Multiple sensor fault detection in heat exchanger systems

A two stage strategy for fault detection, isolation and estimation of multiple gross measurement errors (faults) in a class of systems described simultaneously by linear and bilinear equations is presented. The first stage consists of the detection and isolation of gross measurement errors intervening only in the linear equations. The second stage deals with the detection and isolation of gross measurement errors intervening on the bilinear equations by using corrected measurements of the preceding stage. A generalised likelihood ratio (GLR) method is employed to detect and to isolate the faults. An application of the proposed strategy to a heat exchanger system is presented in which the process model consists of a set of linear and bilinear equations. Simulations were performed to test the efficiency of the proposed method.