Research On Maintenance Strategy Of Catenary System Based On Multistate Markov Model

The reliability of the catenary system is the precondition for ensuring the safe and stable operation of the electric locomotive,and is directly related to the safety and efficiency of the entire railway transportation system.Preventive maintenance system is an important means to ensure the reliability and safety of contact catenary equipment.The design of maintenance system usually needs to consider many factors,such as the system reliability and the maintenance cost et al.A multi-objective optimization model considering both reliability and maintenance cost is proposed in this paper to solve the contradiction between reliability and maintenance cost in catenary system maintenance activities.The Non-dominated Sorting Genetic Algorithm(NSGA2)is applied to multi-objective optimization,and the optimization result is a set of Pareto solutions.The contents of this paper are as follows:(1)By analyzing the structure of the catenary system and the failure of the equipment in the system,and combining the information of the history fault of the catenary,it was found that the contact line,the messenger wire,overlap,the insulator,the compensator,the positioning device and the dropper are the main components that cause the fault of the catenary.Firstly,the defect level of the catenary devices are divided according to the operation and maintenance rules of the high-speed railway catenary,then multistate failure mode analysis is conducted for the main devices leading to the failure of catenary.The reliability and failure mode of the whole catenary system is analyzed through the relationship between the reliability diagrams of each device.The mathematical relationship between system reliability and maintenance cost is derived which considers the existing catenary preventive maintenance mode to improve the reliability of the system.(2)Secondly,an Improved NSGA2(INSGA2)is proposed in order to solve the problem of population diversity deficiency and uneven distribution of Pareto solutions in the optimization process of NSGA2,which improves population diversity by improving selection operator,and introduces local search strategy to ensure that population distribution is more uniform.The results compared the two kinds of algorithm on the ZDT series functions show that the population diversity is better and the solution is more uniform in the optimization results of INSGA2.The application of catenary maintenance system shows that the results obtained by INSGA2 are better continuity and more uniform distribution than NSGA2 in terms of maintenance cost and reliability.(3)The INSGA2 is applied to multi-objective optimization of system reliability and maintenance cost,under different maintenance periods.The decision-makers can choose the reasonable solution as the maintenance scheme in the optimization results by weighing the relationship between the system reliability and the maintenance cost.The maintenance scheme can ensure that the reliability of the system is as high as possible,and the maintenance cost is the lowest.Therefore,the decision-maker can select the reasonable maintenance schedule from optimization results and make the corresponding maintenance plan.