Distributed fault detection in interconnected nonlinear uncertain systems

In this paper, a distributed fault detection method is developed for a class of interconnected nonlinear uncertain systems. The interconnection between neighboring subsystems is unknown, but assumed to be bounded by a function of system states, inputs and outputs. A fault detection component is designed for each subsystem in the interconnected system by utilizing local measurements and certain communicated information from neighboring fault detection components associated with subsystems that are directly interconnected to the particular subsystem under consideration. Under certain assumptions, adaptive thresholds for distributed fault detection in each subsystem are derived, ensuring robustness with respect to interconnections among subsystems and system modeling uncertainty. Moreover, the fault detectability condition is rigorously investigated, characterizing the class of faults in each subsystem that are detectable by the proposed method. A multimachine power system simulation example is used to illustrate the effectiveness of the method.