Title: A robust method for coupling detection among process variables

Authors: Sajid Hussain; Hossam A. Gabbar

Addresses: Faculty of Engineering and Applied Science, University of Ontario Institute of Technology, 2000 Simcoe St. North, Oshawa, Ontario L1H 7K4, Canada. ' Faculty of Engineering and Applied Science, University of Ontario Institute of Technology, 2000 Simcoe St. North, Oshawa, Ontario L1H 7K4, Canada

Abstract: Investigating complex interaction patterns among multiple process variables (PVs) is an important task. This paper demonstrates a robust method to estimate direction and strength of interactions among process variables. The method captures rapid changes in process variables through wavelet analysis. It uses single degree of freedom (SDOF) modelling to approximate a non-linear system in terms of linear damped forced oscillators. Phase interaction theory then extracts coupling direction and strength among process variables. The robustness of the proposed technique is verified on simulated Van der Pol oscillators with known directionality and coupling strength with varying signal to noise ratio (SNR). The effectiveness and feasibility of the proposed method have also been demonstrated on simulated data emanating from Canada Deuterium Uranium (CANDU) nuclear power plant steam generator level control mechanism. The extracted patterns of interaction structure among PVs aid to uncover the polishing mechanisms and provide more insights to investigate fault propagation scenarios.

Keywords: process monitoring; coupling detection; shock response; wavelet analysis; process variables; interaction patterns; modelling; nonlinear systems; linear damped forced oscillation; phase interaction theory; nuclear power plants; NPP; nuclear energy; nuclear power; steam generators; generator level control; polishing mechanisms; fault propagation.

DOI: 10.1504/IJPSE.2012.045901

International Journal of Process Systems Engineering, 2012 Vol.2 No.1, pp.93 - 110

Available online: 18 Mar 2012 *

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