Quantitative Analysis and Allocation of Safety Integrity Level Indexes for Urban Rail Transit Vehicle System

Abstract

Objective Development and application of FAO (fully automatic operation)system in urban rail transit train requires higher safety of urban rail vehicle system. Under the new operation scenario where FAO needs to be confirmed, it is necessary to sort through the safety requirements for urban rail transit train from the top level, determine the SIL (safety integrity level) of the critical system in urban rail transit vehicle. Method FTA (fault tree analysis), Risk Matrix and FMECA (failure mode, effects and criticality analysis) are all used to conduct hazard identification, risk analysis, and quantitative index allocation layer by layer from the system level of entire train line to the vehicle system level, the vehicle subsystem level. Result & Conclusion The safety requirements and the SIL of urban rail transit vehicle system are obtained through analysis. The safety functions of the traction system include emergency braking traction cut off function, direction control function, traction enable function, and braking control function, except the first one belongs to SIL3, all other three functions are SIL2. The safety functions of the braking system include emergency braking function, anti-skid control function, service braking function, and brake holding function, belonging to SIL4, SIL3, SIL2, and SIL2 respectively. The safety functions of the network system include brake holding function, driver′s cabin activation function, direction management function, traction braking command management function, and level management function, all belonging to SIL2.

Keywords

• urban rail transit
• vehicle system
• sil
• risk analysis