Reliability analysis of a railway system line's electrical power supply system

In railway systems, traction power supply system and type of transmission for the tarction power have an important place. Substations that ensure the traction power and catenary system that ensure the transmission of the traction power consist of various electrical elements. One of the most important of these is circuit breaker which is considered as the main protection element. Minimizing the risk of the circuit breakers that have an important role and place for the system to an acceptable level has a significant impact in terms of reliability of the whole system. Primary objective of the railway systems is that ensure operation continuity by providing continuous and reliable energy to achieve traction power. This case can be achieved by running system components which are available in traction power supply system of rail transportation system with minimum failure and by using energy efficient as much as possible running.Therefore failure modes of traction power system's components as possible should be detemined, risks of the system as possible should be mitigated and safety integrity level (SIL) of the system should be reduced to acceptable level in order to a continuous operation as much as possible in rail transportation systems can be obtained. Protection functions ensure an active protection by means of circuit breakers against unintended events that may be occured. Active protection systems have an important role for continuity and quality of electrical power supply. Subsystems which contain elements as circuit breaker that is considered as a part of active protection system are considered with Safety Related System - SRS when this entegration in system is considered. In this study, reliability of traction power supply system of Kabataş - Bağcılar T1 tramline that is operated by Istanbul Transportation Co. is anaylzed. In this scope, firstly failure modes of elements and subsystems which are available in the system, influences of these failure modes on system and parameters about reliability are examined. And then, PFDavg values of subsystem which contain circuit breaker, exist on MV and DC parts and is considered with Safety Related System process was obtained by using markov model and made an assesment about SIL levels. Lastly, reliability analysis of the T1 tramline system is made by considering the electrical system that scope a part of the T1 tramline which from main supply point to catenary system. Fault tree analysis method was used when reliability analysis of the whole system is made.