The Research On Expert System Of Contact Network Fault Analysis

The overhead contact system is an important part of electrified railway traction power supply system.Due to the particularity of design,the accident rate is high.Once the overhead contact system is failure,if the rescue is not timely,it will seriously affect the railway transportation,and even threaten the personal safety of passengers.Therefore,the overhead contact system after the failure of the repair efficiency is essential.Based on the contact network fault as the research object,this paper combined with fault mode of the contact network and the development direction of fault diagnosis expert system develop the contact network fault diagnosis expert system of fault tree and cases.In this paper,a lot of contact network fault information was collected by referring to the domestic and foreign references and field investigation.After sorting,the failure mode,failure cause and repair measures were analyzed,and the fault tree of the contact system was established.For hard to build up the fault tree of failure as accident cases in the system was putted forward into the system case database which is used as an auxiliary case diagnosis method.Taking the fault tree of the contact line as an example,the specific steps of the qualitative and quantitative analysis of the fault tree were introduced.And then the minimum cut sets,the important degree of the minimal cut,probability importance of all bottom events sets and the critical importance were obtained,which provided theory and data support for the establishment of system knowledge base and inference engine.Through the study of rule-based expert system,the failure fault tree of contact system can be converted to knowledge of computer identification form by the knowledge representation based on rules and frame.Combining with the knowledge base of knowledge representation,the inference engine which was based on fault tree and auxiliary case diagnosis was designed by using the forward reasoning mode.And the explaining mechanism was designed by combining the text explanation method and path following method.Finally,the knowledge database was built based on the Access 2003 database as the background database,and by using ADO database connection technology established the manage system of fault tree,knowledge database and the cases database,and with the help of Visual Basic 6.0 system programming system procedure.The paper verified the function of each module based on the contact line fault as an example.Experiments show that the system can quickly find the cause of the fault and give the corresponding troubleshooting methods,with good fault tolerance,good versatility and expansibility.