The invention provides a double-layer fault diagnosis method and
system for an industrial
interconnection system, and belongs to the technical field of fault diagnosis of the industrial
interconnection system. The method comprises the following steps: firstly, based on a
state space model of each subsystem in the industrial
interconnection system, deducing input and output data of each subsystem of the industrial interconnection system, and realizing distributed identification of a subspace parameter matrix by using the input and output data of each subsystem so as to give full play to complementary advantages of mechanism modeling and data driving. Secondly, a
Granger causality analysis method is used for calculating the
coupling connection relation between the subsystems, and distributed optimization of a subspace parameter matrix is achieved in combination with an alternating direction
multiplier method; and finally, distributed residual error generator design and residual error evaluation are carried out on the subsystem side, distributed fault detection of the industrial interconnection system is realized, residual error signals of the subsystems are transmitted to a centralized
processing unit, and when a fault is detected, a fault source subsystem is found by calculating a comprehensive fault
score of each subsystem.