Many cities have extensive distribution networks that supply natural or town gas to domestic, industrial, and power plant consumers. A typical network may have hundreds of pressure regulating stations that are of different types and capacities, but most legacy networks are sparsely instrumented. The reliability of these stations is the first priority for ensuring uninterrupted gas supplies; hence, condition monitoring and prescriptive maintenance are critical. In this study, mathematical models were developed for two types of commonly used regulators: spring-loaded and lever-type regulators. We also considered three faults that are typically of interest: filter choking, valve seat damage, and diaphragm deterioration. The proposed methodologies used the available measured data and mathematical models to diagnose faults, track prognoses, and estimate the remaining useful life of the regulators. The applicability of our proposed methodologies was demonstrated using real data from an existing distribution network. To facilitate industrial use, the methodologies were packaged into a user-friendly dashboard that could act as an interface with the operational database and display the health status of the regulators.

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Plant-wide oscillations are common in many industrial processes. During the past few years, various methods have been proposed for the detection of plant-wide oscillations, including methods based on the autocorrelation function, the independent components analysis (ICA) and the spectral envelope. This article is aimed at understanding the advantages and limitations of the available methods using simulated data sets. The ICA based method is also improved by deriving approaches for determining the number of dominant ICs and for differentiating between oscillatory and non-oscillatory ICs.

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