• 대한전기학회논문지:전력기술부문A
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• 제51권5호
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• pp.232-237
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• 2002

It is increased for methodology to evaluate distribution power system interruption cost in power supply zones under competitive electricity market. This paper presents algorithms to evaluate system interruption cost in distribution power supply zones taking into consideration failure rate of distribution facilities and composite customer interruption cost. In this paper, it is introduced for weighting factor for each customer failure duration and failure rate of distribution facilities to evaluate reasonable system interruption cost in distribution power supply area. Also, this Paper estimates evaluation results of system interruption cost using a sample model system. Finally, evaluation results of system interruption cost based on failure rate of distribution facilities and composite customer interruption cost are shown in detail.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 춘계학술대회 논문집
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• pp.1414-1419
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• 2011

In this paper we study the modeling to quantitatively assess the failure rate of USN system designed for fault-tolerant architecture, aiming at applying the world's best domestic USN technology to safety-critical railways. In order to apply the USN system to the safety-critical field like a train control sector that the failures of controllers may cause severe railway accidents such as train collision and derailment, the quantitative reliability and safety evaluation recommended in IEC 62278 must be preceded. We also develop the evaluation model for overall system failure rate for the distributed network structure, which is the characteristics of USN system. Especially, we allocate reliability targets to component units, and present an availability evaluation plan through the plan on the quantitative achievement of failure rate for sensor nodes, gateways, radio-communication network and servers, along with the failure rate model of the overall system considering network operational features.

• 융합정보논문지
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• 제12권5호
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• pp.15-20
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• 2022

본 연구는 소프트웨어 품질 특성인 기능적합성, 신뢰성, 사용성, 이식성, 유지보수성, 성능효율성, 보안성, 호환성 중에서 신뢰성에 대한 평가 방안을 연구하였다. 소프트웨어 품질 측정에 있어 신뢰성의 정량적 평가 방안을 제시한다. 본 연구는 소프트웨어 품질 특성 중 하나인 신뢰성 평가 중 성숙성에 포함되는 고장률을 측정하는 방법에 대해서 소개하고 고장 데이터의 형태에 따라 고장률이 어떻게 변화하는지에 대해 실험데이터를 가지고 연구한 내용이다. 소프트웨어 테스팅을 중심으로 매일의 고장 수를 중심으로 소프트웨어 신뢰성 성장 모델에 적용하여 고장률을 측정하여 고장 데이터의 형태에 따라 비교 분석하였다. 6일간의 테스트를 통해서 발견된 고장 시간을 중심으로 고장률을 측정하고 측정결과를 이용해서 국제표준 ISO/IEC 25023에서 제시하고 있는 고장률과 비교 하였으며 데이터 형태에 따라 적용방안을 검토하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 추계학술대회 논문집 전력기술부문
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• pp.272-274
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• 2003

Distribution system reliability evaluation estimates by approach methods such as Makove modelling or Monte Carlo simulation, equation of state and failure rate that is on one basic data used to these assessment technique is described as probability of average value. because average failure rate equipment device is aged as time goes by but there is shortcoming that such used failure rate does not evaluate thing which is correct in reliability change hereafter. In this paper, failure rate displayed that apply aging to basis equipment device by passing time using Weibull distribution one of life evaluation method and for express aging of component from utility's failure database.

• International Journal of Precision Engineering and Manufacturing
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• 제8권3호
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• pp.50-53
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• 2007

Improving the reliability or long-term dependability of a system requires a different approach from the previous emphasis on short-term concerns. The purpose of this paper is to present a reliability evaluation method for an oil cooler intended for high-precision machining centers. The oil cooler system in question is a cooling device that minimizes the deformation caused from the heat generated by driving devices. This system is used for machine tools and semiconductor equipment. We predicted the reliability of the system based on the failure rate database and conducted the reliability test using a test-bed to evaluate the life of the oil cooler. The results provided an indication of the reliability of the system in terms of the failure rate and the MTBF of the oil cooler system and its components, as well as a distribution of the failure mode. These results will help increase the reliability of oil cooler systems. The evaluation method can also be used to determine the reliability of other machinery products.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회B
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• pp.2845-2849
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• 2008

Long Term Asset Management(LTAM) means a plan developed by using LCM(Life Cycle Management) process for optimum life cycle management of significant plant assets at each plant across the fleet. As a part of development of LTAM Strategies on nuclear turbines, a method so as to determine the future failure rates for low pressure turbine facilities at a nuclear plant was studied and developed by using both plant specific and industry-wide performance data. INPO's EPIX data were analyzed and some failure rate evaluation values considering preventive maintenance practices were calculated by using EPRI's PM Basis software. As the result, failure rate functions applicable to a priori and a posteriori replacement of low pressure turbines at a nuclear plant were developed and utilized in an assessment of economics of LCM alternatives on the nuclear turbine facilities in the respects of 40-year and 60-year operation bases.

• 전기학회논문지
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• 제62권6호
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• pp.870-875
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• 2013

After introducing diagnosis equipment power failure prevention activities for distribution system have become more active. To do facility diagnosis and maintenance work more efficiently we need to evaluate reliability for the system and should determine the priority line with appropriate criteria. Thus, to calculate risk factor for the power distribution line that are composed of many component facilities its historical failure events for the last 5 years are collected and analysed. The failure statics show that more than 60% of various failures are related to environment factors randomly and about 20% of the failures are refer to the aging. As a strategic evaluation system reflecting these environmental influence is needed, a system on the basis of the probabilistic approach related statical variables in terms of failure rate and failure probability of electrical components is proposed. The figures for the evaluation are derived from the field failure DB. With adopting Bayesian rule we can calculate easily about conditional probability query. The proposed evaluation system is demonstrated with model system and the calculated indices representing the properties of the model line are discussed.

• 전기학회논문지P
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• 제59권2호
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• pp.154-157
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• 2010

In this paper, the Time-varying Failure Rates(TFR) of power distribution system components are extracted from the recorded failure data of KEPCO(Korea Electric Power Corporation) and the reliability of power distribution system is evaluated using Mean Failure Rate(MFR) and TFR. The TFR is approximated to bathtub curve using the exponential and Weibull distribution function. In addition, Kaplan-Meier estimation is applied to TFR extraction because of incomplete failure data of KEPCO. Also the reliability of the real power distribution system of Korea is evaluated using the MFR and TFR extracted from real failure data, respectively and the results of each case are compared with each other. As a result, it is proved that the reliability evaluation using the TFR is more realistic than MFR. In addition, it is presented that the application method at power distribution system maintenance and repair using the result of TFR.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.1914-1917
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• 2005

Recently, the reliability evaluation and analysis are applied for many industrial products, and many products are required to guarantee in quality and in efficiency. The purpose of this paper is to present some of reliability evaluation methodologies that are applicable to machine tools. Especially ATC(Automatic Too Changer), which is core component of line center, was chosen as the target of the reliability evaluation and analysis. The scope of research is reliability prediction, reliability test and evaluates their results. The results of this research has shown the failure rate, MTBF(Mean Time Between Failure), reliability for those components and real tests reliability through constructed reliability test-bed. It is expected that proposed methodologies will increase reliability for high speed line center.

• 대한전기학회논문지:전력기술부문A
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• 제54권11호
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• pp.548-556
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• 2005

Reliability evaluation of power distribution system is very important to both power utilities and customers. It present the probabilistic number and duration of interruption such as failure rate, SATDI, SAIFI, and CAIDI. However, it has a fatal weakness at reliability index because of accuracy of failure rate. In this paper, the Time-varying Failure Rate(TFR) of power distribution system equipment is extracted from the recorded failure data of KEPCO(Korea Electric Power Corporation) in Korea. For TFR extraction, it is used that the fault data accumulated by KEPCO during 10 years. The TFR is approximated to bathtub curve using the exponential(random failure) and Weibull(aging failure) distribution function. In addition, Kaplan-Meier estimation is applied to TFR extraction because of incomplete failure data of KEPCO. Finally, Probability plot and regression analysis is applied. It is presented that the extracted TFR is more effective and useful than Mean Failure Rate(MfR) through the comparison between TFR and MFR