| With the continuous development of subways,the importance of reliability analysis and evaluation of subway power supply systems has become increasingly prominent.At present,the research on reliability evaluation of subway power supply systems is mainly focused on the single power supply equipment,the main substation or the traction substation,and there lacks comprehensive reliability evaluation of subway power supply systems.Subway power supply system features its complex topological structures,large scale,multiple pieces of equipment and diverse backup modes.Existing research establishes the system model by analyzing all failure modes,which entails massive workload and is difficult to perform.When the subway power supply system structure or operation mode changes,its minimum fault path will change,which requires the system reliability assessment model to be re-established.Therefore,this paper analyzes and evaluates the reliability of the subway power supply system,establishes a general model for the reliability evaluation,proposes a reliability index system and quantifies the reliability of the system,and then identifies the weak links and key equipment that affect the subway power supply system.It provides scientific advice and guidance for ensuring the safe and reliable operation of the subway power supply system.Based on the topological structure and operation mode of the subway power supply system,this paper divides the subway power supply system into multiple sections,simplifies the complex system and propose the concept of the "minimum basic unit" of the system,and establish the FTA model of the minimum basic unit.A universal FTA model for reliability evaluation of subway power supply system is constructed through the flexible combination of the smallest basic units,thereby overcoming the shortcomings of flexibility and versatility of the FTA modeling method based on the minimum path of traversal system faults,and simplifying the reliability evaluation of complex systems modeling process.Secondly,based on subway power supply system reliability evaluation model,the sequential Monte Carlo method is applied to calculate the system reliability evaluation index,and quantify the operation reliability level of the subway power supply system.The equipment importance of the subway power supply system is analyzed on the basis of reliability evaluation.The equipment importance indicators are defined and the key equipment and weak links that affect the reliability of the subway power supply system are analyzed,which provides corresponding references for system operation and maintenance.Finally,in view of weak link for subway power supply system,and put forward the method to improve reliability,make quantitative reliability target value,based on the system topology structure and the logical relationship between various regions,the system reliability indices are distributed from the overall to local by layer,the subway power supply equipment reliability parameters are clarified and the reliability evaluation method is verified.The reliability level of traction substation is guaranteed from the perspective of improving the reliability level of power supply equipment,and the corresponding guidance is provided for improving the reliability of weak links in the system.This paper proposed subway power supply system reliability evaluation model based on FTA metro power supply system partition can improve the universality and flexibility of the overall system reliability modeling,reduce the problem of difficult modification due to change of system structure and design.Sequential Monte Carlo method is used to solve the system reliability index and quantify the operational reliability level of the system.The importance of the system is analyzed and the key equipment and weak links of the subway power supply system are identified.Improving the reliability level of weak links in the system and clarifying the parameter requirements for reliability improvement of power supply equipment can provide guidance for improving the reliability level of the system. |
