This paper presents
a new integrated methodology for fault detection
and diagnosis. The methodology is built using the multivariate exponentially
weighted moving average principal component analysis (MEWMA-PCA) and
the Bayesian network (BN) model. The fault detection is carried out
using the MEWMA-PCA; diagnosis is completed utilizing the BN models.
A novel supervisory learning-based methodology has been proposed to
develop the BNs from the historical fault symptoms. Although the algorithm
has been extensively applied to the Tennessee Eastman (TE) chemical
process, monitoring of three specific (difficult to observe) faults,
IDV 3, IDV 9, and IDV 15, has been demonstrated in this article. Most
of the existing data-based methods have faced the challenge to detect
these faults with a good detection rate (DR). Hence, these faults
have been reported as either unobservable or strenuous to detect.
Overall, fault detection performance of the squared prediction error
(SPE) statistics combined with the MEWMA-PCA was found to be better
than the T
2-based monitoring model. Although
the cumulative sum (CUSUM) PCA-based approaches have demonstrated
successful detection and diagnosis to these specific faults, the comparative
studies suggest that the proposed methodology can outperform the CUSUM
PCA approach.