Study On The Reliability, The Fatigue Damage Evaluation With Maintenance And Repairing Approach Of Energy-Fed Supply System In Urban Mass Transit

Energy-fed supply system gains obvious advantages over its conventional counterpart, due to its peculiar bi-directional AC/DC power flow control capability and fully controllable DC output characteristic,. It means much for supply system in urban mass transit to keep a high reliability and excellent power quality, especially for the newly-borne energy-fed supply system. In this dissertation, the reliability modeling and optimized dynamic maintenance and repairing theory for supply system is thoroughly introduced, based on mathematical modeling theory, accumulated fatigue theory, dynamic optimizing theory, and out of reliability-centered maintenance theory.First, this dissertation builds the reliability model of energy-fed supply system with suitable layering of the system. The reliability evaluation process is catalogued into three levels, together with related reliability influence on substation from the application of energy-fed supply-set. Out of the characteristics of energy-fed supply system, different operating modes are taken as different topologies for the evaluation of reliability, from topology-equivalent theory. What's more, the reliability expressions are obtained and reliability peculiarities of energy-fed supply system are presented.Second, in the dissertation is presented fatigue damage evaluation approach based on accumulated fatigue theory. The key part played by accumulated fatigue degree is stressed and the fatigue analysis of key equipment(electrolyric capacitors, transformers, DC switches and catenary) in the supply system, as well as overall accumulated fatigue is generated with the calculation of accumulated fatigue degree. There is also the introduction to the building of supply system operation and maintenance file, along with the self-adjusting mechanism of the parameters in mathematical model.Third, dynamic maintenance theory is applied into energy-fed supply system, together with optimization approach. Maintenance and repairing mode is chosen by dynamic maintenance/repair model, and with the knowledge of life span and reliability level of the system's components, maintenance range can be decided. Multi-objective planning is conducted from the aspects of maximum reliability and minimum maintenance cost, then are obtained the preventive maintenance intervals. The optimizing process comes along with time passing by and with the operation modes, realizing a maximum reliability, highest power efficiency and minimum maintenance/repair cost.In this dissertation, the relation between the fatigue of key components and the overall system, as well as influencing factors on fatigue is obtained from the reliability model at first. After that, actual functioning history of the influencing factors is recorded and added by accumulated fatigue degree for the fatigue evaluation of key components and the overall system. Finally, optimized dynamic planning is applied into the knowledge of fatigue variation characteristics obtained from above, for the decision-making of optimized maintenance range and interval of energy-fed supply system.The results from the study introduced in this paper make valuable move in the reliability modeling and maintenance theory of energy-fed supply system, and will act as an effective promotion for urban mass transit.