• Journal of Korean Society for Quality Management
• /
• v.48 no.4
• /
• pp.597-608
• /
• 2020

Purpose: The purpose of this paper is to present a probability distribution of the burst pressure of API 5L X65 pipes for the reliability assessment of corroded gas pipelines. Methods: Corrosion is a major cause of weakening the residual strength of the pipe. The mean residual strength on the corrosion defect can be obtained using the burst pressure code. However, in order to obtain the pipe reliability, a probability distribution of the burst pressure should be provided. This study is concerned with estimating the burst pressure distribution using Monte Carlo simulation. A response surface method is employed to represent the distribution parameter as a model of the corrosion defect size. Results: The experimental results suggest that the normal or Weibull distribution should be suitable as the probability distribution of the burst pressure. In particular, it was shown that the probability distribution parameters can be well predicted by using the depth and length of the corrosion defect. Conclusion: Given a corrosion defect on the pipe, its corresponding burst pressure distribution can be provided at instant. Subsequently, a reliability assessment of the pipe is conducted as well.

• Journal of the Korean Data and Information Science Society
• /
• v.11 no.2
• /
• pp.303-312
• /
• 2000

We compare the MLE, UMVUE and Jackknife Estimators for the reliability function of the weibull distribution when the sample size is small.

• The Transactions of the Korean Institute of Electrical Engineers A
• /
• v.48 no.10
• /
• pp.1198-1205
• /
• 1999

This study is focused on the reliability evaluation for distribution system based on deterministic evaluation technique. Average failure rates, average outage time, and average annual outage time of electrical parts and load points are calculated through network reduction method and failure mode & effective analysis method. And reliability indices of distribution system are calculated. Finally, by employing analytic hierarchy process method, unique index which evaluates and improves the distribution system is calculated. As a result, finding weak points and expansion schedule of the system is possible. The usefulness of this method is verified by applying it to the Inchon International Airport.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.16 no.3
• /
• pp.61-66
• /
• 2002

Electric power distribution networks are prime examples of systems where a very high degree of reliability is expected. Reliability is the probability of a device or system performing its function adequately for the period of time intended and intented operating conditions intented. This paper shows that a better meshed distribution configuration over the case study of radial configuration distribution system was selected by comparing the indices obtained from EDSA\`s reliability worth assessment of distribution systems program.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.58 no.11
• /
• pp.2122-2127
• /
• 2009

This study presents the failure rate and repair rate of Superconducting Fault Current Limiter(SFCL) and adjacent distribution equipments. When the fault current penetrated SFCL, the supply of electric power to the customers can be partly continued. It is expected that SFCL makes to improve the reliability index of customers. Contrary to the expectations, the series connection between SFCL and distribution system could deteriorate the reliability index. To evaluate the reliability index in the distribution system including SFCL, the failure rate and repair rate of SFCL are required as well as that of distribution equipments. Also, the insertion of SFCL makes to change the failure rate and repair rate of adjacent equipments. This study proposes a method to calculate the failure rate and repair rate of a component combining SFCL and adjacent equipments.

• Proceedings of the KIEE Conference
• /
• summer
• /
• pp.39-41
• /
• 2004

This paper presents a analytical method for the reliability evaluation of distribution system, including the distributed generations. Unlike the generators of transmission system, those of distribution system have complexities in analyzing and determining the operation. In the process of evaluate reliability, it could be shown that the analytical method is simpler than the monte-carlo simulation. Modeling technique of distributed generation to analysis distribution system reliability using frequency and duration method is proposed in this paper, and is compared with the simulation method as a result of the distribution system reliability evaluation.

• The Transactions of the Korean Institute of Electrical Engineers A
• /
• v.55 no.11
• /
• pp.476-484
• /
• 2006

The failure prediction and preventive maintenance for the equipment of nuclear power plant area using reliability-centered maintenance have been grown. On the other hand, the maintenance for power distribution system consists of time-based maintenance mainly. In this paper, the new maintenance algorithms for power distribution system are developed considering reliability indices. First of all, Time-varying failure rates are extracted from data accumulated at KEPCO using exponential distribution function and weibull distribution function. Next, based on the extracted failure rate, reliability for real power distribution system is evaluated for applying the effective maintenance algorithm which is the analytic method deciding the maintenance point of time and searching the feeder affecting the specific customer. Also the algorithm deciding the maintenance priority order are presented based on sensitivity analysis and equipment investment plan are analyzed through the presented algorithm at real power distribution system.

• Journal of the Korean Data and Information Science Society
• /
• v.17 no.4
• /
• pp.1343-1348
• /
• 2006

Parametric estimation of a truncated point in a right truncated Rayleigh distribution will be considered. The MLE, a bias reduced estimator and the ordinary jackknife estimator of the truncated point in the right truncated Rayleigh distribution will be compared by mean square errors. And proposed estimators of the reliability in the right truncated Rayleigh distribution will be compared by their mean squared errors.

• Journal of the Korean Data and Information Science Society
• /
• v.18 no.4
• /
• pp.1205-1214
• /
• 2007

We define a skew-symmetric double Rayleigh distribution by a symmetric double Rayleigh distribution, and derive an approximate maximum likelihood estimator(AML) and a moment estimator(MME) of a skewed parameter in a skew-symmetric double Rayleigh distribution, and hence compare simulated mean squared errors of those two estimators. We also compare simulated mean squared errors of two proposed estimators of reliability in two independent skew-symmetric double Rayleigh distributions.

• Journal of Energy Engineering
• /
• v.14 no.3 s.43
• /
• pp.167-172
• /
• 2005

This paper presents a methodology to support decision making for distribution system planning based on value. To evaluate the reliability value, we employ valued-based distribution reliability assessment. To evaluate the harmonics value, we employ a marginal pricing method, and by using reliability cost, harmonics cost, and construction cost, we can make the most economic decision. By applying the method to the real system, we show this method can get the best result which meet reliability and harmonics level.