• 전기학회논문지P
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• 제58권4호
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• pp.410-415
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• 2009

With the implementation of electric power industry reform, the utilities are looking for effective ways to improve the economic efficiency. One area in particular, the equipment maintenance, is being scrutinized for reducing costs while keeping a reasonable level of the reliability in the overall system. Here the conventional RCM requires the tradeoff between the upfront maintenance costs and the potential costs of losing loads. In this paper we describe the issues related to applying so-called the "Reliability-centered Maintenance" (RCM) method in managing electric power distribution equipment. The RCM method is especially useful as it explicitly incorporates the cost-tradeoff of interest, i.e. the upfront maintenance costs and the potential interruption costs, in determining which equipment to be maintained and how often. In comparison, the "Time-based Maintenance" (TBM) method, the traditional method widely used, only takes the lifetime of equipment into consideration. In this paper, the modified Markov model for maintenance is developed. First, the existing Markov model for maintenance is explained and analyzed about transformer and circuit breaker, so on. Second, developed model is introduced and described. This model has two different points compared with existing model: TVFR and nonlinear customer interruption cost (CIC). That is, normal stage at the middle of bathtub curve has not CFR but the gradual increasing failure rate and the unit cost of CIC is increasing as the interruption time is increasing. The results of case studies represent the optimal maintenance interval to maintain the equipment with minimum costs. A numerical example is presented for illustration purposes.

• 한국소음진동공학회논문집
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• 제21권11호
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• pp.1051-1058
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• 2011

The military communication equipment is required the high reliability for operating adequate functions under severe conditions. This reliability is the essential element for the quality of the product, for the uncontrolled factors, such as the clearance, damage of the material, the reduction of stiffness, which are the designer is unable to handle. In this paper, the uncertainty for the dimension was supposed to the probability model for the military communication equipment, and the average of the objective function was minimized for reducing design uncertainty. The reliability-based design optimization which was implemented the limit state function was formulated into the mathematical model, so the reliable optimized structure was implemented than the base-line design.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2011년도 추계학술대회 논문집
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• pp.504-509
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• 2011

The military communication equipment is required the high reliability for operating adequate functions under severe conditions. This reliability is the essential element for the quality of the product, for the uncontrolled factors, such as the clearance, damage of the material, the reduction of stiffness, which are the designer is unable to handle. In this paper, the uncertainty for the design was supposed to the probability model for the military communication equipment, and the average of the objective function was minimized for reducing design uncertainty. The reliability-based design optimization which was implemented the limit state function was formulated into the mathematical model, so the reliable optimized structure was implemented than the base-line design.

• 품질경영학회지
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• 제19권1호
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• pp.43-50
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• 1991

Very little work has been done in the design of process with purchased equipment; therefore it is the intent of this project to expand the current application of reliability considerations to purchased equipment. The procurement of equipment in a manufacturing system which has both qualitative and quantitative aspects.

• 한국철도학회논문집
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• 제9권6호
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• pp.732-738
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• 2006

This research provides a scheme for Highly Accelerated Stress Test that is necessary to demonstrate reliability prediction of Korean Rapid Transit Railway Train Control System sub-equipment, which is calculated by a relevant standard for failure rate prediction of electronic products. Although determining failure information generated in the process of trial running by statistic analysis is widely accepted as a measure of confirmation for reliability prediction, this research suggests the modeling for System Life Test determined by accelerating stress factors as a measure of confirmation for reliability prediction of sub-equipment unit that is generated ahead of a trial running in System Life Cycle. Consequently, the research demonstrates sub-equipment unit reliability test, which is based on the model derived from Accelerated Stress Test, according to accuracy level and the number of samples, and conducts an official experiment by making out a reliability test procedure sheet based on test time as well.

• Journal of Electrical Engineering and Technology
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• 제4권1호
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• pp.43-48
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• 2009

The purpose of the this paper is to make decision of the maintenance priority of power distribution system using Time-Varying Failure Rate(TVFR) with interruption cost. This paper emphasizes the practical use of the reliability indices and interruption cost. To make a decision of maintenance priority on power distribution system equipment, the quantification of the reliability level should be represented as a cost. In this paper, the TVFR of power distribution system equipment applied in this paper utilizes analytic method to use the historical data of KEPCO. From this result, the sensitivity analysis on TVFR of equipment was done for the priority, which represents that high priority of the equipment has more effect on system reliability, such as SAIDI or SAIFI, than other equipment. By this priority, the investment plan is established. In this result, customer interruption cost(CIC) could be extracted, and CIC is used as weighting factor to consider a importance of customer. After that, the result calculated the proposal method in this paper is compared with other priority method, such as lifetime, failure rate or only sensitivity.

• 한국가스학회지
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• 제10권1호
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• pp.13-18
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• 2006

산업재해를 방지하고 사고시에 적절한 대책을 마련하기 위해서는 각 위험설비와 위험물질로부터 발생할 수 있는 사고유형, 발생가능성 및 피해를 객관적인 단위로 평가하는 정략적 위험성평가가 수행되어야 하며, 이러한 정량적 평가를 수행하기 위해서는 신뢰도 데이터베이스가 필수적이다. 따라서, 본 연구에서는 사업장에서 설비 및 기기에 대한 신뢰도 데이터베이스를 구축하기 위해서 신뢰도 데이터 수집 및 분석체계구축, 자료 입력 및 분석 소프트웨어를 개발하여 구축된 자료를 토대로 정량적 위험성 평가에 활용할 수 있는 방법론을 제시하였다.

• 전기학회논문지P
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• 제65권3호
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• pp.199-203
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• 2016

The cost needed to managing equipment is constantly increasing because of increase of power equipment. The regulations such as PAS 55 and ISO 55000 were enacted to manage equipment assets. The advanced management methods such as real-time monitoring, condition evaluation, and health indices are avalable in generation system, transmission system, and substation transformers. However, These methods can not be applied to distribution equipment because of a lot of equipment. Therefore reliability assessment is very important in case of distribution equipment. In this paper, failure rates are extracted considering characteristics of regions, and which are the essential factors to reliability evaluation.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2005년도 춘계학술대회 논문집
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• pp.806-812
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• 2005

This paper proposes a new reliability evaluation for traction power system. The electric railway consists of traction power systems, various vehicles, operating equipment, track, overhead line and electric equipment. It is a fundamental function of traction power systems that supply customers with reasonable price, acceptable reliability and high quality power. In a general way, the power system reliability deals with the ability to satisfy load demands in supply capability or rating of every factor. On the other hand, the reliability of traction power systems has been focused on train time delay caused by power outage. In this paper, we make a selection optimum reliability indices for the reliability evaluation of electric traction power systems. The reliability study not only applies a plan for traction supply system after detecting the vulnerable point of existing traction supply systems but also makes a role in stable operating railway.

• 한국철도학회논문집
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• 제12권6호
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• pp.852-858
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• 2009

본 논문은 기존선을 고속으로 운행하기 위해 개발된 한국형 틸팅열차 차상신호장치의 신뢰성관리방안에 대한 연구이다. 기존선 자동열차방호(ATP) 및 자동열차정지(ATS)구간을 운행하는 틸팅열차의 안전한 운행을 위해, 선행 열차위치 및 선로환경에 따라 부여된 이동권한 및 제한속도를 기준으로 제동곡선을 생성하여 기관사 실수 및 장애로부터 열차의 안전을 확보하는 차상신호장치의 신뢰성관리방안을 제시한다. 또한 제시된 방안을 기준으로 열차제어시스템의 신뢰도를 예측하고, 검증하는 방안을 국제규격인 IEC 62278(EN 50126)을 기준으로 수행한 사례를 제시한다.