A method for detecting non-stationary oscillations in process plants

This paper proposes a method for detecting oscillations in non-stationary timeseries based on the statistical properties of zero-crossings. The main development presented is atechnique to remove non-stationary trend component from the analysed signals before applyingan oscillation detection procedure. First, the method extracts the signal's baseline that is utilizedto stationarize the signal. Then, an index describing the regularity of the stationarized signal'szero-crossings is computed in order to determine the presence of oscillation. The propertiesand performance of the method are analysed in simulation studies. Furthermore, the methodis comprehensively tested with industrial data in a comparative study in which the proposedmethod is tested against other oscillation detection methods using industrial benchmark dataand in tests on paperboard machine process. Finally, the simulation and industrial results areanalysed and discussed.Peer reviewe