A Study on the assessment of life span for the extension of a superannuated signaling system

摘要

While a study on the reliability of controller composed by electronic parts has been studied since 1960s by the Department of United States Defense, in railroad area it has been studied around Europe since 1990s. Especially in Korea, after a reliability study on the signaling equipments started on 2000 year, the reliability assessment has been required to effectively extend the using span for the superannuated signaling system. The concept of the extension of life span has adopted restrictively in the nuclear power station or the huge system plant, but now it is on a general trend to use it in the wider-industry areas. The most important issue in accounting for the extension of life span is to determine whether the extension of life span is efficient or not, through the Cost- Benefit analysis for different kinds of failure causes. Furthermore, in railroad a similar situation occurs often in determining whether new installation introduce or existent plants go on by considering procurement o f components. In this study, a method for expecting life span on the overage signaling installation over 20 years will be presented in the case that there is no monitoring and analysis on the reliability data such as failure rate of the component unit or failure occurred during operation. The first step is to calculate the reliability of signaling system in component unit according to MIL-HDBK- 217FN2, and then calculate the remaining life by assuming an expected life as a designed life. Where, in order to attain the remaining life, the parameter provided in the 217F Plus shall be used in calculation of the signaling system's failure rate for the each failure patterns. And you should make sure if remaining life is calculated with a function of remaining life and confirm whether the system meet the estimated values. As a method to verify the identified extension of life time, you should determine a period of non-failure assurance testing, calculate a test time and a accelerating coefficient for accelerated assurance testing, and develop a assessment model for accelerated assurance testing. Finally, the developed model will be used to establish a future maintenance policy of railroad operator which manages the overage signaling system.