Study On Condition-based Maintenance For Urban Rail Traction Power Supply Equipment Considering The Accelerated Degradation Of Performance

The operation and maintenance of traction power supply equipment is an important guarantee for the reliable operation of the urban rail system.With the development of economy and the progress of science and technology,the existing maintenance mode has gradually revealed its disadvantages in terms of economy and efficiency.Therefore,the more economical and effective mode of condition-based maintenance has become the main breakthrough direction.Considering the characteristics of accelerated deterioration of equipment performance during service,this paper studies the assessment method of deterioration degree of equipment status and the decision-making method of optimal maintenance scheme.In this paper,starting from the state assessment part of the content of condition-based maintenance,the initial weight describing the relative importance of each index on equipment performance is calculated by using the historical data of multiple indexes,so as to characterize the common characteristics of the relative importance of each index.Based on the real-time detection value of each index and the difference of the operation state,the weight correction values of the normal state and the failure state are calculated respectively to represent the individual characteristics of the relative importance of each index.Finally,combined with the common and individual characteristics of each index to achieve a comprehensive assessment of the deterioration degree of urban rail traction power supply equipment.For maintenance scheme decision,this paper comprehensively considered the characteristics of equipment performance gradually accelerating deterioration with the passage of service time and the actual situation of imperfect maintenance.The available linearized Wiener process was used to establish the basic deterioration model,and the normal distribution fuction was used to describe the imperfection of maintenance.The whole life cycle degradation model was established by combing the two models.Then,the possible inspection and repair situations in the whole life cycle were analyzed,and a decision-making model with the goal of the lowest unit time operation cost in the whole life cycle was established in combination with each maintenance cost.Finally,the Monte Carlo method was used to solve the decision model,so as to realize the decision of optimal periodic inpection and maintenance scheme in the whole life cycle.Considering that the traction power supply equipment of urban rail transit is vulnerable to load impact,a new damage model was added on the basis of the gradual accelerated degradation model,and a comprehensive accelerated degradation model was established.At the same time,the detection planning function is introduced to develop the irregular detection scheme which determines the next detection cycle according to the actual state of the equipment after detection.Then,the possible inspection and repair situations in an overhaul cycle were analyzed,and a decision-making model with the lowest unit time operation cost in an overhaul cycle was established in combination with each maintenance cost.Finally,the Monte Carlo method was used to solve the decision-making model,and the decision of the optimal non-periodic detection and maintenance scheme within a overhaul cycle was realized.In this paper,the state assessment and maintenance scheme are studied in two aspects of condition-based maintenance work.The comprehensive assessment of deterioration degree using multi-index information and the formulation of maintenance sheme considering performance accelerated deterioration are realized.The obtained state assessment method and maintenance decision-making method can provide a theoretical basis for on-site maintenance personnel of traction power supply equipment.