To enhance the maintenance and management level of secondary devices in the power system

a data mining and analysing method for secondary device defects based on the Apriori algorithm is proposed. Firstly

the basic ideas of association rules and Apriori algorithm are analyzed. Then a secondary defect model based on association rules is proposed

in which several important properties of secondary equipment defects(including secondary equipment manufacturer

device type

causes of device defects

position of device defect and defect levels)are taken into account. Furthermore

by taking the defect data of automation equipment as examples

the defect data mining and analyzing method based on data mining results are presented. Analysis results show that the proposed method is able to search for the weaknesses of secondary devices and the causes of weaknesses

while enunciating the family defects of devices.