Risk assessment of traction power supply system considering reliability of the protection scheme

Adequate protection scheme is an important defense mechanism for traction power supply system (TPSS), and the reliability of its operation could affect the normal operation of the system. Therefore, in order to maintain the system in safe operation, it is of great importance to quantify the influence of protection scheme on traction power supply system. This paper presents a risk assessment method for traction power supply system considering the reliability of system protection. A risk probability model for system protection is established. Based on Markovian state-space method, the reliability of the protection system is evaluated; the misoperations of the protection system and their possible consequences are analyzed by FMEA method. Three types of economic loss indices are defined to establish the quantitative risk consequence model; the risk of traction power supply system is thereby quantified by integrating risk probability and risk consequence. Practical traction power supply system is taken as an example to prove the effectiveness of the proposed method. The evaluation results can help formulate corresponding measures, and provide guidance for maintenance strategies, thus reducing system risk.