Safety Assessment Of Train Control Center Based On Improved FMEA

With the implementation of the “one Belt one Road” strategy,the railway industry of our country has entered into a vigorous development stage.Under the trend of continuous increasing of the running speed and reducing of the tracking time,safety requirements of the Train Control Center(TCC),which is the core equipment in train control system ground equipment,are becoming more and more strict.In order to avoid the occurrence of the serious train accident,and ensure the train operate efficiently and smoothly,it is imperative to establish a complete safety assessment method for TCC.Therefore,the basic functions of TCC and its related interface units are selected as research objects for safety assessment in this thesis.Due to the high safety and reliability of the TCC equipment itself,little fault data can be obtained.Besides,it is difficult to collect the data systematically.Therefore,on-site expert evaluation can be applied in the assessment.In order to increase the accuracy and objectivity of the assessment process,the traditional Failure Mode And Effects Analysis(FMEA)method has been improved in this thesis.Firstly,the risk factor set for the basic functions of TCC and its related interface units can be identified,and the FMEA analysis table for each module can be built after analyzing the causes and consequences of the risk.Secondly,the experts evaluate each risk level according to the existing safety risk classification standards.Evidence theory is applied to get the degree of conflict in the expert assessment,and the corresponding amendment can be made to establish a more accurate comment set.Then,taking the interface unit between TCC and Centralized Traffic Control(CTC)as an example,the Occurrence,Severity and Detection of each risk factor are evaluated.After the correction by the evidence theory,the assessment values of Occurrence,Severity and Detection can be obtained.The assessment model is established by using grey relational analysis,prioritizing all risk factors and completing the assessment process.Finally,the cloud image of each risk factor can be simulated by the fuzzy comprehensive evaluation method based on the cloud model,and then the priority ranking results can be calculated.To verify the accuracy of the improved FMEA,the results obtained are compared with those of the improved FMEA.The assessment results show that the priority rankings of the two methods have the same trend generally.The cloud model based on Matlab simulation makes the assessment cloud of the risk factor in a certain range of fuzzy interval,and the randomness of expert evaluation can be characterized,and thus assessment result of the improved FMEA is commendably verified.The improved FMEA method can not only correct the source of assessment data,but also increase the accuracy of the assessment process,which is a complete safety assessment method.By studying the assessment results,the factors of higher risk level in the system havebeen found out,and the causes of factors are analyzed in detail,which can lay the foundation for improving the system safety design in the future or formulating the corresponding maintenance strategy.