Control Strategy Study On Preventive Maintenance Of Repairable Complex Power Equipment Based On Condition Monitoring

In view of the limitations that the optimal examining item do not have dynamic real-time speciality and do not reflect the actual state of equipment in the traditional preventive maintenance model of repairable complex power equipment, a control strategy is proposed by using checking rate as control variable based on the state of equipment. The differential equations that are used to describe the dynamic behavior of the maintenance system are established and the performance indexes of maintenance system that include the steady-state availability, the mean time to failure(MTTF) and the average time of staying in state are given out. The dynamic control strategy on the checking rate is designed and the stability of the corresponding control system are analyzed. The essence of the control method is to achieve the expected probability index by changing and controlling the probability behavior of the maintenance system, which will ensure the safety production target of the system,modify the MTTF of the maintenance system, and reduce the maintenance cost at the same time. The theoretical analysis and simulation results indicate that the method can improve the utilization rate of devices and provide theoretical support for actual maintenance decision of devices. In this thesis, the main research content is as follows.(1) According to reliability theory, stability theory and state transition theory as well as random process theory, etc, some scientific hypotheticals are established based on the law of failure process of complicated equipment and actual operation situation of electric power equipment, and the states of complicated electric power equipment are defined and divided,and state transition figure and state transition equations including three state and four state are established. And the reliability of the maintenance system is analyzed, and reliability indexes including the transient and steady-state probability of system, and the steady-state availability as well as the MTTF of the maintenance system are given out.(2) According to the safety production target that is the expected steady-state probability and failure rate and distribution pf the maintenance time, dynamic control strategies including model reference control strategy, and the adaptive control strategies based on Lyapunov stability theory and hyperstability theory on checking interval of preventive maintenance including checking interval of working component and stocking component are studied. The control strategies and state probability curve as well as reliability indexes beginning in different areas are given out by dividing the areas of the state variable. According to monitoring information of state, estimating equation of system state is given out, and the norm inequality of actual state probability of the system is given out by using the vector comparison method, and error threshold and checking time are given out by using law of largenumbers and central limit theorem. Control strategy with probability estimation and error control at the core is given out.(3) Using jiuquan qiaoxi wind farm as an example of simulation and verification and giving out reliability indexes of the system. Using checking rate control the probability behavior of actual system to achieve the expected steady-state target by applying the method of probability estimating and error control. The simulation results and theoretical calculation results are the same, which indicates that this strategy is correct and effective.