• Title/Summary/Keyword: reliability evaluation

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Reliability Evaluation Technique for Electrical Distribution Networks Considering Planned Outages

  • Hu, Bo;He, Xiao-Hui;Cao, Kan
    • Journal of Electrical Engineering and Technology
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    • v.9 no.5
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    • pp.1482-1488
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    • 2014
  • The reliability evaluation of the electrical distribution networks (EDN) requires sufficient consideration of the effects of planned outages. The planned outages of the EDN can be divided, by outage models and their effects on the reliability into two major categories: by equipment and by feeder. After studying the characteristics of different categories of planned outages, this paper expands the classification of load points by outage time from 4 types to 7 types and defines corresponding reliability parameters for the different types. By using the section algorithm, this paper proposes a reliability evaluation technique of EDN considering equipment random failures and two categories of planned outages. The proposed technique has been applied to the RBTS-BUS6 test system and some practical EDNs in China. The study results demonstrate that the proposed technique is of higher practical value and can be used for evaluating the reliability performance of EDN more efficiently considering the planned outages.

An Empirical Analysis of Comprehensive Competitiveness Evaluation Model on the Korean Manufacturing Sector (종합경쟁력 평가모형의 개발 및 측정에 관한 연구: 한국 제조업부문을 중심으로)

  • 임양택;임채숙
    • Journal of Technology Innovation
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    • v.12 no.1
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    • pp.67-114
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    • 2004
  • This study attempts to integrate causal model with competitiveness evaluation model, both of which have developed independently of each other, in connection with many studies on PMES (performance measurement and evaluation system) including the BSC (balanced scorecard) of Kaplan and Norton (1992, 1996). For this attempt, this study is composed of four analyses : First, this study develops a structural model for evaluating and diagnosing corporate ‘comprehensive’ competitiveness including quality competitiveness, derive CCI (comprehensive competitiveness index) and QCI (quality competitiveness index) ; Second, this study analyzes the determinants of quality competitiveness, the impacts of quality competitiveness, on product design and product reliability, and the impacts of product design and product reliability on quality competitiveness in the comprehensive competitiveness evaluation model of this study. Third, this study empirically identifies the positioning of product design in the quality competitiveness evaluation model of this study and the functional relationship between product design and other functions : product development, manufacturing, marketing, and marketing, and sales in the same comprehensive competitiveness evaluation model, estimate the determinants of product design and its impacts, thereby providing some empirical findings for the foundation of design management theory, and Fourth, this study identifies the positioning of product reliability in the same quality competitiveness evaluation model, estimate the reliability function and the functional relationship between product reliability and other dimensions of product quality, and tests the hypotheses on the causality of product reliability.

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A Study on the Failure and Life Assessment of High Speed Spindle (고속주축의 고장 및 수명평가에 관한 연구)

  • Lee, Tae Hong
    • Journal of the Korean Society for Precision Engineering
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    • v.31 no.1
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    • pp.67-73
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    • 2014
  • A reliability evaluation or prediction can be defined as MTBF which stands for mean time between failures (Exclusively for repairable failures). Spindle system has huge effect on performance of machine tools and working quality as well as is required of high reliability. Especially, it takes great importance in producing automobiles which includes a large number of working processes. However, it is unusually difficult to predict reliability because there are lack of data and research about reliability of spindle system. Standards and methods of examinations for reliability evaluation of machine tools are scarce at local and abroad as well. Therefore, this research is meant to improve the reliability of spindle system before mass produced with developing standards of reliability and methods of examinations through FMEA to assess reliability of spindle system in prototype stages of developing high speed spindle system of machining center.

A Study on Reliability Evaluation and Improvement Process of Aerospace Electronic Equipments using Operational Reliability-Cost Matrix (신뢰성-비용 매트릭스를 이용한 항공전자장비의 신뢰성 평가 및 개선 프로세스 연구)

  • Jo, In-Tak;Lee, Sang-Cheon;Park, Jong-Hun;Bae, Sung-Moon
    • Journal of Korean Society for Quality Management
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    • v.42 no.4
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    • pp.633-646
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    • 2014
  • Purpose: The conventional predicted MFTBF by military standard has a wide discrepancy to that of real-world operation, which leads to overstock and increase operation cost. This paper introduces a analyzing frame using operational reliability and cost data to overcome the discrepancy, and provides reliability improvement process employing the analyzing frame. Methods: This paper suggests Reliability-Cost Matrix (R-C Matrix) and Operational Reliability & Cost Index (ORCI) as a tool for reliability evaluation. Results: KOREIP(KAI's Operational Reliability Evaluation and Improvement Process) is developed employing Reliability-Cost Matrix and Operational Reliability & Cost Index. Conclusion: KOREIP provides a process and its activities based on Reliability-Cost Matrix frame. The process and activities leads reliability improvement of aerospace electronic equipments by means of categorizing and follow-up action based on the concept of frame.

A Study on Assessment of Forced Outage Rates for Reliability Evaluation of Power System (전력계통의 확률론적 신뢰도평가를 위한 사고확률 추정에 관한 연구)

  • Lee Sang Sik;Tran Trung Tinh;Choi Jae Seok;Jeon D.;Kim T.;Cha S.;Choo J.
    • Proceedings of the KIEE Conference
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    • summer
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    • pp.195-198
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    • 2004
  • In recent, the Importance and necessity of some studies on reliability evaluation of grid comes from the recent black-out accidents occurred in the world. The quantity evaluation of transmission system reliability is very important under competitive electricity environment. Accurate probabilistic reliability evaluation depends on assessment of forced outage rate of elements, generators, transmission lines. This paper describes basic theory of relationship between outage rates and reliability evaluation for assessing FOR(forced outage rate) of elements of power system. In case study, FORs assessed and supplied from Canada Electricity Association is introduced and FORs assessed from using actual historical data from 1997 to 2002 for transmission lines of KEPCO system.

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Reliability Evaluation of Semiconductor using Ultrasonic (초음파를 이용한 반도체의 신뢰성 평가)

  • Jang, Hyo-Sung;Ha, Yop;Jang, Kyung-Young;Kim, Jung-Kyu
    • Proceedings of the Korean Reliability Society Conference
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    • 2001.06a
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    • pp.239-244
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    • 2001
  • Today, Ultrasonic is used as an important non-destructive test tool of semiconductor reliability evaluation and failure analysis. The semiconductor packaging trend goes to develop thin package, this trend makes difficult to inspect to defect in semiconductor package. One of the important problem in all semiconductor is moisture absorption in the atmosphere. This moisture causes crack or delamination to package when the semiconductor package is soldered on PCB. Reliability evaluation of semiconductor's object is investigating the effect of this moisture. For that reason, this study is investigating the effect of this moisture and reliability evaluation of semiconductor after preconditioning test and scanning acoustic microscope.

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A Study on the Reliability Evaluation for Interconnecting Power Systems in Northeast Asia (동북아 전력계통 연계를 위한 신뢰도 산정에 관한 연구)

  • Choi, Jae-Seok;Cha, Jun-Min
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.57 no.7
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    • pp.1129-1134
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    • 2008
  • This paper proposes a reliability evaluation for interconnection planning using a tie line equivalent assisting generator model (TEAG) that considers the uncertainties of the interconnected transmission systems and the tie lines. Development of this model was triggered by the need to perform probabilistic reliability evaluations on the NEAREST (North East Asia Region Electric Systems Tied) interconnection. The TEAG is the basis for the newly developed interconnection systems reliability evaluation computer program, NEAREL. The model is capable of considering uncertainties associated with generators, tie lines, and the tied grids. Reliability evaluations for six interconnection scenarios involving the power systems of six countries in the Asian north eastern region were performed using NEAREL. Sensitivity analysis was used to determine reasonable tie line capacities for three interconnected country scenarios of the six countries. Test results and summarized comments of the scenarios are included in the paper.

Probabilistic Reliability Evaluation of Power System using TRELSS II - Focused on Case Studies of IEEE RTS - (TRELSS를 이용한 전력계통의 확률론적 신뢰도 평가 II - IEEE RTS 사례연구를 중심으로 -)

  • Tran, Tungtinh;Kang, Sung-Rok;Choi, Jae-Sok;Jeon, Dong-Hoon;Choo, Jin-Boo
    • Proceedings of the KIEE Conference
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    • 2003.11a
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    • pp.67-70
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    • 2003
  • In recent, the importance and necessity of some studies on reliability evaluation of grid come from the recent black-out accidents occurred in the world. The quantity evaluation of transmission system reliability is very important under competitive electricity environment. The reason is that the successful operation of electric power under the deregulated electricity market depends on transmission system reliability management. The various results of many case studies for the IEEE 25buses system using the Transmission Reliability Evaluation for Large-Scale Systems(TRELSS) Version 5_1, a program made in EPRI are introduced in this paper. Some sensitivity analysis has been included. This paper suggests that the some important input parameters of the TRELSS can be determined optimally from this sensitivity analysis for high reliability level operation of a system.

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Factors driving Fashion Chatbot Reliability -Focusing on the Mediating Effect of Perceived Intelligence and Positive Cognition- (패션상품 챗봇에 대한 신뢰 형성 요인 - 지각된 지능과 긍정적 인지의 매개효과를 중심으로 -)

  • Lee, Ha Kyung;Yoon, Namhee
    • Fashion & Textile Research Journal
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    • v.24 no.2
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    • pp.229-240
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    • 2022
  • This study explores the effect of anthropomorphism on fashion chatbot reliability, mediated by perceived intelligence and cognitive evaluation. The moderating effects of individuals' need for human interaction between chatbot anthropomorphism and perceived intelligence, cognitive evaluation, and chatbot reliability are also explored. Participants, who were recruited through the online research firm, responded to questions after watching a video clip showing a conversation with a fashion chatbot on a mobile screen. The data were collected through Mturk, a crowdsourcing platform with an online research panel. All responses (N = 212) were analyzed using SPSS 26.0 for the descriptive statistics, frequency analysis, reliability analysis, exploratory factor analysis, and PROCESS procedure. The results demonstrate that chatbot anthropomorphism increases chatbot reliability, and this is mediated by chatbot intelligence. Although chatbot anthropomorphism increases cognitive evaluation, the effect of cognitive evaluation on chatbot reliability is not significant; thereby, the effect of chatbot anthropomorphism on chatbot reliability is not mediated by the cognitive evaluation. The direct effect of anthropomorphism on chatbot reliability is also moderated by individuals' need for human interaction. For participants with a high need for human interaction, chatbot anthropomorphism increases chatbot reliability; however, anthropomorphism does not significantly affect chatbot reliability for participants with a low need for human interaction. The study's findings contribute to expanding the literature on consumers' new technology acceptance by testing the antecedents affecting service reliability.

Reliability Evaluation of Thruster Break for Aerogenerator (풍력발전기용 쓰러스터 브레이크의 신뢰성 평가)

  • Jung, Dong Soo
    • Journal of Applied Reliability
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    • v.13 no.3
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    • pp.165-174
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    • 2013
  • Thruster break for aerogenerator performs a role that is stopping the rotor in case of emergency such as strong wind, system abnormality or maintenance check. In this study, failure analysis and test evaluation on the thruster break for aerogenerator are proposed, and the entire process to improve reliability of the product through design improvement is presented. The typical failure case is fatigue and wear, and failure cause on these are identified and improvement plan is presented. Lastly, reliability improvement is established to analyse test results before after the life test.