Study On Maintenance And Overhaul For Urban Railwaysistemkey Equipment Considering Multiple Maintenance Mode

The period of urban rail transit's(URT)full-scale operation and maintenance is coming along with the end of high speed construction.The work core of urban rail transit department will gradually shift from construction to maintenance.The urban rail transit traction power supply equipment(URTPSE)provides qualified electric supply for the normal operation of the whole urban rail transit system(URTS).So,theURTPSE repair work will become the focus of the urban rail transit department's maintenance work.The current maintenance mode of URTPSE mainly follow regular maintenance of rail system,but this mode has been difficult to meet the advocation ofprecisely,accurately,fastlycontemporary work style.Aiming at the URTPSE'sdifferent kind,function,the importance degree in whole sytem and other characteristics,this article collects and arranges the common fault mode of key equipments.Throughclassifying the common fault mode,a combination of FailureMode and Effect Analysis(FMEA)and Fault Tree Analysis(FTA)method is used to assess the importance of all key equipment.Further more,the optimal maintenance mode of every key equipmentsare decided by comparing the importance of every different influence factor.Finally,the optimal dicision scheme of each maintenance mode is obtained by establishing economic decision objective and constraint conditions of reliability.This paper introduces URTS key equipment's kinds(such as dry-type traction transformer,traction rectifier,DC switch cubicle and DC feeder cable),main function and brief working principle.The paper summarizes URTS key equipment's common fault by collecting,sorting and analysis the related data.Therefore,the foundation of subsequent research is laid by these works.The URTS key equipments play different roles in URTS's operation,so their importance is different in URTS.Based on the analysis of the common faults,FMEA method is used to establish the key equipments' logic analysis table of common faults,and provide a reference basis for the maintenance work of URTS's key equipments.At the same time,the URTS is analyzedaccording to the established FMEA table,and the analysis result is used to establish fault tree analysis model by FTA method.So,all of the URTS key equipments' s importance degree is obtained.Based on the calculated importance degree of key equipments and combining the human factors,environment fator,economic factor and resources fator,anAnalytic Hierarchy Process method is used to decide which of the maintenance mode breakdown maintenance,periodic maintenance and condition-based maintenance is the optimal maintenance for each key equipments.After deciding the maintenance mode of each key equipment,aiming at different maintenance mode(regular maintenance,condition-based maintenance),the Weibull distribution mathematical model is used to match equipments' performance evolution law.Considering combining the economy and reliability,the paper realizes optimal decision scheme for different maintenance mode.The research work of this paper realized the optimal overall maintenance process decision from importance degress evaluation-maintenance mode selection-optimal scheme of each maintenance mode for URTS key equipments.