• Title/Summary/Keyword: fault tree

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Safety Assessment for the Design of Digital Reactor Protection System of Nuclear Power Plant (원자력 발전소 디지털 원자로 보호시스템의 설계에 대한 안전성 평가)

  • Kong, Myung-Bock;Lee, Sang-Yong
    • IE interfaces
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    • v.23 no.1
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    • pp.68-77
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    • 2010
  • Digital reactor protection system which consists of many identical modules, is fault- tolerant to provide high safety. The modules themselves including DSP(digital signal processing) card are also fault-tolerant in nature. This paper assesses the safety for being-designed digital reactor protection system of 2-out-of-4 G structure with lockout. Some interesting design alternatives are compared. Fault tree analysis for assessing system safety is performed by Relex software. The selected reactor protection system fully satisfies EPRIURD stipulation of mean failure time of 50 years.

Remote Fault Diagnosis Method of Wind Power Generation Equipment Based on Internet of Things

  • Bing, Chen;Ding, Liu
    • Journal of Information Processing Systems
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    • v.18 no.6
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    • pp.822-829
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    • 2022
  • According to existing study into the remote fault diagnosis procedure, the current diagnostic approach has an imperfect decision model, which only supports communication in a close distance. An Internet of Things (IoT)-based remote fault diagnostic approach for wind power equipment is created to address this issue and expand the communication distance of fault diagnosis. Specifically, a decision model for active power coordination is built with the mechanical energy storage of power generation equipment with a remote diagnosis mode set by decision tree algorithms. These models help calculate the failure frequency of bearings in power generation equipment, summarize the characteristics of failure types and detect the operation status of wind power equipment through IoT. In addition, they can also generate the point inspection data and evaluate the equipment status. The findings demonstrate that the average communication distances of the designed remote diagnosis method and the other two remote diagnosis methods are 587.46 m, 435.61 m, and 454.32 m, respectively, indicating its application value.

An Efficient Algorithm for Test Pattern Compaction using Independent Faults and Compatible Faults (독립고장과 양립 가능한 고장을 이용한 효율적인 테스트 패턴 압축 기법)

  • Yun, Do-Hyeon;Gang, Seong-Ho;Min, Hyeong-Bok
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.38 no.2
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    • pp.145-153
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    • 2001
  • As combinational ATPG algorithms achieve effectively 100% fault coverage, reducing the length of test set without loosing its fault coverage becomes a challenging work. The new approach is based on the independent and the compatible relationships between faults. For more compact test set, the size of compatible fault set must be maximized, thus this algorithm generates fault-pattern pairs, and a fault-pattern pair tree structure using the independent and the compatible relationships between faults. With the fault-pattern pair tree structure, a compact test set effectively generated. The experimental results for ISCAS 85 and 89 benchmark circuits demonstrate the effectiveness of the proposed method.

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Bus Reconfiguration Strategy Based on Local Minimum Tree Search for the Event Processing of Automated Distribution Substations

  • Ko Yun-Seok
    • KIEE International Transactions on Power Engineering
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    • v.5A no.2
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    • pp.177-185
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    • 2005
  • This paper proposes an expert system that can enhance the accuracy of real-time bus reconfiguration strategy by adopting the local minimum tree search method and that can minimize the spreading effect of the fault by considering the operating condition when a main transformer fault occurs in an automated substation. The local minimum tree search method is used to expand the best-first search method. This method has the advantage that it can improve the solution performance within the limits of the real-time condition. The inference strategy proposed expert system consists of two stages. The first stage determines the switching candidate set by searching possible switching candidates starting from the main transformer or busbar related to the event. The second stage determines the rational real-time bus reconfiguration strategy based on heuristic rules from the obtained switching candidate set. Also, this paper proposes generalized distribution substation modeling using graph theory, and a substation database based on the study results is designed.

Development of Human Factor Risk Model for Use in Disaster System A Study on Safety Analysis (재난시스템에서 사용하기 위한 인적요인 위험 모델의 개발)

  • Park, Jong hun
    • Proceedings of the Korean Society of Disaster Information Conference
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    • 2022.10a
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    • pp.227-228
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    • 2022
  • 전통적인 HRA(Human Reliability Analysis)방법은 특정 애플리케이션 또는 산업을 염두에 두고 있으며. 또한 이러한 방법은 종종 복잡하며, 시간이 많이 걸리고 적용하는 데 비용이 많이 들며 직접 비교하기에는 적합하지 않다. 제안된 HFHM(Human Factors Hazard Model: 인적 요인 위험 모델)은 기검증되고 시간 테스트를 거친 FTA(Fault Tree Analysis:결함 트리 분석)및 ETA(Event Tree Analysis:이벤트 트리 분석)의 확률 분석 도구 및 새로 개발된 HEP(Human Error Probability:인적 오류 확률)예측 도구와 통합되고, 인간과 관련된 PSF(Performance Shaping Factors:성능 형성 요인)를 중심으로 새로운 접근 방식으로 개발되었다. 인간-시스템은 상호작용으로 인한 재난사고 가능성을 모델링하는 위험분석 접근법 HFHM은 다음과 같은 상용 소프트웨어 도구 내에서 예시되고 자동화된다. HFHM에서 생성된 데이터는 SE 분석가 및 설계에 대한 표준화된 가이드로 사용될 수 있다. 본 연구에서는 인적 위험을 예측하는 이 새로운 접근 방식을 통해, 전체 시스템에 대한 포괄적인 재난안전 분석을 가능하게 한다.

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Fault Tree Analysis Model Based on Trapezoidal Fuzzy Number (사다리꼴퍼지수에 기초한 F.T.A. 모형에 관한 연구)

  • Sin, Mun-Sik;Jo, Nam-Ho
    • Journal of Korean Society for Quality Management
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    • v.20 no.1
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    • pp.118-125
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    • 1992
  • Studies upto date for estimating the reliability by means of one accarate value contain risks of many erroneous options. The objective of this paper is to presents a fault tree analueis model on the basis of the membership functions of trape Zoidal fuzzy number after imposing an interval of Confidence on the residual possibility theory. The results from the model Show that the value of Stability was reliable.

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Reliability Analysis of Distribution Systems by using FTA (FTA를 이용한 배전계통 신뢰도 분석)

  • Ku, Bon-Hui;Cha, Jun-Min;Kim, Hyung-Chul
    • Proceedings of the KIEE Conference
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    • 2008.11a
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    • pp.247-249
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    • 2008
  • 배전계통은 수용가에 전력을 공급하는 설비로서 계통의 안정적인 운영을 위하여 배전계통의 신뢰도를 산정하는 것은 중요한 의미를 갖는다. 본 논문에서는 배전계통을 구성하는 설비와 수용가의 전력 공급 유무에 따른 신뢰도를 산정하였다. Fault Tree Analysis(FTA)는 시스템의 고장을 해석하는 방법으로 사용된다. 시스템의 고장을 발생시키는 사건원인을 분석하여 Fault Tree(FT: 고장목)를 작성하고, 시스템을 구성하는 설비들의 고장확률 계산을 통하여 전 시스템의 신뢰성을 산정할 수 있다. 본 연구에서는 Relex 7.7 프로그램을 사용하여 FTA를 수행하였다.

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Analysis of Risk Control Options for Blockage Treatment (Subsea X-mas Tree에서의 Blockage 처리 실패에 대한 위험도 저감 방안 분석)

  • Yoo, Won-Woo;Park, Min-Sun;Yang, Young-Soon
    • Journal of Ocean Engineering and Technology
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    • v.27 no.2
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    • pp.47-52
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    • 2013
  • A subsea chemical injection system treats blockage problems in a subsea production system. It is important to treat problems quickly, because production delays cause fatal profit losses in a subsea production system. Therefore, the subsea industry requires a relatively higher reliability level for a production system compared to other industries. In this study, a subsea chemical injection system (linked to a control system) to inject chemicals into a subsea X-mas tree was analyzed. By using FSA (Formal Safety Assessment), the risk factors were defined and a quantitative risk analysis utilizing FTA (Fault Tree Analysis) and ETA (Event Tree Analysis) was performed. As a result, the effectiveness of a risk reduction option was evaluated.

Seismic Fragility Analysis of Substation Systems by Using the Fault Tree Method (고장수목을 이용한 변전소의 지진취약도 분석)

  • Kim, Min-Kyu;Choun, Young-Sun;Choi, In-Kil;Oh, Keum-Ho
    • Journal of the Earthquake Engineering Society of Korea
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    • v.13 no.2
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    • pp.47-58
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    • 2009
  • In this study, a seismic fragility analysis was performed for substation systems in Korea. To evaluate the seismic fragility function of the substation systems, a fragility analysis of the individual equipment and facilities of the substation systems was first performed, and then all systems were considered in the fragility analysis of the substation systems using a fault-tree method. For this research, the status of the substation systems in Korea was investigated for the classification of the substation systems. Following the classification of the substation systems, target equipment was selected based on previous damage records in earthquake hazards. The substation systems were classified as 765kV, 345kV, and 154kV systems. Transformer and bushing were chosen as target equipment. The failure modes and criteria for transformer and bushing were decided, and fragility analysis performed. Finally, the fragility functions of substation system were evaluated using the fault tree method according to damage status.