Multiple Hotelling's T² tests for distributed fault detection of large-scale systems

The distributed configuration is an effective approach for implementing Hotelling's T² test to detect faults in large-scale systems. Multiple T² tests are employed in the distributed configuration in which each test uses measurements from a different set of sensors. A decomposition (i.e. an allocation of the sensors among different sets called subsystems) must first be selected to implement the multiple T² tests. The detection performance of the multiple T² tests and their ability to satisfy certain operational constraints depend on the decomposition. We propose two methods that find a feasible decomposition of a large-scale system for which the detection performance of the multiple T² tests is near optimal. The methods first use greedy algorithms to generate many feasible candidate subsystems and decompositions. The methods then quickly evaluate the detection performance of these feasible candidates using easy to compute analytic expressions and finally select a feasible decomposition with the best performance.