• 한국안전학회지
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• 제26권2호
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• pp.20-25
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• 2011

The fire event occurred in fire proof zone often causes serious electrical problems such as shorts, ground faults, or open circuits in nuclear power plants. These would be directed to the loss of safe shutdown capabilities performed by safety related systems and equipments. The fire event can treat the basic design principle that safety systems should keep their functions with redundancy and independency. In case of a multi-core cable fire, operators can not perform their mission properly and can misjudge the situation because of spurious operation, wrong indication or instrument. These would deteriorate the plant capabilities of safety shutdown and make disastrous conditions. In this paper, the characteristic of cable fire is investigated and the heat-flux evaluation for cable fire is studied. Moreover, a diagnostic methodology for degraded cable in nuclear power plants is presented.

• 한국안전학회지
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• 제26권5호
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• pp.41-45
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• 2011

The fire event occurred in fire proof zone often causes serious electrical problems such as shorts, ground faults, or open circuits in nuclear power plants. These would be directed to the loss of safe shutdown capabilities performed by safety related systems and equipments The fire event can treat the basic design principle that safety systems should keep their functions with redundancy and independency. In case of a cable fire, operators can not perform their mission properly and can misjudge the situation because of spurious operation, wrong indication or instrument. These would deteriorate the plant capabilities of safety shutdown and make disastrous conditions. In this paper, the cables of the representative nuclear power plant in korea is selected and the cable functional failure temperature by exposed fire using Cable Response to Live Fire(CAROLFIRE) is studied. It is expected that the results are very useful to know the cable failure temperature by exposed fire. We confirmed the safety and integrity of the cable by exposed fire and those results will use the based data of cable exposed fire characteristics.

• Nuclear Engineering and Technology
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• 제55권4호
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• pp.1571-1584
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• 2023

In this study, a numerical analysis was performed as part of an international joint research project to reproduce a real cable tray fire that occurred in the heater bay area of the turbine building of a nuclear power plant. A sensitivity analysis was performed on various input parameters to derive results consistent with the sprinkler activation time obtained from the fire event analysis. For all sensitive parameters, the normalized sprinkler activation time correlated well with the power function of the normalized sprinkler height. A correlation equation was developed to identify the sprinkler activation time at any location when determining the slope or fire growth rate under the conditions assuming a linear or t-squared heat release rate (HRR) time curve. Various cable fire growth assumptions were used to determine which assumption was better to provide the prediction coincident with the information given from the fire event analysis in terms of the sprinkler activation time and total energy generated from cables damaged by fire. In the comprehensive analysis of all the sensitive parameters, the standard deviation of the input parameters increased as the sprinkler height decreased. Within the range of the sensitivity parameter values given in this study, when considering all sprinkler heights, the standard deviation of the cable model change was the largest and that of the overhang position change was the smallest.

• 한국안전학회지
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• 제20권2호
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• pp.61-66
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• 2005

This paper presents an human reliability assessment(HRA) for a installation task of the temporary power cable in construction fields. HRA is evolved to ensure that the workers could reliably perform critical tasks such as a process of the temporary power cable. Human errors are extremely commonplace, with almost everyone committing at least some errors every day. The considerable parts of electric shock accidents in the construction field are caused by a series of human errors. Therefore it is required to analyze the human errors contained in the task causing electric shock event, the event tree analysis(ETA) is adopted in this paper, and particularly human reliability was estimated for a installation task of the temporary power cables. It was assumed that the error probabilities of the human actions may be obtained using the technique for human error rate prediction(THERP). The results show that the predominant task on reliability in the cable installation tasks is check-out tasks and the probability causing electric shock by human errors was calculated as $1.0\times10^{-9}$.

• 한국화재소방학회논문지
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• 제26권1호
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• pp.10-15
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• 2012

원전 방화지역에서 화재가 발생할 경우 안전정지 케이블은 단락, 접지, 단선 등 전기적 고장으로 케이블에 고장이 발생하여 그 결과로 안전정지계통의 설비와 기기는 안전정지 기능을 상실할 수 있다. 따라서 원자력 발전소 안전정지계통의 설비와 기능은 다중설계, 계열간 독립 및 분리 원칙에 따라 운영되고 있다. 케이블 화재의 경우 기기 오동작과 오지시 또는 잘못된 계측을 유발할 수 있으며 운전원의 상황 판단에 오류를 일으켜 안전정지 기능을 저해할 수 있다. 본 논문에서는 원자력발전소 케이블 화재 조사 및 원인 분석, 케이블 화재온도 및 기능상실 기준 및 국내 원자력발전소에서 사용중인 케이블을 선정하여 노출 화재 시 케이블 기능상실 온도를 분석하여 케이블 안전성을 확인하였다.

• 한국안전학회지
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• 제31권5호
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• pp.16-21
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• 2016

The purpose of this paper is to conduct ETA on 15 components of power installations: the DS/LBS, LA, MOF, CT, PT, A/V meter, VCB, OCR, COS, PF, Transformer, Condenser(C), Grounding, Cable and Connector. To achieve that, power installations work flow and its components are categorized. Based on performance, human, environmental, management, and safety, this paper drew Initiation events (IE) and End states (ES). ETA is applied to the main functions of each component, and the end states that may occur in one initiation event are suggested. In addition, detailed classification was performed to induce various end states on the basis of the suggested initiation events. If the suggested IEs and ESs are applied on the basis of power installations event cases, it is expected to prevent the same kinds of accident and operate power installations safely.

• 조명전기설비학회논문지
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• 제22권4호
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• pp.54-60
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• 2008

2002년부터 시행되어오고 있는 제조물 책임법에 의해 사고케이블의 원인분석과 사고패턴에 대한 데이터베이스화가 중요하다. 더욱이 가속열화상태에서 전력케이블 사고의 패턴 및 모의실험은 데이터베이스 시스템 구축에 필요하다. 본 논문에서는 열 열화 따른 22.9[kV]이하 케이블의 열 충격시험을 수행하였다. 이 시험은 IEC60811-3-1에 따른다. 시험결과로부터, 22.9[kV]급 A사 전력케이블은 표면이 변색되었고 길이방향으로 급격하게 감소되었다. 특히, A사 전력케이블의 열 중량 특성이 심하게 변함에 따라, 케이블 제조상의 문제일 것이라 추측된다. 만약 전력케이블의 제조상의 결함에 의한 것이라면, 피해자들은 PL환경 하에 손해배상을 받을 수 있을 것이다.

• 한국지진공학회논문집
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• 제18권5호
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• pp.253-259
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• 2014

Porcelain surge arrestor is very vulnerable to earthquake but there is very few information on its dynamic characteristics which are necessary to the seismic design. Therefore, the dynamic characteristics of the porcelain surge arrestor are evaluated considering the variation of its cable tension and stiffness by shaking table test. The test results show that the first natural frequencies are 5.3 Hz and 5.2 Hz in the horizontal x- and y-axis directions, respectively, and higher than 30 Hz in the vertical z-axis direction, respectively. The installation of cable on the surge arrestor reduces the horizontal natural frequencies due to the constraint effect of the cable but cable tension has no effect on the natural frequency. Also, the natural frequency is proportional to the stiffness of the surge arrestor. This test result will be used for the seismic design and seismic capacity assessment of domestic substations and contribute to the stability of the electric power supply under earthquake event.

• 한국화재소방학회논문지
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• 제30권3호
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• pp.79-85
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• 2016

원자력발전소의 방화지역에서 전기적인 단락, 지락, 전기회로 개방 등의 전기 문제로 화재가 발생할 수 있다. 전기 화재가 발생할 경우 안전계통 및 관련기기의 안전정지 기능이 상실된다. 이러한 사고를 예방하기 위하여 안전계통은 다중성, 독립성으로 설계되어 있다. 그러나 케이블 화재시 운전원은 오동작, 잘못된 지시 및 계측으로 발전소 상황을 잘 못 판단하여 적절한 조치를 하지 못할 수 있다. 따라서 주제어실 화재시 케이블 기능상실온도에서 최소 운전원 조치 요구시간인 5분은 매우 중요하다. 본 논문에서 주제어실 화재시 케이블의 기능상실온도 시간을 분석하여 운전원 조치시간이 충분한지 평가하여 주제어실 화재에 대한 안전성을 확인하였다.

• 한국전기전자재료학회논문지
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• 제20권1호
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• pp.57-64
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• 2007

One of the cause of insulation failure in power cable is well known by electrical treeing discharge. This is occurred for imposed continuous stress at cable. And this event is related to safety, reliability and maintenance. In this paper, throughout analysis of partial discharge(PD) distribution when occurring the electrical tree, is studied for the purpose of knowing of electrical treeing discharge characteristics according to defects. Own characteristic of tree will be differently processed in each defect and this reason is the first purpose of this paper. To acquire PD data, three defective tree models were made. And their own data is shown by the phase-resolved partial discharge method (PRPD). As a result of PRPD, tree discharge sources have their own characteristics. And if other defects (void, metal particle) exist internal power cable then their characteristics are shown very different. This result Is related to the time of breakdown and this is importance of cable diagnosis. And classification method of PD sources was studied in this paper. It needs select the most useful method to apply PD data classification one of the proposed method. To meet the requirement, we select methods of different type. That is, neural network(NN-BP), adaptive neuro-fuzzy inference system and PCA-LDA were applied to result. As a result of, ANFIS shows the highest rate which value is 98 %. Generally, PCA-LDA and ANFIS are better than BP. Finally, we performed classification of tree progress using ANFIS and that result is 92 %.