Bayesian method for event-based alarm annunciation

The concept of an event-based alarm system is introduced and a Bayesian method to annunciate event alarms is presented in this article. Unlike the current variable-based system, event alarms are allocated to abnormal events and are annunciated based on the risk of such events. The event-based alarm system design involves identification of abnormal events, identification of the sets of variables associated with each event and development of a model to predict the risk of each event using process measurements. Risk estimation involves the estimation of probabilities of individual events and their consequences. This article presents a method for estimating the probability of occurrence of abnormal events for the purpose of annunciation of an alarm. The methodology is demonstrated using the example of a simulated continuous stirred tank reactor.