Condition Based Maintenance Decision Making For Electric Equipment In Power Grid Using The D-S Evidence Theory

The development of Information Technology, Microelectronic Technology, Network Communication Technology provides a good online technical support for the on-line condition monitoring of electrical equipment and promotes the use and development of Condition Based Maintenance(CBM) technology. Meanwhile, as an important part of the construction of strong smart grid and Life-cycle Asset Management, CBM has become an essential part of the research on the scientific development taken place in the power enterprises, and as a predictive maintenance which can arrange the maintenance schedules well before equipment performance drop to a certain level or failure and can effectively shorten the outage time, to extend the economic life of the device, as well as reducing maintenance costs and improving the security and reliability of the power system.CBM generally include three parts, condition monitoring, condition assessment and maintenance decision, which are sequentially conducted. Condition monitoring and condition assessment are the prerequisite and basis for CBM, while maintenance decision the core and target. Therefore, how to make the maintenance decision is the key to realize the value of CBM. This paper launch researches on its center, that is the CBM decision-making, for individual equipment and power transmission system, which can get the optimal results that make the individual equipment, or the entire power transmission system both reach the whole good level, respectively.Multi-objective and group decision-making research based on D-S Evidence Theory in CBM for transmission and transformation equipment. Under the guide of the established maintenance decision-making framework, the evidences, also the decision indexes whose first layer indexes are effectiveness and cost are summed up, and the quantitative method is given; the maintenance methods that are formed on the basis of the maintenance guidelines and maintenance periods that are divided from equipment’s predicted remaining life based on its current state, which both consist of the schedule sets to be the recognition framework, the final result that includes the method and period can be produced by synthesizing the decisions of each indicator and decision-maker. Then a numerical example is used to illustrate that the indicators’ subjective weights given by the decision-makers can effectively realize the control of the decision-making process considering the decision makers’ intends. The result can make all indicators reach the whole good level.Research on CBM for power transmission system Considering the real-time correlation of the devices and the power transmission system, the concept and the decision-making model of CBM for power transmission system are proposed. This article summarize the guiding principles of the CBM for power transmission system from an entire system prospect, which are the basic of the combination and selection of all possible schemes that depend on the individual decision-making, and we can get the collection of the possible schemes of the power transmission system. Then the decision-making indicators that can fully reflect the safety, reliability and economy of the power transmission system are established, and their quantitative methods are given. Furthermore, a maintenance decision model based on D-S evidence theory is established; Under the guidance of the indicators, the decision-making can be performed to get the final decision-making result of the power transmission system which can make the individual equipment and the entire power transmission system reach the whole good level.