are extracted from MFL images and taken as input parameter to train the neural network. A comparative study on characterization have been carried out using feed-forward back propagation (FFBP) and cascade-forward back propagation (CFBP) algorithms. The results of both algorithms are evaluated with Mean Square Error (MSE) as a prediction performance measure. The average percentage error for length, depth and width are also computed. The result shows that the feed-forward back propagation network model performs better in characterizing the defects.

• 한국소음진동공학회논문집
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• 제20권9호
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• pp.828-833
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• 2010

Steam leakage is one of the major issues for the structural fracture of pipes of nuclear power plants. Therefore a method to inspect a large area of piping systems quickly and accurately is needed. In this paper, we proposed the method for the detecting steam leakage by using image signal processing. Our basic idea come from heat shimmer which shine with a soft light that looks as if it shakes slightly. To test the performance of this technique, experiments have been performed for simple heat source and steam generator. Results show that the proposed technique is quite powerful in the steam leak detection.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2011년도 추계학술대회 초록집
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• pp.139.1-139.1
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• 2011

Electric vehicle use independent electricity of high voltage. if isolation of electricity is destructed, devices and people are considerably damaged. Therefore, detection of ground fault is necessary for electric vehicle. As the existing detection method of ground fault can not detect ground fault when isolation of both positive side and negative side of electricity is destructed, and change of voltage of electricity. This paper proposed detection method for ground fault of both two sides of electricity and change of voltage. The proposed method is verified by analysis of equivalent circuit.