Fault diagnosis method and system for C4F7N mixed gas insulation equipment

The invention discloses a fault diagnosis method and system for C4F7N mixed gas insulation equipment, and the method comprises the steps: carrying out the tests under the fault defects of power frequency breakdown, suspension discharge and corona discharge on C4F7N mixed gas based on the decomposition simulation test of the C4F7N mixed gas in a specific proportion in engineering application, and analyzing the decomposition components of the C4F7N mixed gas; performing data dimension reduction on the decomposition product content of the C4F7N mixed gas by using a grey relational analysis method; calculating the correlation degree between each decomposition product of the C4F7N mixed gas and the fault type by using a grey correlation degree analysis method; selecting three types of decomposition products with the highest correlation degree as characteristic products for fault identification of the C4F7N mixed gas insulation equipment; a back propagation neural network is adopted to train decomposition product c