Research On Maintenance Theory Of Distribution Network Based On Change Of F Ailure Rate

With the rapid development of the power industry,more high-tech electrical equipment has been incorporated,and the system structure has gradually become diversified.Traditional planned maintenance methods or post-failure maintenance methods have begun to show drawbacks,while state maintenance is based on the real-time health of the equipment.The status of the equipment to be overhauled is scheduled for maintenance,so compared with the planned maintenance,it has better economic efficiency and higher social benefits.Considering that about 80% of the load point power supply interruption events are due to the failure of the distribution system,and the equipment involved mainly includes overhead lines,cable lines,transformers and various switchgear,so according to the real-time status information of the distribution network equipment,It is of great practical significance to establish a strategy model for the condition maintenance of distribution network equipment.Equipment failure rate is an important parameter that affects the timing of state overhaul.It is easier to collect real-time data of grid operation in the context of smart grid.Based on the collected state information,the initial equipment failure rate of the current situation can be obtained.Taking into account the change of the equipment status index after maintenance,which causes the equipment failure rate to decrease,the service age regression factor is introduced to solve the failure rate of the distribution network equipment under the effect of multi-level maintenance,and to study the effect of maintenance on the equipment failure rate.Considering that conditional overhaul is a way to arrange overhauls based on the health of the equipment,less attention is paid to the overall grid in the process of arranging overhauls.In order to coordinate the arrangement of individual equipment and the grid as a whole,a scientific and reasonable overhaul plan is obtained,and the status is adopted.The method selects the state of the system,and quantifies the grid failure risk and grid maintenance risk when the failure mode is N-1 or N-2,and obtains the planned and unplanned losses during the maintenance process.Considering that the importance of equipment of different loads and different types is different when the maintenance arrangements are made for multiple equipment in the power grid.For important equipment,the higher the maintenance sequence,the lower the probability of failure from the beginning of the maintenance schedule to the time of the maintenance.The lower the risk of various types of unplanned losses.Use the importance of equipment maintenance to guide maintenance arrangements.With the minimum total maintenance risk as the objective function,establish a distribution network state maintenance model that takes into account the grid failure risk and the grid maintenance risk,and set the maintenance time constraint,power flow constraint and other constraints to screen reasonable and scientific maintenance modes and quantify the grid operation risk Combining the characteristics of the distribution network,the distribution network system is layered,the forward and back-substitution method is used to calculate the power flow of the distribution network,and then the continuous tabu simplex search algorithm(Continuous Tabu Simplex Search,CTSS)is used to solve the model.In order to improve the search speed,mutation operation is added to the algorithm to reduce the time of falling into the local optimum and achieve the optimal effect of economy and reliability coordination.According to the data comparison of SAIFI,SAIDI,ASAI,determine its overhaul level and guide overhaul arrangements.Finally,on a typical radial distribution network structure,the relationship between the total risk of overhaul and the changes in the reliability of the system before and after overhaul and the overhaul mode,the load situation at the time of overhaul and the user’s situation are studied,and a typical distribution network is adopted.The network reliability test system RBTS-Bus2 is used to verify the rationality of the model and compared with the traditional method.The results show that the model is closer to the actual situation of the power grid,and the risk assessment is more comprehensive,and the resulting maintenance decisions are lower.Risks and better economy can provide certain guidance for the maintenance of the distribution network.