Condition-based Maintenance Decision-making For Power System Based On Master-slave Association Sets Decomposition

In the power system,one of the most critical tasks is ensuring the safety and reliability of the power system,and equipment maintenance has become one of most important means to ensure the safety and reliability of the power system.When the timing of equipment maintenance is appropriate,it will bring great benefits to the power system.On the contrary,when the timing of equipment maintenance is not appropriate,it will waste the reliability of the equipment or reduce the reliability of the whole power system,thus causing the loss and affecting the economy and reliability of the power system operation.So for a long time,equipment maintenance decision-making has always been the focus of the research.With the gradual improvement of power system on-line monitor technology,state evaluation and forecasting technology,Condition based maintenance is becoming more and more widely used in power system.Condition based maintenance is generally based on the equipment on-line monitoring status,historical statistics,and so on to obtain the current state of the equipment,so as to determine the timing of their maintenance.The existing condition based maintenance theory generally focuses on the individual performance of the equipment running in the grid.However,there are many kinds of equipment in the power system,and there are many kinds of interrelationships among the quipments.If only based on a single equipment performance to make decision about maintenance,it often attend to one thing and lose another,can't draw a good maintenance plan and unavoidably will produce the contradiction between the individual and the whole.Therefore,for equipment maintenance decision-making,it's necessary to consider the individual and the overall system and compromise the maintenance strategys between equipments from a system point,otherwise the contradiction will not be eliminated.In this background,in order to fully consider the functional dependence between devices,this paper combines the condition based maintenance theory with the risk assessment technology and puts forward the concept of master-slave association set by drawing on the idea of opportunity maintenance.Thus,the coordination between the individual performance of the equipment and the whole running performance of the power system is come true and the functional dependence between equipments is integrated into the coordination by using probability and regarding money as scale.The main work and innovation are as follows:(1)During the research period,the individual performance of the equipment is affected by factors such as equipment running time,break maintenance and preventive maintenance.Therefore,these factors need to be taken into account when establishing the time-varying component outage model.The relationship between individual performance and the running time of the device has been conducted an in-depth study by the existing traditional Markov model.Break maintenance as an event companion the equipment failure due to the equipment failure is considered as a rondom event,therefore likewise be considered as a rondom event.And by the different ways of break maintenance,it is divided into different maintenance models,such as perfect maintenance,imperfect maintenance and minimal maintenance.In this paper,three maintenance mades are analyzed and established the time-varying component outage model separately.Then a general model accommodating all these kinds of maintenance model is established and the equipment availability function of the running time for the equipment is used to represent the changes of equipment individual performance after break maintenance.Preventive maintenance is not accompanied by the equipment failure,but is made decision according to a combination of factors such as the performance of individual equipment before maintenance,therefore preventive maintenance can not be considered a random event,but rather as a certainty incident.This paper combines the renewal theory with the previously established break maintenance integrated model and gives the equipment available function of the combination of preventive maintenance and break maintenance,noting that the equipment available analytic formula is a function of the running time and preventive maintenance timing.(2)There are a lot of equipment in the power system,the equipment is not independent of each other,there is a correlation between each other.In this paper,the concept of master-slave association set is proposed for the inter-device functional dependence.At the same time,according to the characteristics of some devices with the same state,the state probablilistic function of the master-slave association set is defined by combining individual performance with the concept of opportunity maintenance,which provides a powerful analysis tool for the analysis of the correlation between devices in the power system and a good foundation for condition based maintenance of grid.It is beneficial to the generalization and realization of the condition based maintenance.(3)Based on the concept of master-slave association set,this paper establishes the criterion of master-slave association set and analyzes the common main wiring of power grid,so as to spend 20%of the analysis work to achieve 80%of the actual situation that may be encountered.It is beneficial to the generalization and realization of the condition based maintenance.(4)In the process of power system state maintenance decision-making,it is necessary to consider the individual performance of the equipment,the overall operation performance of the power system and the inter-device correlation.It is helpful to reduce the calculative amount and the difficulty of the condition based maintenance decision-making by regard master-slave association set as the unit of the condition based maintenance decision-making.At the same time,the condition based maintenance decision-making model based on the master-slave association set can effectively coordinate the relationship between the equipment and the relationship between the individual performance and the overall performance of the power system,and make the condition based maintenance be more consistent with the transfer trend of the individual performance of the equipment,extending the concept and improving the effectiveness of the condition based maintenance with good theory and application prospects.