Grey box process modelling for fault detection and isolation

The effect of the type and quality of process models applied for fault detection and isolation is investigated in this paper. It is shown that the level of details and the modelled processes within the applied grey box model determine the detectability of the faults as well as the sensitivity and detection delay of a particular fault detection method. The concepts and results are illustrated on the example of fault detection of heat exchange surface deterioration and leaking in a countercurrent heat exchanger.