• Title, Summary, Keyword: 정비주기

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A case study on the optimal maintenance interval or I&C component for YGN Units l&2 (영광 1,2호기 계측기 정비 주기 최적화에 관한 적용사례)

  • 최광희;정현종;이상용;김성훈;김재오
    • Proceedings of the Korean Reliability Society Conference
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    • pp.195-195
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    • 2002
  • 영광 원자력발전소 1,2호기의 계측제어기기에 대한 예방정비 최적화 분석을 수행중 기기의 정비주기 설정을 위하여 모델별 고장율 분석을 통하여 권고 주기를 산정 하였다. 현재 정비주기는 각 발전소 및 산업설비에서 제작사 지침의 적용과 현장 경험에 의한 선정이 이루어지고 있으나 제작사에 의한 주기 제시가 전체적으로 미미하여 경험에 크게 의존하고 있는 상태이다. 이에 본 논문에서는 정비주기의 최적화를 위하여 계측기 모델별 고장내용의 분석을 통한 data를 NCSL S2의 단순화 모델인 Jackson method를 기본으로 적용하여 최적주기 산정작업을 수행한 사례를 기술하고자 한다.

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Determination of Maintenance Period Considering Reliability Function and Mission Reliability of Electromagnetic Valves of EMU Doors Considering Air Leakage Failure (전동차 출입문 전자변 누기고장의 신뢰도 함수와 임무 신뢰도를 고려한 정비 주기 결정)

  • Park, Heuiseop;Koo, Jeongseo;Kim, Gildong
    • Journal of the Korean Society for Railway
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    • v.20 no.5
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    • pp.569-576
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    • 2017
  • The electromagnetic valve of pneumatic doors of EMUs has a high failure rate due to air leakage because it supplies air on and off to operate the doors repeatedly. The electromagnetic valve is a very important safety component for which a very high reliability is required because failure makes it impossible to operate the passenger cars. However, domestic urban railway operators maintain electronic valves of the EMU door under a fixed cycle with a spare period according to the full overhaul cycle of the EMU. An improvement of the current maintenance cycle was suggested based on the reliability function and mission reliability. Using the statistical program MINITAB for the operational data of EMU line 6, we analyzed the characteristics of the fault distribution and derived the shape and scale parameters of the reliability function. If we limit the specific reliability probability to under a certain failure rate and calculate its statistical parameters, we can calculate the allowable inspection period with mission reliability. Through this study, we suggested a maintenance period based on RCM (reliability centered-maintenance) to improve the reliability of electromagnetic valves from 68% to 95%.

Development of the Preventive Maintenance Template for Static Exciter in the Nuclear Power Plant (원자력발전소 정지형 여자기의 예방정비기준(PMT) 개발)

  • Chin, Soo-Hwan;Park, Jin-Youb;Hong, Young-Hee
    • Journal of Energy Engineering
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    • v.20 no.2
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    • pp.154-162
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    • 2011
  • PMT(Preventive Maintenance Template) is a standardized maintenance program that describes maintenance items & period as operation condition to increase component reliability at the component level. The existing maintenance programs are focused on time based maintenance to inspect and repair component depend on fixed period. But recently, we have developed advanced maintenance program(named PMT) to increase reliability and optimize maintenance program of the plant significant component. This paper presents how to develop the PMT for nuclear power plant's static exciter.

Selection of Maintenance Interval Based on RCM for a Coal Handling Equipment (신뢰도중심정비에 의한 석탄취급설비 정비주기선정)

  • Cho, Il-Yong;Moon, Seung-Jae
    • Plant Journal
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    • v.9 no.4
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    • pp.37-42
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    • 2013
  • Power plants have many components and equipment. It is difficult for operators to know the each equipment fails or what equipment fails. It is important to prevent failure in advance. Recently, outlook of maintenance tasks is changing from time based maintenance to condition based maintenance. In this study, we selected RCM-based maintenance intervals for coal handling equipment at coal power plant. For RCM analysis, we have made great progress in a maintenance task and interval. If we apply RCM analysis to the whole plant system, we can expect qualitative improvement and efficient operation of power plant system.

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Determination of Maintenance Period and Failure Probability for Turbine Using Maintenance Record (터빈설비의 정비이력을 이용한 고장확률 예측 및 정비주기 설정에의 응용)

  • Song, Gee-Wook;Koo, Jae-Raeyang;Choi, Woo-Sung
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.34 no.9
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    • pp.1325-1330
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    • 2010
  • The breakdown of any critical component of a turbine results in the outage of power plants. Unexpected failure decreases equipment utilization and causes enormous economic losses. Currently, we conduct conservative preventive maintenance for a maintenance period that is proposed by a vendor. In the rapidly changing business environment, reliability-based maintenance is required in order to remain competitive and reduce maintenance costs while maintaining the reliability of equipment. In order to determine an appropriate maintenance period for guaranteeing reliability, we must determine the failure probability by carefully analyzing the failure history of the equipment. In this study, we created a database of failure history for power-plant turbines, predicted the best repair time using the Weibull function, and investigated how the appropriate maintenance cycle can be determined.

Evaluation of Optimal Time Between Overhaul Period of the First Driving Devices for High-Speed Railway Vehicle (고속철도차량 1차 구동장치에 대한 완전분해정비의 최적 주기 평가)

  • Jung, Jin-Tae;Kim, Chul-Su
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.16 no.12
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    • pp.8700-8706
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    • 2015
  • The first driving device of the power bogies for the Korean high-speed railway vehicle consists of the traction motor (TM) and the motor reduction gears unit (MRU). Although TM and MRU are the mechanically integrated structures, their time between overhauls (TBO) have two separate intervals due to different technical requirements(i.e. TBO of MRU: $1.8{\times}10^6km$, TBO of TM: $2.5{\times}10^6km$). Therefore, to reduce the unnecessary number of preventive maintenances, it is important to evaluate the optimal TBO with a viewpoint of reliability-center maintenance towards cost-effective solution. In this study, derived from the field data in maintenance, fault tree analysis and failure rate of the subsystem considering criticality of the components are evaluated respectively. To minimize the conventional total maintenance cost, the same optimal TBO of the components is derived from genetic algorithm considering target reliability and improvement factor. In this algorithm, a chromosome which comprised of each individual is the minimum preventive maintenance interval. The fitness function of the individual in generation is acquired through the formulation using an inverse number of the total maintenance cost. Whereas the lowest common multiple method produces only a four percent reduction compared to what the existing method did, the optimal TBO of them using genetic algorithm is $2.25{\times}10^6$km, which is reduced to about 14% comparing the conventional method.

A Development of EMAS (Easy Maintenance Assistance Solution) for Industrial Gas Turbine (산업용 가스터빈을 위한 정비지원 시스템 개발에 관한 연구)

  • Kang, Myoungcheol;Ki, Jayoung
    • Journal of the Korean Society of Propulsion Engineers
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    • v.21 no.3
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    • pp.91-100
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    • 2017
  • The solution was developed for the maintenance decision support of combined cycle power plant gas turbine. The developed solution was applied to MHI501G gas turbine and is, in present, on the process of field test at GUNSAN combined cycle power plant, South Korea. The developed solution provides the calculated result of optimal overhaul maintenance period through following modules: Real Time Performance Monitoring, Model-Based Diagnostics, Performance Trend Analysis, Optimal Overhaul Maintenance Interval, Compressor Washing Period Management, and Blade Path Temperature Analysis. Model-Based Diagnostics module analyzed the differences between the data of gas turbine performance model and the online measurement. Compressor washing management module suggests the optimal point of balancing between the compressor performance and the maintenance cost.

Reliability Analysis for Decoy using Maintenance Data (정비 데이터를 이용한 기만체계 신뢰도 분석)

  • Gwak, Hye-Rim;Hong, Seok-Jin;Jang, Min-Ki
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.19 no.10
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    • pp.82-88
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    • 2018
  • The decoy defensive weapon system is a one-shot system. Reliability is maintained through periodic inspection and high reliability is required to confirm whether or not the functioning is normal after launch. The maintenance cycle of a decoy was set up without target reliability and reliability prediction during the development period. However, the number of operations in the military has been increasing, necessitating the optimization of the maintenance cycle. Reliability is analyzed using the maintenance data of a decoy operated for several decades and the optimal maintenance cycle is suggested. In chapter 2, data collection and classification methods are presented and analysis methodology is briefly introduced. In chapter 3, the data distribution analysis and fitness verification confirmed that applying the Weibull distribution is the most suitable for the maintenance data of the decoy. In chapter 4, we present the analysis result of percentile, survival probability and MTBF and the optimal maintenance cycle was derived from the reliability analysis. Finally, we suggest the application methods for this paper in the future.

A Study on the Determination of Optimal Preventive Maintenance Periods using Simulation (시뮬레이션을 이용한 최적예방정비주기 결정에 관한 연구)

  • 윤익근;하종만;김호연;김동혁
    • Proceedings of the Korean Operations and Management Science Society Conference
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    • pp.590-597
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    • 2002
  • LNG고압펌프계통은 천연가스 고압 송출에 있어 가용도가 매우 중요한 계통이다. 본 연구에서는 현재 적용되고 있는 예방(계획)정비주기를 가용성 측면에서 재검토했다. 확률적인 운전대수와 운전 및 보전 형태에 연관된 여러제약이 고려할 때 계통 불가용도를 정량화하기 위하여 시뮬레이션 기법을 적용했다. 중도 절단된 형태의 펌프 수명 데이터를 분석해 욕조형의 고장율 함수를 도출했으며 보수시간 데이터를 분석해 확률분포모수를 구했다. 또한 주요 펌프부대설비에 대해서는 상수형의 고장율과 보전율을 도출했다. 분석된 확률모수를 작성된 시뮬레이션 모형에 입력하고 과거의 운전대수 시나리오를 설정해 실험한 결과와 실제 보수 및 운전 자료를 비교해 모형의 유효성을 보였다. 그리고 차후 예상되는 운전요구대수 시나리오를 기정하고 각 예방정비주기별로 반복 실험하여 계통의 불가용도를 보이고 적합한 예방정비주기를 도출했으며 펌프부품 교체비용의 기대 절감액을 보였다.

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A Study on Developing & Operating Concept of Reliability Analysis & Evaluation System for Aircraft Parts (항공기 부품 신뢰도 분석평가체계 개발 및 운영개념 연구)

  • Son, Seok-Hee;Ko, Seung-Chul
    • Journal of the military operations research society of Korea
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    • v.33 no.1
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    • pp.19-29
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    • 2007
  • This study deals with developing and operating Reliability Analysis & Evaluation System for aircraft parts by analyzing ROKAF's AMMIS and phase inspection data for optimal inspection frequency. We suggest operating model with improving and adjusting inspection cycle by analyzing failure time data and tendency of crack with RELEX and Minitab software.