Fault diagnosis method based on multi-reduction and reliability

The invention discloses a fault diagnosis method based on multi-reduction and reliability. The fault diagnosis method comprises the following steps: establishing an original decision table of a fault diagnosis system of a transformer substation according to the actual operation condition of a digital transformer substation; reducing the decision table of the fault diagnosis system of the transformer substation by using an Apriori algorithm without considering a decision attribute of a fault device; acquiring fault region reliability through the reduced decision table of the fault diagnosis system of the transformer substation, determining the regions of faults according to the maximum reliability value, and determining the devices of faults according to the maximum reliability value by reducing a part of original decision table which just comprises the fault region by using the Apriori algorithm and calculating the reliability of the fault device by using the reduced part of original decision table. The method fully utilizes a GOOSE message and a sampling value message of the digital transformer substation and a relatively good diagnostic result can be obtained under the condition that information transmission is not correct.