Research On Reliability Evaluation Method Of Railway Signal Safety Relays

At present,with the rapid development of the railway network system in our country,the security requirements for its operation control system and signal equipment system are more and more strict.Safety relays are one of the most important basic components in the railway signal equipment system.Their reliability will affect the safety of the railway signal system.Regular maintenance and replacement of failed equipment which is used now cannot adapt the relay damage accumulation change monitoring and precise maintenance needs.A research method based on failure mechanism,life expectancy and reliability system logic is proposed from the perspective of cost-saving and safety-assurance.First of all,the working characteristics and reliability of safety relays in the domestic and international research status were analyzed.The research methods and results used in this field at the present stage was clarified.The difference between the mechanical life and the electrical life of the relay were analyzed.According to the characteristics of the failure,the similarities and differences between the stochastic failure and the degenerative failure were analyzed.For the degenerative failure,the contact was selected as a relay contact research object.Their surface morphologies varied depending on the degree of material transfer.Depending on the failure mechanism of the relay,the characteristic parameters which could represent the degradation trend were also different.The method of dealing with the characteristic parameters was different from the failure threshold.Therefore,through detailed analysis of different failure processes,deeply discussing the internal mechanism,the failure thresholds,processing methods and theoretical models of the characteristic parameters of different failure modes were obtained.Aiming at the stochastic failure,a variety of manifestations,randomness and maintainability were analyzed.Then six characteristic parameters under the three failure modes of pollution failure,bridging failure and wear failure were discriminated based on the Fisher discriminant criterion after classifying the mechanism of failure,and the characteristic parameters that could most reflect the failure trend were selected as the electric life prediction parameters.Empirical mode decomposition method was used to reduce noise for tested data.A degenerate statistical model was established to describe the process of degenerative failure.A fuzzy discriminant method was applied to establish the four degenerate statistical models.At the same time,stochastic Petri nets fault models were built,and the stochastic and repairable properties were introduced to describe the dynamics.A reachable tree and state transition diagram were constructed.Finally the contact and coil measurement circuit of RT-01 relay reliability life detection system were designed.And characteristic parameter algorithm was built to transform the collected data.A variety of function curve fitting models were established and simulated.After that,effect evaluation of the curve fitting effect was carried out.According to the known service life calculated the prediction accuracy,the reliability of failure time was calculated by using the predicted electrical life value.The best degenerate model based on the prediction of life using fuzzy evaluation method was determined,and got the relay reliability curve.At the same time,in order to deal with the stochastic failure of relays,the stochastic Petri net was used to establish the failure models of internal components.Then Markov method was used to quantitatively calculate the failure rate and reliability curve.The results of two reliability research methods were comprehensively analyzed to get the comprehensive reliability analysis of the relay.The process of change was accurately showing the normal degradation of the relay process,the accuracy of about 95%.