Analysis On The Reliablility Of The Overhead Contact System Of Traction Power Supply

Because of its great disposable transportation, high efficiency of transporting, completeusage of energy, less environmental pollution, etc., railway becomes the developmentdirection of China’s road transport. With the development of the railway, the volume of trafficis improving. While as a core part of the railway, traction power supply system, must havehigh reliability. Traction power supply system consists of traction network, substation andelectric locomotive. The overhead contact system(OCS) is a major component of tractionnetwork. Among the parts of traction power supply system, the OCS total failure accountedfor more than ninety percent of total failure in traction power supply systems. Thus,improving the reliability of the OCS becomes critical to improve the reliability of tractionpower supply system. Based on the key projects of Ministry of Railways, combined withsurvey data, and specific analysis of the reliability of the OCS, this thesis proposes measuresto improve the reliability of the OCS.First, this thesis states the basic theoretical knowledge of the reliability in details, mainlyintroducing its evaluation index and research methods. The research methods introduced inthis thesis include fault tree analysis and Markov analysis. In addition, allocation methods ofthe reliability are introduced.Secondly, according to the structural characteristics of the OCS of the traction powersupply system and the non-comprehensiveness of the existing fault tree analysis of the OCSreliability modeling, combined with large amounts of research data, the OCS fault trees areimproved. The improved fault tree considers fault types leading to the invalidation of the OCSin the traction power supply system and its reasons. through the quantitative analysis, the typeof fault which is easy to cause the OSC failure is found out. This thesis qualitatively analysesthe OSC fault tree, while combined with the research data, the author quantitatively analysesit based on the result of qualitative analysis.Thirdly, due to the characteristics of the maintainability of the OCS, the OCS reliabilitymodel is built by the Markov process algorithm, According to the Markov process algorithm,the characteristic quantities of the OCS is calculated, such as the availability of the OCS,average frequency of failure, average time to repair, etc. For examples, with the Markovmodel, based on the Markov model had met, reliability of the OSC is calculated and analyzedin two different conditions, the maintenance and the non maintenance.Finally, through the analysis on its influential factors, the OSC reliability index isallocated optimally by the fuzzily comprehensive evaluation. This evaluation is based on theprinciple of fuzzy mathematics, is based on the principle of fuzzy mathematics. The first stepis to determine the factors influenced by reliability level of the components of the OCS and their weight sets. The second step is to make a fuzzily comprehensive decision based on theaffiliated degree of the OCS components to each factor. Based on the fuzzy decision, the thirdstep is to allocate the reliability index set in the design accordingly to each subsystemconsisting of the OCS, which ensures good economic benefits and obtains high reliability ofthe whole system.