• Title/Summary/Keyword: In-leakage

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A Numerical Analysis on Thermal Stratification Phenomenon by In-Leakage in a Branch Piping

  • Park Jong-Il
    • Journal of Mechanical Science and Technology
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    • v.19 no.12
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    • pp.2245-2252
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    • 2005
  • Thermal stratification in the branch piping of power plants can be generated by turbulent penetration or by valve leakage. In this study, a numerical analysis was performed to estimate the thermal stratification phenomenon by in-leakage in the SIS branch piping of nuclear power plant. Leakage rate, leakage area and leakage location were selected as evaluation factors to investigate the thermal stratification effect. As a result of the thermal stratification effect according to leakage rate, the maximum temperature difference between top and bottom of the horizontal piping was evaluated to be about 185K when the valve leakage rate was about 10 times as much as the allowed leakage rate. For leakage rate more than 10 times the allowed leakage rate, the temperature difference was rapidly decreased due to the increased mixing effect. In the result according to leakage area, the magnitude of temperature difference was shown in order of $3\%,\;1\%\;and\;5\%$ leakage area of the total disk area. In the thermal stratification effect, according to the leakage location, temperature difference when leakage occurred in the lower disk was considerably higher than that of when leakage occurred in the upper disk.

Development and Safety Estimation of Resistive Leakage Current(Igr) of Detection Outlet (저항성 누설전류(Igr) 검출 콘센트의 개발 및 안전성 평가)

  • Kim, Chang-Soung;Hanh, Song-Yop;Choi, Chung-Seog
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.58 no.2
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    • pp.221-226
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    • 2009
  • In this paper, we analyzed form of flowing leakage current in electrical installation. Leakage current ($I_g$) is consisted of resistive leakage current($I_{gr}$), capacitive leakage current($I_{gc}$), and inductive leakage current($I_{gl}$). Resistive leakage current($I_{gr}$) is big occasion than capacitive leakage current($I_{gc}$) in system, Residual Current Protective Device(RCD) detects correctly leakage current. But,$I_{gc}$ is big occasion than $I_{gr}$, RCD is malfunctioned It is resistance to lead to electric fire in electrical device. We manufactured outlet that resistive leakage current detecting circuit is had. Manufactured outlet displayed performance exactly in leakage current of 5 mA Therefore, this product estimates that contribute on electric fire courtesy call.

Study on the Resistivity Leakage Current Detection and Properties Analysis of Electrical Installat ion (전기설비의 저항성 누설전류 검출 및 특성 해석에 관한 연구)

  • Choi, Chung-Seog;Hahn, Song-Yop
    • Proceedings of the KIEE Conference
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    • 2008.09a
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    • pp.301-304
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    • 2008
  • In this paper, we study from of flowing leakage current in electrical installation. Leakage current is expressed by a resistivity leakage current($I_{gr}$), a capacitive leakage current($I_{gc}$), an inductivity leakage current($I_{gl}$). General Zero Phase Current Transformer (ZCT) detect a leakage current($I_{g}$) that are conjoined resistivity leakage current and capacitive leakage current. In case $I_{gr}$ is big than $I_{gc}$, there is no singular problem in leakage current detection of system. But, in case $I_{gc}$ is big than $I_{gr}$, earth leakage breaker can not prevent accident effectively. Can lower electric leakage perception current to 5 mA if apply resistivity leakage current detecting circuit. We can achieve prevention of electricity disaster spontaneously.

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A leak detection and 3D source localization method on a plant piping system by using multiple cameras

  • Kim, Se-Oh;Park, Jae-Seok;Park, Jong Won
    • Nuclear Engineering and Technology
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    • v.51 no.1
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    • pp.155-162
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    • 2019
  • To reduce the secondary damage caused by leakage accidents in plant piping systems, a constant surveillance system is necessary. To ensure leaks are promptly addressed, the surveillance system should be able to detect not only the leak itself, but also the location of the leak. Recently, research to develop new methods has been conducted using cameras to detect leakage and to estimate the location of leakage. However, existing methods solely estimate whether a leak exists or not, or only provide two-dimensional coordinates of the leakage location. In this paper, a method using multiple cameras to detect leakage and estimate the three-dimensional coordinates of the leakage location is presented. Leakage is detected by each camera using MADI(Moving Average Differential Image) and histogram analysis. The two-dimensional leakage location is estimated using the detected leakage area. The three-dimensional leakage location is subsequently estimated based on the two-dimensional leakage location. To achieve this, the coordinates (x, z) for the leakage are calculated for a horizontal section (XZ plane) in the monitoring area. Then, the y-coordinate of leakage is calculated using a vertical section from each camera. The method proposed in this paper could accurately estimate the three-dimensional location of a leak using multiple cameras.

DC Leakage Current Properties Analysis of the LED Lamps of Road and Landscape Lighting (LED 가로등 및 경관조명의 직류 누전 특성 분석)

  • Kim, Hyang-Kon;Kim, Dong-Woo;Choi, Hyo-Sang
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.60 no.4
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    • pp.885-891
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    • 2011
  • In this paper, we studied dc leakage current properties analysis of LED lamps of road and landscape lighting when leakage current appeared in dc power line. Generally, converter of LED lighting is divides to insulated type and non-insulated type according to components. When electric leakage happened in AC power line, earth leakage breaker(ELB) senses leakage current and interrupts electric circuit. In dc power source, We need experimental verification about dc electric leakage for electricity safety. In normal wiring conditions and in the water, in case of using insulated type of converter, dc leakage current did not occur. However, in case of using non-insulated type of converter, dc leakage current occurred and passed through into the ground. We found that there is a hazard of electric shock by dc leakage current. We expect that the results of these studies would be helpful for electrical safety of LED lamps for road and landscape lighting.

A Study on Multi-story Building Users' Opinions about the Installation of Emergency Plumbing Equipment for Preventing the Spread of Water Leakage (다층건물 사용자의 누수확대 방지용 비상배수설비 설치에 대한 의견 연구)

  • Yeon, Cheol-Soo;Seo, Jin-Hyeong
    • Journal of the Korean housing association
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    • v.27 no.4
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    • pp.59-66
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    • 2016
  • The purpose of this study is to examine the necessity of 'emergency plumbing equipment for preventing the spread of water leakage'. It reviews social and economic costs when there is spread of water leakage and finds out that those are enormous. Expansion of water leakage causes conflicts between neighbors, economic loss and inconvenience from damages on facilities like elevator and power failure. Next, it examines the inability of existing plumbing equipment when it comes to spread of water leakage. Newly defined 'Surface Leakage' means rapid leak in the surface, and 'Internal Leakage' means seeping out slowly and gradually buried in the pipeline. It will also be analyzed by separating the concept of a leak in the two concepts of a 'Surface Leakage' and 'Internal Leakage'. It proposes emergency plumbing equipment for preventing the spread of water leakage as a solution for the expansion of water leakage. It explains general concepts of emergency plumbing equipment for preventing the spread of water leakage. It will also examine the effectiveness of the user by performing a survey of 420 multi-level building their opinion on the effects of an emergency plumbing equipments to prevent the spread of water leakage.

Study on Statistical Analysis of Measured Fluid Leakage Data and Estimation of the Leakage Rate for Power Plant Valve (발전용 밸브 유체누설 측정 데이터의 통계적 평가 및 누설량 예측 연구)

  • Lee, S.G.;Kim, D.W.;Kim, Y.S.;Park, J.H;Jeong, H.
    • Journal of Power System Engineering
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    • v.13 no.5
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    • pp.59-66
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    • 2009
  • High temperature and pressure valves in power plant have been used for fluid flowing and leakage occurred owing to valve internal damage such as disc wear, crack and inserting of foreign objects etc. in these valves. Recently, multi-measuring technique applied both ultrasonic and acoustic method have been used for evaluation of valve internal leakage in order to raise measurement reliability. Therefore, we have performed various leakage tests using ultrasonic and acoustic measuring system and acquired leakage data for the various leakage conditions. In this study, we developed the estimation method of regression model through leakage data, and expectation method for valve opening ratio, which is directly proportion to leakage rate, using the established estimation model from the measured data, valve size and fluid pressure so as to enhance data reliability. As a result of this study, it was founded that expectation method of leakage rate by statistical analysis method is appropriate to valve leakage evaluation.

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Effects of the Leakage Tangential Velocity on the Leakage Flow Path in Shrouded Axial Compressor Cascades (축류압축기 슈라우드 캐비티내의 누수유동 경로에 대한 연구)

  • Sohn, Dae-Woong;Kim, Tong-Beum;Song, Seung-Jin
    • 유체기계공업학회:학술대회논문집
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    • 2005.12a
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    • pp.311-317
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    • 2005
  • Measurements of the leakage flow in the shrouded cavity were performed in axial compressor cascades at $Re=2.6{\times}10^5$. This paper describes the effects of the leakage flow tangential velocity on kinematics of the leakage flow in the shrouded cavity and consequent overall loss and exit flow turning at stator blade row downstream. Flow data and flow visualization images consistently indicate that leakage flow circumferentially migrates 2, 4 and 5 blade passages in the direction of rotation for ${\upsilon}_y/c=0.09$, 0.35 and 0.45, respectively where ${\upsilon}_y$ is the leakage tangential velocity and c is the mainstream velocity. The leakage flow contracts to a jet across the seal-tooth resulting in an increase in the leakage axial velocity-doubling the leakage axial velocity in upstream cavity compared to that in the downstream cavity. Consequently, two flow regions are distinguished before and after the seal-tooth. As increasing the leakage tangential velocity, the overall loss downstream of stator blade row decreases and the exit flow turning in the range of span. from the hub endwall to 15% increases while the decreases in the flow turning from 15% to 30% span is observed.

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침수 누전에 대한 자계 특성

  • Kim, Tak-Yong;Lee, Gyeong-Seop;Kim, Jin-Sa;Kim, Chung-Hyeok
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2009.11a
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    • pp.147-147
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    • 2009
  • Every year respect a countermeasure establishment the electric leakage detection system and electric leakage investigation work are becoming enforcement line plentifully in about the electric leakage accident which is increasing, measuring in compliance with a most ground connection voltage and an image electric current mainly is become accomplished, inputs a pulsation group signal in the line and detects a signal change between the line a method which there is. In order to investigate the quality in compliance with an electric leakage electric current from the electric leakage area after conferring the electric leakage environment in compliance with a flooding when the electric leakage electric current exists in the surface, it investigated the electric leakage electric current quality from the electric current distribution and flooded districts from the present paper.

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Development of an Earth Leakage Breaker Operating by Resistive Leakage Current using a Resetable Integrator (적분기를 이용한 저항성 누전전류 작동방식 누전차단기 개발)

  • Ham, Seung-Jin;Hahn, Song-Yop;Koh, Chang-Seop
    • Proceedings of the KIEE Conference
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    • 2007.07a
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    • pp.917-918
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    • 2007
  • The former earth leakage breaker is operating by total leakage current which is the vector-sum of resistive leakage current and capacitive leakage current. However, the electric disaster like the electric shock and fire is caused mainly by resistive leakage current. Therefore, the earth leakage breaker is ideal when it is operating by resistive leakage current. In this paper, the theory for finding the component of resistive leakage current from total leakage current is suggested and it is embodied to actual circuit. The resistive leakage current can be found by integrating the total leakage current during half cycle of line voltage. Thus, we can simply find resistive leakage current by using OP-AMP integrators, and we can confirm that the resistive leakage current is computed exactly from total leakage current obtained by resistive leakage current and capacitive leakage current. The results that the earth leakage breaker is operating within regular interrupt time are verified when the former earth leakage breaker's controller circuit is replaced by the proposed controller circuit.

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