Convergent cross mapping (CCM) based approach for isolating the source of plant-wide disturbances

Disturbances originating in one control loop of a large industrial plant can propagate far from the source, giving rise to plant-wide oscillations. The underlying interactions among the different control loops make it hard to identify the origin of such large scale disturbances. This paper studies the application of the convergent cross mapping (CCM) based technique to isolate the source of a plant-wide disturbance. The proposed scheme exploits the cause and effect relationships among the affected variables to find the source of disturbance. The states of the causative factors are estimated from the effect variable and the directionality of information flow is established using the correlation between the original and estimated signal. The method is applied to the industrial case study and is shown to be effective in isolating the disturbance origin.

I. Introduction

In an industrial control system plant-wide disturbances can result in product variability and excessive use of precious resources, with both economically and environmentally detrimental consequences. Thus there is clear motivation to look for the root cause/source of these disturbances, so that targeted remedial action can be taken. Disturbances in a large scale plant may arise due to number of reasons such as a) poor controller tuning b) process degradation, and c) equipment wear and failure, etc. Once started these disturbances travel away from their origin due to mass and energy flows as well as control loop interactions, thus giving rise to plant wide disturbances [1], [2]. In such a scenario, the early and accurate identification of the origin of the disturbance is a key to reduce maintenance and shut down time and thus improving the overall economics.