Research On Association Analysis For Device Defect Data And Fault Diagnosis Method For The Secondary Circuits Of Relay Protection In Substations

The operation of reliable relay protection device is the guarantee for operation of smart substations.With the development of smart stations,it is a huge challenge for engineers to face complex intelligent device,optical fiber network and standardized communication model.It is difficult to manage and use kinds of multi-source heterogeneous data uniformly,analyze a lot of defect data of relay protection device effiectively,and diagnose the secondary circuit fault of relay protection.To solve above problems,reduce secondary device defects and realize fault diagnosis,this paper studies association analysis for defect data and secondary circuits fault diagnosis for relay protection in substations.The main work is as follows:First,the characteristics of data sources and data distribution about relay protection system are summarized.The extraction,checking and loading of multi-source heterogeneous data are studied.Based on these,this paper puts forward the united model of comprehensive database systerm of relay protection,by which the barriers between the various multi-source data are broken and the data can be managed uniformly.It provide data for subsequent researches.Secondly,in order to improve the low utilization rate of defect data of relay protection device,the defect data model of relay protection device in smart substations is established,a association analysis of defect data based on improved Apriori algorithm is proposed.The case study indicates that the method can be used to analyze the device defect,search for the device weakness,and help engineers establish defect inspection pattern and maintenance strategy.Compared with the traditional algorithm,the improved Apriori algorithm can reduce the time complexity and memory consumption effectively.Thirdly,according to the SCD files stored in comprehensive database systerm of relay protection,the physical-loop and virtual-loop models of the secondary circuit are established,and their mapping relationship is implemented.Based on mapping relationship,the fault proof table is established and used to obtain the suspicious fault component set in secondary circuits.Finally,with the component self-check alarm as the evidence source,the improved D-S evidence theory is proposed to evaluate the components in suspicious fault component set,and the probability of each component causing fault is obtained for the realization of fault diagnosis.The case study demonstrates that this method can deal with the the excessive conflict between different evidence source and identify fault component accurately.